Which endosurgical treatment for gastroparesis: pyloromyotomy or gastric electrical stimulation?

There has been a boom in performing pyloromyotomy for gastroparesis over the past 10 years, particularly since endoscopic pyloromyotomy (gastric peroral endoscopic myotomy [G-POEM] or pyloromyotomy [POP]) was introduced. How do we place the use of pyloromyotomy, particularly G-POEM, with other treatments for gastroparesis, particularly gastric electrical stimulation (GES)?

“Our current clinical protocol for patients with refractory gastroparesis is the following: if gastric emptying is significantly delayed, especially with symptoms of early satiety, patients undergo pyloromyotomy; if patients have significant nausea and vomiting with markedly delayed gastric emptying, they undergo both stimulator placement and pyloroplasty.”

GES is a controversial therapy for gastroparesis. The Enterra Gastric Electrical Stimulator System (Medtronic, Minneapolis, Minnesota, USA) received US Food and Drug Administration approval under a Humanitarian Device Exemption (HDE) in 2000, considering the device to be safe and of probable benefit. In the initial two multicenter studies assessing efficacy, the system was shown to decrease vomiting frequency in patients with gastroparesis that was refractory to medication. However, subsequent studies performed for approval for efficacy did not meet their predefined endpoint. Some physicians, including myself, use GES for patients with refractory gastroparesis under the HDE and with institutional review board approval, but many physicians do not. Our early studies suggested three factors that helped with patient selection for GES: 1) diabetic patients respond better than idiopathic patients; 2) symptoms of nausea and vomiting improve whereas abdominal pain generally does not; 3) patients using opiate narcotic medications do not respond that favorably [1]. The National Institutes of Health (NIH) Gastroparesis Clinical Research Consortium recently reported the symptom response with gastric stimulation for clinical care of patients with gastroparesis compared with patients who do not receive this treatment [2]. In this observational study in multiple practice settings, 15 % of patients with symptoms of gastroparesis in the NIH registry underwent gastric stimulation. Patients with more severe overall symptoms were more likely to improve symptomatically over 48 weeks, primarily through reduction in nausea severity. A recent article by the French group brings support for GES in a double-blind study, showing that gastric stimulation significantly reduced nausea and vomiting, both in diabetic and nondiabetic patients, and in both those with delayed and normal gastric emptying [3].

In the past 5 years, pyloromyotomy for gastroparesis has re-emerged as a treatment for gastroparesis, especially when performed endoscopically (G-POEM or POP). Multiple studies, primarily single-center studies, suggest that this treatment improves both gastroparesis symptoms and gastric emptying.

There have been few studies comparing the outcomes of the two types of surgical treatments for gastroparesis: pyloromyotomy and GES. In this issue of Endoscopy, Shen et al. compare the results of G-POEM and GES performed over the past decade [4]. The study was a retrospective review of their experience with both treatments at Emory University, and used propensity analysis to match patients in the two treatment groups according to baseline characteristics: 23 patients who underwent G-POEM were matched with 23 patients who received GES. After 2 years of follow-up, the response was 77 % in the G-POEM group, which was better than the 54 % in the GES group. Of the subgroups of gastroparesis, G-POEM was particularly more favorable than GES in idiopathic gastroparesis; G-POEM and GES were fairly similar for diabetic gastroparesis. As G-POEM is a newer procedure, GES was generally performed during a period before G-POEM was available. This is a retrospective chart review, not necessarily capturing similar symptoms using similar measurement tools. The propensity analysis, though helpful for matching patients between treatment groups, does exclude a number of patients undergoing the procedures.

The pyloric sphincter, being the distal muscle of the stomach, helps control gastric emptying. However, there is more to the pathophysiology of gastroparesis than pyloric sphincter dysfunction; there is also antral hypomotility, impairment of fundic tone, gastric dysrhythmias, and perhaps sensory dysfunction. Thus, one would not expect all patients with gastroparesis to respond to pyloromyotomy. A recent study suggests that patients with abnormally reduced pyloric sphincter compliance, as measured by the endoscopic functional luminal imaging probe, respond better to pyloromyotomy than patients with normal pyloric sphincter function [5]. We have also theorized that those patients who respond to botulinum toxin injection into the pylorus might also respond favorably to pyloromyotomy [6]. Perhaps symptoms might help to select patients. G-POEM improves gastric emptying and should improve symptoms of delayed gastric emptying (whatever they are!). Symptoms of gastroparesis are not well correlated with the degree of gastric emptying delay, although in a recent study evaluating studies using optimal gastric emptying test methodology, there were significant associations between gastric emptying and nausea, vomiting, and early satiety/fullness, respectively [7].

When should one perform GES or pyloromyotomy? Generally, these procedures are performed for patients who have not responded to several prokinetic medications and several antiemetic medications. At our center, we perform both stimulator placement and pyloromyotomy procedures in patients with refractory gastroparesis symptoms with delayed gastric emptying. We have found that patients with refractory symptoms of gastroparesis undergoing stimulator placement, pyloromyotomy or combined stimulator with pyloromyotomy each had improvement of their gastroparesis symptoms [8]. However, we found that gastric stimulation improved nausea/vomiting, whereas pyloromyotomy tended to improve early satiety and postprandial fullness. Our current clinical protocol for patients with refractory gastroparesis (not responding to metoclopramide, domperidone, 5-HT₃ receptor antagonists, mirtazapine) is the following: if nausea and vomiting are particularly severe, we proceed with gastric stimulation; if gastric emptying is significantly delayed, especially with symptoms of early satiety, patients undergo pyloromyotomy; if patients have significant nausea and vomiting with markedly delayed gastric emptying, they undergo both stimulator placement and pyloroplasty. Studies are currently being performed to evaluate this type of patient-oriented management approach.

Where do we go from here? Clearly, more studies need to be done. First, we need studies to show that performing these treatments is better than not performing them (placebo-controlled studies). Some studies suggest that patients with idiopathic gastroparesis slowly improve over time, particularly those that may fit the postviral category. Second, comparative studies need to be performed in a prospective randomized fashion to truly compare the two procedures. Third, we need to understand what symptoms get better with each treatment. Fourth, we need to determine what type of patient might be best suited to G-POEM vs. GES. This could be based on etiology of gastroparesis, severity of gastroparesis, pathophysiology, and specific symptoms. Fifth, long-term clinical outcome studies would be helpful to assess durability of the procedures.

Publication History

Article published online:
22 April 2020

• References

• 1 Maranki JL, Lytes V, Meilahn JE. et al. Predictive factors for clinical improvement with Enterra gastric electric stimulation treatment for refractory gastroparesis. Dig Dis Sci 2008; 53: 2072-2078
• 2 Abell TL, Yamada G, McCallum RW. et al. Effectiveness of gastric electrical stimulation in gastroparesis: results from a large prospectively collected database of national gastroparesis registries. Neurogastroenterol Motil 2019; 31: e13714
• 3 Jacques J, Pagnon L, Hure F. et al. Peroral endoscopic pyloromyotomy is efficacious and safe for refractory gastroparesis: prospective trial with assessment of pyloric function. Endoscopy 2019; 51: 40-49
• 4 Shen S, Luo H, Vachaparambil C. et al. Gastric peroral endoscopic pyloromyotomy versus gastric electrical stimulation in the treatment of refractory gastroparesis: a propensity score-matched analysis of long term outcomes. Endoscopy 2020; 52: 349-358 DOI: 10.1055/a-1111-8566.
• 5 Ducrotte P, Coffin B, Bonaz B. et al. Gastric electrical stimulation reduces refractory vomiting in a randomized crossover trial. Gastroenterology 2020; 158: 506-514.e2
• 6 Malik Z, Kataria R, Modayil R. et al. Gastric per oral endoscopic myotomy (G-POEM) for the treatment of refractory gastroparesis: early experience. Dig Dis Sci 2018; 63: 2405-2412
• 7 Vijayvargiya P, Jameie-Oskooei S, Camilleri M. et al. Association between delayed gastric emptying and upper gastrointestinal symptoms: a systematic review and meta-analysis. Gut 2019; 68: 804-813
• 8 Zoll B, Jehangir A, Edwards MA. et al. Surgical treatment for refractory gastroparesis: stimulator, pyloric surgery, or both?. J Gastrointest Surg 2019; DOI: 10.1007/s11605-019-043.