Endovascular Repair of Aortic Diseases
Number: 0651
Table Of Contents
PolicyApplicable CPT / HCPCS / ICD-10 Codes
Background
References
Policy
Scope of Policy
This Clinical Policy Bulletin addresses endovascular repair of aortic diseases.
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Medical Necessity
Aetna considers the following interventions medically necessary:
- Endovascular repair of infra-renal abdominal aortic or aorto-iliac aneurysms with a Food and Drug Administration (FDA)-approved fenestrated, branched or non-fenestrated endovascular stent graft;
- Endovascular repair of descending thoracic aortic aneurysms with an FDA-approved endoprosthesis;
- Endovascular stenting (with a FDA-approved stent) for the treatment of aortic coarctation in persons with body weight of 1.5 kg (3.3 lbs) or more, and who exhibit systemic arterial hypertension and resting arm-leg pressure gradient of greater than 20 mmHg;
- Endovascular treatment for pulmonary artery stenosis and/or hypoplasia in a child.
Note: For post aortic endovascular/open surgery surveillance studies, see the following EviCore guidelines.
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- EviCore Peripheral Vascular Disease (PVD) Imaging Guidelines
- EviCore Pediatric Peripheral Vascular Disease (PVD) Imaging Guidelines
To access these clinical guidelines from landing page, select "Cardiovascular & Radiology", enter "EviCore by Evernorth" in search bar, accept terms and agreement, then scroll to find link to the guideline of interest.
EviCore guidelines undergo a formal review annually; however, EviCore reserves the right to change and update the guidelines without prior notice. Draft guidelines are posted 90 days prior to implementation. Additional clinical guidelines may be developed as needed or may be withdrawn from use.
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Experimental, Investigational, or Unproven
Aetna considers the following interventions experimental, investigational, or unproven because the effectiveness of these approaches has not been established:
- Bifurcated-bifurcated aneurysm repair of aorto-iliac aneurysms;
- Endovascular aneurysm sealing system (Nellix device) for the treatment of abdominal aortic aneurysms (including failed endovascular aneurysm repairs);
- Endovascular repair for the treatment of non-dissected ascending aortic diseases;
- Fabric/mesh wrapping of abdominal aortic aneurysms;
- Implanted wireless pressure sensors for detection of endoleaks in the aneurysmal sac following endovascular repair;
- Nectero Endovascular Aneurysm Stabilization Treatment (EAST) system;
- Pre-operative embolization of the inferior mesenteric artery to reduce the rate of type II endoleak following endovascular abdominal aortic aneurysm repair;
- Total endovascular aortic arch repair for the treatment of aortic arch disease.
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Related Policies
Background
Aortic aneurysms can develop anywhere along the length of the aorta, but three-quarters are located in the abdominal aorta. Thoracic aortic aneurysms, including those that extend from the descending thoracic aorta into the upper abdomen (thoraco-abdominal aneurysms), account for one-quarter of aortic aneurysms.
Abdominal aortic aneurysms (AAAs) are the most common form of aortic aneurysm and are a potentially life-threatening condition. It is estimated that 1 to 4% of persons over age 50 years are affected (O'Connor, 2002). Rupture of an AAA is the 13th most common cause of death in the United States.
Abdominal aortic aneurysm is usually the result of degeneration in the media of the arterial wall, resulting in a slow and continuous dilatation of the lumen of the vessel. In fewer than 5% of cases, AAA is caused by mycotic aneurysm of hematogenous origin. Abdominal aortic aneurysms are usually asymptomatic until they expand or rupture. The presence of a pulsatile abdominal mass is virtually diagnostic but is found in less than 50% of cases. Rupture is uncommon if aneurysms are less than 5 cm in diameter, but ruptures are dramatically more common for aneurysms greater than 6 cm in diameter. Without prompt intervention, ruptured aneurysms are often fatal. Thus, elective surgical repair is usually recommended for all aneurysms greater than 6 cm unless surgery is contraindicated (Beers et al., 1999). In patients who are good surgical risks, elective repair is generally recommended for aneurysms between 5 and 6 cm (mortality, about 2 to 5%).
- diameter of aneurysm is greater than 5 cm; or
- diameter of aneurysm is 4 to 5 cm and has increased in size by 0.5 cm in the past 6 months; or
- diameter of aneurysm is twice the diameter of the normal infra-renal aorta.
Current endovascular graft stents require an infra-renal non-aneurysmal neck length of at least 15 mm; however, there are case reports that describe the use of a fenestrated stent graft (Zenith, Cook, Inc., Bloomington, IN) customized to meet the anatomic needs of the individual patient. The Zenith fenestrated graft, which is not FDA-approved, is based on Cook's FDA-approved Zenith AAA endovascular graft design. It incorporates scallops at the top and openings in the graft wall called fenestrations that allow it to be implanted precisely in the aorta across adjacent blood vessels without blocking blood flow through those vessels. Accurate placement of a fenestration over the orifice of a target vessel is feasible, but long-term maintenance of position is dependent on secure graft fixation (Stanley, 2001).
Verhoeven et al. (2004) used a customized fenestrated graft based on the Cook Zenith composite system on 18 patients who met the following criteria: abdominal aneurysm at least 55 mm in diameter, a short neck (less than 15 mm), and contraindications for open repair (cardiopulmonary impairment or a hostile abdomen). Additional stents were used to ensure apposition of the fenestrations with the side branches. Of the 46 targeted side branches, 45 were patent at the end of the procedure. At follow-up (mean of 9.4 months), all of the remaining targeted vessels stayed patent. The authors concluded that by customizing fenestrated stent-grafts, it is possible to position the first covered stent completely inside the proximal neck, thus achieving a more stable position. This technique may become a valuable alternative for patients with a short infra-renal non-aneurysmal neck length; however, more patients with longer follow-up are required to determine the long-term safety and effectiveness of the device.
Verhoeven and colleagues (2009) noted that recent developments with fenestrated and branched stent grafts have opened the way to treat complex aortic aneurysms involving the visceral arteries. Early reports on endovascular treatment of thoraco-abdominal aneurysms have demonstrated the feasibility of the technique. Given the sparse literature, its safety has not yet been established. These researchers performed a literature review and also presented the results of their own series of 30 patients treated with a custom-made Zenith device with fixed branches. Most of the patients were refused open surgery mainly due to the extent of the disease combined with comorbidity, which included a combination of several risk factors in most patients. The mean aneurysm size was 70 mm, and the extent of the aneurysm was type I in 8 cases, type II in 5, type III in 12, and type IV in 5 patients. Technical success in the authors' series was achieved in 93% (28/30). Two out of 97 (2%) targeted vessels were lost. In one patient, a renal artery ruptured during the insertion of the bridging stent graft. In a second patient, a celiac artery could not be catheterized and was lost. The 30-day mortality was 6.7%, corroborated with 5.5% in the largest series reported so far. The 6-month and 1-year survival rates were 89.3% and 76.0%, respectively. The authors concluded that the results of fully endovascular repair of selected thoraco-abdominal aneurysms are promising. A learning curve should be expected. Anatomical limitations such as extremely tortuous vessels and access problems should be taken into account, as well as the quality of the targeted side branches. Although longer-term results need to be awaited, it is likely that endovascular repair of thoraco-abdominal aneurysms will become a preferential treatment option for many patients in the future.
The Zenith Alpha thoracic endovascular graft was approved by the FDA on September 15, 2015. It is indicated for the endovascular treatment of patients with isolated lesions of the descending thoracic aorta (not including dissections) having vascular anatomy suitable for endovascular repair, including:
- Iliac/femoral anatomy that is suitable for access with the required introduction systems; and
- Non-aneurysmal aortic segments (fixation sites) proximal and distal to the thoracic lesion:
- with a length of at least 20 mm, and
- with a diameter measured outer wall to outer wall of no greater than 42 mm and no less than 15 mm.
Monahan and Schneider (2009) stated that open surgical repair of complex aortic aneurysms, such as juxta-renal or thoraco-abdominal aortic aneurysms, is a highly demanding procedure. These repairs frequently require major surgical exposure through both the thoracic and abdominal cavities, supra-renal or supra-celiac aortic cross-clamping, and exposure of the visceral and renal arteries. Endovascular aortic repair and thoracic endovascular aortic repair have become the mainstay of treatment for infra-renal AAAs and descending thoracic aneurysms. However, the need to maintain perfusion of the visceral and renal arteries has limited the application of endovascular techniques to the treatment of more complex aneurysms. Fenestrated and branched stent grafts are being developed to address this need and enable the repair of complex aneurysms involving branch vessels exclusively using minimally invasive techniques. Although these devices remain investigational in the United States, they have recently become commercially available in other countries and play an increasing role in the management of complex aortic aneurysms.
Amiot and associates (2010) evaluated the medium-term outcomes following aortic aneurysm repair using fenestrated endografts performed in 16 French academic centers. A retrospective analysis of prospectively collected data was carried out. This study included all patients treated with fenestrated endografts in France between May 2004 and January 2009. Patients were judged to be at high risk for open surgical repair. Fenestrated endografts were designed using computed tomography (CT) reconstructions performed on 3-dimensional workstations. All patients were evaluated with CT, duplex ultrasound, and plain film radiograph at discharge, 6, 12, 18, and 24 months, and annually thereafter. A total of 134 patients (129 males) were treated over the study period. The median age and aneurysm size were 73 years (range of 48 to 91 years) and 56 mm (range of 45 to 91 mm), respectively. A total of 403 visceral vessels were perfused through a fabric fenestration, including 265 renal arteries. One early conversion to open surgery was required. Completion angiography and discharge CT scans showed that 398/403 (99%) and 389/394 (99%) of the respective target vessels were patent. The 30-day mortality rate was 2% (3/134). Pre-discharge imaging identified 16 (12%) endoleaks: 3 type I, 12 type II, and 1 type III. After the procedure, transient or permanent dialysis was required in 4 (3%) and 2 (1%) patients, respectively. The median duration of follow-up was 15 months (range of 2 to 53 months). No aneurysms ruptured or required open conversion during the follow-up period. Twelve of 131 patients (9%) died during follow-up (actuarial survival at 12 and 24 months: 93% and 86%, respectively). The median time from procedure to death was 15 months. None of these deaths were aneurysm-related. Aneurysm sac size decreased by more than 5 mm in 52%, 65.6%, and 75% of patients at 1, 2, and 3 years, respectively. Three (4%) patients had sac enlargement within the first year, associated with a persistent endoleak. During follow-up, 4 renal artery occlusions were detected. A total of 12 procedure-related re-interventions were performed in 12 patients during follow-up, including 6 to correct endoleaks and 5 to correct threatened visceral vessels. The authors concluded that the use of endovascular prostheses with graft material incorporating the visceral arteries is safe and effective in preventing rupture in the medium term. A predictable high mortality rate was depicted during follow-up in this high-risk cohort. Meticulous follow-up to assess sac behavior and visceral ostia is critical to ensure optimal results.
An evidence report from the Agency for Healthcare Research and Quality (Wilt et al., 2006) on treatment options to repair AAA found that more research is needed to evaluate the long-term benefits and harms of endovascular repair versus open surgical repair. According to this report, in patients medically fit for surgery and with an AAA of 5.5 cm or more, endovascular repair is a less invasive procedure, requires a shorter length of stay, and is associated with lower 30-day morbidity and mortality compared to open surgical repair. However, studies have not shown improved quality of life beyond 3 months or survival beyond 2 years, according to the report. Endovascular repair is associated with more complications, an increased need for re-intervention, more long-term radiological monitoring, and greater costs when compared with open surgical repair. A 4-year study of 166 endovascular repair patients medically unfit for surgery found that endovascular repair did not confer any survival benefit compared with no intervention. The authors concluded that research is needed to evaluate the cost-effectiveness of endovascular repair in the United States (Wilt et al., 2006). Research is also needed to evaluate whether the outcomes of endovascular repair procedures are influenced by either hospital volume or the surgeon's experience.
Lee and Faries (2007) noted that the increasing use of endografts to treat AAA has prompted the need for improved post-operative imaging and surveillance. Although patients benefit from decreased morbidity with endovascular repair compared with open AAA repair, the long-term outcome of stent repair has yet to be fully determined.
Jonk et al. (2007) performed a systematic review of the cost-effectiveness of AAA repair. Of the 20 eligible articles, there were 3 randomized controlled trials (RCTs), 12 case series, 4 Markov models, and 1 systematic review. Regardless of the time frame, all studies found that endovascular repair costs more than open surgery. Although the high cost of the endovascular prosthesis was partially offset by reduced intensive care, hospital length of stay, operating time, blood transfusions, and peri-operative complications, hospital costs were still greater for endovascular than open surgical repair. For patients medically fit for open surgery, mid-term costs were greater for endovascular repair with no difference in overall survival or quality of life. For patients medically unfit for open surgery, endovascular repair costs more than no intervention with no difference in survival. The authors stated that although conclusions regarding the cost-effectiveness of AAA treatment options are time-dependent and vary by institutional perspective, from a societal perspective, endovascular repair is not currently cost-effective for patients with large AAA regardless of medical fitness.
On the other hand, Brewster and colleagues (2006) reviewed a 12-year experience with endovascular AAA repair (EVAR) to document late outcomes. During the interval between January 7, 1994, and December 31, 2005, a total of 873 patients underwent EVAR utilizing 10 different stent graft devices. Primary outcomes examined included operative mortality, aneurysm rupture, aneurysm-related mortality, open surgical conversion, and late survival rates. The incidence of endoleak, migration, aneurysm enlargement, and graft patency was also determined. Finally, the need for re-intervention and the success of such secondary procedures were evaluated. Kaplan-Meier and multivariate methodology were used for analysis. Mean patient age was 75.7 years (range of 49 to 99 years); 81.4% were male. Mean follow-up was 27 months; 39.3% of patients had 2 or more major comorbidities, and 19.5% would be categorized as unfit for open repair. On an intent-to-treat basis, device deployment was successful in 99.3%. The 30-day mortality was 1.8%. By Kaplan-Meier analysis, freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years. Significant risk factors for late AAA rupture included female gender (odds ratio [OR], 6.9; p = 0.004) and device-related endoleak (OR, 16.06; p = 0.009). Aneurysm-related death was avoided in 96.1% of patients, with the need for any re-intervention (OR, 5.7; p = 0.006), family history of aneurysmal disease (OR, 9.5; p = 0.075), and renal insufficiency (OR, 7.1; p = 0.003) among its most important predictors. A total of 87 (10%) patients required re-intervention, with 92% of such procedures being catheter-based and a success rate of 84%. Significant predictors of re-intervention included the use of first-generation devices (OR, 1.2; p < 0.01) and late-onset endoleak (OR, 64; p < 0.001). Current generation stent grafts correlated with significantly improved outcomes. Cumulative freedom from conversion to open repair was 93.3% at 5 through 9 years, with the need for prior re-intervention (OR, 16.7; p = 0.001) being its most important predictor. Cumulative survival was 52% at 5 years. The authors concluded that EVAR using contemporary devices is a safe, effective, and durable method to prevent AAA rupture and aneurysm-related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.
Frank et al. (2007) performed a systematic review and meta-analysis of 12 years of EVAR. A total of 163 studies pertaining to 28,862 patients undergoing EVAR were identified as relevant for the review and meta-analysis. The pooled estimate for operative mortality was 3.3% (95% confidence interval [CI]: 2.9 to 3.6%). The pooled estimate for type 1 endoleaks was 10.5% (95% CI: 9.0 to 12.1%), with an annual rate of 8.4% (95% CI: 5.7 to 12.2%). The pooled estimate of type 2, 3, and 4 endoleaks was 13.7% (95% CI: 12.3 to 15.3%), with an annual rate of 10.2% (95% CI: 7.4 to 14.1%). The pooled estimate for primary conversion to open repair was 3.8% (95% CI: 3.2 to 4.4%), and for secondary conversion to open repair, it was 3.4% (95% CI: 2.8 to 4.2%). The pooled estimate for post-operative rupture was 1.3% (95% CI: 1.1 to 1.7%), with an annual rupture rate of 0.6% (95% CI: 0.5 to 0.8%). Multivariate meta-regression analysis showed that rates of operative mortality, post-operative rupture, and total number of endoleaks all fell significantly (p < 0.05) over time. The authors concluded that this study demonstrated a low mortality and a gradual reduction in vascular morbidity and mortality associated with EVAR since it was first introduced.
In a systematic review, Lederle et al. (2007) compared the effectiveness of treatment options, including active surveillance, open repair, and endovascular repair, for unruptured AAAs. Randomized trials that compared open or endovascular AAA repair with another treatment strategy and published clinical outcomes were included. Two trials compared open repair with surveillance for small AAAs (n = 2,226). Repair did not improve all-cause mortality (relative risk, 1.01 [95% CI: 0.77 to 1.32]) or AAA-related mortality (relative risk, 0.78 [CI: 0.56 to 1.10]). Four trials compared open repair with endovascular repair (n = 1,532). Endovascular repair reduced 30-day mortality (relative risk, 0.33 [CI: 0.17 to 0.64]) but not mid-term (up to 4 years) mortality (relative risk, 0.95 [CI: 0.76 to 1.19]). One trial compared endovascular repair with observation in 338 patients who were unfit for open repair. Endovascular repair did not reduce all-cause mortality or AAA-related mortality, but high crossover and procedural mortality rates complicate the interpretation of results. The authors concluded that repairing AAAs smaller than 5.5 cm has not been shown to improve survival. Endovascular repair is associated with lower operative mortality than open repair, similar mid-term mortality, and unknown long-term mortality, and has not been shown to improve survival in patients unfit for open repair. They stated that long-term trial data comparing endovascular repair with open repair are needed, as is another trial comparing endovascular repair with observation in high-risk patients.
Thoracic aortic aneurysms (TAAs) may be idiopathic and have been associated with congenital connective tissue disorders (e.g., Ehlers-Danlos syndrome, Marfan's syndrome). Tertiary syphilis is an uncommon cause of aneurysms. Thoracic aneurysms may become huge while remaining asymptomatic. Symptoms relate to pressure against or erosion of adjacent structures by the enlarging aorta, such as pain, cough, wheezing, hemoptysis, dysphagia, or hoarseness. Thoracic aneurysms generally should be resected if greater than or equal to 6 cm (Beers et al., 1999). However, aneurysms in patients with Marfan's syndrome are prone to rupture, so elective surgical repair is recommended for aneurysms 5 to 6 cm. Surgical repair consists of resection of the aneurysm and replacement with a synthetic conduit. Some surgeons use a homograft of the proximal aorta and aortic valve instead of synthetic materials.
Following diagnosis, untreated patients with TAAs have a 2-year survival rate of less than 30%, with 50% of all deaths caused by aneurysm rupture. Complications of conventional repair include post-operative paraplegia (25%), renal failure (20%), bleeding, stroke, and prolonged ventilator dependence. In addition, the operative mortality of the open procedure has been reported to be about 10%.
Endovascular repair of TAAs is one of the most recent technological advancements in vascular surgery. The current technique and available technology allow the repair of TAAs distal to the left subclavian artery (Najibi et al., 2002). This less-invasive approach has the potential to reduce the morbidity and mortality associated with the traditional open operative repair of TAAs. In addition, high-risk patients who would not be considered for open repair and would not be treated may now be candidates for this minimally invasive procedure.
- adequate iliac/femoral access;
- aortic inner diameter in the range of 23 mm to 27 mm; and
- less than or equal to 2 cm non-aneurysmal aorta proximal and distal to the aneurysm.
The graft is made of expanded polytetrafluoroethylene (ePTFE) with an outer self-expanding nitinol support structure and is inserted into the diseased area of the aorta through a catheter inserted in the groin.
Gore's non-randomized pivotal study compared the TAG device (n = 140) with open surgery (n = 94) across 17 U.S. sites. The control group included patients who had already undergone open surgical repair of thoracic aortic aneurysms (n = 50) as well as concurrent patients (n = 44), some of whom were unsuitable for the device cohort due to aneurysm neck length, while others were TAG-eligible. Gore conducted a confirmatory study (n = 51) after redesigning the graft to avoid fracture. The study results indicated that the TAG group was associated with reduced aneurysm-related deaths compared to the surgical group. The proportion of subjects who experienced at least one major adverse event (e.g., bleeding, hematoma, renal failure) within one year post-treatment was 42% for the TAG group versus 77% for the control group. One major adverse event was reported between months 12 and 24. In the confirmatory study, the proportion of subjects who experienced at least one major adverse event was 12% of the 51 TAG patients versus 70% of the control group. No deaths were reported for the TAG group during the first 30 days compared with 6% of the surgical control. Additionally, Gore reported that the median stay in intensive care was 1 day for the TAG group versus 3 days for the control group, and the median length of hospital stay was 3 days for TAG versus 10 days for surgery patients. The TAG group also experienced less median blood loss and returned to normal daily activities sooner.
The Interventional Procedures Advisory Committee of the National Institute for Clinical Excellence (NICE, 2005) examined endovascular stent-graft placement in thoracic aortic aneurysms (TAAs). Provisional recommendations from the Committee state that it is a suitable alternative to surgery in properly selected patients; however, the Committee emphasizes that these recommendations are provisional and subject to change.
A systematic review of the published evidence on this procedure, commissioned by NICE (2004), identified a total of 29 studies of endovascular stent-grafting for TAAs: 27 case series and 2 comparative observational studies. In one comparative study, the technical success rate was 100% (67/67 patients). The systematic review reported that the overall technical success rate was 93% over 18 studies (16 case series and 2 comparative studies).
The systematic review reported that the rate of conversion to open repair varied from 0% (0/26 patients) to 7% (1/14 patients). The proportion of patients who experienced an increase in aneurysm size varied from 0% (0/18) to 7% (2/29) of patients. In the study with the largest number of patients, the aneurysm increased in size (by ≥ 5 mm) in 5% (4/84) of patients. The proportion of patients who experienced a decrease in aneurysm size varied from 100% of patients (18/18) to 17% (5/29) of patients. The 30-day mortality rate varied from 0% (in several studies with a combined population of 94 patients) to 14% (2/14) of patients. The overall mortality ranged from 3% (1/37 patients) to 24% (11/46 patients) across 17 studies over a mean follow-up of 14 months.
The most commonly reported complication following TAA stent-graft placement was endoleak (incomplete sealing of the aneurysm). Nineteen studies reported at least one patient with an endoleak, with a mean incidence of 13% over 12 months (the total number of patients in these studies was 752; follow-up ranged from 3 to 25 months). Five studies with a total of 83 patients reported that there were no cases of endoleak during a mean follow-up period of 12 months. Injuries to the access artery were reported in 9 case series, including iliac artery dissection in 4% (1/26 patients), perforation of the iliac artery in 4% (1/27 patients), and dissection/rupture of the femoral artery in 6% (2/34 patients). One case series reported stent fracture in 13% (11/84) of patients, and 6 cases of stent migration were reported over 15 case series. Other reported complications included wound complications in 25% (8/32) of patients, stroke in 19% (8/43), renal failure requiring dialysis in 11% (2/19), and paraplegia in 7% (3/43) of patients. The NICE Interventional Procedure Advisory Committee noted that there is a lack of long-term data on the durability of TAA stent-grafts.
Gore is conducting a post-approval study to evaluate all-cause mortality, aneurysm-related mortality, morbidity, and device-related adverse events at 30 days and 1 year post-procedure. Another condition of approval is the completion of a 2-day training program as a prerequisite for ordering TAG.
Other endoprostheses for TAAs under clinical investigation in the United States include the Talent (Medtronic Inc., Sunrise, FL), Valiant with the Xcelerant delivery system (Medtronic Inc., Sunrise, FL), and Zenith TX2 (Cook, Inc., Bloomington, IN).
Surgically repaired abdominal aortic aneurysms have a risk of rupture due to leakage around the graft. Patients are periodically monitored with contrast-enhanced computed tomography (CT) after stent graft placement for endoleak and sac dilation, which indicate an increased risk of rupture.
To reduce the risks of rupture, endosensors are being developed to monitor abdominal aortic aneurysm pressure after endovascular repair. One manufacturer is developing a wireless radiofrequency endosensor (e.g., CardioMEMS Endosensor, CardioMEMS, Inc., Atlanta, GA). Once implanted into the aneurysm, the endosensor measures the pressure inside the sac. The pressure measurements are transmitted via radiofrequency to a device held over the patient's body, where pressure readings are recorded. This device may reduce the necessary frequency of periodic monitoring of the aneurysmal sac with contrast-enhanced CT. Clinical studies of the CardioMEMS Endosensor are currently ongoing.
Another endosensor, the Impressure AAA Sac Pressure Transducer, is being developed by Remon Medical and consists of a piezoelectric membrane, which, when actuated by ultrasound waves from a handheld probe, charges a capacitor. Once charged, the transducer measures ambient pressure, then generates an ultrasound signal, which is relayed to the probe. The data can then be downloaded and exported as an Excel data file consisting of pressure measurements and the corresponding times at which the measurements were taken.
Ellozy et al. (2004) reported on the first clinical experience with the use of the Impressure permanently implantable, ultrasound-activated remote pressure transducer to measure intra-sac pressure after endovascular repair of abdominal aortic aneurysms. Over 7 months, 14 patients underwent endovascular repair of an infra-renal AAA with implantation of the remote pressure transducer fixed to the outside of the stent graft and exposed to the excluded aortic sac. Twelve patients received modular bifurcated stent grafts, and 2 patients received aorto-uniiliac devices. Intra-sac pressures were measured directly with an intravascular catheter and by the remote sensor at stent-graft deployment. Follow-up sac pressures were measured with a remote sensor and correlated with systemic arterial pressure at each follow-up visit. The mean follow-up was 2.6 ± 1.9 months. The investigators reported "excellent" concordance between catheter-derived and transducer-derived intra-sac pressure intra-operatively, with a Pearson correlation coefficient for systolic, diastolic, and pulse pressures of 0.97, 0.97, and 0.96, respectively (p < 0.001). Pulsatile waveforms were seen in all functioning transducers at each evaluation interval. One implant ceased to function at 2 months of follow-up. In one patient, a type I endoleak was diagnosed on 1-month CT scans; 3 type II endoleaks were observed. The investigators reported that those patients with complete exclusion of the aneurysm on CT scans had a significant difference in systemic and sac systolic pressures initially (p < 0.001) and at 1 month (p < 0.001). Initial sac diastolic pressures were higher than systemic diastolic pressures (p < 0.001). The investigators reported that the ratio of systemic to sac systolic pressure increased over time in those patients with complete aneurysm exclusion (p < 0.001). Four of 6 patients with no endoleak and greater than 1-month follow-up had a diminution of sac systolic pressure to 40 mm Hg or less by 3 months. The investigators concluded that additional clinical follow-up will be necessary to determine whether aneurysm sac pressure monitoring can replace CT in the long-term surveillance of patients after endovascular repair of aortic aneurysms.
Ohki et al. (2007) stated that complete exclusion and de-pressurization of the aneurysm sac is the prime goal of endovascular aneurysm repair (EVAR) of AAAs. Thus, any EVAR that results in a type I or III endoleak has been classified as a technical failure. The current method to detect endoleaks uses intra-operative aortography. However, aortography is limited by its subjective nature, inability to quantify the significance of the endoleak, and artifacts such as bowel gas that may mimic an endoleak. Additionally, repetitive contrast injection may impair renal function. To increase the safety and effectiveness of intra-operative endoleak detection, a wireless pressure-monitoring system has been developed and tested in the clinical setting. The APEX trial (Acute Pressure Measurement to Confirm Aneurysm Sac EXclusion) is a prospective, multi-center/international trial sponsored by CardioMEMS to evaluate the safety and effectiveness of the EndoSure wireless pressure sensor for EVAR. The 30 x 5 x 1.5-mm sensor contains no battery and is powered externally with radiofrequency energy. The sensors are extremely stable, operate over the full physiological range of pressures, and have a resolution of 1 mm Hg. A total of 90 patients were enrolled at 12 sites, 76 of whom were eligible for analysis. The sensor was implanted via the contralateral femoral artery at the time of EVAR. The sac pulse pressure was measured with both an angiographical catheter and the sensor after deployment of the main endograft but before the deployment of the contralateral limb (type I endoleak equivalent). Sac pressure was again measured with the sensor after deployment of the contralateral limb and completion of the EVAR. Data were collected in a prospective manner. In all of the eligible patients (n = 76), the initial sensor pressure measurement agreed closely with the angiographical catheter pressure measurement of the type I endoleak equivalent. At the completion of the procedure, there was agreement between the sensor measurement and angiography regarding the presence or absence of a type I or III endoleak in 92.1% (n = 70) of the measurements. Overall, the sensitivity was 0.94 and the specificity was 0.80 for detecting type I or III endoleaks. Final pulse pressures decreased significantly compared with baseline measurements. The authors concluded that implantation of the wireless pressure sensor is safe, and remote aneurysm sac pressure sensing is feasible. It was a valuable guide in evaluating the completeness of the EVAR procedure. Moreover, they stated that a long-term study will be needed to prove its effectiveness for post-operative surveillance.
Fabric wrapping for abdominal aortic aneurysms entails wrapping aneurysms with cellophane or fascia lata. Karkos et al. (2002) stated that "whether external wrapping does alter the outcome in patients with unresected AAAs and a gain in longevity for the individual can be achieved is unclear…. the question of whether one could justify employing this old-fashioned technique, as a last resort, to delay rupture in selected poor-risk patients unfit for open repair, with large aneurysms that extend above the renal arteries and those unsuitable for endovascular surgery remains unanswered."
Fabric wrapping for abdominal aortic aneurysms has not been demonstrated to prevent eventual rupture. In extremely rare instances, external wall reinforcement may be indicated when the current accepted treatment (excision of the aneurysm and reconstruction with synthetic materials) is not a viable alternative, but external wall reinforcement is not fabric wrapping. It should also be noted that fabric wrapping of abdominal aortic aneurysms is not covered by Medicare (2001).
Guidance from the National Institute for Health and Clinical Excellence (NICE, 2009) concluded that endovascular aortic stent-grafts are not recommended for patients with ruptured aneurysms except in the context of research.
Foster et al. (2010) examined whether a policy for endovascular repair as the primary mode of treatment for ruptured abdominal aortic aneurysms (rAAAs) would improve outcomes. A total of 1,328 papers were found; of these, 24 presented the best evidence to answer the clinical question. The author, journal, date, and country of publication, patient group studies, study type, relevant outcomes, results, and study weaknesses of these papers were tabulated. The majority of data available derives from level 2b evidence, with only one single level 1b and no level 1a studies available. Appraisal of these studies was constrained by limited patient numbers, selection bias, and heterogeneity in treatment protocols between the reported series. The sole prospective randomized controlled trial comparing open and endovascular treatments found a 53% mortality among patients treated by either modality. This study was, however, under-powered and contrary to numerous cohort series that show reduced mortality with EVAR. The largest body of evidence was found in a cooperative multi-center cohort study spanning 49 institutions that showed superiority of EVAR over open repair in terms of 30-day mortality. The authors concluded that, within the limitations of the published literature to date, endovascular repair as the primary treatment for rAAA is achievable and appears to be associated with favorable mortality over open repair with appropriate case selection.
On the other hand, other published studies indicated that EVAR is not an established procedure in treating ruptured aneurysms. Vetrhus and associates (2009) noted that repair of AAAs is performed in more than 800 patients annually in Norway. Open repair is an established procedure, but an increasing number of patients have undergone endovascular repair during the last decades. This paper delivered an updated discussion of infra-renal AAA repair. A systematic search was performed in PubMed, and literature containing the search terms "abdominal aortic aneurysm" and "mortality" (from 2004 to 2009) was retrieved. The review was based on randomized, multi-center, and registry studies examining complications and mortality in endovascular and open repair. Peri-operative mortality is lower in endovascular repair. The initial survival benefit is not sustained over time. The mortality rate is still high in ruptured AAAs, but endovascular repair may improve mortality in selected patients. The authors concluded that even though peri-operative mortality associated with endovascular repair is lower than that of open repair, questions concerning benefit and selection of patients are still left unanswered.
- single-center series,
- systematic reviews, and
- population-based studies.
In order to validate EVAR, this technique was compared to the conventional open repair. These studies were heterogeneous, and often failed to demonstrate any significant difference between EVAR and open repair. More recently, some population-based studies from the United States suggested that there are advantages of EVAR over open repair with regard to 30-day mortality and morbidity. Some bias have influenced the reported results including criteria for choice of EVAR varied across the studies according to the policy of the authors. Therefore, any meta-analysis should be interpreted with caution. Patients' conditions have directed the authors towards a technique instead of the other, namely, pathophysiological factors of the patients, and anatomical conditions of the AAAs. The authors concluded that according to the current literature, the role of EVAR in the management of rAAAs must be further checked; RCTs could provide the evidence to define adequate indication to EVAR.
Karkos et al. (2009) documented mortality after endovascular repair of ruptured abdominal aortic aneurysms (rAAAs). They identified articles reporting data on mortality after endovascular repair of rAAAs, including only patients with true ruptures. Additionally, they sought information on mortality after concurrent open repair. One of the authors reviewed all studies and extracted appropriate data. A total of 43 articles were identified, with 14 excluded, resulting in 29 articles with 897 patients who underwent endovascular repair meeting the inclusion criteria. Among the patients with available information, 86% were men; 29% had been operated on under local anesthesia; 28% were hemodynamically unstable; 17% required intra-aortic balloon occlusion; 48% received bifurcated stent grafts; 6% had endovascular procedures converted to open repair intra-operatively; and 5.5% developed abdominal compartment syndrome. In-hospital and/or 30-day mortality ranged between 0% and 54% in different series, while the pooled mortality after endovascular repair was 24.5% (95% CI: 19.8% to 29.4%). In 19 studies reporting results of both endovascular and concurrent open repair from the same unit, the pooled mortality after open repair was 44.4% (95% CI: 40.0% to 48.8%), and the pooled overall mortality for rAAA undergoing either endovascular or open repair was 35% (95% CI: 30% to 41%). The authors concluded that endovascular repair of rAAAs is associated with acceptable mortality rates and stated that additional studies are needed to verify these promising results and precisely define the role of endovascular treatment as an additional therapeutic option for rAAAs.
Hinchliffe and colleagues (2009) performed a systematic literature review of endovascular aneurysm repair (EVAR) of rAAAs from 1994 to 2009. The literature analyzed included systematic reviews and population-based studies of rAAAs. A total of 7 systematic reviews were identified, all demonstrating that patients with EVAR of rAAAs had significantly reduced mortality compared with controls. Six recently published population-based studies from the United States demonstrated low mortality rates associated with EVAR; however, only a small proportion of rAAAs were treated by EVAR. Both systematic reviews and population-based studies raised concerns about patient selection and publication bias. Two randomized controlled trials (RCTs) are in progress, and one is due to commence in 2009. The authors concluded that the outcome of EVAR in a non-selected patient population remains unknown, and one or more definitive RCTs could provide the level I evidence to resolve these issues.
In a systematic review, Chambers et al. (2009) examined the clinical effectiveness and cost-effectiveness of EVAR of AAAs in patients at varying levels of risk. The following bibliographic databases were searched (2005 to February 2007): BIOSIS Previews, CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, ISI Proceedings, MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, Science Citation Index, and Zetoc Conferences. A systematic review of the clinical effectiveness of EVAR was performed using standard methods, and meta-analysis was employed to estimate a summary measure of treatment effect on relevant outcomes based on intention-to-treat analyses. A second systematic review was undertaken to identify existing cost-effectiveness analyses of EVAR compared with open surgery and non-surgical interventions. Two new decision models were developed to inform the review. A total of 6 RCTs were included in the clinical effectiveness review, and 34 studies evaluated the role of patients' baseline characteristics in predicting risks of particular outcomes after EVAR. The majority were based on data relating to devices in current use from the EUROSTAR registry. Compared with open repair, EVAR reduces operative mortality (OR 0.35, 95% CI: 0.19 to 0.63) and medium-term aneurysm-related mortality (hazard ratio 0.49, 95% CI: 0.29 to 0.83) but offers no significant difference in all-cause mortality. Endovascular aneurysm repair is associated with increased rates of complications and re-interventions, which are not offset by any increase in health-related quality of life. The EVAR Trial 2, comparing EVAR with non-surgical management in patients unfit for open repair, found no differences in mortality between groups; however, substantial numbers of patients randomized to non-surgical management crossed over to receive surgical repair of their aneurysm. The cost-effectiveness systematic review identified 6 published decision models. Both models considered relevant for the decision in the United Kingdom concluded that EVAR was not cost-effective on average compared with open repair at a threshold of £20,000 per quality-adjusted life-year (QALY). Another model concluded that EVAR would be on average more cost-effective than no surgical intervention in unfit patients at this threshold. The Medtronic model concluded that EVAR was more cost-effective than open repair for fit patients at this threshold. The York economic evaluations found that EVAR is not cost-effective compared with open repair on average at a threshold of £30,000 per QALY, with results very sensitive to model assumptions and the baseline risk of operative mortality. Exploratory analysis to evaluate management options in patients unsuitable for open surgery suggested that the cost-effectiveness of EVAR may be sensitive to aneurysm size and patient's age at operation. Indicative modeling suggests that EVAR may be cost-effective for small aneurysms in some patient groups. Ongoing RCTs will provide further evidence relating to these patients. The authors concluded that open repair is more likely to be cost-effective than EVAR on average in patients considered fit for open surgery. Endovascular aneurysm repair is likely to be more cost-effective than open repair for a subgroup of patients at higher risk of operative mortality. These results are based on extrapolation of mid-term results of clinical trials, and evidence does not currently support EVAR for the treatment of ruptured aneurysms.
Jonker et al. (2010) stated that thoracic EVAR offers a less invasive approach for the treatment of ruptured descending thoracic aortic aneurysms (rDTAA). Due to the low incidence of this life-threatening condition, little is known about the outcomes of endovascular repair of rDTAA and the factors that affect these outcomes. These investigators retrospectively investigated the outcomes of 87 patients who underwent thoracic EVAR for rDTAA at 7 referral centers between 2002 and 2009. The mean age was 69.8 ± 12 years, and 69.0% of the patients were men. Hypovolemic shock was present in 21.8% of patients, and 40.2% were hemodynamically unstable. The 30-day mortality rate was 18.4%, and hypovolemic shock (OR 4.75; 95% CI: 1.37 to 16.5; p = 0.014) and hemothorax at admission (OR 6.65; 95% CI: 1.64 to 27.1; p = 0.008) were associated with increased 30-day mortality after adjusting for age. Stroke and paraplegia occurred in 8.0% of patients each, and endoleak was diagnosed in 18.4% of patients within the first 30 days after thoracic EVAR. Four additional patients died as a result of procedure-related complications during a median follow-up of 13 months; the estimated aneurysm-related mortality at 4 years was 25.4%. The authors concluded that endovascular repair of rDTAA is associated with encouraging results. However, the endovascular approach was associated with considerable rates of neurological complications and procedure-related complications such as endoleak. Further improvements in current endovascular devices are needed to reduce endograft-related complications and deaths during follow-up.
In an editorial accompanying the study by Jonker et al., Coselli and Gopaldas (2010) stated that "[a]lthough the current use of TEVAR for ruptured thoracic aneurysms remains off-label, the success demonstrated by Jonker and colleagues and by several others establishes a strong foundation that would support the use of TEVAR as the primary modality for treating ruptured DTAA in the near future."
A scientific statement on "Surgical management of descending thoracic aortic disease: Open and endovascular approaches" from the American Heart Association (Coady et al., 2010) noted that "[t]reatment of acute aortic syndromes that affect the descending thoracic aorta continues to evolve with the development of new technologies and management strategies. Although data presented in this summary have highlighted current outcomes of endovascular stenting compared with conventional open repair, it must be stressed that there have been no prospective randomized trials to compare these treatment strategies on a head-to-head basis. In addition, although endovascular stenting offers a minimally invasive method of treatment, its long-term durability is still largely unknown. Ongoing experience and national and international registries will continue to define precise roles for both surgical and endovascular therapy."
Huddle et al. (2009) determined what laboratory values predict the prognosis of patients following EVAR. MEDLINE and Cochrane Library databases were searched, resulting in 13 relevant articles. Data were pooled, and meta-analyses were performed. A meta-analysis including 5,655 patients showed that pre-operative serum creatinine greater than 1.5 mg/dL was a significant risk indicator for increased 30-day mortality (relative risk 3.0, 95% CI: 2.3 to 4.1; p < 0.0001). Four other studies showed that other cut-off values of creatinine or glomerular filtration rate (GFR) can predict mortality and complications following EVAR. One study suggested that reduced pre-operative hemoglobin is a risk indicator for reduced long-term survival. Increased serum creatinine, reduced GFR, and reduced hemoglobin are significant and strong predictors of mortality and complications after EVAR. The authors concluded that current evidence remains limited, and further research is needed to determine conclusively additional laboratory values that may predict the outcome of patients following EVAR.
Linsen et al. (2012) performed a systematic review of the current literature to analyze the immediate and follow-up results of fenestrated EVAR (FEVAR) in patients with para-renal AAAs. The Medline, Embase, and Cochrane databases were searched to identify all studies reporting FEVAR of para-renal AAAs published between January 2000 and May 2011. Two independent observers selected studies for inclusion, assessed the quality of the included studies, and performed data extraction based on specific pre-defined criteria. Outcomes were technical success (successfully completed procedure with endograft patency, preservation of target vessels, and no evidence of type I or III endoleak at post-procedural imaging), 30-day mortality, all-cause mortality, branch vessel patency, renal impairment, and secondary interventions. Between-study heterogeneity was calculated using I(2) statistics, and pooled estimates were calculated using a fixed-effects (I(2) < 25%) or a random-effects (I(2) > 25% to < 50%) model. A total of 9 studies were included, reporting 629 patients who underwent FEVAR for a para-renal AAA, incorporating 1,622 target vessels in an endograft design. Between-study heterogeneity was less than or equal to 41% for all outcomes. The pooled estimate (95% CI) was 90.4% (87.7% to 92.5%) for technical success, 2.1% (1.2% to 3.7%) for 30-day mortality, and 16% (12.5% to 20.4%) for all-cause mortality. Follow-up was 15 to 25 months. The pooled estimate (95% CI) during follow-up was 93.2% (90.4% to 95.3%) for branch vessel patency, 22.2% (16% to 30.1%) for renal impairment, and 17.8% (13.5% to 22.6%) for secondary interventions. The authors concluded that promising immediate and mid-term results (up to 2 years) support FEVAR as a feasible, safe, and effective treatment in a relatively high-risk cohort of patients with para-renal AAAs.
Cross et al. (2012) stated that FEVAR is a technically challenging operation. The duration, blood loss, and risk of limb ischemia, contrast-induced nephropathy, and re-perfusion injury are likely to be higher than after standard EVAR. Benefits of FEVAR over open repair may be less than those seen with standard infrarenal EVAR. These investigators performed a meta-analysis of observational studies of all published data for FEVAR, aiming to highlight current issues around the evidence for the potential benefit of FEVAR. A search was performed for studies describing FEVAR for juxta-renal AAAs. Small series of fewer than 10 procedures and studies describing predominantly branched endografts or FEVAR for aortic dissection were excluded. Authors of included papers were contacted to eliminate patient duplication. A total of 11 studies were identified describing a total of 660 procedures. Definitions of aneurysm morphology were variable, and clear inclusion and exclusion criteria were not always documented. Double fenestrations were more common than triple or quadruple fenestrations. Target vessel perfusion rates ranged from 90.5% to 100%. Eleven deaths occurred within 30 days, giving a 30-day proportional mortality rate of 2.0%. Morbidity was poorly reported. The authors concluded that FEVAR for repair of supra-renal and juxta-renal aneurysms is a viable alternative to open repair. However, there is no level 1 evidence for FEVAR, and current evidence is weak with many unanswered questions.
In a Cochrane review, Filardo et al. (2012) compared long-term survival in patients with AAAs of diameter 4.0 to 5.5 cm who received immediate repair versus routine ultrasound surveillance. For this update, the Cochrane Peripheral Vascular Diseases Group searched their Specialized Register (February 2012) and CENTRAL (2012, Issue 1). Reference lists of relevant articles were checked for additional studies, and the searches were supplemented by hand-searches of recent conference proceedings and information from experts in the field. Randomized controlled trials in which men and women with asymptomatic AAAs of diameter 4.0 to 5.5 cm were randomly allocated to immediate repair or imaging-based surveillance at least every 6 months were included. Outcomes had to include mortality or survival. Two authors abstracted the data, which were cross-checked by the other authors. Due to the small number of trials, formal tests of heterogeneity and sensitivity analyses were not conducted. Four trials with a combined total of 3,314 patients—the UK Small Aneurysm Trial (UKSAT), the Aneurysm Detection and Management (ADAM) trial, the Comparison of Surveillance Versus Aortic Endografting for Small Aneurysm Repair (CAESAR), and the Positive Impact of Endovascular Options for treating Aneurysms Early (PIVOTAL)—fulfilled the inclusion criteria. The 4 trials showed an early survival benefit in the surveillance group (due to 30-day operative mortality with surgery) but no significant differences in long-term survival (adjusted hazard ratio (HR) 0.88, 95% CI: 0.75 to 1.02, mean follow-up 10 years (UKSAT); HR 1.21, 95% CI: 0.95 to 1.54, mean follow-up 4.9 years (ADAM); HR 0.76, 95% CI: 0.30 to 1.93, median follow-up 32.4 months (CAESAR); HR 1.01, 95% CI: 0.49 to 2.07, mean follow-up 20 months (PIVOTAL)). The meta-analyses of mortality at 1 year (CAESAR and PIVOTAL only) and 6 years (UKSAT and ADAM only) revealed a non-significant association (Peto odds ratio at one year 1.15, 95% CI: 0.59 to 2.25; Peto odds ratio at 6 years 1.11, 95% CI: 0.91 to 1.34). The authors concluded that these findings from the 4 trials to date demonstrated no advantage to early repair (via open or endovascular surgery) for small AAAs (4.0 to 5.5 cm) and suggested that "best care" for these patients favors surveillance. Furthermore, the more recent trials focused on the efficacy of EVAR and still failed to show benefit. Thus, both open and endovascular repair of small AAAs are not supported by currently available evidence.
Brown and associates (2012) evaluated the effectiveness of EVAR against standard alternative management in patients with large AAAs. These researchers examined 2 national, multi-center randomized trials—EVAR trials 1 and 2. Patients were recruited from 38 out of 41 eligible United Kingdom (UK) hospitals. Men and women aged at least 60 years, with an AAA measuring at least 5.5 cm on a CT scan that was regarded as anatomically suitable for EVAR, were assessed for fitness for open repair. Patients considered fit were randomized to EVAR or open repair in EVAR trial 1, and patients considered unfit were randomized to EVAR or no intervention in EVAR trial 2. The primary outcome was mortality (operative, all-cause, and AAA-related). Patients were flagged at the UK Office for National Statistics with centrally coded death certificates assessed by an Endpoints Committee. Power calculations based on mortality indicated that 900 and 280 patients were required for EVAR trials 1 and 2, respectively. Secondary outcomes included graft-related complications and re-interventions, adverse events, renal function, health-related quality of life, and costs. Cost-effectiveness analyses were performed for both trials. Recruitment occurred between September 1, 1999, and August 31, 2004, with targets exceeded in both trials: 1,252 randomized into EVAR trial 1 (626 to EVAR) and 404 randomized into EVAR trial 2 (197 to EVAR). Follow-up closed in December 2009 with very little loss to follow-up (1%). In EVAR trial 1, 30-day operative mortalities were 1.8% and 4.3% in the EVAR and open-repair groups, respectively: adjusted odds ratio 0.39 (95% CI: 0.18 to 0.87), p = 0.02. During a total of 6,904 person-years of follow-up, 524 deaths occurred (76 AAA-related). Overall, there was no significant difference between the groups in terms of all-cause mortality: adjusted hazard ratio (HR) 1.03 (95% CI: 0.86 to 1.23), p = 0.72. The EVAR group demonstrated an early advantage in terms of AAA-related mortality, which was sustained for the first few years but lost by the end of the study, primarily due to fatal endograft ruptures: adjusted HR 0.92 (95% CI: 0.57 to 1.49), p = 0.73. The EVAR procedure was more expensive than open repair (mean difference of £1,177) and not found to be cost-effective, but the model was sensitive to alternative assumptions. In EVAR trial 2, during a total of 1,413 person-years of follow-up, a total of 305 deaths occurred (78 AAA-related). The 30-day operative mortality was 7.3% in the EVAR group. However, this group later demonstrated a significant advantage in terms of AAA-related mortality, but this became apparent only after 4 years: overall adjusted HR 0.53 (95% CI: 0.32 to 0.89), p = 0.02. Sadly, this advantage did not result in any benefit in terms of all-cause mortality: adjusted HR 0.99 (95% CI: 0.78 to 1.27), p = 0.97. Overall, EVAR was more expensive than no intervention (mean difference of £10,222) and not found to be cost-effective. The authors concluded that EVAR offers a clear operative mortality benefit over open repair in patients fit for both procedures, but this early benefit is not translated into a long-term survival advantage. Among patients unfit for open repair, EVAR is associated with a significant long-term reduction in AAA-related mortality, but this does not appear to influence all-cause mortality.
Di and colleagues (2013) noted that the development of endovascular technology has led to the introduction of fenestrated endovascular aneurysm repair (FEVAR) to treat para-renal abdominal aortic aneurysms (PRAAAs) that are deemed unsuitable for standard endovascular repair. These investigators performed a systematic review and meta-analysis of data from the literature to determine the outcomes of the fenestrated technology. They searched the Medline, Embase, and Cochrane databases for studies published in English between January 1996 and May 2011 that reported on FEVAR for PRAAAs. Separate meta-analyses were conducted for primary outcomes (i.e., 30-day mortality, technical success rate, primary target vessel patency rate, and 12-month patency rate) and secondary outcomes (i.e., re-intervention rate, target renal artery occlusion rate, and post-operative permanent dialysis rate). Subgroup analyses were performed to determine differences in outcomes between varying types of studies (prospective or retrospective), and regression analyses were conducted to explore associations between outcomes and various factors (i.e., mid-date of study, study size, and procedure time). A total of 12 studies conducted between 2006 and 2011, consisting of 776 cases of FEVAR, were included. The pooled estimate for 30-day mortality was 2.52% (95% CI: 1.55 to 4.08). Technical success was measured at 92.8% (95% CI: 87.5 to 96.0). Primary target vessel patency was 98.3% (95% CI: 97.4 to 98.8), and the 12-month target vessel patency was 94.5% (95% CI: 92.1 to 96.2). The post-operative re-intervention rate was 17.6% (95% CI: 12.0 to 25.1), the target renal artery occlusion rate was 6.1% (95% CI: 4.1 to 8.8), and the post-operative permanent dialysis rate was 2.6% (95% CI: 1.5 to 4.4). Subgroup analyses found no significant differences between the major outcomes of retrospective and prospective studies. Regression analyses suggested that larger series had higher 12-month target vessel patency rates than smaller series. The authors concluded that this study revealed that FEVAR treatment for PRAAAs has acceptable early and mid-term outcomes.
Dijkstra et al. (2014) noted that in the past decade, the management of short-neck infra-renal and juxta-renal aortic aneurysms with FEVAR has been shown to be successful, with good early and mid-term results. Recently, a new fenestrated device, the fenestrated Anaconda (Vascutek, Renfrewshire, Scotland), was introduced. These researchers presented the current Dutch experience with this device. They analyzed a prospectively held database of patients treated with the fenestrated Anaconda endograft. The decision to treat was based on current international guidelines, with indications for FEVAR including an AAA with unsuitable neck anatomy for EVAR. Planning was performed using computed tomography angiography images on a 3-D workstation. Between May 2011 and September 2013, a total of 25 patients were treated in 8 institutions for juxta-renal (n = 23) and short-neck AAA (n = 2). The median AAA size was 61 mm (range 59 to 68.5 mm). All procedures except one were performed with bifurcated devices. A total of 56 fenestrations were incorporated, and 53 (94.6%) were successfully cannulated and stented. One patient died of bowel ischemia caused by occlusion of the superior mesenteric artery. On completion angiography, 3 type I endoleaks and 7 type II endoleaks were observed. At 1 month of follow-up, all endoleaks had spontaneously resolved. The median follow-up was 11 months (range 1 to 29 months). There were no aneurysm ruptures or aneurysm-related deaths, and no re-interventions to date. Primary patency at 1 month of cannulated and stented target vessels was 96%. The authors concluded that initial and short-term results of FEVAR using the fenestrated Anaconda endograft are promising, with acceptable technical success and short-term complication rates. They also stated that growing experience and long-term results are needed to support these findings.
Raux et al. (2014) stated that the benefit of FEVAR compared with open surgical repair (OSR) of complex AAAs (CAAAs) is unknown. These researchers compared 30-day outcomes of these procedures from two high-volume centers where FEVAR was undertaken for high-risk patients. Patients undergoing FEVAR with commercially available devices and OSR of CAAAs (total supra-renal/supra-visceral clamp position) were propensity-matched by demographic, clinical, and anatomic criteria to identify similar patient cohorts. Peri-operative outcomes were evaluated using univariate and multivariate methods. From July 2001 to August 2012, a total of 59 FEVAR and 324 OSR patients were identified. After 1:4 propensity matching for age, gender, hypertension, congestive heart failure, coronary disease, chronic obstructive pulmonary disease, stroke, diabetes, pre-operative creatinine, and anticipated/actual aortic clamp site, the study cohort consisted of 42 FEVARs and 147 OSRs. The most frequent FEVAR construct was two renal fenestrations, with or without a single mesenteric scallop, in 50% of cases. An average of 2.9 vessels were treated per patient. Univariate analysis demonstrated that FEVAR had higher rates of 30-day mortality (9.5% versus 2%; p = 0.05), any complication (41% versus 23%; p = 0.01), procedural complications (24% versus 7%; p < 0.01), and graft complications (30% versus 2%; p < 0.01). Multivariable analysis showed that FEVAR was associated with an increased risk of 30-day mortality (OR, 5.1; 95% CI: 1.1 to 24; p = 0.04), any complication (OR, 2.3; 95% CI: 1.1 to 4.9; p = 0.01), and graft complications (OR, 24; 95% CI: 4.8 to 66; p < 0.01). The authors concluded that FEVAR, in this two-center study, was associated with a significantly higher risk of peri-operative mortality and morbidity compared with OSR for the management of CAAAs. These data suggested that extending the paradigm shift comparing EVAR with OSR for routine AAAs to patients with CAAAs is not appropriate. Moreover, they stated that further study is needed to establish proper patient selection for FEVAR instead of OSR before widespread use should be considered.
In a Cochrane review, Jackson et al. (2014) compared the clinical outcomes of percutaneous access with standard femoral artery access in elective bifurcated abdominal EVAR. The Cochrane Peripheral Vascular Diseases Group Trials Search Coordinator searched their Specialized Register (last searched July 2013), CENTRAL (2013, Issue 6), and clinical trials databases. Reference lists of retrieved articles were checked. Only randomized controlled trials (RCTs) were considered. The primary intervention was a totally percutaneous endovascular repair, compared against standard femoral artery endovascular repair. Only studies investigating elective repairs were included, while studies reporting emergency surgery for a rAAA and those reporting aorto-uni-iliac repairs were excluded. All data were collected independently by two review authors. Due to the small number of trials identified, no formal assessment of heterogeneity or sensitivity analysis was conducted. Only one trial met the inclusion criteria, involving a total of 30 participants, with 15 undergoing the percutaneous technique and 15 treated by the standard femoral cut-down approach. There were no significant differences between the two groups at baseline. No mortality or failure of aneurysm exclusion was observed in either group. Three wound infections occurred in the standard femoral cut-down group, whereas none was observed in the percutaneous group, although this was not statistically significant. Only one major complication was observed in the study, a conversion to the cut-down technique in the percutaneous access group. No long-term outcomes were reported. One episode of a bleeding complication was reported in the percutaneous group. Significant differences were detected in surgery time (percutaneous 86.7 ± 27 minutes versus conventional 107.8 ± 38.5 minutes; p < 0.05). The included study had a small sample size and failed to adequately report the method of randomization, allocation concealment, and the pre-selected outcomes. The authors concluded that only one small study was identified, which did not provide adequate evidence to determine the safety and effectiveness of the percutaneous approach compared with endovascular aneurysm repairs. This review identified a clear need for further research into this potentially beneficial technique, with one ongoing study identified in the search that may provide an improved evidence base in the future.
Glebova et al. (2015) noted that a recent prospective study found that FEVAR was safe and effective in appropriately selected patients at experienced centers. As this new technology is disseminated to the community, it will be important to understand how it compares with standard EVAR. These researchers compared the outcomes of FEVAR versus EVAR of AAAs. They queried the American College of Surgeons-National Surgical Quality Improvement Program database from 2005 to 2012 for AAAs (International Classification of Diseases, ninth Revision code 441.4). Patients were stratified according to procedure (FEVAR versus EVAR). A bivariate analysis was conducted to assess pre-operative and intra-operative risk factors for post-operative outcomes; 30-day post-operative mortality and complication rates were described for each procedure type. Multivariable logistic regression was performed to assess the association between the type of procedure and the risk of post-operative complications. A total of 458 patients underwent FEVAR, and 19,060 patients underwent EVAR for AAA. Patients undergoing FEVAR were older (p = 0.02) and less likely to have a bleeding disorder (p = 0.046). Otherwise, the incidence of comorbidities in both groups was similar. Fenestrated EVAR was associated with increased median operative time (156 versus 137 minutes; p < 0.001) and average post-operative length of stay (3.3 versus 2.8 days; p = 0.03). There was a statistically significant increase in overall complications (23.6% versus 14.3%; p < 0.001) and post-operative transfusions (15.3% versus 6.1%; p < 0.001), with trends toward increased cardiac complications (2.2% versus 1.3%; p = 0.09) and the need for dialysis (1.5% versus 0.8%; p = 0.08) in the FEVAR group. Mortality (2.4% versus 1.5%; p = 0.12) was not statistically different. On multivariable analysis, FEVAR remained independently associated with the need for post-operative transfusions when operative time was less than the 75th percentile (adjusted OR, 1.72; 95% CI: 1.09 to 2.72; p = 0.02) as well as when operative time was greater than the 75th percentile for respective procedures (adjusted OR, 5.33; 95% CI: 3.55 to 8.00; p < 0.001). The authors concluded that patients undergoing FEVAR are more likely than those undergoing EVAR to receive blood transfusions post-operatively and are more likely to sustain post-operative complications. They noted that although mortality was similar, trends toward increased cardiac and renal complications may suggest the need for judicious dissemination of this new technology. They stated that future research with a larger number of FEVAR cases is needed to determine if these associations remain.
Capoccia and Riambau (2015) stated that inflammatory AAA (IAAA) is a rare but potentially life-threatening condition characterized by marked thickening of the aortic wall, peri-aneurysmal and retro-peritoneal fibrosis, and dense adhesions of adjacent abdominal organs. The pathogenesis of IAAA remains an enigma. The principal objective of invasive or surgical therapy for AAAs is the prevention or correction of aortic rupture. Prevention or treatment of AAA rupture by open or endovascular repair is supported by numerous studies published in the literature. However, treatment of IAAA poses a different challenge to surgeons compared with traditional atherosclerotic AAA due to the potential for iatrogenic injury in open repair or, alternatively, the potential increased inflammatory response to endoprosthesis implantation. These investigators evaluated the effects of elective endovascular versus open repair for IAAA. The Cochrane Peripheral Vascular Diseases Group Trials Search Coordinator searched the Specialised Register (April 2015) and the Cochrane Register of Studies (CRS) (Issue 3, 2015). The TSC searched trial databases for details of ongoing and unpublished studies. The authors sought all published and unpublished RCTs, quasi-RCTs, and controlled clinical trials comparing the results of elective endovascular or open repair of IAAAs without language restriction. Both review authors independently assessed studies identified for potential inclusion in the review. They planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Review of Interventions. The researchers identified no studies that met the inclusion criteria. The authors concluded that they found no published RCTs, quasi-RCTs, or controlled clinical trials comparing open repair and elective endovascular repair for IAAA, assessing immediate (30-day), intermediate (up to 1-year follow-up), and long-term (more than 1-year follow-up) mortality or complication rates. They stated that high-quality studies evaluating the best treatment for inflammatory abdominal aneurysm repair are needed.
Walker et al. (2015) reported their long-term experience with type II endoleaks (T2Ls) management in a large multi-center registry. Between 2000 and 2010, a total of 1,736 patients underwent EVAR, and these investigators recorded the incidence of T2L. Primary outcomes were mortality and aneurysm-related mortality (ARM). Secondary outcomes included changes in aneurysm sac size, major adverse events, and re-intervention. During the follow-up (median of 32.2 months; interquartile range [IQR] of 14.2 to 52.8 months), T2L was identified in 474 patients (27.3%). There were no late AAA ruptures attributable to a T2L. Overall mortality (p = 0.47) and ARM (p = 0.26) did not differ between patients with and without T2L. Sac growth (median of 5 mm; IQR of 2 to 10 mm) was seen in 213 (44.9%) of the patients with T2L. Of these patients with a T2L and sac growth, 36 (16.9%) had an additional type of endoleak. Of all patients with T2L, 111 (23.4%) received re-interventions, including 39 patients who underwent multiple procedures; 74% of the re-interventions were performed in patients with sac growth. Re-interventions included lumbar embolization in 66 patients (59.5%), placement of additional stents in 48 (43.2%), open surgical revision in 14 (12.6%), and direct sac injection in 22 (19.8%). The re-intervention was successful in 35 patients (31.5%). After excluding patients with other types of endoleak, no difference in overall all-cause mortality (p = 0.57) or ARM (p = 0.09) was observed between patients with T2L-associated sac growth who underwent re-intervention and those in whom T2L was left untreated. The authors concluded that in their multi-center EVAR registry, overall all-cause mortality and ARM were unaffected by the presence of a T2L. Moreover, patients who were simply observed for T2L-associated sac growth had aneurysm-related outcomes similar to those in patients who underwent re-intervention. They stated that their future work will investigate the most cost-effective ways to select patients for intervention beyond sac growth alone.
CT Surveillance after Endovascular (Stent) Aortic Repair
MedSolutions guidelines recommend CT surveillance after endovascular (stent) aortic repair at 1 month, 6 months, and 12 months following repair, then every year.
Multi-Branched Stent-Grafts
- JRAAAs and
- TAAAs.
Resources were searched from inception to October 2013, including Medline (OvidSP), Embase (OvidSP) and the Cochrane Central Register of Controlled Trials (Wiley) and, additionally, for cost-effectiveness, NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost). Conference abstracts were also searched. Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative, i.e., explicitly selected on the basis of prognosis. For clinical effectiveness, searches retrieved 5,253 records before de-duplication. Owing to overlap between the databases, 1,985 duplicate records were removed. Of the remaining 3,268 records, based on titles and abstracts, 3,244 records were excluded, leaving 24 publications to be ordered. All 24 studies were excluded as none of them satisfied the inclusion criteria – 16 studies were excluded on study design, 6 on intervention and 2 on comparator; 5 out of 16 studies excluded on study design reported a comparison. However, all of the studies acknowledged that they had groups that were not comparable at baseline given that they had selectively assigned younger, fitter patients to OSR. Therefore, these studies were considered "non-comparative". For cost-effectiveness, searches identified 104 references before de-duplication. Owing to overlap between the databases, 34 duplicate records were removed. Of the remaining 70 records, 7 were included for the full assessment based on initial screening. After a full-text review, no studies were included. Because of the lack of clinical effectiveness evidence and difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead a detailed description of modelling methods was provided. The authors concluded that despite a thorough search, no studies could be found that met the inclusion criteria. All studies that compared either fEVAR or bEVAR with either OSR or no surgery explicitly selected patients based on prognosis, i.e., essentially the populations for each comparator were not the same. The authors recommended that at least 1 clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery. This trial should also collect data for a CEA.
Michel and co-workers (2015) compared 30-day outcomes and costs of fenestrated endovascular aneurysm repair (fEVAR), branched endovascular aneurysm repair (bEVAR), and open surgical repair (OSR) for the treatment of complex abdominal aortic aneurysms (AAAs) and thoracoabdominal aortic aneurysms (TAAAs). The multi-center, prospective WINDOW Trial was designed to evaluate fEVAR/bEVAR in high-risk patients with para-renal AA (PRAA) or juxta-renal AA (JRAAA), as well as infra-diaphragmatic and supra-diaphragmatic TAAAs. A control group of patients treated by OSR was extracted from the national hospital discharge database. The primary endpoint was 30-day mortality, while secondary endpoints included severe complications, length of stay, and costs. Mortality was assessed through survival analysis and univariate and multivariate Cox regression analyses using pre- and post-operative characteristics. Bootstrap methods were employed to estimate the cost-effectiveness of fEVAR/bEVAR versus OSR. A total of 268 cases and 1,678 controls were included. There was no difference in 30-day mortality (6.7% versus 5.4%, p = 0.40), but costs were higher with fEVAR/bEVAR (€38,212 versus €16,497, p < 0.001). After group stratification, mortality was similar for both treatments for PRAA/JRAAA (4.3% versus 5.8%, p = 0.26) and supra-diaphragmatic TAAA (11.9% versus 19.7%, p = 0.70), while fEVAR/bEVAR had higher mortality for infra-diaphragmatic TAAA (11.9% versus 4.0%, p = 0.010). Costs were higher with fEVAR/bEVAR for PRAA/JRAAA (€34,425 versus €14,907, p < 0.0001) and infra-diaphragmatic TAAA (€37,927 versus €17,530, p < 0.0001), but not significantly different for supra-diaphragmatic TAAA (€54,710 versus €44,163, p = 0.18). The authors concluded that fEVAR/bEVAR did not appear justified for patients with PRAA/JRAAA and infra-diaphragmatic TAAA who are fit for OSR; however, it may be an attractive option for patients with PRAA/JRAAA not eligible for surgery and for those with supra-diaphragmatic TAAA.
Eagleton and colleagues (2016) evaluated the technical and clinical outcomes of fEVAR/bEVAR for extensive type II and III TAAAs. Data from 354 high-risk patients enrolled in a physician-sponsored investigational device exemption (IDE) trial (2004 to 2013) undergoing fEVAR/bEVAR for type II and III TAAAs were analyzed. Technical success, peri-operative clinical outcomes, and mid-term outcomes (36 months) for branch patency, re-intervention, aneurysm-related death, and all-cause mortality were assessed. Data were presented as mean ± standard deviation (S.D.) and were analyzed using Kaplan-Meier, univariate, and multivariate analysis; fEVAR/bEVAR incorporating 1,305 fenestrations/branches were implanted with a 96% success rate for stenting target vessels. Completion aortography showed that 2.8% of patients had a type I or III endoleak. Procedure duration was longer for type II TAAA (6.0 ± 1.7 versus 5.5 ± 1.6 hours; p < 0.01), as was hospital stay (13.1 ± 10.1 versus 10.2 ± 7.4 days; p < 0.01). Peri-operative mortality was greater in type II repairs (7.0% versus 3.5%; p < 0.001). Permanent spinal cord ischemia (SCI) occurred in 4% of patients, and renal failure requiring hemodialysis occurred in 2.8%. A total of 27 branches (7.6%) required re-intervention for stenosis or occlusion, with celiac artery, superior mesenteric artery, and renal artery secondary patency at 36 months being 96% (95% CI: 0.93 to 0.99), 98% (95% CI: 0.97 to 1.0), and 98% (95% CI: 0.96 to 1.0), respectively. A total of 80 endoleak repairs were performed in 67 patients, including 55 branch-related endoleaks, 4 type Ia, 5 type Ib, and 15 type II endoleaks. At 36 months, freedom from aneurysm-related death was 91% (95% CI: 0.88 to 0.95), and freedom from all-cause mortality was 57% (95% CI: 0.50 to 0.63). The treatment of type II TAAA (p < 0.01), age (p < 0.01), and chronic obstructive pulmonary disease (p < 0.05) negatively affected survival. The authors concluded that fEVAR/bEVAR is a robust therapeutic option for patients at increased risk for conventional repair of extensive TAAAs. Technical success and branch patency were excellent, but some patients will require re-intervention for branch-related endoleak. The extent of the aneurysm portends a higher risk of peri-operative and long-term morbidity and mortality. They stated that additional efforts are needed to improve outcomes and understand the utility of this therapeutic option in the general TAAA population.
In a systematic review and meta-analysis, Hu and colleagues (2016) evaluated the available literature on endovascular repair of TAAAs and PRAAs using multi-branched stent-grafts. They searched the Medline, Embase, and Cochrane databases between January 2001 and June 2015 to identify articles related to the use of multi-branched stent-grafts for the treatment of TAAAs and PRAAs. Articles with fewer than 4 cases and those on juxta-renal aortic aneurysms were excluded. Meta-analyses were conducted to evaluate 30-day mortality, all-cause mortality, spinal cord ischemia (SCI), renal insufficiency, endoleak, target vessel patency, and re-intervention. Of 370 articles screened, only 4 articles encompassing 185 patients (mean age of 71.1 years; 137 men) met the inclusion criteria. There were 23 PRAAs, and the mean aneurysm diameter was 64.5 mm. The Crawford TAAA classification included 10 type I, 47 type II, 37 type III, 58 type IV, and 9 type V; there was 1 Stanford type B dissection associated with a large TAAA. Results of the meta-analyses are reported as proportions and 95% CI. Pooled analysis indicated a technical success rate of 98.9%. Due to significant study heterogeneity, random effects models were used for meta-analysis. The rate for 30-day mortality was 9% (95% CI: 3% to 19%), for all-cause mortality 27% (95% CI: 17% to 38%), endoleaks 10% (95% CI: 1% to 25%), target vessel patency 98% (95% CI: 95% to 99%), SCI 17% (95% CI: 1% to 26%), irreversible SCI 6% (95% CI: 3% to 10%), renal insufficiency 15% (95% CI: 0.8% to 41%), and re-interventions 21% (95% CI: 4% to 47%). The authors concluded that the use of multi-branched stent-grafts in the treatment of TAAAs and PRAAs appeared to be feasible and safe based on satisfactory early outcomes in the limited literature available to date. Moreover, they stated that long-term surveillance and further studies are needed to determine the durability of this technique.
Intravenous Heparin During Ruptured Abdominal Aortic Aneurysmal Repair
Lammy and colleagues (2016) noted that there have been enormous advances in the screening, diagnosis, intervention and overall prognosis of AAAs in the last decade, but despite these, rAAAs still cause around 3,500 to 6,000 deaths in England and Wales each year. Open repair remains standard treatment for rAAA in most centers but increasingly EVAR is being adopted. This has a 30-day post-operative mortality of 40%, which has remained static despite surgical, anesthetic and critical care advances. One significant change to current practice for elective repairs of AAAs, as opposed to emergency repairs of rAAAs, has been the introduction of intravenous heparin. This provides a protective effect against cardiac and thrombotic disease in the post-operative period. This practice has not gained widespread acceptance for emergency repairs of rAAA even though a reduction in mortality and morbidity has been demonstrated in elective repairs. In a Cochrane review, these researchers examined the effect of intravenous heparin on all-cause mortality in rAAA management in patients undergoing an emergency repair. The secondary objectives were to evaluate the effect of intravenous heparin in rAAA management on the incidence of general arterial disease (e.g., cardiovascular, cerebral, pulmonary and renal pathologies) in patients undergoing emergency repair. The Cochrane Vascular Information Specialist (CIS) searched the Specialized Register (December 2015). In addition the CIS searched CENTRAL;2015, Issue 11). The CIS searched clinical trials registries for details of ongoing or unpublished studies. These researchers sought all published and unpublished RCTs and controlled clinical trials (CCTs) of intravenous heparin in rAAA repairs (including parallel designs). Two review authors independently assessed studies identified for potential inclusion in the review. They used standard methodological procedures in accordance with the Cochrane Handbook for Systematic Review of Interventions. They identified no RCTs or CCTs that satisfied the inclusion criteria. The authors concluded that they identified no RCTs or CCTs of intravenous heparin in rAAA repairs (including parallel designs). Thus, they were unable to evaluate the effect of intravenous heparin on all-cause mortality and incidence of general arterial disease in patients undergoing an emergency repair. They stated that a RCT is needed to address this question in rAAA management as there is no high quality evidence.
Pre-Operative Inferior Mesenteric Artery Embolization to Reduce the Rate of Type II Endoleak Following Endovascular Abdominal Aortic Aneurysm Repair
Brown and associates (2016) stated that type II endoleaks are the most common endovascular complications of EVAR; however, there has been a divided opinion regarding their significance in EVAR. Some advocate a conservative approach unless there is clear evidence of sac expansion, while others maintain early intervention is best to prevent adverse late outcomes such as rupture. There is a lack of Level I Evidence in this challenging group of patients, and due to a low event rate of complications, large numbers of patients would be needed in well-designed trials to fully understand the natural history of type II endoleak. These investigators noted that due to a lack of evidence regarding the natural history of type II endoleaks and their association with adverse outcomes such as sac expansion and rupture, intervention is typically offered for persistent endoleaks and for those which demonstrate sac expansion (greater than 10 mm) or increased intra-sac pressure. Unfortunately, optimal thresholds are not clear. Moreover, they stated that future studies should aim to compare not only different approaches to the treatment of type II endoleak, but also different embolents. More focus is needed on long-term outcomes and complications rather than technical success alone. A multi-center registry of type II endoleak intervention and outcomes would be ideal to uncover solutions to some of the remaining challenges in the management of this challenging group of patients.
- those who did not undergo IMA embolization (control) before EVAR, and
- those who did.
Rates of type II endoleaks, aneurysm sac regression, and secondary interventions were analyzed. A total of 620 patients from 6 studies were analyzed, including 258 patients who underwent an attempted IMA embolization before EVAR with a cumulative success rate of 99.2% (range of 93.8% to 100%). There was 1 fatality associated with IMA embolization. A meta-analysis showed that pre-operative IMA embolization protected against type II endoleaks compared to the control group (OR, 0.31 [0.17 to 0.57]; p < 0.001, I2 = 43%). Furthermore, the rate of secondary intervention was significantly lower in the treatment group (OR, 0.12 [0.004 to 0.36]; p < 0.001, I2 = 0%). After IMA embolization, type II endoleak resulted from patent lumbar arteries in all 62 patients with persistent endoleak. The authors concluded that pre-operative embolization of the IMA protected against the development of type II endoleaks and secondary interventions and may potentially lead to a rapid aneurysm sac regression. The procedure can be performed with a high technical success rate and minimal complications and should be considered in patients with IMA greater than 3 mm before EVAR. Moreover, they stated that a randomized trial is needed to clearly delineate the clinical significance of this technique.
Fenestrated Prosthesis for Repair of Abdominal Aortic Aneurysms
Graves and Jackson (2015) noted that endovascular abdominal aortic aneurysm repair (EVAR) provides an attractive alternative to traditional open techniques. However, endovascular repair is often limited by factors such as aortic aneurysm neck angulation, the absence of an adequate infra-renal neck, and the need for internal iliac artery preservation. To address these challenges, several devices have been developed to incorporate visceral artery segments and preserve the internal iliac artery, thereby broadening the patient population suitable for endovascular repair. The researchers reviewed the current literature regarding fenestrated devices, branch devices, off-the-shelf devices, and physician-modified devices, highlighting iliac branch stent grafts currently in trial for internal iliac artery preservation. The authors concluded that the data thus far suggest these devices will be both safe and effective options for anatomically challenging abdominal aortic aneurysms (AAAs). They emphasized that fenestrated and branched stent grafts have significantly expanded therapeutic options for aortic aneurysmal disease, and their clinical use is expected to grow as technologies advance.
Glorion et al. (2016) stated that despite the technical advances of fenestrated and branched endografts, endovascular exclusion of aneurysms involving renal, visceral, and/or supra-aortic branches remains a challenge. In-situ fenestration (ISF) of standard endografts represents another endovascular method to maintain perfusion to such branches. These investigators reviewed current indications, technical descriptions, and results of ISF. They conducted a review of the English language literature using Medline databases, Cochrane Database, Web of Science, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A total of 67 relevant papers were selected, with 33 excluded, leaving 34 articles as the basis of the review. Most experimental papers evaluated the feasibility of ISF and assessed its consequences on graft fabric. Regarding clinical papers, 73 ISF procedures were attempted in 58 patients, including 26 (45%) emergent and 3 (5%) bailout cases; 65 (89%) ISF were located at the level of the arch, and 8 (11%) in the abdominal aorta. Graft perforation was performed by physical, mechanical, or unspecified means in 33 (45%), 38 (52%), and 2 vessels (3%), respectively. ISF was technically successful in 68 out of 73 (93%) arteries. At 30 days, 2 (3.4%) patients died due to an aorto-bronchial fistula and an aorto-esophageal fistula, respectively. No post-operative deaths, major complications, or endoleaks were observed as secondary to the ISF procedure. With follow-up ranging from 0 to 72 months, 4 (6.9%) late deaths were noted, unrelated to the aorta; 1 (1.7%) left subclavian artery stent was stenosed without symptoms. The authors concluded that although there may be publication bias, multiple techniques for performing ISF were described with satisfactory short-term results, though long-term data remain scarce. They stated that aortic endograft ISF is an off-label procedure that should not be used outside of emergent bailout techniques or investigational studies, and a comparison with alternative techniques for preserving aortic side branches is needed.
Blankensteijn et al. (2017) noted that the fenestrated Anaconda endograft (Vascutek, Renfrewshire, Scotland) was introduced in 2010 and showed promising short-term results with high technical success and low morbidity rates. These researchers presented the mid-term results, with a minimum of 12 months follow-up, for all patients treated with the fenestrated Anaconda endograft in the Netherlands. Patients treated with the fenestrated Anaconda endograft between May 2011 and February 2015 were included. Follow-up consisted of computed tomography angiography at 1 month and 1 year, and duplex ultrasound yearly thereafter, with additional computed tomography angiography if indicated using a standard protocol. A total of 60 patients were included; 48 patients (80.0%) were treated for juxta-renal aneurysms, and 12 (20.0%) for short-neck infra-renal aneurysms. The mean aneurysm size was 64 ± 9 mm. A total of 140 fenestrations were incorporated. The median follow-up was 16.4 months (inter-quartile range [IQR], 11.9 to 27.4). The 30-day mortality was 3.4% (n = 2). Kaplan-Meier estimates for 1-year, 2-year, and 3-year survival were 91.4%, 89.5%, and 86.3%, respectively, with no aneurysm-related mortality during follow-up. Main body primary and secondary endograft patencies were 98.3% and 100%, respectively. Target vessel primary and secondary patencies were 95.0% and 98.6%, respectively. Early type IA endoleaks occurred in 7 patients (11.7%) and spontaneously resolved in all patients. At 1-year follow-up, 4 (6.7%) type II endoleaks persisted; 1 patient experienced aneurysm rupture due to a late type III endoleak attributable to a dislodged renal stent and subsequently underwent successful conversion to open surgery. The authors concluded that the fenestrated Anaconda is a viable therapeutic option for complex abdominal aortic aneurysms, with acceptable mortality and morbidity and low re-intervention rates contributing to good mid-term results. They noted that the occurrence of early type I endoleak was relatively common, but these resolved spontaneously in all patients, and long-term follow-up data are needed.
Timaran et al. (2017) stated that fenestrated endovascular aneurysm repair (FEVAR) is an alternative to open repair of complex aortic aneurysms. Despite promising short-term results, the technical complexities of this procedure remain a considerable challenge. The risk of technical failure with loss of visceral or renal arteries is prevalent even in the most experienced hands, leading to many patients with unfavorable anatomy being frequently denied FEVAR. These researchers adopted a new technique for FEVAR that involves retrograde brachial artery access and step-wise deployment of the endograft during target vessel catheterization, overcoming many anatomic limitations encountered from a trans-femoral (TF) approach. This technique, termed sequential catheterization amid progressive endograft deployment, has become the authors’ preferred approach for FEVAR. Moreover, they noted that currently available Food and Drug Administration-approved fenestrated endografts may not be amenable to this technique, as it requires pre-loaded wires incorporated into the endografts.
Falkensammer et al. (2017) stated that FEVAR allows for the extension of the proximal sealing zone above the renal arteries to an adequate, healthier segment of the aorta. This feature makes FEVAR an option for treating patients with a diseased aortic neck or type Ia endoleak after EVAR. These investigators presented a single-center experience with FEVAR for patients with an abdominal aortic endograft in-situ compared with primary FEVAR. They screened a prospectively held database on FEVAR patients treated with the fenestrated Anaconda device (Vascutek/Terumo, Inchinnan, Scotland, United Kingdom) at their institution for individuals who had previously undergone EVAR. Between April 1, 2013, and July 31, 2016, a total of 94 fenestrated Anaconda devices were implanted at their institution; 12 patients with prior EVAR were treated for pathology of the proximal neck: type I endoleak (n = 7), stent migration with aneurysm progression but no visible endoleak (n = 2), and progressive aortic disease at the level of the visceral segment (n = 3). When comparing redo cases and primary FEVARs, primary technical success rates were 58.3% and 87.8% (p = 0.02), and primary functional success rates were 91.7% and 95.1%, respectively (p = 0.62). The peri-operative rates of major deployment-related (14.6% and 16.7%) and systemic complications (8.5% and 8.3%) as well as 30-day mortality (6.1% and 0%; p = 0.5) were comparable between groups. After an average follow-up interval of 10 months (range of 0 to 43 months), no late occlusions of connecting stents were observed. The late re-intervention rates were 11.0% and 16.7%, respectively (p = 0.57). The authors concluded that the risk of failure to cannulate one or more visceral arteries through the respective fenestrations was increased in patients who had previously undergone EVAR. This was likely due to increased friction between the fenestrated endograft and the failing graft in-situ, which may impair the adaptation of the unsupported Anaconda device to the aortic wall. Consequently, fenestrations may not align perfectly with the respective openings of the visceral or renal arteries, and folding of the fabric may be increased, making cannulation of the fenestrations more difficult.
Georgiadis et al. (2017) noted that the established use of fenestrated and branched devices to treat complex aortic aneurysms as a first-line management option has been previously reported. These researchers reviewed the current literature on the use of fenestrated devices to treat complex abdominal and thoraco-abdominal type IV aortic aneurysms as a first-line management option. A literature search was performed, focusing on all aspects of the use and results of fenestrated stent-grafts (SGs) in patients with complex abdominal and type IV thoraco-abdominal aortic aneurysms, summarizing the available evidence. The use of fenestrated SGs for complex aortic aneurysm disease has grown significantly in recent years; SGs with fenestrations, scallops, and occasionally branches must be customized to each patient's anatomy and precisely deployed in-vivo. Bridging covered stents between the main graft and the target vessels ultimately exclude the aneurysm while preserving blood flow to vital organs. Multiple device morphologies have been used, incorporating the visceral arteries in various combinations. High technical success rates and satisfactory peri-operative outcomes have been reported, as well as mid- and long-term success and durability, including target vessel and branch stent perfusion, with data emerging mainly from high-volume specialized centers. The percentage of target vessels successfully perfused was reported between 90.5% and 100%; 30-day mortality was reported between 0% and 4.1%, while the lowest rates of type I or type III endoleaks were 2.5% and 1.3%, respectively. Migration rates were kept below 3%. Renal failure was the most frequent complication reported. Advances in SG technology have reduced but not eliminated secondary interventions. Outcomes depend primarily on the proximal extension of the disease, which also increases the complexity of the repair. A high level of expertise and organizational facilities are required for better mid- and long-term outcomes. The authors concluded that fenestrated EVAR (fEVAR) has been shown to be safe and effective in the short and mid-term follow-up. Remaining issues, including secondary interventions and the need for follow-up, are still within the range of those reported for EVAR, which continue to affect fEVAR for complex abdominal or type IV thoraco-abdominal aortic aneurysms.
Farber et al. (2017) reported prospective data on an off-the-shelf fenestrated endograft (Zenith p-Branch; Cook Medical, Bloomington, IN) from four centers for the treatment of patients with para-renal AAAs. Data were combined from four single-center investigational studies conducted in the United States and Europe. The p-Branch endograft consists of a proximal off-the-shelf component incorporating a scallop for the celiac artery, a superior mesenteric artery fenestration, and two conical pivot fenestrations to preserve flow to the renal vessels. The device is available in two configurations: a left renal fenestration at the same (configuration A) or lower (configuration B) longitudinal position than the right to accommodate varied patient anatomy. Between August 2011 and September 2015, a total of 76 patients (82% men; mean age of 72 years; 65 elective and 11 emergent) were enrolled, with 55% implanted with option A and 45% with B. The device was deployed successfully in all patients, and stents were placed in all target vessels except in three cases (1 elective, 2 emergent): a left kidney was sacrificed in one patient, and a right renal artery was left unstented in two patients during the index procedure. There was no 30-day mortality. During follow-up (mean of 25 ± 13 months), 10 late deaths occurred (6 elective, 4 emergent; none related to the device or procedure), and there were no ruptures or conversions to open repair; two patients experienced bowel ischemia; one case resolved with non-operative treatment, and one required superior mesenteric artery and celiac artery angioplasty and stent placement. Renal artery occlusion occurred in 8 patients (11%) and was deemed procedure-related in 63% (5/8) of these patients; four of these were successfully intervened on with preservation of renal function. The overall incidence of renal insufficiency was 7% (5/76); one patient developed renal failure requiring dialysis. The authors concluded that early results incorporating learning curves for physicians with a new device and delivery system indicated that the use of the Zenith p-Branch device is feasible and safe; however, long-term follow-up is needed to assess the effectiveness and durability of this treatment strategy and to refine the indications for use.
Oderich et al. (2017) examined the outcomes of manufactured fenestrated and branched endovascular aortic repair (F-BEVAR) endografts based on supra-celiac sealing zones to treat para-renal aortic aneurysms and thoraco-abdominal aortic aneurysms (TAAAs). A total of 127 patients (91 men; mean age of 75 ± 10 years) were enrolled in a prospective, non-randomized, single-center study using manufactured F-BEVAR from November 2013 to March 2015. Stent design was based on a supra-celiac sealing zone in all patients, with greater than or equal to 4 vessels in 111 (89%). Follow-up included clinical examination, laboratory studies, duplex ultrasound, and computed tomography imaging at discharge, 1 month, 6 months, and yearly. Endpoints adjudicated by an independent clinical event committee included mortality, major adverse events (any mortality, myocardial infarction, stroke, paraplegia, acute kidney injury, respiratory failure, bowel ischemia, blood loss of more than 1 L), freedom from re-intervention, and branch-related instability (occlusion, stenosis, endoleak, or disconnection requiring re-intervention), target vessel patency, sac aneurysm enlargement, and aneurysm rupture. There were 47 para-renal, 42 type IV, and 38 type I-III TAAAs with a mean diameter of 59 ± 17 mm. A total of 496 renal-mesenteric arteries were incorporated by 352 fenestrations, 125 directional branches, and 19 celiac scallops, with a mean of 3.9 ± 0.5 vessels per patient. Technical success of target vessel incorporation was 99.6% (n = 493/496). There were no 30-day or in-hospital deaths, dialysis, ruptures, or conversions to open surgical repair. Major adverse events occurred in 27 patients (21%). Paraplegia occurred in 2 patients (1 with type IV, 1 with type II TAAAs). Follow-up was greater than 30 days in all patients, greater than 6 months in 79, and greater than 12 months in 34. No patients were lost to follow-up. After a mean follow-up of 9.2 ± 7 months, 23 patients (18%) had re-interventions (15 aortic, 8 non-aortic), 4 renal artery stents were occluded, 5 patients had type Ia or III endoleaks, and none had aneurysm sac enlargement. Primary and secondary target vessel patency was 96% ± 1% and 98% ± 0.7%, respectively, at 1 year. Freedom from any branch instability and any re-intervention was 93% ± 2% and 93% ± 2% at 1 year, respectively. Patient survival was 96% ± 2% at 1 year for the entire cohort. The authors concluded that endovascular repair of para-renal aortic aneurysms and TAAAs using manufactured F-BEVAR with supra-celiac sealing zones was safe and efficacious; however, long-term follow-up is needed to assess the impact of 4-vessel designs on device-related complications and the progression of aortic disease.
Zeinali et al. (2018) stated that "more complex thoracoabdominal and juxta-renal abdominal aortic aneurysms can now be treated with new stent grafts and techniques." Fenestrated endovascular aortic aneurysm repair (FEVAR) with fenestrated stent grafts was initiated in their center after performing hundreds of cases of endovascular aortic repair. So far, four serial complex cases deemed inoperable (two juxta-renal abdominal aortic aneurysms, one thoracoabdominal aneurysm, and one thoracoabdominal pseudoaneurysm) have been treated with FEVAR. All these patients required custom-made stent grafts, which were designed and implanted successfully under general anesthesia in the catheterization laboratory. They were followed up for more than 1 year, with a median follow-up period of 23.0 months. There were no major in-hospital or short-term complications. Only one patient experienced midterm unilateral iliac artery thrombosis, which was successfully managed interventionally. Computed tomography angiography at 1 year’s follow-up showed that the stent grafts were patent and their visceral branch cover stents had no endoleak. Due to the limited number of procedures and the variety in patients’ conditions and clinical settings, reporting the outcome of every procedure remains challenging. This study was conducted at a single center with a limited number of cases in Iran.
Oderich from the Mayo Clinic (2018) stated that "endovascular repair of complex aneurysms involving the visceral arteries has become a reality." Fenestrated stent-grafts are increasingly utilized to treat para-renal and thoraco-abdominal aneurysms. The technique is safe, effective, and can be performed with high technical success and low risk of complications by experienced physicians. More than 8,000 patients have been treated with fenestrated and branched stent-grafts, and over 5,500 with iliac branch devices. Based on results from single-center reports, systematic reviews, and the U.S. prospective trial, technical success is high (greater than 98%) with low rates of type I and type III endoleak, migration, aneurysm rupture, and conversion to open repair. Branch patency averages greater than 95% with covered stents. These results should serve as a benchmark for comparison with alternative endovascular techniques for branch vessel incorporation, including debranching, snorkel, and physician-modified grafts. Long-term comparisons with open surgical repair are still required.
Wang et al. (2018) stated that the Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, IN) aortic stent graft system was approved for commercial use by the Food and Drug Administration (FDA) in April 2012. These researchers report their single-center experience of 100 consecutive patients treated with the ZFEN platform from October 2012 to March 2017. A retrospective review of their prospectively maintained fenestrated endovascular aneurysm repair (FEVAR) database at a tertiary care academic institution located in the Midwest United States was performed for descriptive analysis. All continuous variables were reported as a mean ± standard deviation and compared using two-sided Student t-tests. Categorical variables were compared using two-sided Fisher exact tests. All but one of the procedures were elective in nature. Overall intra-operative characteristics included a mean estimated blood loss of 388 ± 385 ml, fluoroscopy time of 63 ± 30 minutes, radiation dose of 437 ± 272 rad, contrast material volume of 99 ± 36 ml, and operative time of 236 ± 87 minutes. The average number of visceral arteries stented was 2.1 ± 0.5. Technical success was achieved in 98% of the patients. A statistically significant (p < 0.05) improvement in estimated blood loss (2.1-fold) was observed in the second half of their series. Interestingly, no improvements were made in terms of fluoroscopy time, radiation exposure, contrast material use, or operative time. However, procedural difficulty increased in the last half by the number of visceral arteries stented as a surrogate (1.9 versus 2.2; p < 0.05). The mean length of stay (LOS) was 3.6 ± 4.3 days. Peri-operative mortality at 30 days was 2%. Peri-operative morbidity included a 5% incidence of any bowel ischemia, 1% of spinal cord ischemia, 3% of renal failure requiring hemodialysis, 1% of stroke, and 4% of myocardial infarction (MI). The average follow-up was 1.7 ± 1.4 years. Re-intervention during the follow-up phase was 20%. Of the 209 visceral arteries stented, the investigators noted 6 instances of stent thrombosis, 6 of kinking or stenosis, and 1 of stent fracture during follow-up. Endoleak, most commonly type II, was present or could not be excluded in 15% of all FEVARs at the last available computed tomography angiography (CTA). The authors concluded that in their experience, FEVAR with the ZFEN system continued to be safe and effective; however, there was a significant rate of re-intervention observed, and close monitoring is fundamental to maintaining good clinical results. They noted that the main drawbacks of this study were its retrospective design, being a single-center study, and mid-term results; well-designed studies with long-term follow-up are needed to validate these findings.
Armstrong et al. (2014) noted that patients with large abdominal aortic aneurysms (AAAs) are typically offered reparative treatment due to the high mortality risk associated with these conditions. However, there is uncertainty regarding the treatment of juxta-renal AAAs (JRAAAs) and thoracoabdominal aortic aneurysms (TAAAs). Endovascular repair of an abdominal aortic aneurysm (EVAR) is often perceived as safer and easier than open surgical repair (OSR). Nevertheless, the endovascular treatment of JRAAAs or TAAAs necessitates specially manufactured stent grafts with openings to allow blood flow to the branches of the aorta. The investigators explained that there is an increasing demand for fenestrated EVAR (fEVAR) and branched EVAR (bEVAR), but it remains unclear whether the additional costs associated with these procedures are justified by the benefits for patients. To address this, the researchers conducted a systematic evidence review to assess the clinical effectiveness, safety, and cost-effectiveness of fEVAR and bEVAR compared to conventional treatment (i.e., no surgery) or OSR for JRAAAs and TAAAs. The systematic review was funded by the National Institute for Health Research Health Technology Assessment Programme. They searched resources from inception to October 2013, including MEDLINE (OvidSP), EMBASE (OvidSP), and the Cochrane Central Register of Controlled Trials (Wiley), as well as the NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost) for cost-effectiveness. Conference abstracts were also included in the search. Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative. The searches retrieved 5,253 records before deduplication, with 1,985 duplicate records removed. Of the remaining 3,268 records, 3,244 were excluded based on titles and abstracts, leaving 24 publications to be ordered. All 24 studies were ultimately excluded as none met the inclusion criteria. Sixteen studies were excluded due to study design, six due to intervention, and two due to comparator issues. Five out of the 16 studies excluded on study design reported a comparison, but all acknowledged that they had groups that were not comparable at baseline, as they had selectively assigned younger, fitter patients to OSR. For cost-effectiveness, searches identified 104 references before deduplication, with 34 duplicates removed. Of the remaining 70 records, seven were included for full assessment based on initial screening, but after a full-text review, no studies were included. Due to the lack of clinical effectiveness evidence and the difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead, a detailed description of modeling methods was provided. The investigators concluded that despite a thorough search, no studies met the inclusion criteria, and all studies comparing fEVAR or bEVAR with OSR or no surgery explicitly selected patients based on prognosis, indicating that the populations for each comparator were not the same. They recommended at least one clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery, which should also collect data for a CEA.
O'Donnell et al. (2020) compared outcomes of fenestrated endovascular aneurysm repair (FEVAR) and open repairs of complex abdominal aortic aneurysms (cAAA). The investigators noted that FEVAR has emerged as an alternative to open surgery for treating cAAA, but direct comparisons are limited. They studied all repairs of intact or symptomatic cAAA in the Vascular Quality Initiative between 2012 and 2018, excluding chimney/snorkel techniques and any devices implanted under Investigational Device Exemption studies. The investigators compared open repairs, commercially available FEVAR devices, and physician-modified endografts (PMEG) using inverse probability weighting. As a secondary analysis, they compared PMEG separately. The study identified 3,253 cAAA repairs: 2,125 open (65%), 877 FEVAR (27%), and 251 PMEG (8%). Patients undergoing FEVAR were older, had larger aneurysms, and more comorbidities. Propensity-weighted perioperative mortality was similar between open repair and FEVAR (4.7% vs. 3.3%, respectively, P = 0.17), but open repair was associated with higher rates of myocardial infarction (5.0% vs. 3.0%, P = 0.03), acute kidney injury (25% vs. 16%, P < 0.001), and new dialysis (4.3% vs. 2.1%, P = 0.003). However, propensity-weighted long-term mortality was higher following FEVAR [Hazard Ratio (HR) 1.7 (1.1-2.6), P = 0.02]. Although outcomes of commercially available FEVAR and PMEG were similar, there was a trend toward higher long-term mortality with PMEG compared to FEVAR [HR 1.7 (0.9-3.1), P = 0.09]. The investigators concluded that in patients undergoing cAAA repair, open surgery was associated with higher overall survival than FEVAR, with similar perioperative mortality, but longer lengths of stay and higher rates of postoperative renal dysfunction and myocardial infarction. PMEG were associated with similar perioperative results as commercially available FEVAR, but further study is needed to establish their long-term durability.
Li et al. (2016) noted that juxta-renal aortic aneurysms (JAA) account for approximately 15% of abdominal aortic aneurysms. Both fenestrated endovascular aneurysm repair (FEVAR) and chimney endovascular aneurysm repair (CH-EVAR) are effective methods to treat JAAs, but the comparative effectiveness of these treatment modalities is unclear. The authors searched the PubMed, Medline, Embase, and Cochrane databases to identify English language articles published between January 2005 and September 2013 on the management of JAA with fenestrated and chimney techniques to conduct a systematic review comparing outcomes of patients with JAA treated with the two techniques. They compared nine F-EVAR cohort studies including 542 JAA patients and eight CH-EVAR cohorts with 158 JAA patients regarding technique success rates, 30-day mortality, late mortality, endoleak events, and secondary intervention rates. The results of this systematic review indicated that both fenestrated and chimney techniques are attractive options for JAA treatment, with encouraging early and mid-term outcomes.
Yaoguo et al. (2017) reviewed data pertaining to fenestrated endograft techniques and chimney stent repair of complex aortic aneurysms for comparative analysis of outcomes. A comprehensive search of relevant databases was conducted to identify articles in English related to the treatment of complex aortic aneurysms with fenestrated endovascular aneurysm repair and chimney stent repair, published until January 2015. A total of 42 relevant studies and 2,264 patients with aortic aneurysms undergoing fenestrated endovascular aneurysm repair and chimney stent repair were included in the review, involving 4,413 vessels. The cumulative 30-day mortality was 2.4% for fenestrated endovascular aneurysm repair and 3.2% for chimney stent repair (p = 0.459). The follow-up aneurysm-related mortality was 1.4% for fenestrated endovascular aneurysm repair and 3.2% for chimney stent repair (p = 0.018), and target organ dysfunction was 5.0% for fenestrated endovascular aneurysm repair and 4.0% for chimney stent repair, respectively (p = 0.27). A total of 156 vessels showed restenosis or occlusion after primary intervention (3.6% for fenestrated endovascular aneurysm repair and 3.4% for chimney stent repair, respectively, p = 0.792). The cumulative type I endoleak was 2.0% (38/1884) after fenestrated endovascular aneurysm repair compared with 3.4% (13/380) after chimney stent repair (p = 0.092), and the type II endoleak was 5.4% (102/1884) and 5.3% (20/380), respectively (p = 0.905). Approximately, 1.1% and 1.6% increases in aneurysm size were observed following fenestrated endovascular aneurysm repair and chimney stent repair, respectively (p = 0.437). The re-intervention frequency was 205 cases after fenestrated endovascular aneurysm repair and 19 cases after chimney stent repair, respectively (11.7% vs. 5.6%, p = 0.001). The authors concluded that both fenestrated endovascular aneurysm repair and chimney stent repair are safe and effective in treating patients with complex aortic aneurysms. A higher aneurysm-related mortality was observed in chimney stent repair, while fenestrated endovascular aneurysm repair was associated with a higher re-intervention rate.
Rao et al. (2015) observed that open repair is the gold standard management for juxta-renal aneurysms, while fenestrated endovascular aneurysm repair (FEVAR) is indicated for high-risk patients. The long-term outcomes of FEVAR are largely unknown, and there is no Level I comparative evidence. The authors conducted a systematic review and meta-analysis of case series to compare elective juxta-renal aneurysm surgery by open repair and FEVAR. They performed a systematic literature search for all published studies on elective repair of juxta-renal aneurysms by FEVAR and open repair. The MEDLINE, EMBASE, and Cochrane databases were searched from 1947 to April 2013. Exclusion criteria included case series of fewer than 10 patients or ruptured aneurysms. The primary outcomes were perioperative mortality and postoperative renal insufficiency, while secondary outcomes included secondary reinterventions and long-term survival. The authors identified 35 case series with data on 2,326 patients. Perioperative mortality was 4.1% in both open repair and FEVAR case series (odds ratio for open repair vs. FEVAR, 1.059; 95% confidence interval, 0.642-1.747; P = .822). Postoperative renal insufficiency was not significantly different (odds ratio for open repair vs. FEVAR, 1.136; 95% confidence interval, 0.754-1.713; P = .542). FEVAR patients had higher rates of secondary reintervention, renal impairment during follow-up, and lower long-term survival compared with open repair patients. The authors concluded that FEVAR and open repair have similar short-term outcomes but diverging long-term outcomes that may be secondary to the selection bias of FEVAR being offered to high-risk patients. FEVAR is a favorable option for high-risk patients, while open repair remains the gold standard.
Ou et al. (2015) stated that fenestrated endovascular repair is an alternative to open repair in managing juxta-renal aortic aneurysms and short-neck abdominal aortic aneurysms (AAAs). The investigators sought to examine the evidence in published literature on the use of fenestrated endovascular stent grafts in the treatment of juxta-renal and short-neck AAAs. They formulated a systematic review under the guidance of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles published from January 1996 to October 2014 in English were included. They systematically searched and reviewed published studies on fenestrated endovascular stent grafts for treating juxta-renal and short-neck AAAs through a computerized search of PubMed and Ovid MEDLINE, along with cross-referencing. A total of 529 non-duplicated publications were identified, but only 15 articles were eligible for qualitative analysis, involving 763 patients and 2,040 target vessels. Twelve studies were included in cohort studies with a short or medium follow-up period (median range, 6-67 months). The mean 30-day and late follow-up mortality rates were 1.7% (range, 0-4%) and 20.1% (range, 4-50%), respectively, with 5.3% of late deaths being aneurysm-related. A total of 74 target vessels (3.6%) were lost across all studies, with 65 of them (87.8%) lost postoperatively. Overall, 28.8% of patients experienced renal dysfunction postoperatively, while 2.5% required dialysis. Target vessel events and endoleaks were the two major indications for reintervention, accounting for 63.8%. Fourteen aneurysm sacs (1.8%) were continuously enlarged during follow-up, with half attributed to type II endoleaks. Migration of the proximal fenestration component was reported at 3.0%. One registry study reported 4.1% early mortality, higher than any cohort studies, while the target vessel loss was relatively low (1.6%). Freedom from late secondary intervention decreased from 90% at year 1 to 70% at year 3. Two non-random controlled comparative studies showed no definitive superiority of fenestrated repair over open surgery. The authors concluded that contemporary published literature does not provide a high enough level of evidence to warrant a change in treatment guidelines for juxta-renal or short-neck aneurysms. Fenestrated endovascular repair is a safe and efficacious treatment, particularly for those deemed surgically high risk. Growing experience and innovation in stent grafts are essential for the advancement of fenestrated grafting.
Kamman et al. (2015) stated that the optimal management strategy for chronic type B aortic dissections (CBAD) is unknown. Therefore, the authors systematically reviewed the literature to compare the results of open surgical repair (OSR), standard thoracic endovascular aortic repair (TEVAR), or branched and fenestrated TEVAR (BEVAR/FEVAR) for CBAD. They searched the EMBASE and MEDLINE databases for eligible studies between January 2000 and October 2015. Studies describing outcomes of OSR, TEVAR, B/FEVAR, or all, for CBAD patients initially treated with medical therapy were included. Primary endpoints were early mortality, and one-year and five-year survival. Secondary endpoints included the occurrence of complications. Additionally, a Time until Treatment Equipoise (TUTE) graph was constructed. Thirty-five articles were selected for systematic review, identifying a total of 1,081 OSR patients, 1,397 TEVAR patients, and 61 B/FEVAR patients. Early mortality ranged from 5.6% to 21.0% for OSR, 0.0% to 13.7% for TEVAR, and 0.0% to 9.7% for B/FEVAR. For OSR, one-year and five-year survival ranged from 72.0% to 92.0% and 53.0% to 86.7%, respectively. For TEVAR, one-year survival was 82.9% to 100.0% and five-year survival was 70.0% to 88.9%. For B/FEVAR, only one-year survival was available, ranging from 76.4% to 100.0%. The most common postoperative complications included stroke (OSR 0.0% to 13.3%, TEVAR 0.0% to 11.8%), spinal cord ischemia (OSR 0.0% to 16.4%, TEVAR 0.0% to 12.5%, B/FEVAR 0.0% to 12.9%), and acute renal failure (OSR 0.0% to 33.3%, TEVAR 0.0% to 34.4%, B/FEVAR 0.0% to 3.2%). The most common long-term complications after OSR included aneurysm formation (5.8% to 20.0%) and new type A dissection (1.7% to 2.2%). Early complications after TEVAR included retrograde dissection (0.0% to 7.1%), malperfusion (1.3% to 9.4%), cardiac complications (0.0% to 5.9%), and rupture (0.5% to 5.0%). No short-term aortic rupture or malperfusion was observed after B/FEVAR. Long-term complications included malperfusion (6.5%) and endoleaks (0.0% to 66.7%). Reintervention rates after OSR, TEVAR, and B/FEVAR were 5.8% to 29.0%, 4.3% to 47.4%, and 0.0% to 53.3%, respectively. The TUTE for OSR was 2.7 years, for TEVAR 9.9 months, and for B/FEVAR 10.3 months. The authors stated that they found a limited early survival benefit of standard TEVAR over OSR for CBAD. Complication rates after TEVAR are higher, but complications after OSR are usually more serious. Initial experiences with B/FEVAR show its feasibility, but long-term results are needed to compare it to OSR and standard TEVAR. The authors concluded that the optimal treatment of CBAD remains debatable and merits a patient-specific decision. TUTE seems a feasible and useful tool to better understand management outcomes of CBAD.
An international assessment by Health Technology Scotland (2018) found higher perioperative morbidity with open surgical repair, but higher reintervention rates with fenestrated/branched grafts compared to open surgical repair. Most data are derived from retrospective case series, with only one prospective comparative study identified. They also noted the lack of long-term data for the fenestrated grafts. Based on the single prospective comparative study, there were no significant differences in 30-day mortality when comparing open surgery to fenestrated/branched stent grafts.
An international evidence review by NICE (2018) found, based on "low quality evidence," that complex endovascular repair of aortic aneurysms was associated with a shorter hospital stay than open surgical repair. However, based on "very low quality evidence," they could not differentiate differences in 30-day mortality between complex EVAR and open surgical repair, nor could they differentiate between rates of hemodialysis, pneumonia, stroke, and reintervention rates between patients treated by complex EVAR and those treated by open repair. These conclusions were based on the only prospective comparative study of complex EVAR, which followed 90 patients for a mean follow-up of 15.2 months. The assessment also found, based on modeling, that endovascular repair of complex aortic aneurysms was dominated by no intervention, meaning that complex EVAR resulted in higher costs and fewer quality-adjusted life years (QALYs) than no intervention. The report concluded: "The committee noted that the evidence comparing complex EVAR with open surgical repair was extremely limited in quantity and quality. No randomized controlled trials (RCTs) were identified, and the single non-randomized comparative study that met this review’s inclusion criteria was small in size and only assessed mortality rates at 30-day follow-up. The results of the study, coupled with results from a new health economic model developed for this population, led the committee to conclude that there was no evidence that complex EVAR yields a net advantage over open surgery. However, the committee was mindful that longer-term evidence from large RCTs could clarify the clinical utility of complex EVAR and inform future health economic modeling. Thus, they recommended that the procedure should not be performed outside the confines of an RCT."
Bifurcated-Bifurcated Aneurysm Repair of Aorto-Iliac Aneurysms
Shin and Starnes (2017) noted that up to 40% of AAAs have co-existent iliac artery aneurysms (IAAs). In the past, successful endovascular repair required internal iliac artery (IIA) embolization, which can lead to pelvic or buttock ischemia. These investigators described a technique that uses a readily available solution with a minimally altered off-the-shelf bifurcated graft in the IAA to maintain IIA perfusion. From August 2009 to May 2015, a total of 14 patients with AAAs and co-existing IAAs underwent repair with a bifurcated-bifurcated approach. A 22-mm or 24-mm bifurcated main body device was used in the IAA with extension of the "contralateral" limb into the IIA. Intra-operative details including operative time, fluoroscopy time, and contrast agent use were recorded. Outcome measures assessed were operative technical success and a composite outcome measure of IIA patency, freedom from re-intervention, and clinically significant endoleak at 1 year. Technical success was achieved in 93% of patients, with successful treatment of the AAA and IAA and preservation of flow to at least 1 IIA. The procedure was performed with a completely percutaneous bilateral femoral approach in 92% of patients; 3 patients had a type II endoleak on initial follow-up imaging, but none was clinically significant. There were no cases of bowel ischemia or erectile dysfunction; 1 patient had buttock claudication ipsilateral to IIA coil embolization (contralateral to bifurcated iliac repair and preserved IIA) that resolved by 6-month follow-up; 2 patients required re-interventions; 1 patient presented to his first follow-up visit on post-operative day 25 with thrombosis of the right external iliac limb ipsilateral to the bifurcated iliac repair, which was successfully treated with thrombectomy and stenting of the limb. This same patient presented at 83 months with growth of the preserved IIA to 3.9 cm and underwent coil embolization of the aneurysm. Another patient presented for surveillance 44 months after his original repair with component separation of the mating stent and the iliac bifurcated stent grafts. This was treated with a limb extension and endo-anchors to fuse the endografts. Of the 13 patients who underwent bifurcated-bifurcated repair, 100% of the preserved IIAs remained patent at last follow-up. The composite outcome measure of IIA patency and freedom from re-intervention and clinically significant endoleak at 1 year was 92% (n = 12/13). The authors concluded that in this small retrospective review, bifurcated-bifurcated aneurysm repair of aorto-iliac aneurysms with preservation of perfusion to the IIA was technically feasible and safe with good short-term and mid-term results in male patients. These preliminary findings need to be validated by well-designed studies.
Endovascular Aneurysm Sealing (e.g., the Nellix Device) for the Treatment of Abdominal Aortic Aneurysms
Bockler and associates (2015) noted that despite advancements in endograft devices, operator technique, and patient selection, endovascular repair has not achieved the long-term durability of open surgical aneurysm repair. Persistent or recurrent aneurysm sac flow due to failed proximal sealing, component failure, or branch vessel flow contributes to a significant rate of re-intervention following endovascular repair. The Nellix device (Endologix, Irvine, CA) features a unique design that employs polymer-filled EndoBags surrounding the endograft flow lumens, which seals the aneurysm sac space and may reduce complications from persistent sac flow.
Bockler et al. (2015) reported on a retrospective analysis representing the initial experience with the Nellix device in consecutive patients treated in real-world practice. This study was conducted at six clinical centers in Europe and one in New Zealand during the initial commercialization period of the Nellix device. Patients underwent evaluation with CT and other imaging modalities following local standards of care. Selection for treatment with Nellix was based on each institution's endovascular repair protocol. Clinical and imaging endpoints included technical success (successful device deployment and absence of any endoleak at completion angiography), freedom from all-cause and aneurysm-related mortality, endoleak by type, limb occlusion, aneurysm rupture, and re-intervention. During a 17-month period, a total of 171 patients with AAAs were treated with the Nellix device and observed for a median of 5 months (range of 0 to 14 months). The cohort consisted of 153 men and 18 women with a mean age of 74 ± 7 years, having aneurysms with a mean diameter of 61 ± 9 mm, an average infra-renal neck length of 28 ± 15 mm, and infra-renal angulation of 37 ± 22 degrees. Technical success was achieved in all but two patients (99%); one patient had a type Ib endoleak and another had a type II endoleak. At the last available follow-up, type Ia endoleak was observed in five patients (3%), type Ib endoleak in four patients (2%), and type II endoleak in four patients (2%). There were eight limb occlusions (5%), with seven evident at the 1-month follow-up visit. Aneurysm-related re-interventions were performed in 15 patients (9%). There were no aneurysm ruptures or conversions to open surgery. The authors concluded that this first multi-center post-market report of the Nellix device for infra-renal AAA repair demonstrated satisfactory results during the initial learning phase of this new technology, with a high rate of aneurysm exclusion and low frequency of complications. They stated that more definitive conclusions on the value of this novel device await the results of the ongoing Nellix EVAS FORWARD Global Registry and the EVAS FORWARD investigational device exemption trial.
Carpenter and co-workers (2017) stated that the Nellix EndoVascular Aneurysm Sealing (EVAS) System (Endologix, Inc., Irvine, CA) represents a novel approach to AAA treatment, utilizing polymer to fill the AAA sac. These researchers reported the 1-year results of the IDE pivotal trial, in which eligible patients were treated at 30 sites in the U.S. and Europe. Inclusion criteria required an asymptomatic infra-renal AAA, with a neck length of greater than or equal to 10 mm and less than or equal to a 60° angle, iliac artery blood lumen diameter of 9 to 35 mm, access artery diameter of greater than or equal to 6 mm, and serum creatinine of less than or equal to 2 mg/dL. Follow-up included CT angiography scans at 30 days, 6 months, and 1 year, evaluated by a core laboratory. The primary safety endpoint was 30-day major adverse events (MAEs), compared with a performance goal of less than 56% (the Society for Vascular Surgery open repair control group rate). The primary effectiveness endpoint was treatment success at 1 year, compared with a performance goal of greater than 80%. Treatment success required procedural technical success and the absence of AAA rupture during follow-up, conversion to open surgical repair, endoleak (type I or III) at 1 year, migration of greater than 10 mm causing complications or requiring secondary intervention, aneurysm enlargement, or secondary procedures through 1 year for resolution of endoleak, device obstruction or occlusion, or device defect. Of 150 treated patients, 149 (99.3%) completed 1-year follow-up. The MAEs rate at 30 days was 2.7% (95% CI: 0.7% to 6.7%), satisfying the primary safety endpoint (less than 56%). The 1-year treatment success was 94% (95% CI: 88.6% to 97.4%), achieving the primary effectiveness endpoint (greater than 80%). At 1 year, key secondary outcomes included 6.7% MAEs, 4.7% serious device-related events, 1.3% AAA-related mortality, 3.7% secondary interventions, and 0.7% surgical conversions. MAEs through 1 year included death (n = 6), stroke (n = 3), bowel ischemia (n = 2), renal failure (n = 2), respiratory failure (n = 2), and myocardial infarction (n = 1). One iatrogenic AAA rupture occurred, and one AAA rupture was reported during follow-up. AAA sac enlargement (greater than 5 mm) was observed in 1.5% of patients at 1 year. Endoleaks were present in four patients (3.1%) at 1 year (1 type Ib and 3 type II). Migration of greater than 10 mm occurred in three patients (2.3%), but none required secondary intervention. The authors concluded that outcomes with the Nellix EVAS System for AAA repair were encouraging, with primary safety and effectiveness endpoints met. They noted that low morbidity, low mortality, and high procedural and treatment success were achieved despite the learning curve and unique risks associated with a new device and technique; long-term follow-up is ongoing.
Youssef and associates (2017) examined the technical success and clinical outcomes of re-interventions using the Nellix EVAS System to treat complications after EVAR. A total of 15 consecutive patients (mean age of 79 years; 14 men) with prior EVAR were treated with EVAS between March 2014 and December 2015 at two institutions. The failed prior EVARs included 13 bifurcated endografts, one bifurcated graft plus fenestrated cuff, and one tube endograft. Endoleaks were the predominant indications for re-intervention: type Ia in 10 patients and type III in 5 patients (3 type IIIa and 2 type IIIb). All patients presented with progressive aortic aneurysms (median diameter of 7.85 cm; range of 6.5 to 11 cm); eight patients were treated on an urgent or emergency basis (six symptomatic aneurysms and two contained ruptures). All patients underwent Nellix relining of the failed stent-graft; ten had chimney (Ch) procedures in combination with EVAS (chEVAS) due to inadequate proximal landing zones. Technical success was achieved in 100% of cases. All endoleaks were successfully sealed, and no additional interventions were needed. No further endoleaks after EVAS or chEVAS were recorded. Endobag protrusion occurred in one case without sequelae. One elderly patient with a ruptured aneurysm died from multiple organ failure two months post-operatively. One renal artery guide-wire injury led to nephrectomy due to active bleeding. No re-interventions, aneurysm-related mortalities, graft thrombosis, endoleaks, or chimney graft occlusions were observed during a median follow-up of 8 months (range of 3 to 24 months). The authors concluded that the preliminary experience demonstrated that the use of EVAS/chEVAS was feasible for treating failed EVAR. They stated that this technique may serve as a bailout or alternative treatment when other established methods are infeasible or unavailable.
Unlu and colleagues (2017) stated that despite improvements in endograft design, operator skills, and patient selection, late complications associated with EVAR and the need for re-interventions remain significant challenges. These complications diminish the early benefits of EVAR over open aneurysm repair during long-term follow-up. The recently introduced endovascular aneurysm sealing (EVAS) technology aims to reduce these EVAR-related complications. The investigators reviewed the EVAS technique, its indications, and possible applications, providing a critical appraisal of clinical outcomes. The authors concluded that EVAS is a promising technique for treating AAAs, with encouraging early efficacy data in patients with straightforward anatomy. They noted that the Nellix device is still under development, and long-term results are needed.
Brown and co-workers (2017) noted that there has been a clear shift towards endovascular repair of AAAs due to better peri-operative outcomes compared to open surgical repair. However, follow-up has continued to reveal relatively high rates of endoleaks and re-interventions. Improvements in endovascular stent-grafts aim to decrease these complications. In a systematic review, these investigators determined the early outcomes of AAA sealing. They followed standard PRISMA guidelines and performed a literature search to extract any publication related to the endovascular aneurysm sealing device. The total number of patients in this systematic review of 11 studies was 684, with a mean age of 73.2 years, and 587 (88.0%) were men. The majority were undergoing elective procedures (n = 606, 91.0%), with the remainder as emergencies (n = 30, 4.5% as ruptures; n = 30, 4.5% as symptomatic). The technical success rate, including emergency cases, was 99.1%; the 30-day mortality rate was 2.6% (n = 17) including all cases, and 1.0% (n = 6) including elective cases only; the 30-day endoleak detection rate was 4.7% (n = 31) including all cases, and 4.8% (n = 29) including elective cases only; the 30-day aneurysm-related re-intervention rate was 5.7% (n = 38) including all cases, and 4.6% (n = 28) including elective cases only. There was no conversion to open surgery within 30 days post-op in the elective cases. There were three delayed conversions to open surgery within 30 days and one report of stent migration causing rupture in the emergency setting. The authors concluded that this novel endovascular aneurysm-sealing device for AAA repair has shown respectable early outcomes. Good technical success rates, in both elective and emergency settings, low rates of all-type endoleaks, and low re-intervention rates have all been demonstrated. They stated that endovascular aneurysm sealing is proving to be a safe alternative to open and endovascular aneurysm repair; however, longer-term follow-up results are needed to evaluate the safety and effectiveness of the device in the long term.
Cerebrospinal Fluid Drainage During Endovascular Aortic Aneurysm Repair
Suarez-Pierre and associates (2019) noted that spinal cord ischemia is one of the most devastating complications associated with thoracic endovascular aortic repair (TEVAR). Spinal fluid drainage has been proposed as a viable method to reduce the risk of spinal cord ischemia, but there is limited data to support its routine use. The investigators examined the association between pre-operative spinal fluid drainage and the risk of spinal cord ischemia following TEVAR. They queried the Vascular Quality Initiative (VQI) TEVAR module for adult patients (≥18 years) undergoing TEVAR (covering zones 0 to 5) between September 2014 and March 2018. Patients with pre-operative spinal mal-perfusion, aortic rupture on presentation, and connective tissue disorders were excluded. One-to-one propensity matching was employed to balance patients on 44 separate dimensions using the nearest neighbor principle to compare those with and without pre-operative spinal drainage. The primary endpoint was spinal cord ischemia present at discharge; secondary outcomes included 30-day mortality and prolonged intensive care unit (ICU) stay (greater than 7 days). Among 4,287 patients who underwent TEVAR (mean age 67.1 [SD, 13.7] years; 1,665 [38.8%] women and 2,622 [61.2%] men), 2,076 had a spinal drain placed. Propensity matching yielded 1,292 pairs with adequate co-variate balance (all 44 absolute standardized differences <0.1). In the 2,584 propensity-matched patients, spinal drain placement was associated with a reduced risk of spinal cord ischemia (1.5% vs. 2.5%; risk-adjusted OR, 0.47; 95% CI: 0.24 to 0.89; p = 0.02). The rates of 30-day mortality (4.5% vs. 5.0%; risk-adjusted OR, 0.67; 95% CI: 0.44 to 1.01; p = 0.05) and prolonged ICU stay (7.0% vs. 5.7%; risk-adjusted OR, 1.10; 95% CI: 0.84 to 1.45; p = 0.48) did not differ based on spinal drain placement. The crossover rate was 10% (127/1,292), and those with post-operative drain placement had a 20% (26/127) spinal cord ischemia rate at discharge. The authors concluded that among patients undergoing thoracic and thoraco-abdominal endovascular aortic repair, pre-operative placement of a spinal drain was associated with a reduced risk of spinal cord ischemia compared to no drain. They stated that cerebrospinal fluid drainage (CSFD) as a rescue measure does not provide the same protection as routine pre-operative placement. Further investigation, including randomized controlled trials (RCTs), is needed to more definitively determine the role of spinal drainage in TEVAR.
The authors acknowledged that this study was subject to unexpected confounders due to its observational design; despite extensive risk adjustment, the findings may be considered associative in nature. Large multi-institutional data sets are prone to variability in data entry and miscoding; however, the endpoints examined in this study were concise and interpreted uniformly across practices. Participation in the VQI registry was voluntary; however, participating centers were required to submit 100% of their cases to avoid selection bias. In the multi-variable model, left subclavian artery re-vascularization did not show an association with a decreased rate of spinal cord ischemia, which may reflect the substantial proportion of patients (approximately 30%) with missing values. Factors such as avoidance of hypotension, intra-operative neuromonitoring for signs of spinal cord ischemia, peri-operative hypothermia, technique of drain placement, pressure thresholds for CSF evacuation, and duration of use were not standardized in this multi-institutional study. Complications specific to pre-operative CSFD were not examined.
Malloy and colleagues (2020) noted that spinal cord injury (SCI) is a known complication of aortic aneurysm repair. Previous reports indicated that CSFD may reduce the incidence of SCI during open aortic aneurysm repair, but its utility in endovascular repair remains poorly understood. In a systematic review, these investigators examined the protocols and outcomes of CSFD in patients undergoing endovascular aortic aneurysm repair. They employed PRISMA guidelines to conduct a systematic literature review, searching PubMed, Scopus, Ovid, Cochrane, and Embase for articles published since 2016 using search terms such as "(cerebrospinal fluid diversion OR CSF diversion OR lumbar drain OR subarachnoid drain OR spinal) AND (aortic aneurysm AND thoracic AND endovascular OR TEVAR)." A total of 92 articles were identified and screened by two independent reviewers, with 23 studies meeting the criteria for full-text review after initial screening. Ultimately, eight studies met full inclusion criteria for final analysis; six studies reported the incidence of SCI in patients with CSFD, and two compared SCI incidence between patients with and without CSFD. The protocols for drainage most commonly included draining to a target pressure intra- and post-operatively, typically between 8 and 12 mm Hg. The incidence of SCI ranged from 0% to 17% in patients with CSFD and from 0% to 50% in those without CSFD. Rates of CSFD-related complications ranged from less than 1% to 28%. The authors concluded that there may be a protective benefit of CSFD in preventing SCI, but significant variation in drain placement protocols exists, along with potential bias in the reviewed data. They stated that higher quality studies on the role of CSFD in endovascular aortic aneurysm repair are needed.
Karkkainen and co-workers (2020) examined the rates and risk factors of complications related to CSFD during the first stage and completion of fenestrated-branched endovascular aortic repair (F-BEVAR) of para-renal and thoraco-abdominal aortic aneurysms. These investigators reviewed the outcomes of 293 consecutive patients enrolled in a prospective, non-randomized study examining F-BEVAR outcomes between 2013 and 2018. Patients who received CSFD during first-stage thoracic endovascular aortic repair, index F-BEVAR, or completion of temporary aneurysm sac perfusion procedures were included in the analysis. CSFD complications were graded as severe or moderate if they were life-threatening, escalated the level of care, or prolonged the hospital stay. The presence of substantial degenerative lumbar disease (DLD) was identified based on pre-operative CT review. Endpoints included technical difficulties during CSFD placement and CSFD-related complications. A total of 187 patients (mean age of 73 ± 8 years; 70% men) treated for 20 para-renal and 167 thoraco-abdominal aortic aneurysms received CSFD in 240 procedures, including 51 first-stage thoracic endovascular aortic repairs, 184 index F-BEVARs, and 5 completion temporary aneurysm sac perfusion procedures. Nineteen patients (10%) experienced 22 CSFD-related complications after 21 aortic procedures (9%). Complications were graded as severe-to-moderate in 17 patients (9%). There were 12 patients (6%) with intra-cranial hypotension, including 3 (2%) who had intra-cranial hemorrhage and 9 (5%) with post-dural puncture headache requiring blood patches in 6. Another 6 patients (3%) developed spinal hematomas, resulting in paraplegia in 2 (1%) and transient paraparesis in 2 (1%); 1 patient had CSF leakage from the puncture site (no intervention required); 4 patients experienced bleeding during attempted drain placement, which required postponement of F-BEVAR. Technical difficulties were observed in 57 drain insertions (24%), more often in patients with DLD than in those without DLD (35/113 [31%] vs. 22/121 [18%]; p = 0.03). Fluoroscopic guidance was used in 44 drain placements (18%), resulting in a lower rate of technical difficulties compared to the blind approach (9% vs. 28%; p = 0.01). There was a statistically non-significant trend toward more complications in patients with technical challenges (14% vs. 7%; p = 0.10). Of the 13 study patients who developed SCI during aortic procedures, 4 (31%) were attributed to CSFD. The authors concluded that although CSFD is widely used to prevent ischemic SCI during complex aortic repair, the risk of major CSFD-related complications is not negligible and should be carefully weighed against its potential benefits; one-third of SCIs were caused by CSF drain placement. The use of fluoroscopic guidance may decrease the risk of CSFD-related complications.
The authors acknowledged that the main drawback of this study was the retrospective nature of collecting CSFD-related data. Although the note template for spinal drain insertion procedures was fairly well-structured in the authors’ electronic medical record, there was a possibility of variation in reporting between neuro-radiologists and anesthesiologists, as these specialists used different note templates. The association between CSFD and intra-cranial hemorrhage was often unclear, making causality difficult to establish; the investigators agreed on the etiology of two intra-cranial hemorrhages, while one remained inconclusive. CT scans were often reported in a standardized manner by the radiologists; however, DLD was not well-defined in this retrospective study, as it primarily relied on the radiology report, and it was very common in middle-aged to older individuals. Furthermore, the number of endpoint events was too small to perform meaningful multi-variable analyses.
Early Repair Versus Surveillance with Repair on Subsequent Enlargement in Individuals with Asymptomatic Abdominal Aortic Aneurysms
Ulug and colleagues (2020) noted that an abdominal aortic aneurysm (AAA) is characterized by an abnormal ballooning of the major abdominal artery. Some AAAs present as emergencies requiring surgical intervention, while others remain asymptomatic. The treatment of asymptomatic AAAs is influenced by various factors, with aneurysm size being particularly important, as the risk of rupture increases with size. Large asymptomatic AAAs (greater than 5.5 cm in diameter) are typically repaired surgically, while very small AAAs (less than 4.0 cm in diameter) are monitored using ultrasonography (US). There is ongoing debate regarding the roles of early repair versus surveillance with subsequent repair for individuals with asymptomatic AAAs measuring between 4.0 cm and 5.5 cm in diameter. In an updated Cochrane review, these researchers compared mortality and costs, as well as quality of life (QOL) and aneurysm rupture as secondary outcomes, following early surgical repair versus routine US surveillance in individuals with asymptomatic AAAs within this size range. They conducted a search using the Cochrane Vascular Information Specialist, querying the Cochrane Vascular Specialized Register, CENTRAL, Medline, two other databases, and two trials registers up to July 10, 2019. They also hand-searched conference proceedings and checked reference lists of relevant studies. The review included randomized controlled trials (RCTs) where individuals with asymptomatic AAAs of 4.0 cm to 5.5 cm were randomly allocated to either early repair or imaging-based surveillance at least every six months. Outcomes had to include mortality or survival. Three review authors independently extracted data, which were cross-checked by other team members. The primary outcomes were mortality, costs, QOL, and aneurysm rupture. For mortality, they estimated risk ratios (RR) for endovascular aneurysm repair (EVAR) only, hazard ratios (HR) for open repair only, and 95% confidence intervals (CI) based on Mantel-Haenszel Chi2 statistics at 1 and 6 years (open repair only) following randomization.
The investigators found no new studies for this update; four trials with 3,314 participants met the inclusion criteria. Two trials compared early open repair with surveillance, and two trials compared early EVAR with surveillance. They used GRADE to assess the certainty of the evidence for mortality and cost, which ranged from high to low. The certainty in the evidence was downgraded from high to moderate and low due to concerns about risk of bias and imprecision (some outcomes were reported by only one study). All four trials indicated an early survival benefit in the surveillance group (due to 30-day operative mortality associated with repair), but no evidence of differences in long-term survival. One study comparing early open repair with surveillance reported an adjusted HR of 0.88 (95% CI: 0.75 to 1.02, mean follow-up of 10 years; HR 1.21, 95% CI: 0.95 to 1.54, mean follow-up of 4.9 years). Pooled analysis of participant-level data from the two trials comparing early open repair with surveillance (maximum follow-up of 7 to 8 years) showed no evidence of a difference in survival (propensity score-adjusted HR 0.99, 95% CI: 0.83 to 1.18; 2,226 participants; high-certainty evidence). This lack of treatment effect did not vary by AAA diameter (p = 0.39), participant age (p = 0.61), or for women (HR 0.84, 95% CI: 0.62 to 1.11). Two studies compared EVAR with surveillance, and there was no evidence of a survival benefit for early EVAR at 12 months (RR 1.92, 95% CI: 0.73 to 5.06; 846 participants; low-certainty evidence). Two trials reported costs, indicating that the mean U.K. health service costs per participant over the first 18 months after randomization were higher in the open repair group than in the surveillance group (GBP 4,978 in the repair group versus GBP 3,914 in the surveillance group; mean difference (MD) GBP 1,064, 95% CI: 796 to 1,332; 1,090 participants; moderate-certainty evidence). A similar difference was observed after 12 years. The mean U.S. hospital costs for participants at 6 months after randomization were higher in the EVAR group than in the surveillance group (USD 33,471 with repair versus USD 5,520 with surveillance; MD USD 27,951, 95% CI: 25,156 to 30,746; 614 participants; low-certainty evidence). After 4 years, there was no evidence of a difference in total medical costs between groups (USD 48,669 with repair versus USD 46,112 with surveillance; MD USD 2,557, 95% CI: -8,043 to 13,156; 614 participants; low-certainty evidence). All studies reported QOL, but used different assessment measurements, resulting in conflicting results. All four studies reported aneurysm rupture, with very few ruptures noted in the trials comparing EVAR versus surveillance up to 3 years. In the trials comparing open surgery versus surveillance, ruptures were reported up to at least 6 years, with more ruptures occurring in the surveillance group, most of which were in aneurysms that had exceeded the threshold for surgical repair.
The authors concluded that there was no evidence of an advantage to early repair for small AAAs (4.0 cm to 5.5 cm), regardless of whether open repair or EVAR was used, and at least for open repair, regardless of patient age and AAA diameter. Therefore, neither early open nor early EVAR of small AAAs is supported by currently available evidence. They stated that long-term data from the two trials examining EVAR are not yet available; thus, they could only draw firm conclusions regarding outcomes after the first few years for open repair. The authors emphasized the urgent need for research regarding the risks and management of small AAAs in ethnic minorities and women, as data regarding these populations are lacking.
Endovascular Versus Surgical Repair of Abdominal Aortic Aneurysms
Yokoyama and colleagues (2020) stated that although EVAR for the treatment of AAAs significantly decreases peri-operative mortality compared with open surgical repair (OSR), they have not concluded superiority between EVAR and OSR beyond the peri-operative period. In a meta-analysis, these investigators compared phase-specific survival following EVAR versus OSR. The review was carried out according to the PRISMA guideline. Embase and Medline were searched up to November 2019 to identify RCTs and propensity score-matched studies that examined greater than or equal to 2-year all-cause mortality (primary outcome) following EVAR versus OSR for intact infra-renal AAA. For each study, the HR with 95% CI of mortality for EVAR versus OSR was calculated using survival curves for the following specific phases: early term (0 to 2 years following repair), mid-term (2 to 6 years following repair), long-term (6 to 10 years following repair), and very long-term (greater than or equal to 10 years after repair). The risk ratio (RR) in the peri-operative (in-hospital or 30-day) period was also extracted. Phase-specific HRs or RRs were separately pooled using the random effects model. Sensitivity analyses were carried out by removing 1 study at a time to confirm that these findings were not derived from any single study. Funnel plot asymmetry was also examined using the linear regression test. The search identified 4 RCTs and 7 propensity score-matched studies enrolling a total of 106,243 AAA patients assigned to EVAR (n = 53,123) or OSR (n = 53,120). The mortality following EVAR compared with OSR was significantly lower in the peri-operative period (RR, 0.39; 95% CI: 0.29 to 0.51; p < 0.00001) and similar in the early-term period (HR, 0.93; 95% CI: 0.84 to 1.03; p = 0.16). Notably, significantly higher mortality was observed in the EVAR group compared with the OSR group in the mid-term period (HR, 1.15; 95% CI: 1.03 to 1.29; p = 0.01). However, similar mortality was observed between the EVAR group and the OSR group in the long-term (HR, 1.06; 95% CI: 0.96 to 1.17; p = 0.27) and very-long-term (HR, 1.17; 95% CI: 0.93 to 1.47; p = 0.19) periods. In sensitivity analyses, the significant benefit of EVAR in the peri-operative period and that of OSR in the mid-term period were not changed. No funnel plot asymmetry was identified in all analyses. The authors concluded that compared with OSR, EVAR was associated with lower peri-operative mortality and higher mortality in the mid-term period for intact infra-renal AAA. The superiority of EVAR was absent in the early-term period, and the inferiority of EVAR in the mid-term period disappeared in the long-term and very long-term periods.
Endovascular Stent Grafting Versus Open Surgical Repair for the Treatment of Arch/Descending Thoracic Aortic Aneurysms
In a systematic review and meta-analysis, McCarthy and colleagues (2021) compared the effectiveness of endovascular stent grafting (ESG) against open surgical repair (OSR) for the treatment of chronic arch or descending thoracic aortic aneurysms (TAAs). The researchers conducted a comprehensive search of databases including Medline, Embase, CENTRAL, the World Health Organization (WHO) International Clinical Trials Registry, current controlled trials, clinical trials, and the NIHR portfolio from January 1994 to March 2020. They sought all identified studies that compared ESG and OSR, including randomized controlled trials (RCTs), quasi-randomized and non-RCTs, comparative cohort studies, and case-control studies that matched on primary outcomes. Participants included in the studies had to receive elective treatments for arch or descending TAAs. Studies were excluded if they reported on other thoracic aortic conditions (e.g., rupture or dissection) unless results for patients receiving elective treatment for arch or descending TAAs were reported separately. Data extraction was performed by one reviewer and checked by another, while the risk of bias was assessed using the ROBINS-I tool. Meta-analysis was conducted using random effects, and where meta-analysis was not appropriate, results were reported narratively. A total of five comparative cohort studies met the inclusion criteria, reporting on 3,955 patients who underwent ESG and 21,197 patients who underwent OSR. The meta-analysis of unadjusted short-term (30-day) all-cause mortality favored ESG (OR 0.75; 95% CI: 0.55 to 1.03), although heterogeneity was identified between larger and smaller studies. A sensitivity analysis of four studies that included only descending TAAs showed no statistical significance (OR 0.73, 95% CI: 0.45 to 1.18), with moderate heterogeneity. The meta-analysis of adjusted short-term all-cause mortality also favored ESG (OR 0.71, 95% CI: 0.51 to 0.98), with no heterogeneity observed. In terms of longer-term survival beyond 30 days, OSR was favored in larger studies, while ESG was favored in smaller studies. Freedom from re-intervention in the long term favored OSR. Studies reporting short-term non-fatal complications suggested fewer events following ESG. The authors concluded that there is limited and increasingly dated evidence addressing the comparison of ESG and OSR in the management of elective arch and/or descending thoracic aorta aneurysms. They emphasized the need for further high-quality evidence. Although large RCTs may not be feasible for this relatively rare condition, future studies should employ robust methodological designs to control for potential confounders and reduce biases. Additionally, given the current conflicting evidence, it is important that comparisons of OSR and ESG are conducted in both the short-term and long-term.
The authors acknowledged that the findings of this systematic review and meta-analysis were limited by the number of studies included and the potential for confounding in the five studies analyzed, making definitive conclusions difficult. The adjustment for confounders was likely only partial, and some bias in the estimates of differences in mortality and complications may persist, despite efforts to mitigate bias in the larger studies identified. Furthermore, statistical analysis of non-fatal complications was not possible due to limited and inconsistent reporting.
One- Versus Two-Stage Hybrid Repair of Thoraco-Abdominal Aortic Aneurysms
Wang and colleagues (2021) noted that for TAAAs, it is unclear if it is better to perform hybrid repair in 1- (single) or 2-stage (staged). In a meta-analysis, these researchers compared the clinical outcomes of single versus staged hybrid repair of TAAA. Medline, Embase, and Cochrane Databases (January 1, 1994 to May 11, 2020) were searched for studies on hybrid repair of TAAAs. Cohort studies and case series reporting outcomes of single and staged hybrid repair of TAAAs were eligible for inclusion. The Newcastle-Ottawa scale and an 18-item tool were used to examine the risk of bias. The primary outcome was 30-day mortality, and the secondary outcomes included post-operative complications, overall survival (OS), and other mid-term events. A random effects model was used to calculate pooled estimates. A total of 37 studies was included in the meta-analysis. The quality assessment of the included studies suggested low or moderate risk of bias. The pooled estimates for aneurysm rupture and death during stage interval were 2% (95% CI: 0% to 4%, I2 = 0%) and 4% (95% CI: 2% to 7%, I2 = 0%), respectively. Single repair was associated with a significantly higher 30-day risk of death when compared with patients who completed staged procedures successfully (OR 2.64, 95% CI: 1.36 to 5.12, I2 = 0%). Staged repair also had lower incidence of major adverse cardiac events (MACE) (single: 10%, 95% CI: 5% to 16%; staged: 2%, 95% CI: 0% to 5%) and intestinal complications (single: 15%, 95% CI: 8% to 25%; staged: 3%, 95% CI: 1% to 6%). For mid-term outcomes, single and staged repair had comparable 12-month OS, aneurysm related mortality, rate of re-intervention, and graft patency. The authors concluded that 2-stage hybrid repair may represent a better choice for patients with controlled risk of aneurysm rupture, because it could provide lower 30-day mortality risks, MACE, and intestinal complications, as well as comparable mid-term outcomes. Moreover, these researchers stated that RCTs are needed to determine the effect of repair staging in patients for elective TAAAs.
Intra-Operative Computed Tomography in Endovascular Aneurysm Repair
Hansrani and colleagues (2020) examined the effectiveness of computed tomography (CT) in identifying technical complications intra-operatively during endovascular aneurysm repair (EVAR). They compared the frequency of complications identified by CT with those detected by conventional completion angiography. The researchers conducted a systematic review that adhered to PRISMA guidelines, focusing on studies that reported on the effectiveness of intra-operative CT during EVAR. Their literature search yielded six studies that met the inclusion criteria. Overall, these studies indicated that intra-operative CT was superior to completion angiography in detecting intra-operative complications during EVAR. Despite concerns regarding radiation exposure, the use of intra-operative CT was associated with a lower overall radiation dose, as post-operative CT angiography was no longer necessary. Additionally, no adverse effects on renal function were observed due to the increased use of contrast during intra-operative CT. The authors concluded that the current body of evidence suggests that intra-operative CT is superior to completion angiography for detecting clinically significant complications during EVAR, while also incurring a lower total radiation dose and posing no additional risk of contrast-induced renal impairment. They emphasized the need for further research to fully understand the benefits of intra-operative CT before making definitive recommendations.
The authors noted the significant potential of this new technology to provide reassurance regarding graft deployment and its potential to influence follow-up protocols. They suggested that larger, prospective cohort studies comparing matched cases and controlled clinical trials would be beneficial in enhancing the limited existing evidence. Furthermore, such studies should encompass a variety of outcome measures, including hospital length of stay (LOS), mortality, morbidity, and patient satisfaction. The investigators also indicated that additional research is needed to determine whether intra-operative CT could lead to long-term improved outcomes by reducing the need for secondary interventions and future complications.
Endovascular Stenting for the Treatment of Aortic Coarctation
Kische and colleagues (2010) noted that surgical treatment of aortic coarctation (AC) has significantly increased life expectancy and reduced mortality rates. However, the average lifespan following repair remains only 35 to 50 years, with considerable morbidity persisting due to complications such as aneurysm formation, hypertension, accelerated coronary disease, and stroke. Follow-up studies have revealed re-stenosis rates of 30% and persistent hypertension both at rest and during exercise, sometimes accompanied by compromised cardiac function. The less invasive nature of non-surgical repair using transcatheter therapies has led to the adoption of balloon angioplasty (BA) and, more recently, stent implantation as emerging treatment options for AC.
Jha and associates (2016) highlighted that patients with functional aortic interruption of the descending thoracic aorta at the isthmus due to severe coarctation, particularly in conjunction with an atretic lumen, are extremely rare in the adult population. The management of such cases is challenging and carries high morbidity and mortality risks. These investigators described a successful percutaneous reconstruction using a covered stent in a similar patient who was doing well two years post-intervention. They conducted a literature search to examine management strategies and their long-term outcomes. The authors concluded that their report aimed to emphasize the role of minimally invasive approaches in managing rare, severe AC in adult patients to avoid the morbidity and mortality associated with more invasive procedures. They noted that the initial percutaneous approach for treating AC was BA; however, endovascular stent placement is gaining wider acceptance. The incidence of early and late aneurysms following BA has been reported to be between 5% and 11%, leading to the development of balloon-expandable stents, with covered stents now available on the market as a further advancement. These stents provide support to the vessel wall, prevent aneurysm formation, and are amenable to re-dilatation.
Salcher and colleagues (2016) stated that there is currently no systematic assessment of the available evidence regarding the effectiveness and comparative effectiveness of balloon dilatation and stenting for AC. These investigators systematically searched four online databases to identify and select relevant studies based on a priori criteria. They synthesized results for each intervention from single-arm studies and obtained pooled estimates for relative effectiveness from pairwise and network meta-analyses of comparative studies. The primary analysis included 15 stenting studies (423 participants) and 12 balloon dilatation studies (361 participants), focusing on patients aged 10 years and older. Post-treatment blood pressure (BP) gradient reduction to less than or equal to 20 mm Hg and less than or equal to 10 mm Hg was achieved in 89.5% (95% CI: 83.7 to 95.3) and 66.5% (44.1 to 88.9) of patients undergoing balloon dilatation, respectively, compared to 99.5% (97.5 to 100.0) and 93.8% (88.5 to 99.1) of patients undergoing stenting. The odds of achieving a BP gradient of less than or equal to 20 mm Hg were lower with balloon dilatation compared to stenting (OR, 0.105 [0.010 to 0.886]). Thirty-day survival rates were comparable between the two interventions. However, a numerically higher percentage of patients undergoing balloon dilatation experienced severe complications during admission (6.4% [2.6 to 10.2]) compared to stenting (2.6% [0.5 to 4.7]). This finding was supported by meta-analyses of head-to-head studies (OR, 9.617 [2.654 to 34.845]) and network meta-analyses (OR, 16.23, 95% CI: 4.27 to 62.77) in a secondary analysis involving patients aged one month and older, which included 57 stenting studies (3,397 participants) and 62 balloon dilatation studies (4,331 participants). The authors concluded that despite the limitations of the evidence base, which consisted predominantly of single-arm studies, the findings indicated that stenting achieved superior immediate relief of a relevant pressure gradient compared to balloon dilatation.
Beckmann and Jassar (2018) stated that AC is one of the most common congenital cardiac pathologies. Repair of native AC is now a common and safe procedure; however, late complications, including re-coarctation and aneurysm formation, are not uncommon. Both bare metal stents and covered endografts have been utilized to treat AC. Endovascular stent graft placement offers the advantage of a less invasive approach and potentially quicker recovery. The procedure can be performed with a low peri-operative risk. Stent implantation has largely replaced BA for discrete coarctation in adolescents and adults in most centers. However, stent implantation is generally not recommended for patients weighing less than 25 kg due to an increased risk of femoral artery rupture from the sheath size. Additionally, the native aorta may be relatively small and could outgrow the stent, necessitating re-intervention for transcatheter dilation of the stent. The rates of re-coarctation appear to be comparable to those seen with open surgical approaches; however, aneurysm formation has been observed in 6% of cases following stent graft placement. While it was previously suggested that bare metal stents might predispose patients to future (pseudo) aneurysms, a more recent study comparing the two stent types did not find any significant differences.
Price et al. (2019) noted that AC is a common congenital abnormality that can lead to significant morbidity and mortality if not corrected. Re-coarctation or re-stenosis of the aorta following treatment is a relatively common long-term issue, and the optimal therapy has yet to be determined. These investigators identified the challenges associated with recurrent AC and the most appropriate management strategies for different patient cohorts. Open surgery provides a durable long-term aortic repair; however, due to the complexity of the procedure, it carries a somewhat higher rate of serious complications. Endovascular repair, while less invasive and relatively safe, has limitations in treating complex anatomy and is more likely to require repeat interventions. The authors concluded that open surgical repair is more appropriate for infants who have not previously undergone intervention, while endovascular therapy should be reserved for older children and adults, as well as those requiring repeat interventions.
In a retrospective, single-center study, Hatoum and co-workers (2020) examined the safety and efficacy of endovascular stenting for AC and assessed the impact of clinical parameters and stent characteristics on outcomes. They retrospectively reviewed clinical data from all patients with AC who underwent attempted transcatheter stenting between 2004 and 2019. Eligible patients had either native or recurrent AC with systemic arterial hypertension and a resting arm-leg pressure gradient greater than 20 mm Hg. Exclusions included a distance of less than 10 mm between the take-off of cervical arteries and the stenotic aortic lesion, contraindications to anti-thrombotic therapy, body weight of less than 25 kg, and secondary hypertension. A total of 20 patients (75.0% with native lesions) were included, with a mean age of 18.4 years and a mean body weight of 59.2 kg. The procedure was successful in 90.0% of cases, resulting in an immediate drop in the invasive pressure gradient across lesions. During a median follow-up of 12 months (ranging from 8 to 144.9 months), coarctation recurred in five patients, four of whom required intervention after a median of 104.4 months, with successful outcomes. The use of Cheatham Platinum stents was significantly associated with lower rates of re-coarctation and re-interventions. At the latest follow-up, three out of six patients with persistent hypertension had no re-coarctation. Analysis indicated that the need for anti-hypertensive therapy was not influenced by clinical parameters, aortic arch geometry, or stent characteristics. The authors concluded that stent implantation for AC was a safe and successful procedure, with Cheatham Platinum stents appearing to be associated with better outcomes.
Rossi et al. (2020) stated that AC in adults is typically recognized through systemic arterial hypertension associated with a pressure gradient between the upper and lower extremities. Precise vascular imaging, such as multi-detector CT or magnetic resonance imaging, is essential for a comprehensive evaluation of the thoracic aorta, its branches, and potential collateral vessels. Criteria for invasive treatment in adult patients include a translesional pressure gradient greater than 20 mm Hg and/or evidence of significant collateral vessels. The choice between open surgery and percutaneous endovascular treatment should be made by a multidisciplinary team of surgeons, interventional radiologists, and cardiologists.
Agasthi et al. (2020) emphasized that the hallmark finding of AC is upper extremity hypertension, and therefore, AC should be considered in any young hypertensive patient, warranting the measurement of lower extremity blood pressure at least once in these individuals. The presence of a significant pressure gradient between the arms and legs is highly suggestive of the diagnosis. Early diagnosis and treatment are crucial, as long-term data consistently demonstrate that patients with AC have a reduced life expectancy and an increased risk of cardiovascular complications. Surgical repair has traditionally been the mainstay of therapy; however, advances in endovascular technology, including covered stents or stent grafts, now allow for non-surgical approaches in managing older children and adults with native AC and its complications. Persistent hypertension and vascular dysfunction can lead to an increased risk of coronary disease, which remains the leading cause of long-term mortality. Therefore, blood pressure control and periodic reassessment using transthoracic echocardiography and three-dimensional (3D) imaging (CT or cardiac magnetic resonance) should be conducted regularly, as cardiovascular complications may arise decades after intervention.
Boe et al. (2021) noted that stent implantation (SI) is more effective than balloon angioplasty (BA) for treating AC. Due to technical factors, BA is more commonly performed in smaller patients. In a retrospective, single-center study, these researchers examined the outcomes of percutaneous adult-sized SI for the treatment of AC in small patients. This trial included patients weighing less than or equal to 20 kg who underwent percutaneous adult-sized SI for native or recurrent AC from 2004 to 2015. A total of 39 patients (20 patients weighing less than or equal to 10 kg) were identified, with 28 (71.8%) having recurrent AC and 22 (56.4%) having previously failed BA. At the time of SI, the median patient age and weight were 1.1 years (range 0.3 to 7.9) and 10 kg (range 5.5 to 20.4), respectively. SI resulted in significant improvements in the median pressure gradient (from 26 mm Hg [IQR, 18 to 42] to 0 mm Hg [IQR, 0 to 2]; p < 0.05) and median minimum diameter (from 3.6 mm [IQR, 2.4 to 4.8] to 7.7 mm [IQR, 6.5 to 9.4]; p < 0.05). Seven patients (18%) experienced procedural adverse events, and 27 (69%) patients underwent elective re-intervention at a median time of 49.3 months (IQR, 26.5 to 63.2) following SI, with eight (21%) stents requiring repeat SI due to stent fracture. Over a median follow-up of 67.2 months (IQR, 33.8 to 116.1), 25 patients (69%) were free from hypertension or blood pressure gradient, while three (11%) patients developed femoral arterial occlusion. The authors concluded that adult-sized SI is a viable alternative to surgical intervention for small patients with AC, although it carries a risk of access-related complications that may improve with the development of lower-profile stents with larger maximum diameters.
The Cleveland Clinic’s webpage on “Aortic Coarctation” (2021) states that “Twenty years ago, surgery was the only treatment available for aortic coarctation. Surgery is still considered the gold standard, but today treatment options for adults with this condition also include balloon angioplasty, stenting, stent grafting, or hybrid repair (a combination of open surgery and stent grafts). The choice of treatment is based on the individual's overall health, the size and severity of the coarctation, associated aneurysm or valve disease, and its precise location.”
Chimney/Snorkel Endovascular Repair for the Treatment of Symptomatic and Ruptured Abdominal Aortic Aneurysms
Jernigan et al. (2021) noted that symptomatic and ruptured abdominal aortic aneurysms (AAAs) are increasingly being managed with endovascular aneurysm repair (EVAR). In a retrospective cohort study, these researchers examined the outcomes of patients with symptomatic and ruptured AAAs who underwent EVAR using the chimney or snorkel technique (ChEVAR). The study utilized the Vascular Quality Initiative registry, covering data from March 2013 to July 2019. All patients with symptomatic and ruptured AAAs, characterized by a proximal aortic zone of disease from 6 to 9, who underwent ChEVAR were included. Outcomes were analyzed according to the Society for Vascular Surgery reporting standards for EVAR. ChEVAR was performed in 77 patients, of whom 35 (45.5%) had ruptured AAAs and 42 (54.5%) had symptomatic AAAs. The median age of the cohort was 73.0 years (IQR, 67.0 to 81.0 years), with 54 patients (70.1%) being men. The median maximum aneurysm diameter was 67.5 mm (IQR, 54.5 to 83.3 mm), and all patients had an American Society of Anesthesiologists (ASA) class of III or higher. For patients with ruptured AAAs, the mean lowest pre-operative systolic blood pressure (SBP) was 95.3 ± 29.3 mm Hg. The fluoroscopy time averaged 57.4 minutes (IQR, 41.2 to 79.0 minutes). The proximal aortic zone of disease was classified as zone 6 in 9 patients (11.7%), zone 7 in 21 patients (27.3%), zone 8 in 36 patients (46.8%), and zone 9 in 11 patients (14.3%). ChEVAR involved more than one vessel in 55 patients (71.4%). No significant difference in 30-day mortality was found between patients with ruptured versus symptomatic AAAs (11.4% versus 7.1%; p = 0.695). Re-intervention was required for 10 patients (13.0%) at a median of 9 post-operative days, with 2 (20.0%) of these patients dying. Post-operatively, 31 patients (40.3%) experienced a major complication, including a type I endoleak in 9 patients (11.7%), of whom 2 (22.2%) died. Long-term follow-up data were available for 38 patients (49.4%) at a median of 406.5 days (IQR, 326.8 to 602.0 days) post-operatively. Among the 18 patients with long-term radiographic data, sac growth was detected in 4 (22.2%). A total of 14 patients had died at a median of 26.5 days (IQR, 3.0 to 468.5 days). The authors concluded that ChEVAR for symptomatic and ruptured AAAs can be performed with acceptable rates of morbidity and mortality, but emphasized the need for long-term data to assess durability.
The authors acknowledged that this study was limited by the rigid definitions and pre-populated data entry choices established by a national database, which resulted in less granular data and made it difficult to track the course of individual patients. This limitation was further compounded by the absence of strict guidelines to define urgent, emergent, and semi-urgent cases of AAA. Additionally, meaningful variables were missing data, complicating the characterization of the true rates of various complications and the management of the endoleaks encountered in the study. It was possible that some complications observed in this patient population were not included, as participation in the Vascular Quality Initiative (VQI) database was not mandatory at many centers. Consequently, it was challenging to determine whether the morbidity rates found in this study were artificially low. Although this study was the largest of its kind, the small number of patients could have led to an underestimation of complications. Unreported surgical turn-down rates and a non-standardized patient selection process among the centers in the VQI, along with the absence of a control group, made it difficult to draw firm conclusions from the data presented.
Viabahn Balloon-Expandable Stent Versus Self-Expandable Covered Stents for Branched Endovascular Aortic Repair
Motta et al. (2021) compared the performance between the Viabahn balloon-expandable stent (VBX; Viabahn [W. L. Gore & Associates, Flagstaff, AZ]) and a covered self-expandable stent (SES; Fluency [Bard Peripheral Vascular, Tempe, AZ]) used as bridging stents for directional branches during fenestrated or branched endovascular aneurysm repair of complex aortic aneurysms. Patients with thoraco-abdominal aortic aneurysms (type I to IV) or pararenal aortic aneurysms either at high risk for open repair or unsuitable for endovascular repair with commercially available devices were prospectively enrolled in a physician-sponsored IDE trial. Descriptive statistics of the cohort included demographics, risk factors, and anatomic and device characteristics. Individual branches were grouped as either VBX or SES and had data analyzed for primary patency, branch-related type I or type III endoleaks, branch instability, branch-related secondary intervention, and branch-related aortic rupture or death. Categorical variables were expressed as total and percentage, and continuous variables were expressed as median (IQR). Kaplan-Meier curves were used to estimate long-term results. Groups were compared with the log-rank test; and p value of < 0.05 was considered statistically significant. During the period from July 2012 through June 2019, there were 263 patients treated for complex aortic aneurysm (thoraco-abdominal aortic aneurysm) with fenestrated or branched endografts. The devices used were either custom-manufactured devices or off-the-shelf p-Branch or t-Branch (Cook Medical, Bloomington, IN) devices. The median age was 71 years (IQR, 66 to 79 years); 70% were men, and 81% were white. The most common cardiac risk factors were smoking (92%), hypertension (91%), hyperlipidemia (78%), and chronic obstructive pulmonary disease (COPD; 52%). The total number of vessels incorporated into the repair was 977, with branches representing 18.4% (179 branches). Among these 179 branches, the celiac artery, superior mesenteric artery, right renal artery, and left renal artery received 54 (30%), 56 (31%), 38 (21%), and 31 (18%) branches, respectively. VBX and SES groups represented 96 (54%) and 81 (46%) of the branches implanted. The celiac artery, superior mesenteric artery, right renal artery, and left renal artery received VBX as a bridging stent in 40%, 46.7%, 33.8%, and 32.2% respectively. The overall cohort survival rate was 78.5% at 24 months. There was no branch-related rupture or mortality. Primary patency at 24 months (VBX, 98.1%; SES, 98.6%; log-rank, p = 0.95), freedom from endoleak (VBX, 95.6%; SES, 98.6%; log-rank, p = 0.66), freedom from secondary intervention (VBX, 94.7%; SES, 98.1%; log-rank, p = 0.33), and freedom from branch instability (VBX, 95.6%; SES, 97.2%; log-rank, p = 0.77) were similar between groups. The authors concluded that this initial experience with VBX stents demonstrated excellent primary patency and similarly low rates of branch-related complications and endoleaks, with no branch-related aortic rupture or death. These findings demonstrated that in a high-volume, experienced aortic center, the VBX stent was a safe and effective bridging stent option during branched endovascular aortic repair. Moreover, these investigators stated that multi-center studies with a larger cohort and longer follow-up are needed to validate these findings.
Chimney Versus Fenestrated Endovascular Versus Open Repair for Juxta/Pararenal Abdominal Aortic Aneurysms
In a systematic review and meta-analysis, Zlatanovic et al. (2023) compared the short-term results of FEVAR, ChEVAR, and open surgery for patients with juxta/pararenal AAA (JAAA/PAAA). Medline, SCOPUS, and Web of Science were searched from inception to July 1, 2022. Any comparative studies examining the results of 2 or 3 treatment strategies (ChEVAR, FEVAR, or open surgery) on clinical outcomes for patients with JAAA/PAAA were included. Analyzed outcomes were 30-day mortality, acute kidney injury (AKI), bowel ischemia (BI), and MACE. A total of 22 studies with 8,853 patients were included in the analysis. FEVAR (OR = 0.58, 95% CI: 0.36 to 0.82) and ChEVAR (OR = 0.56, 95% CI: 0.28 to 1.02) were associated with lower 30-day mortality than open surgery. FEVAR (OR = 0.54, 95% CI: 0.33 to 0.85) was associated with lower risk of AKI than open surgery. FEVAR (OR = 0.43, 95% CI: 0.20 to 0.89) and ChEVAR (OR = 0.34, 95% CI: 0.10 to 0.93) compared to open surgery were associated with lower rates of BI. FEVAR (OR = 0.67, 95% CI: 0.49 to 0.90) and ChEVAR (OR = 0.61, 95% CI: 0.35 to 1.02) were associated with lower 30-day MACE risk than open surgery. FEVAR was associated with a higher rate of SCI compared to open surgery (OR = 4.90, 95% CI: 1.55 to 19.17). The authors found a clear benefit for FEVAR and ChEVAR versus open surgery in terms of reduced 30-day mortality, BI, and MACE, as well as AKI for FEVAR suggesting that higher-risk patients might benefit from endovascular treatment of JAAA/PAAA. Moreover, these investigators stated that this approach should be applied in clinical practice with caution, since long-term outcomes were outside of the scope of this review.
Celiac Artery Coverage During Thoracic Endovascular Aortic Repair
In a systematic review and meta-analysis, Hanna et al. (2022) examined the clinical impact of celiac artery (CA) coverage during thoracic endovascular aortic repair (TEVAR). The study was conducted in accordance with PRISMA guidelines, and electronic databases were searched from 1989 to 2020 for studies reporting on outcomes such as visceral ischemia, spinal cord ischemia (SCI), 30-day in-hospital mortality, endoleaks, re-intervention, and caudal stent graft migration following CA coverage in patients undergoing TEVAR. Meta-analysis was performed using random effects modeling, and the quality of the evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. A total of 15 observational studies involving 236 patients (108 men, age range 61.3 to 79 years) were included. The pooled rate of visceral ischemia was found to be 13%, with significant heterogeneity between studies (95% CI: 4 to 24; I² = 72%, p < 0.001). The SCI rate was 5% (95% CI: 2 to 9; I² = 0%); the 30-day in-hospital mortality rate was 4% (95% CI: 1 to 7; I² = 0%); and the overall endoleak rate was 21% (95% CI: 13 to 29; I² = 35%), which included a 5% rate of type Ib endoleak (95% CI: 0 to 13; I² = 38%) and a 2% rate of type II endoleak from retrograde CA flow (95% CI: 0 to 8; I² = 43%). The re-intervention rate was 13% (95% CI: 6 to 22; I² = 54%), and the caudal stent graft migration rate was 3% (95% CI: 0 to 9; I² = 0%). The authors judged the certainty of the evidence to be very low for all outcomes. They concluded that CA coverage during TEVAR was associated with high rates of visceral ischemia, SCI, 30-day in-hospital mortality, endoleaks, and re-intervention. The researchers emphasized that, despite the poor quality of the literature and remaining questions regarding effect estimates, there is evidence suggesting that CA coverage should be avoided whenever possible during TEVAR.
Argyriou et al. (2022) noted that TEVAR has emerged as an attractive alternative for treating thoracoabdominal aortic aneurysm (TAAA) diseases, reporting lower morbidity and mortality rates compared to open or hybrid repair. A challenging situation arises when the aneurysm involves the CA, which precludes a safe distal landing zone. In a systematic review and meta-analysis, these investigators examined the safety and effectiveness of CA coverage in the treatment of complex TAAA diseases during endovascular management. They conducted a literature review in accordance with PRISMA guidelines, searching the Medline and SCOPUS databases. The primary outcomes of interest were peri-operative and 30-day mortality, while secondary endpoints included any type of endoleak, mesenteric ischemia, peri-operative SCI, and re-intervention rates. A random-effects meta-analysis was performed, and summary statistics of event risks were expressed as proportions with 95% confidence intervals (CIs). A total of 10 observational cohort studies published between 2009 and 2020, involving 175 patients, were eligible for quantitative synthesis. Indications for TEVAR included primary TAAAs in 82% of patients, aortic dissection in 14%, type Ib endoleak after previous endograft deployment in 3%, and penetrating aortic ulcer in 1 patient. The re-intervention rate was 9% (95% CI: 4% to 20%), and the SCI rate was 7% (95% CI: 4% to 12%). Type II endoleak was the most common, occurring in 10% of patients (95% CI: 4% to 22%), followed by type I endoleak in 5% (95% CI: 2% to 12%) and type III endoleak in 1% (95% CI: 0% to 16%). Mesenteric ischemia occurred in 6% of patients (95% CI: 3% to 10%), with a 30-day mortality rate of 5% (95% CI: 2% to 13%) and an overall pooled mortality estimate of 21% (95% CI: 14% to 31%). The authors concluded that CA coverage during TEVAR is a challenging but feasible option for treating TAAA diseases, providing acceptable morbidity and mortality rates. They emphasized the necessity of demonstrating adequate visceral collateral pathways before definitive CA coverage to ensure the success of the technique.
Elective Endovascular Versus Open Repair for Elective Abdominal Aortic Aneurysm in Patients Age 80 Years or Older
In a systematic review and meta-analysis, Wang et al. (2023) examined available evidence on clinical outcomes among octogenarians (aged 80 years or older) with AAA managed by elective endovascular repair, compared to conventional open repair. PubMed, Embase, and Scopus databases were systematically searched. Studies that were either observational or RCTs were considered for the review. Included studies were carried out in elderly subjects (80 years or older) with AAA, and clinical and mortality outcomes were compared between endovascular and open surgical repair. Those reporting on outcomes of patients with urgent repair were excluded. The primary outcomes of interest were mortality and risk of complications. The pooled effect sizes were reported as OR for categorical outcomes and weighted mean difference (WMD) for continuous outcomes. STATA software was used for statistical analysis. The meta-analysis included 15 studies. Compared to those undergoing open repair, patients receiving endovascular repair had significantly reduced risk of immediate post-operative mortality (OR 0.23, 95% CI: 0.20 to 0.27), overall complication (OR 0.30, 95% CI: 0.20 to 0 .44), cardiac (OR 0.23, 95% CI: 0.16 to 0 .35), renal (OR 0.29, 95% CI: 0.18 to 0.46), pulmonary (OR 0.14, 95% CI: 0.09 to 0.21) and bleeding related (OR 0.59, 95% CI: 0.42 to 0.83) complications. The risk of mortality at latest follow-up (at 36 months and 60 months) was similar in the 2 groups. The total blood loss (ml) (WMD 1,126.47, 95 % CI: 1,497.81 to 755.13), operative time (min) (WMD 29.40, 95% CI: 56.19 to 2.62), length of ICU stay (days) (WMD 2.27, 95% CI: 3.43 to 2.12) and overall hospital stay (days) (WMD -6.64, 95% CI: 7.60 to 5.68) was significantly lower in those undergoing endovascular repair. The authors concluded that endovascular repair appeared to be better than open repair of AAA in this high-risk, frail population, with respect to short-term outcomes. The benefits of reduced risk of short-term mortality, complications, and better peri- and post-operative outcomes may be considered when making a choice between these 2 surgical approaches. Moreover, these researchers stated that RCTs are needed to provide reliable evidence on the effect of EVAR on long-term survival.
Total Endovascular Aortic Arch Repair
Basha et al. (2023) stated that total endovascular aortic arch repair (TEAAR) represents an emerging alternative for treating aortic arch disease in patients at prohibitive risk for open surgery. In a systematic review, these investigators examined the early outcomes associated with this new technology. They included all studies (excluding single-patient case reports) involving CE-certified "custom made" or "off-the-shelf" zone 0 stent graft deployments. The primary search was conducted across Medline, Embase, CINAHL, and the Cochrane CENTRAL registry, supplemented by searches of Web of Science, ClinicalTrials.gov, and conference abstracts from the last three years, along with a hand-search of citations within relevant articles. Studies underwent a two-stage screening process by two independent reviewers before inclusion. A total of 15 relevant studies were identified. Indications for TEAAR included chronic arch dissection with degenerative aneurysmal disease (54%, 148/273), pure arch aneurysm (41%, 112/273), penetrating atherosclerotic ulcer (2%, 5/273), and type IA endoleak from a zone 2 thoracic endograft (1%, 3/273). The devices used included double-branch (70%, 192/273), triple-branch (19%, 53/273), and single-branch (into the innominate artery; 10%, 28/273) stent grafts. Adjunct left carotid-subclavian bypass was performed in 90% of double- and single-branch procedures. The procedural success rate for TEAAR was 93% (95% CI: 85.8% to 96.3%). The all-cause mortality rate was 16% (95% CI: 8% to 26%), with stroke occurring in 14% (95% CI: 8% to 24%), peripheral vascular events in 7% (95% CI: 1% to 33%), and myocardial infarction (MI) in 4% (95% CI: 2% to 7%). Endoleaks were identified in 13% (95% CI: 7% to 25%) of the study population. The authors concluded that TEAAR represents a promising option for managing aortic arch disease, demonstrating high procedural success rates and acceptable early outcomes in a high-risk patient population.
Wong et al. (2023) described the feasibility and outcomes of endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with a pre-loaded single retrograde left subclavian artery (LSA) branch stent graft. These investigators examined the clinical data and outcomes of consecutive patients enrolled in an ongoing prospective, non-randomized, physician-sponsored investigational device exemption (IDE) study assessing the outcomes of endovascular aortic arch repair using patient-specific arch branch stent grafts between 2019 and 2022. All patients received a design featuring a triple-wide scallop and a single retrograde LSA branch with a pre-loaded catheter. The study included five men with a median age of 77 years (range 72 to 80) who were treated using the single LSA branch stent graft. Technical success was achieved in all patients. The median operating time, fluoroscopy time, and total radiation dose area product were 103 minutes (range 78 to 134 minutes), 26 minutes (range 19 to 39 minutes), and 123 mGy/cm² (range 71 to 270 mGy/cm²), respectively. There were no 30-day or in-hospital mortality, neurological events, or other major adverse events (MAEs). During a median follow-up of 21 months (range 20 to 27 months), all patients remained alive with patent LSA branches, except for one patient who died due to COVID-19 complications. There was no branch instability or need for secondary interventions. The authors concluded that this early feasibility study demonstrated successful endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with a single retrograde LSA branch, achieving no technical failures, mortality, or neurological events. They also stated that larger clinical studies with longer follow-up are necessary to ascertain the effectiveness of this approach in patients requiring endovascular repair with proximal extension into Zone 2.
Endovascular Repair for the Treatment of Non-Dissected Ascending Aortic Diseases
Plichta and Hughes (2018) stated that thoracic endovascular aortic repair (TEVAR) of the ascending aorta (AA) is an emerging alternative treatment strategy specifically aimed at patients who are at high risk for open surgery. TEVAR has been utilized in patients with various pathologies of the AA, including type A dissection, intra-mural hematoma, penetrating ulcers, aneurysms, and pseudoaneurysms. The investigators discussed the available evidence regarding the use of TEVAR for the AA, as well as the latest techniques and potential pitfalls associated with the procedure. They noted that the challenges of this modality are considerable, and the techniques employed draw from various aspects of endovascular experience. The authors concluded that there is limited literature on the use of stent grafts in the AA, and the pool of patients currently considered appropriate candidates for the procedure is small. They emphasized that this is an evolving intervention that warrants further investigation and the development of devices specifically engineered to address the anatomical and physiological challenges of the AA.
Preventza et al. (2022) noted that different pathologies of the AA, including aneurysms, acute and chronic dissections, and pseudoaneurysms, have been successfully treated with open surgical repair, particularly at aortic centers of excellence. However, there exists a subset of patients for whom open surgery is considered to pose high or prohibitive risk. These patients could benefit from a less invasive approach utilizing catheters, wires, percutaneous techniques, and stent grafts. The existing technology was primarily developed for treating descending thoracic aortic pathologies and is not approved for use in the AA by the FDA. Devices designed for the descending thoracic aorta (DTA) have certain size and design limitations that can complicate their use in the AA. Consequently, custom-made endografts have been employed to treat AA pathologies, although their use is feasible only in elective procedures. Furthermore, the AA has specific anatomical and physiological characteristics that raise concerns regarding the long-term durability of current technologies. The researchers stated that while endovascular repair is a promising new direction for treating the AA, the main barrier to widespread use is the lack of devices designed and approved specifically for this purpose. Although several centers have used improvised devices off-label for compassionate use, a device and delivery system tailored to the AA would be invaluable. Additionally, a TEVAR device for AA interventions should be designed with the unique flow characteristics of the AA in mind to enhance durability and improve long-term outcomes.
In a systematic review, Huo et al. (2023) examined the effectiveness of endovascular repair for treating non-dissected diseases of the ascending aorta. Data sources included PubMed, Embase, and SciELO. The investigators conducted a search for all cases of ascending aortic endovascular repair published between January 2007 and July 2023, excluding type A aortic dissection. This review encompassed 56 case reports and 7 observational studies assessing techniques, equipment, procedural steps, and outcomes. The researchers summarized data on age, complications, follow-up time, and access routes. The review included 63 studies reporting on 105 patients (mean age 64.96 ± 17.08 years) who underwent endovascular repair for non-dissected ascending aortic disease. The types of disease included aneurysm (n = 16), pseudoaneurysm (n = 71), penetrating aortic ulcer (n = 10), intra-mural hematoma (n = 2), thrombosis (n = 2), iatrogenic coarctation (n = 1), and aortic rupture (n = 3). The success rate of the procedure was 99.05% (104/105). Complications included endoleak (10.48%, 11/105), stroke (5.71%, 6/105), post-operative infection (1.91%, 2/105), acute renal failure (0.95%, 1/105), aortic rupture (0.95%, 1/105), thrombosis (0.95%, 1/105), and splenic infarction (0.95%, 1/105). A total of 5 patients required conversion to open surgery, and 2 patients underwent endovascular re-intervention, with 4 of these 5 patients requiring surgery due to endoleak. Early mortality was reported at 2.86% (3/105). The authors concluded that while the viability and results of endovascular repair for ascending aortic diseases were acknowledged in certain circumstances, further investigations are needed to ascertain the safety and effectiveness of this treatment approach. They emphasized the need for large clinical trials and the resolution of technical challenges.
Ferraresi et al. (2024) stated that the number of vascular centers performing endovascular repair of ascending aorta (AA) disease is steadily increasing. According to guidelines, open surgical repair remains the gold standard for these pathologies; however, approximately 25% of patients are deemed unfit for open surgery. The investigators described three cases of ascending TEVAR performed at their center. All patients were considered unfit for open surgery by the aortic team—two had ascending aortic pseudoaneurysms, and the third had a focal type A aortic dissection. In two cases, the researchers used two abdominal aortic cuffs deployed from zone 0B to zone 0C, without the need for supra-aortic trunk debranching. In one case, they conducted a "reverse" extra-thoracic debranching and deployed a thoracic endograft from zone 0B to zone 2. Complications included one minor stroke and one inguinal hematoma. In one patient with an infected pseudoaneurysm, ascending TEVAR was performed as a bridge strategy for open repair. This patient developed a type Ia endoleak; however, clinical stabilization and infection control were achieved, allowing for successful heart surgery. The patient subsequently underwent a second re-intervention to address superior mesenteric embolic occlusion. At a two-year follow-up, all three patients were alive. The authors concluded that their preliminary experience with three high-risk patients unfit for open surgical repair demonstrated the technical feasibility and clinical appropriateness of ascending TEVAR for selected ascending aortic pathologies using standard, commercially available endografts. They also noted that long-term results must be confirmed. The decision to treat the AA using endovascular techniques should be made in consultation with an aortic team, with the understanding that open surgery remains the gold standard. However, the introduction of specifically designed devices will help standardize the procedure for ascending TEVAR, establish appropriate indications, and ensure favorable clinical outcomes.
Furthermore, an UpToDate review on “Overview of open surgical repair of the thoracic aorta” (Burke, 2024) states that “Repair of the ascending aorta, whether for acute type A dissection, aortic aneurysm, or aortic intramural hematoma, is approached in a similar manner, with cardiopulmonary bypass including cardioplegia. Aortic root replacement is sometimes required. During ascending aortic and arch repairs, deep hypothermic circulatory arrest, retrograde cerebral perfusion, and selective antegrade cerebral perfusion techniques are used alone or in combination to minimize brain injury. Repair of pathologies affecting the ascending aorta or aortic arch may involve the aortic root, necessitating coronary artery reimplantation and possibly requiring aortic valve replacement or repair. For patients without significant aortic root dilation, valve-sparing aortic root replacement is recommended.”
GORE EXCLUDER Thoraco-Abdominal Branch Endoprosthesis
Spath et al. (2023) noted that pararenal abdominal aortic aneurysms (PRAAAs) require complex endovascular aortic repair or open surgical repair with supra-renal clamping. Custom-made devices (CMD), including fenestrated and branched endovascular aortic repair (F/B-EVAR), as well as off-the-shelf (OTS) multi-branched devices, are available therapeutic options. In a retrospective, single-center study, these researchers examined the additional healthy aortic coverage provided by an OTS multi-branched endograft compared to a CMD for the treatment of PRAAAs. The study included consecutive patients with PRAAAs requiring a proximal landing zone above the celiac artery (CA), who were treated with CMDs (Zenith Fenestrated) between January 2017 and December 2021. Treatment with supra-celiac coverage using available OTS multi-branched devices was simulated using pre-operative images of T-Branch, E-nside, and TAMBE. Study endpoints included the need for additional proximal aortic coverage and the number of segmental arteries covered proximally from the CA for OTS devices compared to CMDs. A total of 83 patients with PRAAAs were treated with CMDs (all FEVAR), including juxta-renal AAAs (n = 46; 56%), supra-renal AAAs (n = 20; 24%), and short-neck AAAs (n = 17; 20%). The study simulated treatment with 249 (3 × 83) OTS endografts. Compared to CMDs, OTS devices required a mean of 74 ± 19 mm of additional proximal healthy aortic coverage from the CA (CMD: 33 ± 19 mm versus OTS: 108 ± 6 mm; p ≤ 0.001), as well as an average sacrifice of 2.5 additional segmental arteries (CMD: 1.3 ± 0.8 versus OTS: 3.8 ± 0.9; p ≤ 0.001). In 94% of patients, at least one of the available multi-branched endografts could have been implanted according to instructions for use. The authors concluded that despite not requiring customization time, OTS endografts for the treatment of PRAAAs resulted in more extensive healthy aortic coverage and an average sacrifice of 2.5 additional segmental arteries compared to CMDs. CMDs appeared to limit unnecessary aortic coverage and the theoretical subsequent risk of spinal cord ischemia.
The authors acknowledged several drawbacks of this study, including its retrospective, single-center design, which relied on assumptions based on CTA scans and lacked clinical data from all patients treated with a CMD graft. A key limitation was that all PRAAA patients were treated with a single fenestrated CMD platform. Additionally, there was no control group to compare clinical data, and safety and morbidity considerations were based on a substantial amount of available literature.
Chen et al. (2025) conducted a meta-analysis to examine the safety and effectiveness of the T-Branch OTS multi-branched endograft for the treatment of thoracoabdominal aortic aneurysms (TAAA). Data sources included PubMed, Embase, and Web of Science, with online databases searched from June 2012 to March 2023. Data were pooled using a random-effects model of proportions. Overall outcomes included technical success, spinal cord ischemia, target vessel occlusion, type I or III endoleak, re-intervention, early mortality (30-day), and mid-term outcomes. Subgroup meta-analyses and meta-regression were conducted to examine variations among studies. A total of 15 studies involving 1,238 patients were included in the meta-analysis, with an overall study quality assessment rated as moderate-to-good. The pooled technical success rate was 97.0% (95% CI: 95.5% to 98.6%, I² = 53.01%, 1,185/1,238 cases, 15 studies). Early mortality was reported at 7.3% (95% CI: 4.4% to 10.1%, I² = 74.48%, 124/1,238 cases, 15 studies). Early spinal cord ischemia occurred in 13.4% (95% CI: 9.6% to 17.2%, I² = 67.24%, 160/1,238 cases, 15 studies), and early type I or III endoleak was observed in 6.0% (95% CI: 3.4% to 8.5%, I² = 53.71%, 68/1,032 cases, 9 studies). Mid-term outcomes indicated target vessel occlusion at 4% (95% CI: 1.4% to 6.5%, I² = 65.18%, 28/528 cases, 10 studies, 5 to 21.2 months), type I or III endoleak at 4.7% (95% CI: 2% to 7.5%, I² = 49.74%, 38/512 cases, 10 studies, 5 to 21.2 months), re-intervention at 11.2% (95% CI: 8.1% to 14.3%, I² = 31.06%, 85/650 cases, 10 studies, 5 to 21.2 months), and pooled mortality at 13.9% (95% CI: 7.2% to 20.7%, I² = 76.32%, 84/550 cases, 11 studies, 5 to 21.2 months). Meta-regression found a significant linear association between higher technical success and earlier publication year (p = 0.014) and studies with anatomical inclusion criteria (p = 0.037). Urgent patients (p = 0.021) and later publication year (p = 0.048) were significantly associated with higher early mortality. The authors concluded that the use of the OTS T-Branch multi-branched endograft for elective or urgent endovascular TAAA repair was associated with high technical success rates and proved to be safe and effective at early and mid-term follow-up. However, they noted that the heterogeneity between the included studies was high, and prospective, randomized clinical trials along with larger studies with long-term follow-up are needed.
In a prospective, non-randomized, multi-center study, Farber et al. (2024) reported the 30-day outcomes of the primary arm of the GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE) pivotal trial for complex AAA repair. This trial included patients enrolled in the primary study arm for extent IV TAAA and PRAAs. Technical success and major adverse events (AEs) were analyzed according to Society for Vascular Surgery (SVS) guidelines. A total of 102 patients in the primary arm underwent endovascular repair using the TAMBE device, with a mean age of 73 ± 6.4 years (range 58 to 82 years), and 84 (84.2%) were men. The mean body mass index (BMI) was 28.3 ± 5.0 kg/m²; 59 patients (57.8%) were treated for extent IV and 43 (42.2%) for pararenal aneurysms, with a mean maximum diameter of the aneurysms at 59.4 ± 7.8 mm. A prophylactic cerebrospinal fluid (CSF) drain was used in 10 patients (9.8%). Technical success was achieved in 99% of patients, with a single failure due to unsuccessful cannulation of the left renal artery. Mean procedure time was 315 ± 103 minutes (range 163 to 944 minutes), estimated blood loss (EBL) was 300 ± 296 ml (range 10 to 2,000 ml), and contrast administration was 153.6 ± 73.5 ml (range 16 to 420 ml). The ICU length of stay (LOS) was 58.7 ± 52.7 hours (range 1 to 288). In 28 patients (27.5%), a total of 32 additional endovascular components were deployed to manage procedural complications, including aortic and target vessel dissections and injuries not related to access. Bridging stent grafts were deployed to incorporate 407 target vessels (mean of 1.6 per vessel; range 1 to 4). Post-operative transfusion was required in 14 patients (13.7%). Major AEs occurred in 7 patients (6.9%) within 30 days, including respiratory failure (n = 2), disabling stroke (n = 1), new-onset renal failure requiring dialysis (n = 2), and paraplegia (n = 2). At 30 days, there was one patient with intra-operative rupture; no severe bowel ischemia or lesion-related/all-cause mortality were reported. The Core lab reported 100% patency in the aortic component, superior mesenteric artery, and celiac artery, and 95.9% in the left renal and 99.0% in the right renal branch components through 30 days of follow-up. Re-interventions within 30 days were performed in 9 of 96 patients (9.4%), all of which were minor. The authors concluded that the early outcomes of the TAMBE device demonstrated a high technical success rate, no 30-day lesion-related mortality, and a low rate of safety events within 30 days of the index procedure. They acknowledged that this procedure is not without risks, including paraplegia, renal failure, and the need for adjuvant stenting to resolve complications both intra-operatively and in follow-up. They emphasized the need for long-term data to determine the role of this treatment strategy in managing patients with TAAA and PRAA.
The authors noted several limitations of this study. First, aneurysm suitability was determined by an experienced screening committee, which may not reflect real-world experience and could significantly impact outcomes. Second, protocol development occurred in 2016, prior to the publication of updated SVS reporting standards in 2021, limiting the ability to align data collection with the new definitions for technical success and major AEs. Third, endoleaks reported from the Core lab analysis were not always consistent with site-reported data (e.g., type II and/or indeterminate endoleaks reported by the Core lab in patients that sites reported as type I or III endoleak). The Core lab follows a uniform, validated protocol for endoleak determination, independent of clinical information available to site investigators, such as physical examination, operative observations, arteriography, and trans-esophageal echocardiography (TEE). The Core lab may not have access to the complete data set (clinical and imaging), which limits their ability to fully assess all events. In contrast, site physicians have non-uniform definitions and criteria for imaging findings and may have different thresholds for reporting adverse events. They may be more likely to assess and report clinically significant observations that align with reported AEs, determining both the presence and type of endoleak based on their best medical judgment through evaluation across multiple imaging modalities.
DiBartolomeo et al. (2024) stated that fenestrated-branched endovascular aortic repair (FB-EVAR) has demonstrated favorable outcomes for the repair of complex aneurysms and thoracoabdominal aortic aneurysms. Physician-modified endografting (PMEG) and the Gore thoracoabdominal multi-branch endoprosthesis (TAMBE) provide custom and off-the-shelf devices for FB-EVAR, respectively. In a retrospective, single-center study, these researchers compared the outcomes of TAMBE and PMEG. They reviewed medical records of patients who underwent TAMBE as part of a multi-center pivotal trial or PMEG as part of a prospective, physician-sponsored investigational device exemption (IDE) trial at a single institution between 2020 and 2022. Patient demographics, characteristics, as well as peri-operative and mid-term outcomes were compared. A total of 68 patients were included, with 12 in the TAMBE group and 56 in the PMEG group. Baseline characteristics were comparable between groups, with thoracoabdominal aortic aneurysm being the most common type in both groups (58% TAMBE and 52% PMEG). TAMBE had a higher rate of upper extremity access (100% versus 63%; p = 0.013) and longer mean procedure time (247 ± 36 minutes versus 189 ± 49 minutes; p < 0.001). Other intra-operative metrics were similar between groups. Technical success was achieved in 100% of the TAMBE group and 95% of the PMEG group (p = 0.412). There was no 30-day mortality in either group. No major AEs occurred in the TAMBE group, while in the PMEG group, 2% experienced respiratory failure, 2% required dialysis, and 4% experienced spinal cord ischemia. Although overall endoleak rates were similar (50% of TAMBE versus 41% of PMEG; p = 0.57), type II endoleaks accounted for all endoleaks in the TAMBE group, whereas type I or type III endoleaks were observed in 11% of PMEG patients. At a median follow-up of 26.7 months for the TAMBE group and 21.2 months for the PMEG group, target vessel instability was observed in 10.4% of TAMBE and 6.9% of PMEG targeted branches (p = 0.401). Re-intervention was required in 33% of TAMBE patients and 27% of PMEG patients (p = 0.646). Estimated freedom from re-intervention rates at 3 years were similar (56% TAMBE versus 62% PMEG, log-rank p = 0.910). Freedom from visceral renal target vessel instability at 3 years was 89% for both groups (log-rank p = 0.459). The Kaplan-Meier 3-year estimated survival was 100% for patients in the TAMBE group and 77% for patients in the PMEG group (log-rank p = 0.157). The authors concluded that both TAMBE and PMEG demonstrated high technical success rates and similar 3-year outcomes, characterized by high re-intervention rates. The introduction of TAMBE represents a promising advancement that may streamline the treatment of complex aortic pathologies. They stated that further investigations through real-world clinical experience are needed to examine the comparative durability of TAMBE and PMEG in patients undergoing FB-EVAR.
The authors acknowledged that this trial was limited by selection bias due to strict adherence to the center’s treatment algorithm, resulting in the inclusion of patients with more favorable anatomy in the TAMBE group. Additionally, the small sample size may limit the generalizability of these findings to extent I, II, and III TAAA and post-dissection TAAA, as most TAMBE patients included in this study were enrolled in the primary arm of the multi-center pivotal study (extent IV TAAA or pararenal abdominal aortic aneurysm). Despite these differences, the results demonstrated that similar outcomes were achieved at the authors’ aortic center while incorporating TAMBE into complex EVAR therapeutic options.
Karaolanis et al. (2025) stated that significant progress has been made in device technology and operator experience in treating complex aortic aneurysms in recent years. Fenestrated and branched custom-made devices (CMDs) require detailed pre-operative planning and production time, which can take 12 weeks or longer. During this waiting period, aortic-related mortality increases. To address this limitation, OTS standardized multi-branched devices have been introduced to the market for treating PRAAs and TAAAs. In a systematic review and meta-analysis, these investigators examined all published studies of OTS endografts for the treatment of PRAAs and TAAAs. They conducted a systematic review to identify all eligible studies reporting outcomes for OTS with inner or outer multi-branched devices and then performed a qualitative synthesis and meta-analysis of the results. The main outcomes assessed included technical success, mortality, target visceral vessel instability, major AEs, and re-intervention rates. The researchers estimated pooled proportions and 95% confidence intervals (CIs). A total of 1,605 study titles were identified through the initial search strategy, of which 13 (8 T-Branch, 3 E-nside, 1 We-Flow, and 1 TAMBE) were deemed eligible for inclusion in the meta-analysis. A total of 595 patients (70% male) were identified among the eligible studies. In terms of procedures, 64.4% were elective, 19.2% were emergent (13.4% outer multi-branched group [OMG]; 6.1% inner multi-branched group [IMG]), and 16.4% were urgent (15.6% OMG; 0.8% IMG). The pooled technical success rate was 92.1% (95% CI: 83.8% to 96.4%) for the OMG and 96.9% (95% CI: 92.5% to 98.8%) for the IMG. The pooled 30-day mortality was 10.4% (95% CI: 6.6% to 16.1%) for the OMG and 4.2% (95% CI: 2.0% to 8.6%) for the IMG. The pooled 30-day and late target visceral vessel instability rates for the OMG were 3.5% (95% CI: 2.0% to 6.1%) and 6.2% (95% CI: 4.7% to 8.0%), respectively, while for the IMG, they were 10.4% (95% CI: 4.5% to 22.5%) and 1.6% (95% CI: 0.7% to 3.3%), respectively. The authors concluded that this pooled analysis indicated good technical success and mortality rates for both devices, despite the high rate of urgent procedures, suggesting that PRAAs and TAAAs can be treated safely using the included devices. They also stated that further investigations are needed to draw additional conclusions for the IMG due to the small sample size.
Furthermore, an UpToDate review on “Endovascular devices for thoracic aortic repair” (Chaer, 2024) states that “Fenestrated grafts—the use of fenestrated-endovascular aneurysm repair (FEVAR) to manage more challenging aortic anatomy continues to evolve. The Zenith Fenestrated AAA Endovascular Graft is the only device approved for use in the US specifically for the treatment of pararenal abdominal aortic aneurysm (AAA). Other branched devices for treating thoracoabdominal aneurysms are under investigation. Enrollment was recently completed in the early feasibility study evaluating the Gore Excluder Thoracoabdominal Branch Endoprosthesis (TAMBE) for the treatment of aortic aneurysms involving the visceral branch vessels. The TAMBE is designed to be the first complete off-the-shelf solution for treating this complex disease and has been approved for commercial use by the US Food and Drug Administration (FDA).”
The GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE) received FDA approval in January 2024 for pararenal and extent IV thoracoabdominal aortic aneurysms. The pivotal trial described above demonstrated 94.1% freedom from all-cause mortality at 1 year, 99% technical success, and no type I/III endoleaks (Farber, et al., 2024).
Endovascular Repair in Children
Aortic coarctations and congenital pulmonary artery stenosis can pose serious health risks in children due to associated hemodynamic complications. Historically, the use of stents in this population was discouraged because fixed stents do not grow with the child. Consequently, only large caliber adult arterial stents were approved for patients weighing over 25 kg, leaving children with hemodynamic issues from aortic coarctations or pulmonary artery stenosis reliant on surgical options that necessitate repeat surgeries as they grow.
Gibb et al. (2024) presented medium-term outcomes for stenting of aortic coarctation (CoA), whether native or re-coarctation, using newer generation low-profile stents (Valeo, Formula, and BeGraft stents) in children weighing under 30 kg. The investigators conducted a retrospective review of patients under 30 kg who received percutaneous stent treatments for coarctation between 2012 and 2021. Clinical and procedural data were collected, including 19 patients. The median age at the time of the procedure was 5.1 years (range 4.1-6.4 years), and the median weight was 21.0 kg (range 17.3-22.3 kg). One patient had a history of re-coarctation, and 13 (68%) patients were on anti-hypertensives prior to the procedure. Various stents were utilized (14 Valeo™, 4 Formula® 535, 1 BeGraft), all of which can be dilated to 18 mm or larger. One patient required a 9 F sheath, while the others required a 7 F sheath. The narrowest diameter in the aorta increased from a median of 3.5 mm (range 3.0-4.5 mm) to 9.4 mm (range 8.9-9.8 mm), with a statistically significant p-value of <0.001. The median pressure gradient across the coarctation decreased from 35.0 mmHg (range 30.0-43.0 mmHg) to 5.0 mmHg (range 0-10.0 mmHg), also with p < 0.001. There were no intra-procedural complications. The median follow-up duration was 56.0 months (range 13.0-65.0 months). Five patients (26%) underwent re-intervention after a median of 40.0 months (range 39.5-52.0 months); four had balloon dilation, and one had repeat stent implantation. Post-intervention, five patients (26%) remained on anti-hypertensive medications. The authors concluded that their single-center experience demonstrated that percutaneous stenting for aortic coarctation in children under 30 kg, using low-profile stents, was safe and effective, with no significant complications during the median follow-up of 56 months and a 26% re-intervention rate. They emphasized the importance of long-term follow-up, as a quarter of patients continued to require anti-hypertensive medication after stenting.
Berman et al. (2024) stated that stent implantation has become the standard of care for older children and adults in treating branch pulmonary artery stenosis (BPAS) and coarctation of the aorta (CoAo). However, there are currently no stents approved or available for infants that can be dilated to adult diameters. The Minima stent was developed to address this unmet need. The investigators reported on a multicenter, prospective, non-randomized early feasibility study evaluating the safety and effectiveness of the Minima stent for treating BPAS and CoAo. Primary endpoints included successful deployment across the lesion, stenosis relief defined as an increase in angiographic diameter of greater than 50%, and freedom from stent explant, embolization, or migration at 30 days and 6 months. Between February 2022 and May 2022, 10 patients underwent Minima stent implantation, with a median age of 9 months (range 4-43 months) and a median weight of 7.6 kg (range 5.1-16.9 kg). Procedural success and predefined stenosis relief were achieved in all cases (CoAo [n = 4], BPAS [n = 6]). Adverse events occurred in 3 patients: transient diminished lower extremity pulse (n = 2) and distal stent on-balloon displacement, which was successfully managed in the catheterization suite (n = 1). There were no deaths or major adverse events. All patients were free from stent explant and migration at both 30 days and 6 months, with no significant restenosis observed at the latest follow-up. The investigators concluded that the implantation of the Renata Minima stent was safe and effective for treating BPAS and CoAo in this small cohort of infants and young children during early follow-up. They suggested that based on these early results, an expanded study with longer follow-up is warranted.
Nectero Endovascular Aneurysm Stabilization Treatment (EAST) System
Nectero’s endovascular aneurysm stabilization treatment (EAST) system (Nectero Medical) is a one-time endovascular treatment designed to slow or stabilize the growth of small- to medium-sized abdominal aortic aneurysms (AAAs). It delivers a pentagalloylglucose drug solution directly into the aneurysmal wall via a dual-balloon catheter. Nectero EAST System is currently being evaluated in the phase 2/3 stAAAble multicenter, randomized clinical trial (NCT06001918) assessing safety and efficacy in patients with small- to medium-sized AAAs.
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