Thrombectomy Systems

Number: 0568

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses AngioJet Rheolytic Thrombectomy System.

1. Medical Necessity

   Aetna considers the AngioJet Rheolytic Thrombectomy System, also known as the Possis AngioJet Rapid Thrombectomy System, medically necessary for the following:

   1. For removing fresh blood clots from any of the following vessels:

      1. Arterio-venous fistulas for hemodialysis by direct anastomosis of artery to vein or by placement of a synthetic graft (e.g., Gortex); or
      2. Coronary arteries or coronary bypass grafts greater than or equal to 2.0 mm in diameter prior to angioplasty or stent placement; or
      3. Infra-inguinal peripheral arteries greater than or equal to 2.0 mm in diameter.

   2. For individuals with lower extremity deep vein thrombosis who have failed pharmacologic thrombolysis or in whom pharmacologic thrombolysis is contraindicated.

2. Experimental, Investigational, or Unproven

   Aetna considers the AngioJet Rheolytic Thrombectomy System experimental, investigational, or unproven for the treatment of the following indications because its clinical value and effectiveness for these indications has not been established (not an all-inclusive list):

   1. Acute aortic occlusion
   2. Acute renal artery thrombosis
   3. Cerebral venous sinus thrombosis
   4. Inferior vena cava filter-related thrombosis
   5. May-Thurner syndrome-related deep venous thrombosis
   6. Pulmonary embolism
   7. Thrombosis of the native aortic valve and of the left ventricular assist device in individuals with heart failure.

   Aetna considers ClotHunter (transluminal mechanical thrombectomy with intravascular ultrasound) experimental, investigational, or unproven for the management of lower extremity deep vein thrombosis because its clinical value and effectiveness has not ben established.

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
CPT codes covered if selection criteria are met:
34201	Embolectomy or thrombectomy, with or without catheter; femoropopliteal, aortoiliac artery, by leg incision
34203	Embolectomy or thrombectomy, with or without catheter; popliteal-tibio-peroneal artery, by leg incision
36904 - 36906	Percutaneous transluminal mechanical thrombectomy and/or infusion for thrombolysis, dialysis circuit, any method, including all imaging and radiological supervision and interpretation, diagnostic angiography, fluoroscopic guidance, catheter placement(s), and intraprocedural pharmacological thrombolytic injection(s)
37187	Percutaneous transluminal mechanical thrombectomy, vein(s), including intraprocedural pharmacological thrombolytic injections and fluoroscopic guidance
37188	Percutaneous transluminal mechanical thrombectomy, vein(s), including intraprocedural pharmacological thrombolytic injections and fluoroscopic guidance, repeat treatment on subsequent day during course of thrombolytic therapy
37211	Transcatheter therapy, arterial infusion for thrombolysis other than coronary or intracranial, any method, including radiological supervision and interpretation, initial treatment day
37212	Transcatheter therapy, venous infusion for thrombolysis, any method, including radiological supervision and interpretation, initial treatment day
37213	Transcatheter therapy, arterial or venous infusion for thrombolysis other than coronary, any method, including radiological supervision and interpretation, continued treatment on subsequent day during course of thrombolytic therapy, including follow-up catheter contrast injection, position change, or exchange, when performed;
37214	cessation of thrombolysis including removal of catheter and vessel closure by any method
37225	Revascularization, endovascular, open or percutaneous, femoral, popliteal artery(s), unilateral; with atherectomy, includes angioplasty within the same vessel, when performed
37227	with transluminal stent placement(s) and atherectomy, includes angioplasty within the same vessel, when performed
37229	Revascularization, endovascular, open or percutaneous, tibial, peroneal artery, unilateral, initial vessel; with atherectomy, includes angioplasty within the same vessel, when performed
37231	with transluminal stent placement(s) and atherectomy, includes angioplasty within the same vessel, when performed
37233	Revascularization, endovascular, open or percutaneous, tibial/peroneal artery, unilateral, each additional vessel; with atherectomy, includes angioplasty within the same vessel, when performed (List separately in addition to code for primary procedure)
37235	with transluminal stent placement(s) and atherectomy, includes angioplasty within the same vessel, when performed (List separately in addition to code for primary procedure)
+ 92973	Percutaneous transluminal coronary thrombectomy (List separately in addition to code for primary procedure)
CPT codes not covered for indications listed in the CPB:
34401	Thrombectomy, direct or with catheter; vena cava, iliac vein, by abdominal incision [treatment of inferior vena cava filter-related thrombosis]
34421	vena cava, iliac, femoropopliteal vein, by leg incision [treatment of inferior vena cava filter-related thrombosis]
34451	vena cava, iliac, femoropopliteal vein, by abdominal and leg incision [treatment of inferior vena cava filter-related thrombosis]
HCPCS codes covered if selection criteria are met:
C1757	Catheter, thrombectomy/embolectomy
HCPCS codes not covered if selection criteria are met:
C7564	Percutaneous transluminal mechanical thrombectomy, vein(s), including intraprocedural pharmacological thrombolytic injections and fluoroscopic guidance with intravascular ultrasound (noncoronary vessel(s)) during diagnostic evaluation and/or therapeutic intervention, including radiological supervision and interpretation
ICD-10 codes covered if selection criteria are met:
I21.01 - I22.9	ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction
I25.10 I25.3 - I25.6 I25.810 - I25.9	Atherosclerotic heart disease of native coronary artery
I70.201 - I70.299	Atherosclerosis of native arteries of the extremities
I70.301 - I70.799	Atherosclerosis of bypass graft of the extremities
I73.9	Peripheral vascular disease, unspecified
I74.3 - I74.4	Embolism and thrombosis of arteries of lower extremities
I74.5	Embolism and thrombosis of iliac artery
I82.220 - I82.221	Embolism and thrombosis of inferior vena cava [deep vein thrombosis]
I82.401 - I82.4z9	Acute embolism and thrombosis of deep veins of lower extremity [deep vein thrombosis]
N18.6	End stage renal disease
N18.9	Chronic kidney disease, unspecified
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
G08	Intracranial and intraspinal phlebitis and thrombophlebitis
I26.01 - I26.99	Pulmonary embolism
I67.6	Nonpyogenic thrombosis of intracranial venous system
I74.09	Other arterial embolism and thrombosis of abdominal aorta [acute aortic occlusion]
I82.210 I82.290 I82.601 - I82.629 I82.a11 - I82.a19 I82.b11 - I82.b19 I82.c11 - I82.c19 I82.890 I82.90	Other acute venous embolism and thrombosis
I82.401 - I82.4Z9	Acute embolism and thrombosis of deep veins of lower extremity
I82.501 - I82.5Z9	Chronic embolism and thrombosis of deep veins of lower extremity
I87.1	Compression of vein [May-Thurner Syndrome-related to deep venous thrombosis]
N28.0	Ischemia and infarction of kidney [acute renal artery thrombosis]
T82.868A – T82.868S	Thrombosis due to vascular prosthetic devices, implants and grafts [treatment of inferior vena cava filter-related thrombosis]

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Background

The AngioJet Rheolytic Thrombectomy System (Possis Medical, Minneapolis, MN) consists of a single-use catheter, single-use pump set, and multi-use drive unit.  The same drive unit and pump set are compatible with various catheters with different design features.  Thrombectomy is accomplished with the introduction of a pressurized saline jet stream through the directed orifices in the catheter distal tip.  The jets generate a localized low pressure zone via the Bernoulli effect, which entrains and macerates thrombus.  The saline and clot particles are then sucked back into the exhaust lumen of the catheter and out of the body for disposal.  Treatment with the device takes about one minute.

United States marketing of the AngioJet System began in 1997 following the receipt of U.S. Food and Drug Administration (FDA) marketing clearance for clot removal in arterio-venous (A-V) fistulas used for dialysis access.  In March 1999, the AngioJet System was approved by the FDA for use in native coronary vessels and coronary bypass grafts and in February 2000, an expansion of this indication was made to include the treatment of fresh thrombus from infra-inguinal peripheral arteries greater than or equal to 2.0 mm in diameter.

The AngioJet has been shown to be appropriate for removal of fresh blood clots from native coronary arteries or coronary bypass grafts prior to angioplasty or stent placement in patients sustaining acute myocardial injury.  Studies show that the AngioJet is similar in effectiveness to urokinase in removing blood clots during a heart attack; therefore, the procedure can be used as an alternative to thrombolytic drugs.

Regarding future AngioJet System applications, a four-hospital FDA clinical study is underway to evaluate AngioJet System safety and effectiveness in treating stroke caused by blood clot blockage of the carotid arteries.

Suarez et al (2004) stated that catheter thrombectomy techniques (e.g., aspiration thrombectomy, fragmentation thrombectomy, and rheolytic thrombectomy) are being developed to provide an alternative treatment modality for severe cases of acute massive pulmonary embolism (PE) when thrombolytics are contraindicated.  Catheter thrombectomy devices have undergone major advances over the last decade, but literature support of their success is limited.

Current evidence for the effectiveness of rheolytic thrombectomy in pulmonary embolism is limited to case reports and one small case series.  Zeni and associates (2003) examined the effectiveness of thrombus removal using the rheolytic thrombectomy catheter (RTC) in 17 patients with acute massive PE.  The RTC was successfully delivered and operated via a 0.035-inch guide wire in all attempted cases.  Treatment resulted in immediate angiographic improvement and initial relief of PE symptoms (improvement in dyspnea and oxygen saturation) in 16 of 17 patients.  One patient developed heart block during the procedure, and further treatment with the RTC was discontinued.  Bradycardia occurred in 1 patient (managed with lidocaine).  After thrombectomy, 10 patients received adjunctive reteplase thrombolysis for treatment of residual thrombus, and 12 received inferior vena cava filters.  In the patient with renal cell carcinoma, histopathological analysis of the evacuated material confirmed tumor origin of the embolism.  There were 2 deaths, both within 24 hours of treatment and secondary to PE.  One death occurred in a patient who had only minimal thrombus removal after treatment with the RTC and no thrombolysis.  The remaining 15 patients showed continued improvement in PE symptoms and were eventually discharged from the hospital with mean length of stay 10.3 +/- 6.5 days (range of 5 to 30 days).  The authors concluded that rheolytic thrombectomy can be performed effectively in patients with massive PE.  However, a large portion of the patients in this study underwent adjuvant overnight thrombolytic infusion.  Further evaluation in a larger cohort of patients is warranted to assess whether this treatment may offer an alternative or complement to thrombolysis or surgical thrombectomy. The Centers for Medicare & Medicaid Services considers as experimental trans-venous (catheter) pulmonary embolectomy procedure for removing pulmonary emboli by passing a catheter through the femoral vein.

The AngioJet is being evaluated for its potential use in the management of patients with deep vein thrombosis.  However, there is insufficient evidence to support its use for this indication.  Bush et al (2004) describe a new method of thrombus removal, with simultaneous percutaneous mechanical thrombectomy (PMT) by means of the AngioJet and thrombolysis in treating symptomatic lower extremity deep venous thrombosis.  These investigators reported that complete thrombus removal was obtained in 15 procedures (65 %), and partial resolution in the remaining 8 procedures (35 %).  The investigators concluded, however, that further outcome measures are needed to examine the effectiveness of this treatment method on preservation of valve function, reduction of chronic venous insufficiency, and improvement in quality of life.

There have been a number of case reports (Siablis et al, 2005; Greenberg et al, 2005; Sternbergh et al, 2000) of the use of the AngioJet thrombectomy catheter for the percutaneous treatment of acute renal-artery thrombosis.  However, the effectiveness of Angiojet for this indication needs to be validated by prospective clinical trials.

Current risk of inadequate myocardial perfusion for thrombus embolization in primary coronary interventions is not negligible.  Margheri et al (2006) evaluated the safety and effectiveness of the AngioJet coronary device in patients with acute myocardial infarction (AMI).  The AngioJet device was used in 116 consecutive patients with AMI and angiographic evidence of extensive thrombosis in a vessel with a reference diameter of greater than 2.5 mm.  Glycoprotein IIb/IIIa inhibitors and stents were used.  Epicardial and myocardial re-perfusion angiographic parameters, and in-hospital major adverse cardiac events (MACE, i.e., cardiac death, myocardial infarction, target vessel re-vascularization) were assessed.  The AngioJet was successfully used in all patients.  Angiographic analysis showed that the AngioJet significantly improved epicardial coronary flow (p < 0.01), frame count (p < 0.01) and myocardial blush (p < 0.01), while stenting yielded significant improvements only in diameter stenosis, minimum lesion diameter and correlated vessel parameters (p < 0.01).  In-hospital MACE were uncommon (9 [8 %]).  When compared to an AMI population with similar thrombus burden but not undergoing thrombectomy, the AngioJet population showed significant improvement of re-perfusion parameters.  Moreover, there was greater AngioJet benefit in the high versus moderate thrombus burden subset; laboratory and operator experience also correlated significantly with final angiographic results.  The authors concluded that the findings of this study supports the favorable risk-benefit profile of AngioJet device use in selected patients with AMI when it is employed in experienced laboratories and by trained operators.

On the other hand, De Luca et al (2007) stated that the benefits of adjunctive mechanical devices to prevent distal embolization in patients with AMI are still a matter of debate.  In a meta-analysis, these researchers combined data from all randomized studies conducted with adjunctive mechanical devices to prevent distal embolization in AMI.  A total of 21 studies with 3721 patients were included (1,877 patients [50.4 %] in the adjunctive mechanical device group and 1,844 [49.6 %] in the control group); 1,502 patients (40.3 %) were randomized in trials with distal protection devices, and 2,219 patients (59.7 %) were randomized in trials with thrombectomy devices.  Adjunctive mechanical devices were associated with a higher rate of post-procedural thrombolysis in myocardial infarction (TIMI) 3 flow (89.4 % versus 87.1 %, p = 0.03), a significantly higher rate of post-procedural myocardial blush grade 3 (48.8 % versus 36.5 %, p < 0.0001), and less distal embolization (6.0 % versus 9.3 %, p = 0.008), without any benefit in terms of 30-day mortality (2.5 % versus 2.6 %, p = 0.88).  No difference was observed in terms of coronary perforations (0.27 % versus 0.07 %, p = 0.24).  The authors concluded that this meta-analysis demonstrates that, among patients with AMI treated with percutaneous coronary intervention, the use of adjunctive mechanical devices to prevent distal embolization is associated with better myocardial perfusion and less distal embolization, but without an apparent improvement in survival.

Chauhan and Kawamura (2007) noted that pulmonary embolism (PE) is a common cardiovascular disease with significant mortality.  Some patients with large PE are not eligible for current treatment options such as thrombolysis or surgical embolectomy.  These investigators reported their experience of percutaneous rheolytic thrombectomy (PRT) using the AngioJet system combined with adjunctive local thrombolytic therapy and inferior vena cava (IVC) filter placement to treat massive or sub-massive PE in patients ineligible for current treatment options.  Of the 14 consecutive patients ineligible for thrombolysis or embolectomy treated with PRT, 10 patients had massive PE (6 patients were hypotensive and 4 patients had intractable hypoxemia) and 4 patients had sub-massive PE.  Adjunctive local thrombolysis was performed in 5 patients.  An IVC filter was placed in 11 patients.  Angiographic success based on Miller score was achieved in 13 patients (92.9 %).  Procedure success was seen in 12 patients (85.7 %). Procedural mortality occurred in 1 patient (7.1 %) who presented in cardiogenic shock and non-fatal hemoptysis occurred in 1 patient (7.1 %).  Total in-hospital mortality occurred in 3 patients (21.4 %).  On a mean follow-up of 9 months, all 11 survivors had noted significant improvement in symptoms without recurrence.  The authors concluded that percutaneous rheolytic thrombectomy using the AngioJet may be a treatment option for patients with massive or sub-massive PE who may not be eligible for thrombolytic therapy or surgical embolectomy.

In a multi-center, randomized, 2-arm, prospective study, Migliorini et al (2010) examined if rheolytic thrombectomy (RT) before direct infarct artery stenting as compared with direct stenting (DS) alone results in improved myocardial re-perfusion and clinical outcome in patients with AMI.  Eligible subjects were patients with AMI, angiographic evidence of thrombus grade 3 to 5, and a reference vessel diameter greater than or equal to 2.5 mm.  Co-primary end points were early ST-segment resolution and (99m)Tc-sestamibi infarct size.  An α value = 0.05 achieved by both co-primary surrogate end points or an α value = 0.025 for a single primary surrogate end point would be considered evidence of statistical significance.  Other surrogate end points were TIMI flow grade 3, corrected TIMI frame count, and TIMI grade 3 blush.  Clinical end points were a composite of major adverse cardiovascular events at 1, 6, and 12 months.  From December 2005 to September 2009, 501 patients were randomly allocated to RT before DS or to DS alone.  The ST-segment resolution was more frequent in the RT arm as compared with the DS alone arm: 85.8 % and 78.8 %, respectively (p = 0.043), while no difference between groups were revealed in the other surrogate end points.  The 6-month major adverse cardiovascular events rate was 11.2 % in the thrombectomy arm and 19.4 % in the DS alone arm (p = 0.011).  The 1-year event-free survival rates were 85.2 +/- 2.3 % for the RT arm, and 75.0 +/- 3.1 % for the DS alone arm (p = 0.009).  The authors concluded that although the primary efficacy end points were not met, the results of this study support the use of RT before infarct artery stenting in patients with AMI and evidence of coronary thrombus.

Barbieri and colleagues (2011) stated that with the diffusion of implantable ventricular assist pumps in heart failure patients refractory to treatments or ineligible to transplantation, acute aortic valve and device thrombosis is an unusual but potentially increasing complication.  These investigators reported a novel application of Angiojet rheolytic thrombectomy for acute and massive thrombosis of the native aortic valve and of the left ventricular assist device in a heart failure patient.  The clinical value of this approach has yet to be determined.

Dashti et al (2013) noted that cerebral venous sinus thrombosis (CVT) is an uncommon cause of stroke that is usually treated medically with intravenous heparin therapy followed by long-term anti-coagulation therapy.  These researchers presented a series of patients with CVT who underwent rheolytic thrombectomy with the AngioJet as a first-line adjunctive treatment in addition to standard anti-coagulation therapy.  Prospectively maintained endovascular databases at 2 institutions were retrospectively reviewed.  The available clinical and imaging data were compiled at each institution and combined for analysis.  Over 18 months, 13 patients (6 men and 7 women; age range of 17 to 73 years, median age of 45 years) with CVT were treated with rheolytic thrombectomy.  Immediate (partial or complete) re-canalization of the thrombosed intra-cranial sinuses was achieved in all patients.  At a median radiographical follow-up of 7 months there was continued patency of all re-canalized sinuses.  Clinical follow-up was available on 9 patients: modified Rankin score of 0 in 4 patients, 1 in 3 patients and 6 in 2 patients.  The authors concluded that this series demonstrated the feasibility of performing mechanical thrombectomy as a first-line treatment for acute CVT.  This technique facilitates the prompt restoration of intracranial venous outflow, which may result in rapid neurological and symptomatic improvement.  The findings of this study need to be validated by well-designed studies.

Bonvini et al (2013) PE associated with hemodynamic instability has exceedingly high mortality.  While intravenous thrombolysis is considered the therapy of choice, percutaneous mechanical thrombectomy may represent an alternative treatment.  In a pilot study, the impact of AngioJet RT in PE associated with cardiogenic shock was assessed in a single-center prospective feasibility study.  A total of 10 consecutive PE patients in cardiogenic shock were included in the study -- 6 patients had thrombolysis contraindications, 8 were intubated before the RT procedure and 6had experienced cardiac arrest prior to the RT procedure.  The RT procedure was technically successful in all cases.  The Miller index improved from 25 to 20 (p = 0.002).  The shock index decreased from 1.22 to 0.9 (p = 0.129).  Thrombolytic agents were administered during or after the procedure in 4 patients because of progressive clinical deterioration.  Seven patients died in the first 24 hours: 2 from multi-organ failure, 1 from post-anoxic cerebral edema, and 4 from progressive right heart failure.  The 3 survivors had favorable outcomes at 1 year.  The authors concluded that the findings of this study suggested that the AngioJet RT procedure may be safely performed in PE patients with cardiogenic shock.  However, despite angiographic and hemodynamic improvements, the procedure does not appear to influence the dismal prognosis of these high-risk patients.

Borhani Haghighi et al (2014) performed a comprehensive literature review on endovascular treatment of cerebral venous sinus thrombosis (CVST) including pharmacological and mechanical thrombolysis.  These investigators searched the English literature on CVST from 1990 to 2012 for all case reports or case series of mechanical thrombectomy.  A total of 64 patients were treated in all published studies.  The techniques for mechanical thrombectomy included rheolytic thrombectomy with an AngioJet device (46.9 %), clot retraction with the Penumbra system (4.7 %), clot retraction with a Fogarty catheter (1.6 %), clot retraction with a micro-snare (3.1 %), balloon venoplasty without stenting (18.7 %), balloon venoplasty with stenting (4.7 %), and an amalgam of techniques (18.7 %).  Nine (16.1 %) patients died.  At the most recent follow-up, 40 (62.5 %) patients had no disability or minor disability and 7 (10.9 %) patients had major disability.  The authors concluded that randomized multi-institutional clinical trials with larger number of participants are needed to sufficiently compare the effect of intra-sinus thrombolysis and mechanical thrombectomy to standard-of-care anti-coagulation therapy.

An UpToDate review on “Treatment of acute pulmonary embolism” (Tapson, 2014) states that rheolytic embolectomy (using a rheolytic embolectomy catheter (i.e., the AngioJet embolectomy system)), rotational embolectomy, suction embolectomy, thrombus fragmentation, and ultrasound plus low-dose thrombolytic therapy are techniques that have been utilized to reduce the embolic burden in patients with acute PE.  Case series using these techniques are small and none of the techniques has been compared with other forms of therapy in randomized trials.  This review states that “Larger studies are needed to determine which, if any, catheter technique is most effective compared to alternative treatment modalities”.

Siddiqui and colleagues (2015) stated that cerebral venous thrombosis is generally treated with anti-coagulation. However, some patients do not respond to medical therapy and these might benefit from mechanical thrombectomy.  These investigators evaluated safety and effectiveness of mechanical thrombectomy in patients with cerebral venous thrombosis, by performing a systematic review of the literature.  They identified studies published between January 1995 and February 2014 from PubMed and Ovid, and included all cases of cerebral venous thrombosis in whom mechanical thrombectomy was performed with or without intra-sinus thrombolysis.  Good outcome was defined as normal or mild neurological deficits at discharge (modified Rankin Scale, 0 to 2).  Secondary outcome variables included peri-procedural complications and re-canalization rates.  This review included 42 studies (185 patients); 60 % of patient had a pre-treatment intracerebral hemorrhage and 47 % were stuporous or comatose.  AngioJet was the most commonly used device (40 %).  Intra-sinus thrombolysis was used in 131 patients (71 %).  Overall, 156 (84 %) patients had a good outcome and 22 (12 %) died; 9 (5 %) patients had no re-canalization, 38 (21 %) had partial, and 137 (74 %) had near to complete re-canalization.  The major peri-procedural complication was new or increased intracerebral hemorrhage (10 %). The use of AngioJet was associated with lower rate of complete re-canalization (odds ratio [OR], 0.2; 95 % confidence interval [CI]: 0.09 to 0.4) and lower chance of good outcome (OR, 0.5; 95 % CI: 0.2 to 1.0).  The authors concluded that the findings of this systematic review suggested that mechanical thrombectomy is reasonably safe; however, controlled studies are needed to provide a definitive answer on its safety and effectiveness in patients with cerebral venous thrombosis.

Deep Vein Thrombosis

Garcia and colleagues (2015) reported procedural and patient outcomes of endovascular treatment for lower-extremity deep venous thrombosis (DVT) with rheolytic thrombectomy (RT).  A total of 32 sites in the U.S. and Europe enrolled patients with DVT in the Peripheral Use of AngioJet Rheolytic Thrombectomy with a Variety of Catheter Lengths (PEARL) registry.  Patient characteristics and outcomes data were collected from consenting patients who underwent RT at investigative sites from January 2007 through June 2013.  A total of 329 patients were enrolled, with 67 % of patients undergoing an AngioJet procedure within 14 days of the onset of symptoms.  Four treatment approaches using ART were identified: RT without lytic agent in 4 % of patients (13 of 329), pharmaco-mechanical catheter-directed thrombolysis (PCDT) in 35 % (115 of 329), PCDT and CDT in 52 % (172 of 329), and RT in combination with CDT in 9 % (29 of 329).  Median procedure times for RT alone, PCDT, PCDT/CDT, and RT/CDT were 1.4, 2, 22, and 41 hours, respectively (p < 0.05, Kruskal-Wallis test).  Procedures were completed in less than 24 hours for 73 % of patients, with 36 % of procedures completed within 6 hours; 86 % of procedures required no more than 2 catheter laboratory sessions.  The 3-, 6-, and 12-month freedom from re-thrombosis rates were 94 %, 87 %, and 83 %, respectively.  Major bleeding events occurred in 12 patients (3.6 %), but none was related to the AngioJet procedure.  The authors concluded that the PEARL registry data demonstrated that rheolytic PCDT treatment of DVT was safe and effective, and could potentially reduce the need for concomitant CDT and intensive care.

Robertson and colleagues (2016) stated that DVT occurs in approximately 1 in 1,000 adults every year, and has an annual mortality of 14.6 %.  In particular, ilio-femoral DVT can lead to recurrent thrombosis and post-thrombotic syndrome (PTS), a painful condition which can lead to chronic venous insufficiency, edema, and ulceration.  It causes significant disability, impaired quality of life (QOL), and economic burden.  Early thrombus removal techniques have been advocated in patients with an ilio-femoral DVT in order to improve vein patency, prevent valvular dysfunction, and reduce future complications, such as PTS and venous ulceration.  One such technique is PMT, a combination of catheter-based thrombectomy and catheter-directed thrombolysis.  These investigators evaluated the effects of PMT versus anti-coagulation (alone or with compression stockings), mechanical thrombectomy, thrombolysis, or other endovascular techniques in the management of people with acute DVT of the ilio-femoral vein.  The Cochrane Vascular Information Specialist searched the Specialized Register (last searched December 2015) and the Cochrane Register of Studies (last searched December 2015).  These investigators searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations; RCTs in which patients with an ilio-femoral DVT were allocated to receive PMT versus anti-coagulation, mechanical thrombectomy, thrombolysis (systemic or catheter directed thrombolysis), or other endovascular techniques for the treatment of ilio-femoral DVT.  At least 2 review authors independently assessed studies identified for potential inclusion.  They found no RCTs that met the eligibility criteria for this review; they identified 1 ongoing study.  The authors concluded that there were no RCTs that assessed the effects of PMT versus anti-coagulation (alone or with compression stockings), mechanical thrombectomy, thrombolysis, or other endovascular techniques in the management of people with acute DVT of the ilio-femoral vein that met the eligibility criteria for this review.  They stated that further high-quality RCTs are needed.

Berencsi and associates (2017) noted that most of the patients with ilio-femoral thrombosis treated with anti-coagulants only are affected with PTS that worsens the patients' QOL.  In the acute phase of proximal DVT catheter-directed (CDT) and PMT may be a reasonable alternative therapeutic method.  These researchers summarized their results using these methods.  Since 2009 , a total of 24 patients with ilio-femoral DVT were treated with these endovascular procedures and with stenting at the authors’ Institution.  The median age of the patients was 35.83 ± 15.9 years, the female: male ratio was approximately 2:1.  The mean time between the onset of the symptoms and the procedures was 11 days; CDT alone was performed in 8 patients, thrombus aspiration in addition to CDT using AngioJet device in 16 patients; in 19 cases the procedure was completed with venous stenting.  During the follow-up, these investigators performed ultrasound (US) examinations and estimated the severity of PTS by Villalta-scale.  The total recanalization-rate was more than 50 %, which even improved during the follow-up.  The total lysis time and the amount of used recombinant tissue plasminogen activator decreased significantly by applying the AngioJet.  They did not find any severe PTS among these patients during the follow-up visits.  The authors concluded that these findings suggested that these methods can be used efficiently and safely in the treatment of acute ilio-femoral DVT.

In a retrospective study, Dumantepe and Uyar (2018) evaluated the safety and effectiveness of percutaneous RT in patients with acute lower extremity DVT.  A total of 68 consecutive patients with acute massive lower extremity DVT were included in this study.  A percutaneous RT device (AngioJet) was used in all patients in an angiography suite through ipsilateral popliteal vein access.  Thrombus clearance and complications were evaluated.  Furthermore, patients underwent a clinical evaluation according to a modified Villalta scale for the investigation of PTS in follow-up.  The Venous Clinical Severity Score, Venous Insufficiency Epidemiological and Economic Study-QOL/Sym questionnaires were completed pre-operatively and re-administered post-operatively.  Overall thrombus clearance (complete re-canalization was achieved in 58 patients (85.2 %) and partial re-canalization was achieved in 7 patients (10.2 %) confirmed through venographic assessment was achieved in 95.5 % of the patient population.  The mean Venous Clinical Severity Score pre-operatively was 13.1 ± 2.2 and decreased to 4.0 ± 1.3 post-operatively (p < 0.01).  The Villalta scale dropped from 12.9 ± 2.8 to 5.5 ± 1.4 post-operatively (p < 0.001).  Overall QOL and symptoms improved as assessed by Venous Insufficiency Epidemiological and Economic Study-QOL/Sym (p < 0.01 and 0.02, respectively).  Only 3 minor bleedings were seen but none of the patients suffered from major bleeding, symptomatic PE, death, or other procedure related complications; 59 out of 65 patients (90.7 %) who were treated successfully with RT remained patent at 12 months according to Doppler ultrasonography and 5 patients (7.3 %) developed a mild PTS.  The authors concluded that RT with or without stenting was superior to anti-coagulant therapy alone in terms of both ensuring venous patency and improving clinical symptoms.  They noted that RT is a safe, effective and easily performed method of endovascular treatment with a low rate of major treatment complications and showed promising clinical mid-term results.

Dopheide and colleagues (2018) stated that RT for acute ilio-femoral DVT with 1st-generation techniques is often incomplete and adjunctive conventional catheter-directed thrombolysis (CDT) is needed in more than 50 % of patients to achieve venous patency.  From the prospective Bern Venous Stent Registry, these investigators examined rates of primary treatment success, primary patency, and PTS from 40 consecutive patients (mean age of 51 ± 19 years, 45 % women) with acute ilio-femoral DVT, treated with a novel directional RT technology and stent placement.  Overall, 24 patients were treated for native-vessel ilio-femoral DVT (11 with single-session RT, 13 with bail-out RT after failed CDT) and 16 for ilio-femoral stent thrombosis.  Pulse-spray thrombolysis (r-tPA 10 mg) was performed in 29 (73 %) patients.  The mean follow-up duration was 193 ± 132 days (minimum 90 days).  Overall, primary treatment success of RT was 95 %; only 2 patients required adjunctive CDT to restore patency.  In 24 patients with native-vessel DVT, 6-month primary patency was 92 % (95 % CI: 75 to 99 %), and 23 patients (96 %) were free from the PTS according to the Villalta score.  In 16 patients with stent thrombosis, 6-month primary patency was 63 % (95 % CI: 35 to 85 %) and 50 % were free from PTS.  Except for transient macroscopic hemoglobinuria in all patients, no other side effects were recorded.  The authors concluded that in patients with ilio-femoral DVT of native or stented vessels, RT followed by stent placement appeared to be safe and effective; the novel technique enabled single-session DVT treatment in the majority of patients without the need for prolonged CDT.

These researchers noted that this study was limited by the relatively low number of study participants (n = 40) and short follow-ups (mean of 193 days).  They stated that future studies should examine the long-term safety and efficacy of this promising technique in large cohorts of patients with acute ilio-femoral DVT.

Liu and associates (2018) compared the treatment outcomes in patients with acute proximal DVT and ilio-femoral stenosis who underwent either direct stenting after ART or staged stenting after ART plus CDT with urokinase.  From June 2014 to February 2016, a total of 91 DVT patients underwent 2 treatments for Duplex ultrasound (US)-verified ilio-femoral stenosis: direct stenting (n = 46; mean age of 54.8 years; 32 men) or staged stenting (n = 45; mean age of 56.5 years; 27 men).  The degree of patency after thrombectomy or thrombolysis was evaluated using the Venous Registry Index (VRI), while the risk of PTS was evaluated according to the Villalta scale.  Patients were followed with periodic Duplex US scans up to 1 year.  The technical success rates were 100 % in both groups; there was no 30-day mortality.  Immediate (24-hour) clinical improvement was achieved in 42 (91 %) of 46 direct group patients versus 33 (73 %) of 45 staged group patients (p < 0.001).  A significant reduction (p < 0.001) in the length of hospital stay was noted in the direct group (4.59 ± 0.91 days) compared with that in the staged group (5.8 ± 1.6 days).  The stents used in the direct group were longer but with similar diameter compared with the staged group.  The thrombolysis rates were 81.50 % ± 5.76 % in the direct group and 85.67 % ± 3.84 % in the staged group (p < 0.001).  The VRIs declined (improved) significantly in both groups (11.68 ± 1.92 to 3.21 ± 1.44 in the direct group and 12.17 ± 2.29 to 2.36 ± 1.19 in the staged group, both p < 0.001).  The Villalta scores were significantly better in the staged group (p < 0.001).  Recurrent DVT occurred in 2 patients in the direct group.  The primary patency rates at 1 year were 93.5 % in the direct group and 97.8 % in the staged group (p = 0.323).  The authors concluded that both direct and staged stenting were effective treatment modalities for patients with acute proximal DVT.  Compared with staged stenting, direct stenting provided similar treatment success and a significant reduction in the length of hospital stay; however, it had lower thrombolysis efficacy, and the risk of PTS at 1 year was greater with direct stenting.

O'Connor and Lookstein (2018) stated that venous thromboembolism, including DVT and PE, occur in up to 900,000 people per year in the U.S.  Current 1st-line treatment consists of systemic anti-coagulation with a goal to prevent additional thrombus formation.  Treatment with anti-coagulation alone provides less than satisfactory results with some studies showing propagation of thrombus in almost 40 % of cases.  Current 1st-line therapy does not include active removal of thrombus and does little to alleviate acute symptoms and the damaging inflammatory response that may result in PTS.  The authors noted that as the public and clinicians continue to recognize the unmet need of venous disease, endovascular therapies, such as CDT, mechanical thrombectomy, and pharmaco-mechanical CDT, have been developed to provide minimally invasive therapy while minimizing complications.

In a retrospective study, Liu and colleagues (2019) reported the clinical outcomes of endovascular treatment for extensive lower extremity DVT with ART plus CDT using a contralateral femoral approach; ART+CDT treatments in 38 DVT patients (Lower Extremity Thrombosis (LET) classification of I to III, from September 2014 to March 2016) was performed.  The technical success rate was 100 %.  Complete lysis was achieved in 82 % of LET III segments (calf veins), 87 % of LET II segments (popliteal-femoral veins), and 90 % of LET III segments (iliac veins).  The best results were obtained in patients treated within 7 days of symptom onset.  During follow-up, well-preserved, competent femoral valves were observed in 86 % of the patients, and re-canalization of LET III, LET II, and LET I segments was achieved in 100 %, 94 %, and 91 % of the patients, respectively.  The post-thrombotic syndrome rate was 17 % during a mean 20-month follow-up.

In a retrospective study, Song and associates (2019) examined the safety and efficacy of ART for the treatment of subacute DVT in the lower extremity.  This trial was carried out in 90 patients with subacute DVT (15 to 90 days) in lower limbs in the authors’ institution from November 2015 to December 2016.  A total of 27 patients with subacute DVT in the lower extremity treated with ART were included in the study, including 17 men and 10 women.  The onset time of thrombosis was between 15 and 75 days; 5 patients were diagnosed bilaterally; 5 patients were diagnosed in the right lower limb; and 17 patients were affected by thrombosis in left lower limb.  All the 27 cases received ART.  After AngioJet thrombectomy, 17 cases were improved to grade II (50 to 99 %), and 10 cases were grade I (less than 50 %); 19 cases were treated with subsequent CDT, and the average time of thrombolysis was 3.2 days, with an average urokinase administration dose of 7.32 million units.  Of the 27 cases, 21 of them received iliac venous balloon dilation, with 10 of them being implanted with the iliac vein stent; 12 stents were implanted in total.  Finally, the angiography suggested that 25 cases (92.6 %) obtained a re-canalization rate higher than grade II, and no serious complications occurred during the peri-operative period.  All patients were followed-up regularly for 3 to 15 months, and 2 patients died from malignant tumor during the follow-up period; 23 cases were followed-up for more than 6 months; 17 cases finished 12-month follow-up.  The primary patency rate at 6 and 12 months was 96.3 % and 88.9 %, respectively.  The Villalta score of post-operative post-thrombosis syndrome symptom at 6 and 12 months was 3.3 ± 2.8 and 3.5 ± 2.8, respectively.  The authors concluded that it was safe and feasible to use the ART in the treatment of subacute DVT in the lower extremity.  In patients without high risk of bleeding, combination of ART and CDT is an effective treatment to reduce the thrombus volume.

In a prospective, multiple-center, non-randomized study, Zhu and co-workers (2019) examined the feasibility, safety, and effectiveness of single-stage endovascular treatment with ART followed by stenting for iliac vein compression syndrome (IVCS) with secondary acute ilio-femoral DVT.  This trial enrolled patients with left-sided acute iliac-common femoral DVT secondary to IVCS.  These researchers carried out ART followed by stenting to assess the success rate, peri-procedural complications, hospital stay, clinical outcomes, and stent-patency rate.  A total of 19 consecutive patients diagnosed with IVCS and secondary acute iliac-common femoral DVT from October 2014 to April 2017 were included in this study.  The technique success rate was 94.7 %, and the mean procedure time was 77 mins.  The 1-year primary and secondary patency rate was 84.2 % and 94.7 %, respectively.  The authors concluded that single-staged endovascular treatment with ART and stenting was feasible, safe, and effective for IVCS with secondary acute ilio-femoral DVT.

In a case-controlled study, Zhu and colleagues (2020) compared the safety and efficacy of ART versus CDT in patients with acute lower extremity DVT.  Between February 2015 and October 2016, a total of 65 patients with documented acute lower extremity DVT were treated with catheter-directed intervention.  These patients were divided into 2 groups: AngioJet group and CDT group.  Comparisons were made with regard to safety and efficacy between these 2 groups.  In the AngioJet group, complete or partial thrombus removal was accomplished in 23 (72 %) and 3 (9 %) patients, respectively.  In the CDT group, complete or partial thrombus removal was accomplished in 27 (82 %) patients and 1 (3 %) patient, respectively.  In the AngioJet group, the perimeter difference between the suffered limb and healthy one declined from 5.1 ± 2.3 cm to 1.4 ± 1.2 cm (p < 0.05).  In the CDT group, the perimeter difference declined from 4.7 ± 1.6 cm to 1.5 ± 0.9 cm (p < 0.05).  The mean urokinase dose was 0.264 ± 0.135 million units in the AngioJet group and 1.869 ± 0.528 million units in the CDT group (p < 0.05).  The duration of thrombolysis was 4.2 ± 1.7 hours in the AngioJet group and 73.6 ± 18.3 hours in the CDT group (p < 0.05).  The occurrence of complications in these 2 groups was 19 % and 18 %, respectively (not significant).  The authors concluded that ART is a safe and effective approach for treating acute lower extremity DVT.  When compared to CDT, ART provided similar success with lower urokinase dosage and shorter duration of thrombolysis.

Furthermore, an UpToDate review on “Endovenous intervention for ilio-caval venous obstruction” (Mousa, 2020) states that “Mechanical thrombectomy uses a variety of devices to break up thrombus with or without the aid of pharmacologic agents.  Outcomes using mechanical thrombectomy alone have been dismal; however, for patients with extensive deep vein thrombosis who are candidates for treatment but in whom pharmacologic thrombolysis is contraindicated, mechanical thrombectomy by itself can be considered.  Available devices include … Rheolytic thrombectomy injects high-velocity saline using Bernoulli's principle to break up and aspirate clot (e.g., Angiojet-Zelante [8 Fr], Angiojet-Solent [6 Fr])”.

Acute Aortic Occlusion

Gursoy and colleagues (2017) reported an endovascular procedure in a patient with acute aortic occlusion causing critical limb ischemia.  Following thrombus debulking with AngioJet system, aorto-iliac patency was achieved with bilateral iliac artery stent placement creating new aortic bifurcation.  The authors concluded that PMT may provide effective debulking of thrombus; it may be utilized before stenting, and may also be curative in selected cases.  These preliminary findings need to be validated by well-designed studies.

Pulmonary Embolism

Chauhan and Kawamura (2017) reported their experience of PRT using the AngioJet system combined with adjunctive local thrombolytic therapy and IVC filter placement to treat massive or sub-massive PE in patients ineligible for current therapeutic options.  Of the 14 consecutive patients ineligible for thrombolysis or embolectomy treated with PRT, 10 had massive PE (6 patients were hypotensive and 4 patients had intractable hypoxemia) and 4 patients had sub-massive PE.  Adjunctive local thrombolysis was performed in 5 patients.  An IVC filter was placed in 11 patients.  Angiographic success based on Miller score was achieved in 13 patients (92.9 %).  Procedure success was obtained in 12 patients (85.7 %).  Procedural mortality occurred in 1 patient who presented in cardiogenic shock (7.1 %) and non-fatal hemoptysis occurred in 1 patient (7.1 %).  Total in-hospital mortality occurred in 3 patients (21.4 %).  On a mean follow-up of 9 months, all 11 survivors had noted significant improvement in symptoms without recurrence.  The authors concluded that PRT using the AngioJet may be a therapeutic option for patients with massive or sub-massive PE who may not be eligible for thrombolytic therapy or surgical embolectomy.

Das and colleagues (2018) performed a retrospective review of treatment of patients with massive or sub-massive PE using the AngioJet rheolytic thrombectomy (ART) system with procedural modifications to improve on the previously reported outcomes.  A total of 13 patients underwent emergent pulmonary artery thrombectomy for massive and sub-massive PE using ART with pharmacological and procedural modification, in comparison to prior reports.  The modifications included the selective use of the Solent Omni AngioJet device in all subjects, distal contrast angiography via the AngioJet catheter before device activation, and limited short run times.  Thrombolytic therapy was not used in any patient.  Patients were monitored for short- and long-term outcomes.  Long-term clinical follow-up and evaluation for persistent pulmonary hypertension with echocardiography was performed.  The pharmacological and procedural modifications resulted in a favorable clinical response without any major complications and without any mortality.  Procedure-related anemia (mean hemoglobin drop of 0.49 g/dL) was the only significant minor complication noted.  There were no bleeding complications and no transfusion requirement.  On a 6-month follow-up, there was no mortality, and there were significant reductions in the pulmonary artery pressures.  The authors concluded that major and minor complications were reduced compared to prior reports using ART.  They stated that a modified ART approach towards treatment of high-risk PE appeared promising both in terms of safety and efficacy.

Pelliccia and colleagues (2020) reported the findings of 33 consecutive patients (20 men and 13 women, age of 43 ± 13 years) with acute PE (APE) and contraindications to thrombolytic therapy who had rheolytic thrombectomy with the AngioJet catheter.  Acute massive PE was initially diagnosed by computed tomography (CT) and then confirmed by pulmonary angiography.  Pulmonary thrombus location was examined before the procedure.  Anemia was defined as a decrease in hematocrit level (less than 39 % for men and less than 36 % for women).  Renal failure was defined as oliguria (urine output of less than 500 ml/24 hours) or an increase in creatinine (greater than 25 % over baseline or an overall increase by 1 g/dL).  Catheter thrombectomy resulted in angiographic improvement in 32 patients (96 %), with a rapid amelioration in functional class (from 3.3 ± 0.9 to 2.1 ± 0.7; p < 0.001) and an increase in oxygen saturation (from 71 ± 15 % to 92 ± 17 %; p < 0.001); no mortality was reported.  Side effects included transient heart block (n = 1), hypotension (n = 3), and bradycardia (n = 5).  Anemia occurred in 4 patients, while renal failure was not detected.  Clinical improvement was maintained during follow-up.  At 1-year follow-up, systolic pulmonary pressure was significantly lower than at baseline (65 ± 31 mm Hg versus 31 ± 19 mm Hg; p < 0.001).  The authors concluded that ART in patients with acute massive PE and contraindications to thrombolysis was an effective therapeutic alternative that was not associated with relevant and persistent side effects, including the risk of death or developing anemia and renal failure.

The authors stated that this study had several drawbacks.  First, their experience was limited by the small sample size (n = 33) and heterogeneity of the patients who had different risk factors for PE and different contraindications to thrombolysis.  Second, the lack of a control group; thus, the findings of this study might not apply in the subset of patients with clinical characteristics different from this study population.  Third, subjects were not randomized to different therapeutic strategies.  However, only a randomized clinical trial may be able to reliably demonstrate a significant effect of any given procedure.

In a retrospective study, Li and associates (2021) examined the therapeutic effects of ART in the treatment of severe APE, including high-risk PE (HR-PE) and intermediate-high-risk PE (IHR-PE).  A total of 44 APE patients (21 HR-PE and 23 IHR-PE) were enrolled and underwent pulmonary ART using 6-French Solent Omini AngioJet device; 19 patients were diagnosed with APE and lower extremity DVT (LEDVT), and underwent thrombectomy of APE and LEDVT simultaneously using ART.  All patients also received local thrombolysis with urokinase.  The results showed that the mean length of stay in intensive care units (ICUs) was 2.4 ± 1.9 days.  The significant improvement in clinical, hemodynamic and angiographic parameters were observed in both groups, and the improvements in shock index, PaO2, and angiographic parameters were improved more obviously in the IHR-PE group; 6 of 44 patients died in-hospital.  During the follow-up, 35 of 38 patients were functioning well and no recurrence of APE was observed.  The authors concluded that pulmonary ART plus local thrombolysis of the pulmonary artery for HR-PE or IHR-PE was feasible and appeared to be safe.  Moreover, these researchers stated that further prospective, controlled studies are needed to examine efficacy compared to existing treatments.

The authors stated that this study had drawbacks due to its retrospective nature and its relatively small sample size (n = 44).  They stated that prospective, multi-center or large randomized controlled trials are needed to confirm and expand these observations.  The risk-benefit balance of local infusion thrombolytics as well as ART in APE patients with relative contraindications to system fibrinolytic therapy was also unclear.

In a retrospective, single-center study, Shi et al (2023) examined the feasibility, safety, and effectiveness of ART in the treatment of APE.  A total of 12 patients with intermediate- or high-risk APE received ART and were followed-up for 6 to 32 months.  The technical success rate, clinical success rate, mortality, complication, as well as ancillary and laboratory tests before and after operation were analyzed retrospectively.  The technical and clinical success rates of ART were both 91.67 % (11/12).  Except for the patient who died of heart failure during the operation, the rest of patients had no serious complications.  After operation, arterial oxygen partial pressure increased while hemoglobin (Hb) and troponin decreased (p < 0.05).  All patients were free of recurrence of APE after 6 to 32 months of follow-up.  Pulmonary artery thrombosis significantly reduced or disappeared.  The authors concluded that ART was an effective treatment for intermediate- and high-risk APE.  It quickly cleared the main pulmonary artery thrombus, relieved pulmonary hypertension, and improved the long-term prognosis of patients.  The findings of this retrospective, single-center study need to be validated by well-designed studies.

Patients with High Thrombus Burden (Thrombolysis in Myocardial Infarction Thrombus Grade-5)

In a retrospective, non-randomized, single-center study, Huang et al (2022) examined the safety and effectiveness of ART among patients with high thrombus burden.  Routine manual thrombus aspiration in patients with ST-segment elevation myocardial infarction (STEMI) does not improve clinical outcomes and was associated with an increased rate of stroke; however, the safety of mechanical thrombus aspiration is still unclear.  In a retrospective, single-center study, these researchers examined the effectiveness of ART in patients (n = 621) with thrombolysis in myocardial infarction thrombus grade-5.  The primary outcome was the composite MACE within 12 months.  The safety outcome was stroke within 1 year.  Propensity matching score was calculated due to the significant baseline differences between the ART group and the routine treatment group; ART was carried out in 117 patients.  After propensity-score matching, there was no significant difference both in the incidence of MACE (11.1 % versus 17.9 %, hazard ratio [HR], 1.641; 95 % CI: 0.822 to 3.277, p = 0.161), and the incidences of stroke (1.7 % versus 2.6 %, HR 1.522; 95 % CI: 0.254 to 9.107, p = 0.646) between the 2 groups at 1-year follow-up.  In patients with thrombolysis in myocardial infarction thrombus grade-5, ART did not improve clinical outcomes at 1 year; however, ART did not increase the risk of stroke in patients with high thrombus burden.  Moreover, these researchers stated that a large multi-center trial is needed to shed light on the benefit and safety of ART in patients with high thrombus burden.

The authors stated that this study has several drawbacks.  First, this was a retrospective, non-randomized study.  Although propensity-score matching was used, the baseline characteristics could not be matched utterly.  There might be selection bias that influenced the findings.  Second, this trial lacked surrogate markers of myocardial re-perfusion, such as myocardial blush grade, ST-segment resolution, or infarct size.  Third, the exact door-to-device time had significant missingness and thus was not analyzed in our study.  However, these researchers were able to confirm that the percentages of delayed PCI (the time of PCI from symptom onset greater than 12 hours) were comparable between the 2 groups.  Finally, this was a single-center study with a small sample size.  

May-Thurner Syndrome-Related Deep Venous Thrombosis

Wei et al (2022) stated that May-Thurner syndrome (MTS) is an anatomic stenotic variation associated with DVT of the left leg.  The classical DVT treatment strategy is medical treatment without thrombus removal.  In a retrospective, cohort study, these researchers examined the clinical outcomes of the combination of ART and stenting for treatment of MTS-related DVT.  They evaluated patients treated for MTS-related DVT from January 2017 to June 2020 at a single institution.  A total of 14 patients (9 women) underwent ART for MTS-related DVT during the study period.  The median DVT onset time was 8 days (IQR, 3 to 21 days).  The median procedure time was 130 mins (IQR, 91 to 189 mins), and the median hospital length of stay (LOS) was 7 days (IQR, 5 to 26 days); 1 patient had a residual thrombus and occluded iliac stent and underwent adjuvant catheter-directed thrombolysis for re-vascularization.  The primary patency rate for the iliac stent was 92.9 % at 12 months.  The authors concluded that concomitant ART and stenting of MTS-induced lesions may be beneficial for patients with MTS-related DVT.

The drawbacks of this study were its small sample size (n = 14); its single-arm, non-randomized, retrospective nature; and its limited follow-up time (12 months).  These researchers stated that further studies with larger populations and longer follow-up periods are needed to examine the patency of ilio-caval stents and the safety of ART in the treatment of patients with MTS-related DVT.

Inferior Vena Cava Filter-Related Thrombosis

Li et al (2023) stated that the inferior vena cava (IVC) filter is used globally to intercept thrombi and to reduce the risk of fatal PE; however, filter-related thrombosis is a complication of filter implantation.  Endovascular methods such as ART and CDT could treat filter-related caval thrombosis; however, the clinical outcomes of both treatment modalities have not been determined.  In a retrospective, single-center study, these researchers compared the treatment outcomes of ART versus CDT in patients with filter-related caval thrombosis.  A total of 65 patients (34 men and 31 women; mean age of 59.0 ± 13.43 years) with intra-filter and inferior vena cava thrombosis were enrolled between January 2021 and August 2022.  Subjects were assigned to either the ART group (n = 44) or the CDT group (n = 21).  Clinical data and imaging information were collected.  Evaluation measures included thrombus clearance rate, peri-procedural complications, urokinase dosage, incidence of PE, limb circumference difference, LOS, and filter removal rate.  Technical success rates were 100%  in both the ART and CDT groups.  In the ART group, grade-II and grade-III thrombus clearance was achieved in 26 (59.09 %) and 14 (31.82 %) patients, respectively.  In the CDT group, grade-II and grade-III thrombus clearance was accomplished in 11 (52.38 %) patients and 8 (38.10 %) patients, respectively (p > 0.05).  The peri-diameter difference of the thigh was significantly reduced in patients from both groups after treatment (p < 0.05).  The median dosage of urokinase was 0.08 (0.02, 0.25) million U in the ART group, and 1.50 (1.17, 1.83) million U in the CDT group (p < 0.05).  Minor bleeding was shown in 4 (19.05 %) patients in the CDT group, and when it was compared with that in the ART group, the difference was statistically significant (p < 0.05).  No major bleeding occurred.  A total of 7 (15.91 %) patients in the ART group had hemoglobinuria, and 1 (4.76 %) patient in the CDT group had bacteremia.  There were 8 (18.18 %) patients with PE in the ART group, and 4 (19.05 %) patients in the CDT group before the intervention (p > 0.05).  Computed tomography angiopulmonography (CTA) showed that PE was resolved after the intervention.  New PE occurred in 4 (9.09 %) patients in the ART group, and in 2 (9.52 %) patients in the CDT group after the intervention (p > 0.05).  These cases of PE were asymptomatic.  The mean LOS was longer in the CDT group (11.67 ± 5.34 days) than in the ART group (10.64 ± 3.52 days) (p < 0.05).  The filter was successfully retrieved in the 1st phase in 10 (47.62 %) patients in the CDT group, and in 15 (34.09 %) patients in the ART group (p > 0.05).  Cumulative removal was accomplished in 17 (80.95 %) out of 21 patients in the CDT group, and in 42 (95.45 %) out of 44 patients in the ART group (p > 0.05).  The median indwelling time for patients with successful retrieval was 16 (13139) days in the CDT group, and 59 (12231) days in the ART group (p > 0.05).  The authors concluded that compared with CDT, ART could achieve similar thrombus clearance effects, improve the filter retrieval rate, reduce the urokinase dosage, and lower the risk of bleeding events in patients with filter-related caval thrombosis.  Moreover, these investigators stated that AngioJet rheolytic thrombectomy, catheter-directed thrombolysis, manual aspiration thrombectomy, and conservative treatment with anticoagulants are effective treatments for patients with IVC thrombosis; large, prospective clinical trials are needed to confirm the clinical outcome of these treatment modalities.

The authors stated that this study had several drawbacks. First, it was a retrospective, single-center retrospective study, which made it prone to patient selection bias and artificial judgment bias for thrombus removal.  Lower extremity deep venous thrombosis (LEDVT) is different from intra-filter and IVC thrombosis.  Thrombus clearance assessment for LEDVT may not be appropriate for IVC thrombosis.  These researchers stated that further investigations are needed to examine objective methods for evaluating thrombus clearance.  Second, the sample size of the study was limited (n = 44 in the ART group).  Third, due to the short follow-up period (median of 4 months, range of 1 to 10), post-thrombotic syndrome (PTS) and venous insufficiency were not evaluated.  Currently, there is a lack of large-scale studies and long-term follow-up on the venous patency rate and incidence of PTS after IVC thrombosis removal.

In a retrospective, single-center study, Gong et al (2024) examined the safety and  effectiveness of ART coupled with dose-reduced recombinant tissue plasminogen activator (rt-PA), compared to CDT alone, for the treatment of massive IVC filter (IVCF)-related thrombosis.  This trial included 40 patients who received either ART or CDT alone as the 1st-line endovascular therapy (ET) between January, 2016 and September, 2022.  The data on demographics, clinical characteristics, technical success, clinical success, complications, and early follow-up were reviewed.  Of the 40 included patients, 24 received ART, and 16 received CDT alone.  The demographics, presentation, lesion characteristics, co-morbidities and risk factors were comparable (all p > 0.05).  Technical success rates were 100 % in both groups.  The total CDT time and infusion agent dosage were lower in the ART group than those in the CDT group (both p < 0.05).  At the end of CDT, clinical success was 81.8 % in the ART group, which was slightly higher than that of 70.8 % in the CDT group (p > 0.05).  At the 6-month follow-up, the incidences of recurrent thrombosis in the 2 groups were 6.9 % and 15.8 %, respectively, and the incidence of PTS was 10.3 % and 21.1 %, respectively.  However, these differences were not statistically significant (p > 0.05).  No major complications were observed in either group, ART appeared to have slightly higher risk of transient macroscopic hemoglobinuria and recoverable acute kidney injury (AKI), but with a lower minor bleeding incidence when compared with CDT alone (4.2 % versus 31.3 %, p < 0.05).  The authors concluded that ART and CDT alone as the 1st-line ETs for IVCF-related thrombosis exhibited comparable outcomes but with different adverse event (AE) profiles.  Both treatment modalities, ART or CDT coupled with dose-reduced rt-PA, were safe and effective in patients with IVCF-related thrombosis.  ART could promote the IVCF retrieval rate, reduce the clot burden speedily, minimize the total thrombolytic agent requirement, and lower minor bleeding complication, but is at potentially increased risk of recoverable AKI.  CDT alone exhibited similar outcomes and lower risk of AKI but has an increased bleeding complication.  Moreover, these investigators stated that further investigations (well-designed, prospective studies with longer follow-up durations) are needed to draw more definitive conclusions.

The authors stated that this study had several drawbacks.  First, a lack of detailed description of the pathophysiology and etiology of IVCF-related thrombosis, which may have partially hampered a comprehensive understanding regarding this disease.  Second, the therapeutic options of ART and CDT in this study may have a biased patient selection, as some patients were transferred from other centers specifically for ART due to the limited medical conditions.  Third, the assessment criterion of clinical outcomes using thrombus removal rate may not be fully appropriate for inferior vena cava thrombosis (IVCT), as it was initially designed for proximal DVT, and there was a lack of standardized criteria for IVCF-related thrombosis.  In the future, specialized criteria for thrombus removal in IVCF-related thrombosis are needed.  Moreover, it should be noted that the percutaneous transluminal angioplasty and stents used were slightly higher in ART treatment, and this study only offered preliminary 6-month follow-up and may not fully capture the potential long-term effects of this interventions.  Fourth, as with any retrospective, single-center study, the presence of unmeasured confounding variables could not be ruled out, and the caution should be exercised when interpreting the conclusion.

Furthermore, an UpToDate review on “Placement of vena cava filters and their complications” (Fedullo and Roberts, 2024) does not mention AngioJet rheolytic thrombectomy as a management / therapeutic option.

ClotHunter (Transluminal Mechanical Thrombectomy with Intravascular Ultrasound) for the Management of Lower Extremity Deep Vein Thrombosis

Shah and Roy (2022) noted that lower extremity DVT results in significant morbidity including pain, swelling, and difficulty walking in the affected limb.  If left untreated, DVT increases the risk of PE, recurrent venous thromboembolism (VTE), and PTS.  These investigators identified catheter-directed interventions and their success rates for the treatment of lower extremity DVT.  They carried out a comprehensive search of current and emerging catheter-directed interventions for lower extremity DVT treatment in PubMed and Google Scholar.  Clinical trials, retrospective and prospective observational studies, as well as case-reports were identified to classify percutaneous mechanical thrombectomy (PMT), catheter-directed thrombolysis (CDT), and pharmaco-mechanical CDT (PCDT) devices based on their mechanism of action and indication of use.  Catheter-directed interventions such as PMT, CDT, and PCDT offer an alternative therapeutic strategy for DVT management, especially in patients with limb-threatening conditions and absolute contraindications to anti-coagulants.  These investigators stated that a few interventional devices such as the Angiovac, ClotTriever, Ekosonic, and Angiojet showed success in treating DVTs lasting longer than 14 days; however, these studies were limited to a small patient size.  Newer mechanical devices are being introduced into the market that are designed to target sub-acute and chronic clots.  Wolf Thrombectomy by Devoro Medical is designed to ingest soft and organized clots; however, there are limited studies examining its effectiveness.  Another promising device is the ClotHunter (Boston Scientific), which is the newest addition to the AngioJet Thrombectomy Systems.  The ClotHunter is a helical shaped attachment for the ZelanteDVT device that rotates 330 degrees clockwise and counter-clockwise to target wall-adherent clots.  It is designed to remove more challenging acute and sub-acute DVTs.  Bench testing by Boston Scientific with the ClotHunter and ZelanteDVT showed 60 % to 80 % greater thrombus removal than with the ZelanteDVT alone; however, there is a lack of evidence supporting the effectiveness of the ClotHunter.  The authors concluded that to-date, there are limited guidelines on the use of mechanical and pharmaco-mechanical devices because of the lack of clinical evidence available for their use in treatment.  These researchers stated that future studies are needed to ascertain the short- and long-term effects of using catheter-directed interventions as well as their effectiveness in treating acute versus sub-acute and chronic DVT.

Elheet et al (2024) stated that acute PE (APE) poses a significant risk to patient health, with therapeutic options varying in safety and effectiveness.  Ultrasound-facilitated CDT (USCDT) has emerged as a potential alternative to conventional CDT for patients with intermediate- to high-risk APE.  In a retrospective, observational study, these researchers compared the safety and effectiveness of USCDT versus conventional CDT in patients with intermediate- to high-risk APE.  This trial was carried out at the Armed Forces Hospital, Al-Hada, Taif, the Kingdom of Saudi Arabia (KSA), on 135 patients diagnosed with APE and treated with either USCDT or CDT (58 underwent CDT, and 77 underwent USCDT).  The primary effectiveness outcome was the change in the right ventricle to the left ventricle (RV/LV) diameter ratio.  Secondary outcomes included changes in systolic pulmonary artery systolic (SPAP) and the Miller angiographic obstruction index score.  Safety outcomes focused on major bleeding events.  Both USCDT and CDT significantly decreased RV/LV diameter ratio (from 1.35 ± 0.14 to 1.05 ± 0.17, p < 0.001) and SPAP (from 55 ± 7 mmHg to 38 ± 7 mmHg, p < 0.001) at 48- and 12-hours post-procedure, respectively, with no significant differences between treatments.  However, USCDT was associated with a significantly lower rate of major bleeding events compared to CDT (0 % versus 3.4 %, p = 0.008).  Multi-variate logistic regression analysis showed that USCDT was associated with a 71.9 % risk reduction of bleeding (OR = 0.281, 95 % CI: 0.126 to 0.627, p = 0.002).  The authors concluded that USCDT was a safe and effective alternative to CDT for the treatment of intermediate- to high-risk APE, as it significantly lowered the risk of major bleeding.  These investigators stated that the drawbacks of this trial included the relatively small number of patients.  In addition the retrospective nature of this study limited the ability to control for all potential confounding factors; thus, prospective, randomized controlled trials (RCTs) are needed to validate these findings.

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References