Gastric Pacing and Gastric Electrical Stimulation

Number: 0678


Aetna considers gastric pacing (gastric pacemaker) and gastric electrical stimulation medically necessary for the treatment of symptoms of nausea and vomiting from chronic gastroparesis, where the diagnosis is confirmed by gastric emptying scintigraphy, that is refractory to medical management (including dietary modification, antiemetics, and prokinetics).

Aetna considers revision or replacement of a previously approved gastric stimulator implant medically necessary for complications associated with gastric pacing (eg, bowel obstruction, gastric wall perforation, infection, lead dislodgement or lead erosion into the small intestine).

Aetna considers gastric pacing and gastric electrical stimulation experimental and investigational for all other indications including the following because their effectiveness for these indications has not been established (not an all-inclusive list):

  • As an initial treatment for gastroparesis
  • For the treatment of autonomic nervous system disorders other than gastroparesis
  • For the treatment of cyclic vomiting syndrome
  • For the treatment of diabetes mellitus in persons without gastroparesis
  • For the treatment of gastrointestinal dysmotility disorders other than gastroparesis
  • For the treatment of obesity.

Note: The use of a second gastric electrical stimulator for the treatment of symptoms of nausea and vomiting from chronic gastroparesis is considered experimental and investigational.


Gastroparesis is a chronic gastric motility disorder of diabetic (both type 1 and type 2 diabetes) or idiopathic etiology.  It is characterized by delayed gastric emptying of solid meals.  Patients with gastroparesis exhibit bloating, distension, nausea, and/or vomiting.  In severe and chronic cases, patients may suffer dehydration, poor nutritional status, and poor glycemic control (in diabetics).  Although gastroparesis is often associated with diabetes, it is also found in chronic pseudo-obstruction, connective tissue disorders, Parkinson disease, and psychological pathology.  Therapeutic options of gastroparesis include prokinetic agents such as metoclopramide, and anti-emetic agents such as metoclopramide, granisetron, or odansetron.  Patients with severe gastroparesis may require enteral or total parenteral nutrition. 

Gastric pacing (gastric stimulation) is utilized to treat individuals with chronic, intractable or drug-refractory nausea and vomiting secondary to gastroparesis. A gastric pacing system delivers electrical stimulation to the gastric muscles by means of two leads that are implanted directly into the stomach and connected to a generator that is implanted into the abdominal area. The device is regulated by an external programmer that noninvasively adjusts the level of gastric stimulation and also allows the device to be completely turned off at any time. Internal battery replacement is required every five to ten years.

Gastric pacing (gastric pacemaker) entails the use of a set of pacing wires attached to the stomach and an external electrical device that provides a low-frequency, high-energy stimulation to entrain the stomach at a rhythm of 3 cycles per minute. However, the gastric pacemaker is cumbersome and problematic for chronic use because of external leads. 

Thus, a newer, implantable device (the Enterra Therapy System by Medtronic, Minneapolis, MN) was developed to provide gastric electrical stimulation (GES).  Unlike gastric pacing, the Enterra delivers a high-frequency (12 cycles per minute), low-energy stimulation to the stomach.  This stimulating frequency does not entrain the stomach, and therefore does not normalize gastric dysrhythmias; hence, the term GES is employed to differentiate between the Enterra and gastric pacing. The Enterra Therapy II system is the only gastric electrical stimulation system approved for marketing by the US Food and Drug Administration (FDA). It is approved under a Humanitarian Device Exemption (HDE). 

The Enterra System was designed to treat intractable nausea and vomiting secondary to gastroparesis.   Electrodes are implanted in the serosa of the stomach laparoscopically or during a laparotomy, and are connected to the pulse generator that is implanted in a subcutaneous pocket.  The Enterra Therapy System (Medtronic, Minneapolis, MN) is currently the only GES that has received approval from the U.S. Food and Drug Administration (FDA).  It was cleared by the FDA as a humanitarian use device.  Thus, the manufacturer was not required to submit the level of evidence that would be required to support a pre-market approval application.  The data presented to the FDA documenting the "probable benefit" of GES (Gastric Electrical Stimulation System) were based on a multi-center double-blind cross-over study (FDA, 2000), which included 33 patients with intractable idiopathic or diabetic gastroparesis.  In the initial phase of the study, all patients underwent implantation of the stimulator and were randomly assigned to stimulation-ON or stimulation-OFF for the first month, with cross-over to OFF and ON during the second month.  The baseline vomiting frequency was 47 episodes per month, which significantly declined in both ON and OFF groups to 23 to 29 episodes, respectively.  However, there were no significant differences in the number of vomiting episodes between the two groups, suggesting a placebo effect.  Thus, long-term results of GES must be validated in longer term randomized studies.  It is important to note that GES did not return gastric emptying to normal in the majority of the treated-patients. 

There exist preliminary data that suggested gastric pacing may be beneficial to patients with refractory gastroparesis.  Forster et al (2001) reported the findings of 25 patients who underwent gastric pacemaker placement.  Both the severity and frequency of nausea and vomiting improved significantly at 3 months and improvements were sustained for 12 months.  Gastric emptying time was also numerically faster over the 12-month period.  Three of the devices were removed and 1 patient died of causes unrelated to the pacemaker 10 months post-operatively.  The authors stated that after placement of the gastric pacemaker, patients rated significantly fewer symptoms and had a modest acceleration of gastric emptying.

Abell et al (2002) performed GES in 33 patients with intractable gastroparesis.  Patients were assessed 3, 5 and 12 months following permanent implantation.  These researchers reported that 97 % of patients experienced greater than 80 % reduction in nausea and vomiting.  For 24 patients who were followed for 1 year, the average weight gain was 5.5 % and 9 of 14 patients receiving enteral or parenteral nutrition were able to discontinue it.  The authors stated that while symptoms improved in the majority of patients following implantation of gastric stimulators, a properly randomized study is needed to ascertain the extent of a favorable placebo response. 

Bortolotti (2002) noted that there are currently 3 principal methods of GES:
  1. gastric electrical pacing,
  2. high-frequency GES, and
  3. sequential neural electrical stimulation. 

The first method aims to reset a regular slow-wave rhythm, but is unable to re-establish efficient contractions and a normal gastric emptying.  High-frequency GES, although inadequate to restore a normal gastric emptying, nevertheless strikingly improves the dyspeptic symptoms, such as nausea and vomiting, giving the patients a better quality of life and a more satisfactory nutritional status.  The last method, neural electrical gastric stimulation, consists of a microprocessor-controlled sequential activation of a series of annular electrodes which encircle the distal 2/3 of the stomach and induce propagated contractions resulting in a forceful emptying of the gastric content.  The latter method is the most promising, but it has so far only been tested in animals and would need to be tested in patients with gastroparesis before it can be used as a solution for this disease.  All the afore-mentioned clinical studies, however, are not controlled and nearly all were published in abstract form.  Thus, further controlled studies are needed to ascertain which of these techniques is more useful for the treatment of gastroparesis.  This is in agreement with Rabine and Barnett (2001) who considered gastric pacing as an experimental technique for the management of patients with gastroparesis.  Additionally, Smith and Ferris (2003) stated that gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation.  Furthermore, in a systematic review of evidence of therapies for gastroparesis, Jones and Maganti (2003) concluded that gastric neurostimulation improves symptoms of nausea and vomiting, but therapeutic gain beyond placebo has not been demonstrated.

Abell et al (2003) reported on a 2-phase clinical study of GES for gastroparesis: in the first phase, lasting 2 months, the investigators attempted to blind participants to stimulation.  In the first phase, 33 patients with gastroparesis (17 diabetic, 16 idiopathic) were randomized to stimulation either ON or OFF for 1 month, then crossed-over to the other mode for 1 month.  During the second uncontrolled phase of the study, all patients had their stimulator turned ON and were followed at 6 and 12 months.  The investigators reported that, during the first phase of the study, vomiting frequency was significantly less in the ON position, than in the off position, with weekly vomiting frequencies of 6.8 and 13.5 episodes, respectively (p < 0.05).  Total symptom score (mean sum of 6 symptoms, rated from 0 (absent) to 4 (severe) was also slightly less in the ON position than the OFF position, with scores of 12.5 + 1.0 and 13.9 + 1.1, respectively.  The investigators noted that 21 patients preferred the ON mode and 7 patients preferred the OFF mode.  An assessment by the National Institute for Clinical Excellence (NICE, 2004) commented that the results of this study are based on short-term follow-up of a small number of patients.  The assessment noted that one of the difficulties in interpreting the evidence on this procedure in this and other studies is the reliance on self-reported measures of symptom relief.   Furthermore, given the nature of the GES procedure, it is possible that patients experienced a placebo response.  The investigators reported that, during the second phase, there were significant improvements from baseline in weekly vomiting frequency, total symptom score, and measures of gastric emptying.  However, only 24 subjects included in this study were followed for 12 months, and gastric emptying data were available for only 20 subjects at 12 months. 

More recent studies have examined the effectiveness of gastric pacing in refractory gastroparesis.  These studies are limited by the lack of a control group, so that the effect of GES on gastroparesis can not be distinguished from the effects of the waxing and waning nature of these symptoms and the effects of concurrent interventions that the patient may be receiving for this condition.  Lin et al (2004) reported on the results of an uncontrolled study of GES in diabetic patients (n = 48) with refractory gastroparesis.  The investigators reported that, after application of high-frequency GES by a permanently implanted system, improvements were observed in upper gastrointestinal symptoms, health-related quality of life, nutritional status, glucose control, and hospitalizations.  van der Voort and colleagues (2005) reported improvements in symptom control and decreases in gastric retention (measured scintigraphically) after 12-months of continuous high-frequency/low-energy GES in a small group (n = 17) of insulin-dependent diabetic subjects suffering from drug-refractory gastroparesis.  The lack of a control group limits the strength of conclusions that can be drawn from these studies.

MaCallum et al (2005) reported on 12 month outcomes of GES in an uncontrolled study of a small group (n = 16) of subjects with post-surgical gastroparesis.  The investigators reported that, after application of GES, there was significant improvement in upper gastrointestinal symptoms, quality of life, nutritional status, and hospitalization requirements.  Lin et al (2005) reported significant reductions in the use of prokinetic/anti-emetic medications and the need for hospitalization after application of GES in an uncontrolled study of refractory gastroparetic patients (n = 37).  The authors also reported that subjects clinical and quality of life outcomes significantly improved after 1 year follow-up.  Other long-term uncontrolled studies include those of Oubre et al (2005) (46 month follow-up) and Cutts et al (2005) (3 year follow-up).

An assessment by the National Institute for Clinical Excellence (2004) concluded that "[c]urrent evidence on the safety and efficacy of gastroelectrical stimulation for gastroparesis does not appear adequate to support the use of this procedure without special arrangements for consent and for audit or research".  The assessment explained that “[c]urrent evidence on the efficacy of the procedure relates mainly to relief from nausea and vomiting, which occurs in some patients. There is little evidence that the procedure improves gastric emptying.”  The assessment reported that one of the difficulties in interpreting the evidence on this procedure is that most studies lack a comparision group, and rely on self-reported measures of symptom relief.

Evidence-based guidelines on gastroparesis from the American Gastroenterological Association (Parkman et al, 2004) state: “Gastric electric stimulation is an emerging therapy for refractory gastroparesis …. Studies to better evaluate the efficacy of gastric electric stimulation are ongoing.  As this type of treatment evolves, further delineation of the overall effectiveness, the type of patient who will likely respond, optimal electrode placement, and stimulus parameters should be explored.”

In a case series study, Filichia and Cendan (2008) assessed the response of transplant patients with gastroparesis to GES (Enterra therapy) and compared to non-transplant recipients.  A questionnaire consisting of 11 questions was administered to investigate symptoms.  Patients were asked to score these symptoms before and after surgery using a 0 to 5 Likert scale.  A total of 13 consecutive patients underwent placement of the Enterra device with a mean follow-up of 12 +/- 6.1 months.  Transplant recipients were as likely as diabetic or idiopathic patients to show improvements in symptoms of nausea, vomiting, as well as retching and prandial symptoms following Enterra therapy.  In fact, transplant patients reported improvement in appetite and bloating symptoms more frequently than diabetics (p = 0.055 and p = 0.037, respectively).  The authors concluded that post-transplantation gastroparesis responds to Enterra therapy as well as in patients with idiopathic or diabetic gastroparesis.  They stated that Enterra therapy should be prospectively investigated in this population of patients.

An UpToDate review on “Electrical stimulation for gastroparesis” (Hasler, 2015) states that “Patients with severe nausea and vomiting (occurring on average at least once-daily), which have proven refractory to aggressive anti-emetic and prokinetic drug therapy for at least 1 year in duration may be candidates for gastric neurostimulation. In the United States, the gastric electrical neurostimulator (Enterra Therapy system, Medtronic, Inc., Minneapolis, MN) has been approved as a humanitarian exemption device only for diabetic and idiopathic gastroparesis”.

Obesity is a major health problem among adults in the United States.  It is also an increasing health concern among American children as well as adolescents.  Various methods are employed in the management of obesity.  One of the new approaches is gastric pacing, which is intended to induce early satiety through electrical stimulation of the gastric wall.  However, the effectiveness of this technique in treating obesity has not been established.  Buchwald and Buchwald (2002) considered gastric pacing as an experimental procedure for the management of morbid obesity.

An assessment of gastric pacing for obesity by the Swedish Council on Technology Assessment in Healthcare (SBU, 2004) found that "[t]here is insufficient scientific evidence on the short-term patient benefit of gastric pacing" for obesity, and that "[t]here is no scientific evidence on the long-term patient benefit of gastric pacing" for this indication.  The assessment concluded:

“Gastric pacing is still an experimental method and should be used only in scientific studies that have been approved by a research ethics committee.  Trials that include adequate control groups are very much needed.”

Yao et al (2005) stated that acute retrograde gastric pacing at a tachygastrial frequency results in a significant reduction of water and food intake and a delay in gastric emptying without inducing any unacceptable symptoms.  The investigators concluded that it is worthy to explore its therapeutic potential for obesity.  In a review on the potential role of new therapies in modifying cardiovascular risk in over-weight patients with metabolic risk factors, Jensen (2006) noted that surgically implanted gastric pacemaker systems that modulate vagus nerve activity and delay gastric emptying are under study.

Salvi et al (2009) reported their 2-year experience on gastric pacing in the treatment of morbid obesity.  From August 2005 to January 2006, a total of 4 patients (mean age of 44 years) underwent placement for implantable gastric stimulation (IGS) therapy.  The mean bone mass index (BMI) was 41.8, mean weight 117.2 kg.  The IGS was activated 30 days after implantation.  Fasting and post-prandial plasma ghrelin concentrations after a test meal were measured before and 1, 2, 3 and 6 months after implantation.  All procedures were successfully completed laparoscopically.  There were no major operative complications.  Post-operative course was uneventful in all cases.  One patient was lost to follow-up after 6 months.  Post-operative lead dislodgement and cutaneous decubitus occurred in another patient, making necessary the removing of the device.  For the remaining 2 patients, there was a significant weight loss (49 kg) in 1, while weight was unchanged in the other.  Plasma ghrelin concentrations were not correlated among patients.  The authors concluded that morbid obese patients can undergo IGS implantation by laparoscopy with minimal peri-operative complications.  Attention to technical details is essential.  In accordance with the manufacturer, these data demonstrated that gastric pacing is a safe procedure for selected patients supported by adequate psychological treatment, but outcome about weight loss should be evaluated among bigger trial.  According to these investigators, their experience with IGS didn't provide satisfactory results, thus discouraging them to carry on with the study.

In a prospective, randomized, placebo-controlled, double-blind, multi-center study, Shikora et al (2009) compared IGS therapy with a standard diet and behavioral therapy regimen in a group of class 2 and 3 obese subjects by evaluating the difference in the percentage of excess weight loss (EWL) between the control and treatment groups.  The primary endpoint was the percentage of EWL from baseline to 12 months after randomization.  A total of 190 subjects were enrolled in this study.  All patients underwent implantation with the implantable gastric stimulator and were randomized to one of the following two groups:
  1. the control group (stimulation off) or
  2. treatment group (stimulation on). 

Patients were evaluated on a monthly basis.  All individuals who enrolled in this study agreed to consume a diet with a 500-kcal/day deficit and to participate in monthly support group meetings.  The procedure resulted in no deaths and a low complication rate.  The primary endpoint of a difference in weight loss between the treatment and control groups was not met.  The control group lost 11.7 % +/- 16.9 % of excess weight and the treatment group lost 11.8 % +/- 17.6 % (p = 0.717) according to an intent-to-treat analysis.  The authors concluded that IGS as a surgical option for the treatment of morbid obesity is a less complex procedure than current bariatric operations.  However, the results of the present study do not support its application.  They stated that additional research is needed to understand the physiology and potential benefits of this therapy.

Policker and colleagues (2009) noted that the TANTALUS System (MetaCure Limited) is a minimally invasive implantable device for the treatment of type 2 diabetes (T2DM).  The system detects food intake by sensing gastric electrical variations and applies electrical stimulation to the gut synchronized to natural gastric activity.  It is commercially available in Europe and Israel and is in clinical trials in the United States.  It has been tested in 132 patients worldwide to date.  These researchers re-analyzed previously reported data from different studies.  This retrospective analysis of the type 2 diabetes sub-population analyzed the expected benefit and characterized the significance of baseline A1c in the determination of the expected clinical outcome.  From the total cohort of 132 patients implanted with the TANTALUS device in 10 different centers in Europe and the United States, these investigators identified 50 subjects (27 females, 23 males) who were obese with uncontrolled T2DM on a stable regime of oral medication for 3 months before implantation of the device.  This population had similar inclusion/exclusion criteria as well as treatment protocols and were all treated for at least 24 weeks.  The analysis was based on the A1c change compared to baseline.  Data after 24 weeks demonstrated a reduction in A1c in 80 % of the patients with average drop in A1c of 1.1 +/- 0.1 %.  The average weight loss was 5.5 +/- 0.7 kg.  The authors concluded that these findings suggested that the TANTALUS stimulation regime can improve glucose levels and induce moderate weight loss in obese T2DM patients.

In an European multi-center, open-label clinical study, Bohdjalian and associates (2009) prospectively investigated the potential effect of the TANTALUS system on glycemic control and weight in over-weight subjects with T2DM.  A total of 13 T2DM obese (7 females, 6 males, BMI of 37.2 +/- 1.0 kg/m(2), range of 30.4-44.0 kg/m(2)) subjects treated with oral anti-diabetic medications but with poor glycemic control (HbA1c greater than or equal to 7 %, range of 7.3 to 9.5 %) were implanted laparoscopically with the TANTALUS system.  Thirteen subjects that had completed 3 months of treatment showed a significant reduction in HbA1c from 8.0 +/- 0.2 % to 6.9 +/- 0.1 % (p < 0.05), whereas fasting blood glucose decreased from 175 +/- 6 mg/dL to 127 +/- 8 mg/dL (p < 0.05).  The glycemic improvement was accompanied by reduction in weight from 104.4 +/- 4.4 kg to 99.7 +/- 4.8 kg, and in waist circumference from 122.3 +/- 3.2 cm to 117.0 +/- 3.0 cm.  The authors concluded that interim results with the TANTALUS system suggest that this stimulation regime can potentially improve glucose levels and induce moderate weight loss in obese T2DM subjects on oral anti-diabetic therapy with poor glycemic control.  They stated that further evaluation is needed to ascertain if this effect is due to induced weight loss and/or due to direct signal-dependent mechanisms.

Thazhath et al (2013) noted that delayed gastric emptying affects a substantial proportion of patients with long-standing diabetes, and when associated with symptoms and/or disordered glycemic control, affects quality of life adversely.  Important clinic-pathological insights have recently been gained by the systematic analysis of gastric biopsies from patients with severe diabetic gastroparesis, which may stimulate the development of new therapies in the coming decade.  The authors stated that experience with prokinetic therapies and treatments, such as pyloric botulinum toxin injection and GES, has established that relief of symptoms does not correlate closely with acceleration of delayed gastric emptying, and that well-designed randomized controlled trials are essential to determine the effectiveness of emerging therapies.

Cha and colleagues (2014) evaluated the current state-of-the-art of GES to treat obesity. These investigators performed systematic reviews of all studies to evaluate the effect of different types of GES on obesity. A total of 31 studies consisting of a total of 33 different trials were included in the systematic review for data analysis. Weight loss was achieved in most studies, especially during the first 12 months, but only very few studies had a follow-up period longer than 1 year. Among those that had a longer follow-up period, many were from the Transcend (Implantable Gastric Stimulation) device group and maintained significant weight loss. Other significant results included changes in appetite/satiety, gastric emptying rate, blood pressure and neuro-hormone levels or biochemical markers such as ghrelin and HbA1c. The authors concluded that GES holds great promises to be an effective obesity treatment. Moreover, they stated that stronger evidence is needed through more studies with a standardized way of carrying out trials and reporting outcomes, to determine the long-term effect of GES on obesity.

Gastric Pacing and Gastric Electrical Stimulation for Gastro-Intestinal Dysmotility

Sallam and associates (2014) stated that patients with gastro-intestinal (GI) dysmotility of systemic sclerosis (SSc, scleroderma) require careful evaluation and intervention. The lack of effective prokinetic drugs motivate researchers to search for alternative treatments. These researchers presented an overview of the pathophysiology of SSc GI dysmotility and the advances in its management, with particular focus on acupuncture-related modalities and innovative therapies. Original research articles were identified based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline methodology. These investigators have searched the MEDLINE database using Medical Subject Heading (MeSH) for all English and non-English articles with an English abstract from 2005 to October 2012. Key words used included gastric electrical stimulation. Only 4 original articles of various study designs were found studying complementary and alternative medicine (CAM) therapies for SSc patients. Despite the small patient study numbers, CAM treatments, acupressure, and transcutaneous electro-acupuncture, showed self-reported and physiologic evidence of improvement of GI functioning and/or symptoms in SSc patients. The authors concluded that CAM therapies include experimental modalities with the potential to offer relief of symptoms from GI dysmotility. They stated that larger studies are needed to investigate their optimal use in patient subsets to tailor therapies to patient needs.

Gastric Pacing and Gastric Electrical Stimulation for Cyclic Vomiting Syndrome

Grover and colleagues (2016) stated that cyclic vomiting syndrome (CVS) is a disabling migraine variant manifesting as severe episodes of nausea and vomiting and often refractory to many therapies. Gastric electrical stimulation, which can reduce nausea and vomiting in gastroparesis, may provide symptomatic relief for drug-refractory CVS.  In a 1-year, non-randomized, clinical study, these researchers examined the effects of GES in reducing the symptoms of CVS and improving quality of life.  A total of 11 consecutive patients with drug-refractory CVS based on Rome III criteria and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN), underwent treatments with temporary GES (Temp GES) and permanent GES (Perm GES).  Post-treatment follow-up was carried out up to 1 year after Perm GES therapy.  Total symptom score decreased by 68 % and 40 % after Temp GES and Perm GES therapies, respectively.  Hospital admission events significantly decreased to 1.50 (± 1.00) events from 9.14 (± 7.21) annual admissions prior to treatment with Perm GES.  Vomiting episodes fell by 83 % post-Temp GES, and 69 % post-Perm GES treatments.  Mucosal electrogram values also changed after temporary stimulation.  The authors concluded that in a small group of drug-refractory CVS patients, treatments with Temp GES and Perm GES significantly reduced the severity of GI symptoms and frequency of hospital admissions.  These preliminary findings need to be validated by well-designed studies.

Gastric Pacing and Gastric Electrical Stimulation for Autonomic Nervous System Disorders

Lee and Abd-Elsayed (2016) stated that neuromodulation (e.g., GES, cavernous nerve stimulation, deep brain stimulation, and vagus nerve stimulation) has been used with success in treating several functional disease conditions.  The FDA has approved the use of neuromodulation for a few indications.  These researchers discussed the evidence of using neuromodulation for treating some important disorders involving the autonomic nervous system (ANS) that are not currently FDA approved.  This was a review article that included a systematic online web search for human clinical studies testing the effectiveness of neuromodulation in treating asthma, erectile dysfunction, gastroparesis, gastro-esophageal reflux disease (GERD), heart failure, and obesity.  This review included all feasibility studies, non-randomized clinical trials, and RCTs.  The systematic literature search found 3, 4, 5, 4, 1, and 4 clinical studies relating to erectile dysfunction, gastroparesis, GERD, obesity, asthma, and heart failure, respectively.  The authors concluded that this review article showed preliminary support based on clinical studies that neuromodulation can be of benefit for patients with important ANS disorders that are not currently approved by the FDA.  They stated that all of these investigational uses are encouraging; further studies are needed for all indications discussed in this review before achieving FDA approval.

Gastric Pacing and Gastric Electrical Stimulation for the Treatment of Obesity

Morales-Conde and colleagues (2018) noted that weight regain following bariatric surgery is not uncommon.  Safe, effective weight loss treatment up to 1 year has been reported with the closed-loop GES (CLGES) system.  Continuous recording of eating and activity behavior by onboard sensors is one of the novel features of this closed-loop electrical stimulation therapy, and may provide improved long-term weight maintenance by enhancing aftercare.  Four centers participating in a 12-month prospective multi-center randomized study monitored all implanted participants (n = 47) up to 24 months after laparoscopic implantation of a CLGES system.  Weight loss, safety, quality of life (QOL), and cardiac risk factors were analyzed.  Weight regain was limited in the 35 (74 %) participants remaining enrolled at 24 months.  Mean percent total body weight loss (%TBWL) changed by only 1.5 % between 12 and 24 months, reported at 14.8 % (95 % confidence interval [CI]: 12.3 to 17.3) and 13.3 % (95 % CI: 10.7 to 15.8), respectively.  The only serious device-/procedure-related adverse events (AEs) were 2 elective system replacements due to lead failure in the first 12 months, while improvements in QOL and cardiovascular risk factors were stable through 24 months.  The authors concluded that during the 24 month follow-up, CLGES was shown to limit weight regain with strong safety outcomes, including no serious AEs in the 2nd year.  These investigators hypothesized that CLGES and objective sensor-based behavior data combined to produce behavior change.  The findings of this study support CLGES as a safe obesity treatment with potential for long-term health benefits.

Busetto and associates (2018) analyzed behavior changes using sensor-based food intake and activity data in participants treated with the CLGES system.  Food intake and activity data (3-D accelerometer) were down-loaded at baseline and monthly/bimonthly for 12 months in a subset of patients with obesity (n = 45) participating in a multi-center trial with CLGES.  Measured food intake parameters included the number of intakes during allowed and disallowed periods, night-time intakes, and between-meal snacks (average/day).  Activity parameters included time in different levels of physical activity (mins/day), sleep/sedentary (hours/day), and estimated energy expenditure (EE).  Weight loss at 12 months averaged 15.7 ± 7.7 % of the baseline body weight.  Stable reduction in the number of disallowed meals and between-meal snacks (p < 0.05), an increase in all levels of physical activity (p < 0.001), and an increase in activity-based EE (303 ± 53 kcal/day on average, p < 0.001) were observed.  The authors concluded that significant and consistent positive changes in eating behavior and physical activity were observed in a small group of patients with severe obesity treated with CLGES therapy for 12 months.  These lifestyle modifications led to a clinically significant 15 % weight loss.  There is an increasing interest today in the use of modern advanced technology in behavioral therapy.  The potential of digital technology, including Web‐based tools, mobile phones and smartphone applications, virtual reality, and gaming technologies, has been reviewed in relation to both general obesity management and specifically in bariatric surgery.  Electronic activity monitor systems have been increasingly studied and have yielded positive results in clinical practice.  The CLGES system used in this study coupled effective and tailored GES with an extensive use of modern technology for behavioral self‐monitoring and modifications.  They stated that this new form of a combined weight loss approach appears promising and warrants further testing and application.

The authors stated that this study had several drawbacks.  First, food intake and physical activity down-loaded from the device at the 1st follow‐up visit, which was 2 weeks following implantation and before CLGES activation, were used as baseline data.  This raised the possibility that the behavior of the patients in this period could be influenced by the recent surgery and not be representative of normal behavior before the surgery.  However, device implantation required only minimal surgery, and patients usually did not experience significant problems or limitations in the early post-operative period.  Second, the follow‐up in this study was limited to 12 months, and this short period of observation raised some concern regarding the durability of behavioral changes and weight loss.  Weight loss has been reported to remain stable until 27 months in a small sample of patients treated with CLGES therapy, but controlled studies with a more extended follow‐up time are needed.  These investigators stated that one of the major issues raised by this study was what part of the effect of the CLGES system was due to the electrical stimulation and what part was due to the behavioral modifications determined by data monitoring.  The magnitude of the weight loss observed in this study was larger than the weight loss usually reported after behavioral programs, suggesting an additive effect between GES and behavioral modifications.  However, the design of this study precluded definitive conclusion.  The exact role played by each of the 2 components could be disentangled only by a specifically designed double‐blind study comparing weight loss in patients having the stimulation turned on or off.

Table: CPT Codes / HCPCS Codes / ICD-10 Codes
Code Code Description

Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":

CPT codes covered if selection criteria are met:

0162T Electronic analysis and programming, reprogramming of gastric neurostimulator (ie, morbid obesity)
43647 Laparoscopy, surgical; implantation or replacement of gastric neurostimulator electrodes, antrum
43648     revision or removal of gastric neurostimulator electrodes, antrum
43881 Implantation or replacement of gastric neurostimulator electrodes, antrum, open
43882 Revision or removal of gastric neurostimulator electrodes, antrum, open
64590 Insertion or replacement of peripheral or gastric neurostimulator pulse generator or receiver, direct or inductive coupling
64595 Revision or removal of peripheral or gastric neurostimulator pulse generator or receiver
95980 Electronic analysis of implanted neurostimulator pulse generator system (e.g., rate, pulse amplitude and duration, configuration of wave form, battery status, electrode selectability, output modulation, cycling, impedance and patient measurements) gastric neurostimulator pulse generator/transmitter; intraoperative, with programming
95981     subsequent, without reprogramming
95982     subsequent, with reprogramming

Other CPT codes related to the CPB:

78264 Gastric emptying imaging study (eg, solid, liquid, or both)
78265 Gastric emptying imaging study (eg, solid, liquid, or both); with small bowel transit
78266 Gastric emptying imaging study (eg, solid, liquid, or both); with small bowel and colon transit, multiple days

HCPCS codes covered if selection criteria are met:

C1767 Generator, neurostimulator (implantable), non-rechargeable
C1778 Lead, neurostimulator (implantable)
L8679 Implantable neurostimulator pulse generator, any type
L8680 Implantable neurostimulator electrode, each
L8688 Implantable neurostimulator pulse generator, dual array, non-rechargeable, includes extension

ICD-10 codes covered if selection criteria are met:

[K31.84 also required]
Diabetic gastroparesis
K31.84 Gastroparesis

ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):

E08.00 - E08.42
E08.44 - E09.42
E09.44 - E10.42
E10.44 - E11.42
E11.44 - E13.42
E13.44 - E13.9
Diabetes mellitus
E66.01 - E66.1
E66.8 - E66.9
Obesity and morbid obesity
F50.81 - F50.89 Other eating disorders [psychogenic cyclic vomiting]
G43.A0 Cyclical vomiting, not intractable
G90.01 - G90.9 Disorders of autonomic nervous system
G43.A1 Cyclical vomiting, intractable
K30 Functional dyspepsia

The above policy is based on the following references:

Gastric Pacing and Gastric Electrical Stimulation for Gastroparesis

  1. Hocking MP, Vogel SB, Sninsky CA. Human gastric myoelectric activity and gastric emptying following gastric surgery and with pacing. Gastroenterology. 1992;103(6):1811-1816. 
  2. Kelly KA. Pacing the gut. Gastroenterology. 1992;103(6):1967-1968.
  3. Meidema BW, Sarr MG, Kelly KA. Pacing the human stomach. Surgery. 1992;111(2):143-150. 
  4. Rothstein RD, Alavi A, Reynolds JC. Electrogastrography in patients with gastroparesis and effect of long-term cisapride. Digestive Dis Sci. 1993;38(8):1518-1524.  
  5. Cullen JJ, Kelly KA. The future of intestinal pacing. Gastroenterology Clin North Am. 1994;23(2):391-402. 
  6. Lin ZY, McCallum RW, Schirmer BD, Chen JD. Effects of pacing parameters on entrainment of gastric slow waves in patients with gastroparesis. Am J Physiol. 1998;274(1 Pt 1):G186-G191.
  7. Hasler WL. The brute force approach to electrical stimulation of gastric emptying: A future treatment for refractory gastroparesis? Gastroenterology. 2000;111(3):456-460. 
  8. U.S. Food and Drug Administration (FDA), Center for Devices and Radiologic Health (CDRH). EnterraTM Therapy System (formerly named Gastric Electrical Stimulation (GES) System). Humanitarian Use Device Exemption H990014, Issued March 31, 2000. Rockville, MD: FDA; August 22, 2000. 
  9. Forster J, Sarosiek I, Delcore R, et al. Gastric pacing is a new surgical treatment for gastroparesis. Am J Surg. 2001;182(6):676-681.
  10. Horowitz M, Su YC, Rayner CK, Jones KL. Gastroparesis: prevalence, clinical significance and treatment. Can J Gastroenterol. 2001;15(12):805-813.
  11. Rabine JC, Barnett JL. Management of the patient with gastroparesis. J Clin Gastroenterol. 2001;32(1):11-18.
  12. Bortolotti M. The "electrical way" to cure gastroparesis. Am J Gastroenterol. 2002;97(8):1874-1883.
  13. Abell TL, Van Cutsem E, Abrahamsson H, et al. Gastric electrical stimulation in intractable symptomatic gastroparesis. Digestion. 2002;66(4):204-212.
  14. Abell T, McCallum R, Hocking M, et al. Gastric electrical stimulation for medically refractory gastroparesis. Gastroenterology. 2003;125(2):421-428.
  15. Smith DS, Ferris CD. Current concepts in diabetic gastroparesis. Drugs. 2003;63(13):1339-1358.
  16. Jones MP, Maganti K. A systematic review of surgical therapy for gastroparesis. Am J Gastroenterol. 2003;98(10):2122-2129.
  17. Forster J, Sarosiek I, Lin Z, et al. Further experience with gastric stimulation to treat drug refractory gastroparesis. Am J Surg. 2003;186(6):690-695.
  18. Lin Z, Forster J, Sarosiek I, McCallum RW. Treatment of diabetic gastroparesis by high-frequency gastric electrical stimulation. Diabetes Care. 2004;27(5):1071-1076.
  19. Lin Z, Forster J, Sarosiek I, McCallum RW. Effect of high-frequency gastric electrical stimulation on gastric myoelectric activity in gastroparetic patients. Neurogastroenterol Motil. 2004;16(2):205-212.
  20. National Institute for Clinical Excellence (NICE). Gastroelectrical stimulation for gastroparesis. Interventional Procedure Guidance 103. London, UK: NICE; December 15, 2004.
  21. Parkman HP, Hasler WL, Fisher RS. American Gastroenterological Association medical position statement: Diagnosis and treatment of gastroparesis. Gastroenterol. 2004;127(5):1589-1591.
  22. Lin Z, Forster J, Sarosiek I, McCallum RW. et al. Treatment of diabetic gastroparesis by high-frequency gastric electrical stimulation. Diabetes Care. 2004;27(5):1071-1076.
  23. McCallum R, Lin Z, Wetzel P, et al. Clinical response to gastric electrical stimulation in patients with postsurgical gastroparesis. Clin Gastroenterol Hepatol. 2005;3(1):49-54.
  24. van der Voort IR, Becker JC, Dietl KH, et al. Gastric electrical stimulation results in improved metabolic control in diabetic patients suffering from gastroparesis. Exp Clin Endocrinol Diabetes. 2005;113(1):38-42.
  25. Cutts TF, Luo J, Starkebaum W, Is gastric electrical stimulation superior to standard pharmacologic therapy in improving GI symptoms, healthcare resources, and long-term health care benefits? Neurogastroenterol Motil. 2005;17(1):35-43.
  26. Lin Z, McElhinney C, Sarosiek I, et al. Chronic gastric electrical stimulation for gastroparesis reduces the use of prokinetic and/or antiemetic medications and the need for hospitalizations. Dig Dis Sci. 2005;50(7):1328-1334.
  27. Oubre B, Luo J, Al-Juburi A, et al. Pilot study on gastric electrical stimulation on surgery-associated gastroparesis: Long-term outcome. South Med J. 2005;98(7):693-697.
  28. Moga C, Harstall C. Gastric electrical stimulation (Enterra Therapy System) for the treatment of gastroparesis. Health Technology Assessment Report No. 37. Edmonton, AB: Alberta Heritage Foundation for Medical Research; January 1, 2006.
  29. Ontario Ministry of Health and Long-Term Care, Medical Advisory Secretariat (MAS). Gastric electrical stimulation. Health Technology Policy Assessment. Toronto, ON: MAS; August 2006.
  30. Gourcerol G, Leblanc I, Leroi AM, et al. Gastric electrical stimulation in medically refractory nausea and vomiting. Eur J Gastroenterol Hepatol. 2007;19(1):29-35.
  31. Filichia LA, Cendan JC. Small case series of gastric stimulation for the management of transplant-induced gastroparesis. J Surg Res. 2008;148(1):90-93.
  32. McKenna D, Beverstein G, Reichelderfer M, et al. Gastric electrical stimulation is an effective and safe treatment for medically refractory gastroparesis. Surgery. 2008;144(4):566-572; discussion 572-574.
  33. Soffer E, Abell T, Lin Z, et al. Review article: Gastric electrical stimulation for gastroparesis -- physiological foundations, technical aspects and clinical implications. Aliment Pharmacol Ther. 2009;30(7):681-694.
  34. O'Grady G, Egbuji JU, Du P, et al. High-frequency gastric electrical stimulation for the treatment of gastroparesis: A meta-analysis. World J Surg. 2009;33(8):1693-1701.
  35. Yin J, Abell TD, McCallum RW, Chen JD. Gastric neuromodulation with enterra system for nausea and vomiting in patients with gastroparesis. Neuromodulation. 2012;15(3):224-231.
  36. Chu H, Lin Z, Zhong L, et al. Treatment of high-frequency gastric electrical stimulation for gastroparesis. J Gastroenterol Hepatol. 2012;27(6):1017-1026. 
  37. Camilleri M, Parkman HP, Shafi MA, et al. Clinical guideline: Management of gastroparesis. Am J Gastroenterol. 2013;108(1):18-37; quiz 38.
  38. Hasler WL. Electrical stimulation for gastroparesis. UpToDate [online serial]. Waltham, MA: UpToDate; reviewed June 2015.
  39. Heckert J, Sankineni A, Hughes WB, et al. Gastric electric stimulation for refractory gastroparesis: A prospective analysis of 151 patients at a single center. Dig Dis Sci. 2016;61(1):168-175.

Gastric Pacing and Gastric Electrical Stimulation for Obesity and Diabetes

  1. Deitel M, Shikora SA. Introduction. Gastric pacing for obesity. Obes Surg. 2002;12 Suppl 1:2S.
  2. Greenstein RJ, Belachew M. Implantable gastric stimulation (IGS) as therapy for human morbid obesity: Report from the 2001 IFSO symposium in Crete. Obes Surg. 2002;12 Suppl 1:3S-5S.
  3. Cigaina V. Gastric pacing as therapy for morbid obesity: Preliminary results. Obes Surg. 2002;12 Suppl 1:12S-16S.
  4. Buchwald H, Buchwald JN. Evolution of operative procedures for the management of morbid obesity 1950-2000. Obes Surg. 2002;12(5):705-717.
  5. Ouyang H, Yin J, Chen JD. Therapeutic potential of gastric electrical stimulation for obesity and its possible mechanisms: A preliminary canine study. Dig Dis Sci. 2003;48(4):698-705.
  6. Cigaina V, Hirschberg AL. Gastric pacing for morbid obesity: Plasma levels of gastrointestinal peptides and leptin. Obes Res. 2003;11(12):1456-1462.
  7. Swedish Council on Technology Assessment in Healthcare (SBU). Gastric pacing (gastric electrical stimulation) for the treatment of obesity -- early assessment briefs (Alert). Stockholm, Sweden: SBU; 2004.
  8. Cigaina V. Long-term follow-up of gastric stimulation for obesity: The Mestre 8-year experience. Obes Surg. 2004;14 Suppl 1:S14-S22.
  9. Liu S, Hou X, Chen JD. Et al. Therapeutic potential of duodenal electrical stimulation for obesity: Acute effects on gastric emptying and water intake. Am J Gastroenterol. 2005;100(4):792-796.
  10. Yao S, Ke M, Wang Z, et al. Retrograde gastric pacing reduces food intake and delays gastric emptying in humans: A potential therapy for obesity? Dig Dis Sci. 2005;50(9):1569-1575.
  11. Jensen MD. Potential role of new therapies in modifying cardiovascular risk in overweight patients with metabolic risk factors. Obesity (Silver Spring). 2006;14 Suppl 3:143S-149S.
  12. McNatt SS, Longhi JJ, Goldman CD, McFadden DW. Surgery for obesity: A review of the current state of the art and future directions. J Gastrointest Surg. 2007;11(3):377-397.
  13. Cigaina V, Hirschberg AL. Plasma ghrelin and gastric pacing in morbidly obese patients. Metabolism. 2007;56(8):1017-1021.
  14. Sanmiguel CP, Haddad W, Aviv R, et al. The TANTALUS system for obesity: Effect on gastric emptying of solids and ghrelin plasma levels. Obes Surg. 2007;17(11):1503-1509.
  15. Salvi PF, Brescia A, Cosenza UM, et al. Gastric pacing to treat morbid obesity: Two years experience in four patients. Ann Ital Chir. 2009;80(1):25-28.
  16. Shikora SA, Bergenstal R, Bessler M, et al. Implantable gastric stimulation for the treatment of clinically severe obesity: Results of the SHAPE trial. Surg Obes Relat Dis. 2009;5(1):31-37.
  17. Policker S, Haddad W, Yaniv I. Treatment of type 2 diabetes using meal-triggered gastric electrical stimulation. Isr Med Assoc J. 2009;11(4):206-208.
  18. Bohdjalian A, Ludvik B, Guerci B, et al. Improvement in glycemic control by gastric electrical stimulation (TANTALUS) in overweight subjects with type 2 diabetes. Surg Endosc. 2009;23(9):1955-1960.
  19. Ma J, Rayner CK, Jones KL, Horowitz M. Diabetic gastroparesis: Diagnosis and management. Drugs. 2009;69(8):971-986.
  20. Hasler WL. Methods of gastric electrical stimulation and pacing: A review of their benefits and mechanisms of action in gastroparesis and obesity. Neurogastroenterol Motil. 2009;21(3):229-243.
  21. Sanmiguel CP, Conklin JL, Cunneen SA, et al. Gastric electrical stimulation with the TANTALUS System in obese type 2 diabetes patients: Effect on weight and glycemic control. J Diabetes Sci Technol. 2009;3(4):964-970.
  22. McCallum RW, Snape W, Brody F, et al. Gastric electrical stimulation with Enterra therapy improves symptoms from diabetic gastroparesis in a prospective study. Clin Gastroenterol Hepatol. 2010;8(11):947-954.
  23. Aljarallah BM. Management of diabetic gastroparesis. Saudi J Gastroenterol. 2011;17(2):97-104.
  24. Mizrahi M, Ben Ya'acov A, Ilan Y. Gastric stimulation for weight loss. World J Gastroenterol. 2012;18(19):2309-2319.
  25. Mintchev MP. Gastric electrical stimulation for the treatment of obesity: From entrainment to bezoars-a functional review. ISRN Gastroenterol. 2013;2013:434706.
  26. Thazhath SS, Jones KL, Horowitz M, Rayner CK. Diabetic gastroparesis: recent insights into pathophysiology and implications for management. Expert Rev Gastroenterol Hepatol. 2013;7(2):127-139.
  27. Cha R, Marescaux J, Diana M. Updates on gastric electrical stimulation to treat obesity: Systematic review and future perspectives. World J Gastrointest Endosc. 2014;6(9):419.
  28. Morales-Conde S, Alarcon Del Agua I, Busetto L, et al. Implanted closed-loop gastric electrical stimulation (CLGES) system with sensor-based feedback safely limits weight regain at 24 months. Obes Surg. 2018;28(6):1766-1774.
  29. Busetto L, Torres AJ, Morales-Conde S, et al. Impact of the feedback provided by a gastric electrical stimulation system on eating behavior and physical activity levels. Obesity (Silver Spring). 2017;25(3):514-521.

Gastric Pacing and Gastric Electrical Stimulation for Gastro-Intestinal Dysmotility

  1. Sallam HS, McNearney TA, Chen JD. Acupuncture-based modalities: Novel alternative approaches in the treatment of gastrointestinal dysmotility in patients with systemic sclerosis. Explore (NY). 2014;10(1):44-52.

Gastric Pacing and Gastric Electrical Stimulation for Cyclic Vomiting Syndrome and Selected Indications

  1. Grover I, Kim R, Spree DC, et al. Gastric electrical stimulation is an option for patients with refractory cyclic vomiting syndrome. J Neurogastroenterol Motil. 2016;22(4):643-649.
  2. Lee S, Abd-Elsayed A. Some non-FDA approved uses for neuromodulation in treating autonomic nervous system disorders: A discussion of the preliminary support. Neuromodulation. 2016;19(8):791-803.