BlueCross and BlueShield of Montana Medical Policy/Codes
Gastric Electrical Stimulation
Chapter: Medicine: Treatments
Current Effective Date: December 27, 2013
Original Effective Date: October 20, 2010
Publish Date: December 27, 2013
Revised Dates: December 6, 2012; December 11, 2013

Gastric electrical stimulation (GES) is performed using an implantable device designed to treat chronic drug-refractory nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology.  The device may be referred to as a gastric pacemaker.

Currently, only one GES system has received approval from the FDA (see note below), the Gastric Electrical Stimulator (GES) System (now called Enterra™ Therapy System), manufactured by Medtronic.  The GES system consists of four components: the implanted pulse generator, two unipolar intramuscular stomach leads, the stimulator programmer, and the memory cartridge.  With the exception of the intramuscular leads, all other components have been used in other implantable neurological stimulators, such as spinal cord or sacral nerve stimulation.  The intramuscular stomach leads are implanted either laparoscopically or during a laparotomy and are connected to the pulse generator, which is implanted in a subcutaneous pocket.  The programmer sets the stimulation parameters, which are typically set at an ON time of 0.1 sec alternating with an OFF time of 5.0 sec.

Gastroparesis is a chronic disorder of gastric motility characterized by delayed emptying of a solid meal.  Symptoms include bloating, distension, nausea, and vomiting.  When severe and chronic, gastroparesis can be associated with dehydration, poor nutritional status, and poor glycemic control in diabetics.  While most commonly associated with diabetes, gastroparesis is also found in chronic pseudo-obstruction, connective tissue disorders, Parkinson's disease, and psychological pathologic conditions.  Treatment of gastroparesis includes prokinetic agents such as cisapride and metoclopramide, and antiemetic agents such as metoclopramide, granisetron, or odansetron.  Severe cases may require enteral or total parenteral nutrition.

GES has also been investigated as a treatment of obesity as a technique to increase a feeling of satiety with subsequent reduced food intake and weight loss.  The exact mechanisms resulting in changes in eating behavior are uncertain but may be related to neuro-hormonal modulation and/or stomach muscle stimulation.  There are no GES devices approved by the FDA for the treatment of obesity.  However, the Transcend™ implantable GES, manufactured by Transneuronix Corporation, is currently available in Europe for treatment of obesity.  Transneuronix is currently funding clinical trials in the United States, and the company hopes to obtain FDA approval in a couple of years for use of the Transcend™ device to promote weight loss in the management of obesity.

Note: The GES System received FDA approval through a “Humanitarian Device Exemption (HDE).”  This regulatory category was established in 1996 and only applies to devices intended to benefit fewer than 4,000 patients.  The approval process is similar to that of a premarket approval application (PMA), but is exempt from the effectiveness requirements of a PMA.  Thus the application is not required to provide results of scientifically valid clinical investigations, but must contain sufficient information for the FDA to determine that the device does not pose unreasonable or significant risk of illness or injury.  A humanitarian use device may only be used in facilities that have an IRB to supervise clinical testing of the device.


Each benefit plan, summary plan description or contract defines which services are covered, which services are excluded, and which services are subject to dollar caps or other limitations, conditions or exclusions.  Members and their providers have the responsibility for consulting the member's benefit plan, summary plan description or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply.  If there is a discrepancy between a Medical Policy and a member's benefit plan, summary plan description or contract, the benefit plan, summary plan description or contract will govern.


Gastric electrical stimulation (GES) using the Enterra Therapy System™ may be considered medically necessary for the treatment of chronic, intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology when ALL of the following criteria are met:

  • Symptomatic gastroparesis ≥ one year, as documented by an initial gastric emptying test; and
  • Refractory or intolerant to at least two anti-emetic and prokinetic drug classes, and
  • On stable medical therapy and, if applicable, stable nutritional support during the month prior to initiation of therapy, and
  • Delayed gastric emptying, defined by > 60% retention at two hours and > 10% retention at four hours, as measure by standardized gastric emptying testing, and
  • As a humanitarian approved device, the Enterra Therapy System™ may only be used in facilities that have an Institutional Review Board (IRB) to supervise clinical testing of the device.

Gastric electrical stimulation is considered experimental, investigational and unproven in all other indications including but not limited to the treatment of obesity.

Note:  The Medtronic Enterra Therapy System™ received a Humanitarian Use Device designation in September 1999 and received U.S. Food and Drug Administration (FDA) approval under a Humanitarian Device Exemption (HDE) in March 2000 for the covered indications.


Gastric Electrical Stimulation for the Treatment of Chronic, Intractable (drug refractory) Nausea and Vomiting Secondary to Gastroparesis (GP) of Diabetic or Idiopathic Etiology

GP is a rare and even life-threatening disorder and in severe and chronic cases, nausea and vomiting may cause weight loss, dehydration, electrolyte disturbances, and poor glycemic control in diabetic patients.  In the randomized crossover study (Worldwide Anti-Vomiting Electrical Stimulation Study [WAVESS]) with results measured at one month of follow-up for stimulation ON and Off with the GES device, the weekly vomiting frequency and total symptom score (TSS) for severity measured separately for diabetic and idiopathic patients showed an improvement compared with baseline values.  The differences between the stimulation ON and OFF period were not statistically significant.

The FDA considers the Medtronic Enterra Therapy System™ to be a legally marketed device under the HDE provision.  An investigational device exemptions application (See 21 CFR Part 812 Investigational Device Exemptions), which would be required for "experimental" or "investigational" use, is not required for the use of this device for the treatment of chronic, intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology.  Furthermore, the act does not require informed consent from individuals treated with a device approved under the HDE provision as would be the case with an investigational device.

The available intermediate and long-term data (some > three years) indicate that GES may be associated with improvements in gastrointestinal symptom scores, nutrition and quality-of-life for patients with GP of diabetic or idiopathic origin and that these improvements are sustained over time.  The mechanism of action, however, is not well known.  GES is used more often for symptom control than for treatment of the motility disorder.  Based on the current evidence, the safety and efficacy of GES for routine use is not adequate.  However, for patients with severe GP the GES using the Enterra™ Therapy system would be considered as a last resort treatment after all conventional treatment regimes have failed.

2008 Update

The policy was updated with a literature review using MEDLINE through April 2008.  None of the publications reported results on a randomized controlled trial of GES for gastroparesis.  Anand and colleagues reported on 214 consecutive drug-refractory patients with the symptoms of gastroparesis (146 idiopathic, 45 diabetic, 23 after surgery) who consented to participate in a variety of clinical research and clinical protocols at three centers from January 1992 through January 2005, resulting in 156 patients implanted with a GES device and 58 patients as controls.  At last follow-up, median four years, most patients implanted (135 of 156) were alive with intact devices, significantly reduced gastrointestinal symptoms, and improved health-related quality of life, with evidence of improved gastric emptying, and 90% of the patients had a response in at least one of three main symptoms.  Most patients, who were explanted, usually for pocket infections, were later re-implanted successfully.  Based on a series of 15 patients, Gourcerol reported that high-frequency gastric electrical stimulation could be an effective therapy for treating intractable nausea and vomiting whether or not gastric emptying was delayed.  In an editorial accompanying the Anand study, Ang comments that without an appropriate control group, the contribution of a placebo effect to the treatment group cannot be excluded.  The editorial comments on the scarce literature about long-term outcome of severe gastroparesis, but that follow-up case series of those who require tube feeding suggest an overall improvement over time.  The editorial also notes, given the high costs involved, the unknown mechanism of action, and the absence of rigorous well-controlled randomized trials, that “we should exercise caution” before embracing GES as a standard of care.  However, no information was found that would change the coverage position of this medical policy for patients with severe GP when using the Enterra™ Therapy system as a last resort treatment after all conventional treatment regimes have failed.

Gastric Stimulation for the Treatment of Obesity

GES is also proposed as a method of weight reduction in morbidly obese individuals.  Gastric stimulation may make patients feel full with less food.  Two separate studies of twelve and twenty-four obese patients respectively were implanted with gastric electrical stimulation therapy.  The published studies provide five-year outcomes on two patients only. Nine-month data on the majority of patients reported mean excess body mass index lost to be 30% or sixteen kilograms.

Due to lack of long term outcomes from well-designed randomized clinical trials, conclusions cannot be made concerning the safety and efficacy of GES in morbidly obese individuals.  No GES devices have received FDA approval for treatment of obesity.   A literature review was conducted using MEDLINE through April 2008.  No significant information was found that would change the coverage position of this medical policy for GES for the treatment of obesity.

2010 Update

A search of the Medline database was conducted through October 2010.

Gastric Electrical Stimulation for the Treatment of Chronic, Intractable (drug refractory) Nausea and Vomiting Secondary to Gastroparesis (GP) of Diabetic or Idiopathic Etiology

Brody and colleagues report on the largest of a series, with 50 patients (20 diabetic, 25 idiopathic, two postsurgical and three connective tissue disorders). Thirty-five patients (70%) were available for follow-up at six months and 30 were available at 12 months.  Total symptom severity score (19.05 + 8.05) decreased at six (12.92 + 7.41, p<0.001) and 12 months (14.05 + 8.28, p<0.01). Total frequency score (20.39 + 8.08) decreased at six months (15.01 + 7.37, p<0.01) and 12 months (15.71 + 7.40, p<0.05).  Gastric retention at two hours decreased from 66% to 50% (p<0.04) and normalized in 11 of 27 patients.

In one recent publication, McCallum and colleagues performed a multicenter prospective study to evaluate GES (Enterra therapy) in patients with chronic intractable nausea and vomiting from diabetic gastroparesis (DGP).  In this study, 55 patients with refractory DGP (5.9 years of DGP) were given implants of the Enterra system.  After surgery, all patients had the stimulator turned on for six weeks and then they randomly were assigned to groups that had consecutive three-month cross-over periods with the device on or off.  After this period, the device was turned on in all patients and they were followed up unblinded for 4.5 months.  During the initial six-week phase with the stimulator turned on, the median reduction in weekly vomiting frequency (WVF) compared with baseline was 57%.  There was no difference in WVF between patients who had the device turned on or off during the three-month cross-over period.  At one year, the WVF of all patients was significantly lower than baseline values (median reduction, 68%; P<0.001).  One of the patients had the device removed due to infection; two patients required surgical intervention due to lead-related problems. 

Gastric Stimulation for the Treatment of Obesity

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 prospective, randomized, placebo-controlled, double-blind multicenter study.  All patients underwent implantation with the GES and were randomized to one of the following two groups: (1) the control group (stimulation off) or (2) treatment group (stimulation on).  All 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.  The authors noted that additional research is needed to understand the physiology and potential benefits of this therapy.  Coverage statement remains unchanged for GES for the treatment of obesity.


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Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy.  They may not be all-inclusive.           

The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers.  Only the written coverage position in a medical policy should be used for such determinations.           

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ICD-9 Codes

536.3, 278, 278.0, 278.00, 278.01, 249.00 - 250.93

ICD-10 Codes
E08.43, E09.43, E10.43, E11.43, E13.43, K31.89, 0DH60MZ, 0DH63MZ, 0DH64MZ
Procedural Codes: 43647, 43648, 43881, 43882, 64590, 64595, 95980, 95981, 95982, E0765
  1. FDA - Medtronic Enterra™ Therapy System, H990014-Summary of Safety and Probable Benefit. (2000 March 31st).
  2. McElhinny, C., Sarosiek, I., et al. Comparison of hospitalization, medications and quality of life in patients receiving gastric electrical stimulation (GES) therapy for severe gastroparesis. Gastroenterology (2002) 122:A82.
  3. Cigaina, V. Gastric pacing as therapy for morbid obesity: preliminary results.  Obesity Surgery (2002) 12 (suppl 1):12S-16S.
  4. D'Argent, J.  Gastric electrical stimulation as therapy of morbid obesity: preliminary results from the French study.  Obesity Surgery (2002) 12(suppl 1):21S-25S.
  5. Abell, T., McCallum, R. et al.  Gastric electrical stimulation for medically refractory gastroparesis. Gastroenterology (2003) 125(2):421-8.
  6. Abell, T., Lou, J., et al.  Gastric electrical stimulation for gastroparesis improves nutritional parameters at short, intermediate and long-term follow-up.  JPEN Journal of Parenternal Enteral Nutrition (2003) 27(4):277-81.
  7. Forster J, Sarosiek I, Lin Z et al.  Further experience with gastric stimulation to treat drug refractory gastroparesis.  American Journal of Surgery (2003) 186(6):690-5.
  8. Cigaina, V. Hirschberg, A.L.  Gastric pacing for morbid obesity: plasma levels of gastrointestinal peptides and leptin.  Obesity Research (2003) 11(12):1456-62.
  9. De Luca, M., Segato, G., et al.  Progress in implantable gastric stimulation: summary of results of the European multi-center study.  Obesity Surgery (2004)14(suppl 1):S33-9.
  10. Lin, Z., Forster, J., et al. Treatment of diabetic gastroparesis by high-frequency gastric electrical stimulation.  Diabetes Care (2004) 27(5):1071-6.
  11. Favretti, F., De Luca, M., et al.  Treatment of morbid obesity with the Transcend Implantable Gastric Stimulator (IGS): a prospective survey.  Obesity Surgery 2004; 14(5):666-70.
  12. Shikora, S.A.  Implantable gastric stimulation for the treatment of severe obesity.  Obesity Surgery (2004) 14(4):545-8.
  13. van der Voort, I.R., Becker, J.C., et al.  Gastric electrical stimulation results in improved metabolic control in diabetic patients suffering from gastroparesis.  Experimental and Clinical Endocrinology and Diabetes (2005)113(1):38-42.
  14. Alberta Heritage Foundation for Medical Research - HTA Report #37, Gastric Electrical Stimulation (Enterra™ Therapy System) for the Treatment of Gastroparesis, (2006 January).
  15. Lin, Z., Sarosiek, J., et al.  Symptom responses, long-term outcomes and adverse events beyond 3 years of high-frequency gastric electrical stimulation for gastroparesis.  Neurogastroenterology and Motility (2006 January) 18(1):18-27.
  16. Mason, R.J., Lipham, J., et al.  Gastric electrical stimulation: an alternative surgical therapy for patients with gastroparesis. Achieves of Surgery (2005) 140(9):841-6.
  17. Anand, C., Al-Juburi, A., et al.  Gastric electrical stimulation is safe and effective: a long-term study in patients with drug refractory gastroparesis in three regional centers.  Digestion (2007) 75(2-3):83-9.
  18. Gourcerol, G., Leblanc, I., et al.  Gastric electrical stimulation in medically refractory nausea and vomiting.  European Journal of Gastroenterology Hematology (2007) 19(1):29-35.
  19. Ang, D., Tack J.  Gastric electrical stimulation for the treatment of gastroparesis: ready for prime time?  Digestion (2007) 75(2-3):80-2.
  20. Brody F, Vaziri K, Saddler A et al. Gastric electrical stimulation for gastroparesis. J Am Coll Surg 2008; 207(4):533-8.
  21. Shikora, S.A, Bergenstal, R. et al.  Implantable gastric stimulation for the treatment of clinically severe obesity : results of the SHAPE trial.  Surg Obes Relat Dis (2009) 5(1):31-7.  
  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 [Epub ahead of print].
  23. Gastric Electrical Stimulation.  Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2010 October) Surgery 7.01.73.
December 2012  Policy updated with literature review, references 1, 15 and 22 added; “post-surgical” added to investigational statement on gastroparesis.  Added CPT 43659. 
December 2013 Policy formatting and language revised.  Removed codes 43659, L8680, L8685, L8686, L8687, and L8688.  Added HCPCs code E0765.  Gastric electrical stimulation previously investigational.  Added medically necessary criteria to policy statement.
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Gastric Electrical Stimulation