Gastric peroral endoscopic myotomy for the treatment of refractory gastroparesis: a prospective single-center experience with mid-term follow-up (with video)

The goals for successful development of treatment in gastroparesis

BACKGROUND

Gastroparesis is a motility disorder of the stomach characterized by cardinal symptoms and delayed gastric emptying of solid food in the absence of mechanical obstruction. There is significant unmet need in its management, and essentially there are no medications approved for its treatment over four decades.

PURPOSE

The objectives of this review are to develop an understanding of the goals of treatment, the evidence-based criteria for treatment success based on the current scientific understanding of gastroparesis as well as patient response outcomes, and to propose evidence-based principles for the successful development of treatments for gastroparesis. Specifically, we discuss the pathophysiologic targets in gastroparesis, eligibility criteria for clinical trial participation based on validated gastric emptying studies, and the patient response outcome measures that have been validated to appraise effects of treatment on clinically relevant outcomes. These considerations lead to recommendations regarding eligibility, design, and duration of proof-of-efficacy studies, and to endorsing the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index Daily Diary as a validated patient response outcome and to justification of the shortening of proof-of-efficacy, placebo-controlled clinical trials to 4 weeks treatment duration after a baseline period. We believe that such approaches will increase the likelihood of successful assessment of efficacy of novel approaches to treating patients with gastroparesis.

Efficacy and Safety of Gastric Per-Oral Endoscopic Myotomy (G-POEM): A Systematic Review and Meta-Analysis

BACKGROUND

Gastric per-oral endoscopic myotomy (G-POEM) is an innovative treatment that has become increasingly utilized for patients with refractory gastroparesis. The aim of this systematic review and meta-analysis was to evaluate the safety and effectiveness of G-POEM for the treatment of gastroparesis.

METHODS

Individualized search strategies were developed through February 2021 in accordance with the PRISMA and MOOSE guidelines. This meta-analysis was performed by calculating pooled proportions and mean difference preprocedure and postprocedure with rates estimated using random effects models. Measured outcomes included technical success, clinical success, improvement in gastroparesis cardinal symptom index (GCSI), change in gastric emptying rate, alterations in impedance planimetry (functional lumen imaging probe [FLIP]) assessment, and adverse events.

RESULTS

A total of 20 studies (n=797 patients; 67.41% female) were included. The mean age was 48.92±11.61 y, with an average duration of 4.24±1.11 y since gastroparesis diagnosis. Technical success was 98.47% [(95% CI: 97.14, 99.19);I2=0.00] with a mean myotomy length of 3.78±1.16 cm. In terms of clinical success, mean preprocedure GCSI scores were 3.38±0.37 and improved significantly postprocedure [weighted mean difference -1.56 (95% CI: -1.89 to -1.24); I2=82.53; P<0.001]. Gastric retention after 4 hours demonstrated ~50% improvement (preprocedure 43.08±9.24% versus postprocedure 22.97±10.19%; P<0.001). FLIP assessment with 40 mL and 50 mL balloons demonstrated a significant increase in diameter, distensibility index, and cross-sectional area postprocedure (all P<0.05). Procedure-associated adverse events occurred among 10.92% [(95% CI 5.09 to 19.32); I2=82.85] of patients.

CONCLUSION

G-POEM appears safe and highly effective for the treatment of patients with refractory gastroparesis regardless of symptom predominance or etiology.

Quantification of interstitial cells of Cajal and fibrosis during gastric per-oral endoscopic myotomy and its association with clinical outcomes

Background and study aims Alterations to interstitial cells of Cajal (ICC) and collagen fibrosis have been implicated in the pathogenesis of gastroparesis. We aimed to evaluate the feasibility and safety of pyloric muscle sampling during gastric peroral endoscopic myotomy (G-POEM) and the association between pyloric ICC density and degree of fibrosis with clinical outcomes. Patients and methods This was a single-center prospective study of gastroparetic patients who underwent G-POEM and intraprocedural pyloric muscle biopsies between January 2022 and April 2023. ICC count was estimated using CD117 stain and trichome for collagen fibrosis. Clinical response to G-POEM was defined as an improvement of ≥ 1 point on the Gastroparesis Cardinal Symptom Index. Results Fifty-six patients (median age 60 years, 71.4% women) underwent G-POEM (100% technical success; 71.4% clinical response). ICC depletion (< 10/high-power field) and fibrosis were encountered in 70.4% and 75% of the cases, respectively. There was no difference in mean ICC count between G-POEM responders vs. non-responders (7±3.6 vs. 7.7±3.3; P = 0.9). There was no association between ICC density or degree of fibrosis with the etiology of gastroparesis, duration of symptoms, gastric emptying rate, or pyloric impedance planimetry. Patients who did not respond to G-POEM had a significantly higher degree of moderate/severe fibrosis when compared with those who responded (81.3% vs. 25%; P = 0.0002). Conclusions Pyloric muscle biopsies during G-POEM was feasible and safe. ICC depletion and pyloric muscle fibrosis are common in gastroparetic patients. The degree of fibrosis may be related to pyloric dysfunction and clinical response to G-POEM. Additional studies are needed to confirm these results.

Role of gastric peroral endoscopic myotomy (GPOEM) in chronic gastroparesis management after pancreas transplantation

Gastroparesis is a common complaint among patients with diabetes. Symptoms tend to improve following successful pancreas transplantation (PTx), but persist despite euglycemia in a subset of patients. We aimed to assess the benefit of gastric peroral endoscopic myotomy (G-POEM) in persistent gastroparesis following PTx. This was a single center retrospective review of all patients who underwent G-POEM for persistent gastroparesis following PTx. Patient demographics, pre and post procedure perception of symptom severity according to the patient assessment of upper gastrointestinal symptoms severity index (PAGI-SYM), gastroparesis cardinal symptom index (GCSI) score, and 36-item short form survey (SF36) score along with gastric emptying scintigraphy (GES) were analyzed. Seven PTx recipients underwent G-POEM for persistent gastroparesis symptoms. The majority were female. All reported nausea/vomiting, abdominal pain, bloating, and post prandial fullness prior to G-POEM. The post procedure survey scores improved in all patients although this was not significant. The improvement in gastric emptying on GES was statistically significant. G-POEM is a relatively new treatment option for gastroparesis. While it requires specialized proceduralist and training, we have documented improvement in the management of symptoms. With increasing experience, we anticipate more significant benefit in post PTx patients with persistent symptoms of gastroparesis undergoing G-POEM.

Interventional functional diagnostics in gastrointestinal endoscopy: Combining diagnostic and therapeutic tools in the endoscopy suite with the functional lumen imaging probe

With technical progress of gastrointestinal functional testing, there has been a demand for more comprehensive examination of esophageal physiology and pathophysiology beyond high-resolution manometry. A new interventional technology based on impedance planimetry, the functional lumen imaging probe (FLIP), enables intraluminal measurement of distensibility and compliance of hollow organs. EndoFLIP uses balloon catheters to measure diameter and distension pressure to calculate cross-sectional area and distensibility in different organs (mostly esophagus, stomach, anorectal region) and can be used in wide variety of indications (diagnostics, pre- and post-treatment evaluation) and currently serves as a helpful adjunctive tool in ambiguous clinical cases. EsoFLIP is a therapeutic variation that uses a stiffer balloon catheter allowing for dilation. The trend to simplify the clinical process from diagnosis to treatment tends to a one-session procedure combining diagnostics and therapeutic interventions. In specified conditions like e.g. achalasia or gastroparesis, a combination of EndoFLIP and EsoFLIP procedures may therefore be useful. The aim of this narrative review is to introduce the clinical use of FLIP and its potential benefit in combined diagnostic-therapeutic procedures.

Gastroparesis: time for a paradigm change

PURPOSE OF REVIEW

Gastroparesis (GP) is a syndrome defined by symptoms and delayed gastric emptying in the absence of mechanical obstruction. Typical symptoms include nausea, vomiting, abdominal pain, and early satiety. Only one medication is currently FDA-approved for the treatment of GP. This review highlights recent research findings pertaining to GP and provides evidence to support a change in the current GP diagnostic and treatment paradigm.

RECENT FINDINGS

An analysis of GP trials over the past four decades demonstrates the power of placebo and the need to perform longer studies with clearly defined patient populations. Two studies highlight the need to evaluate patients with suspected GP carefully and to perform gastric emptying studies properly. The misdiagnosis of GP symptoms is reviewed, preceded by a discussion of whether GP should be considered a disorder of gut-brain interaction. Finally, new data on therapies that target the pylorus are highlighted.

SUMMARY

Gastroparesis is frequently over-diagnosed and incorrectly diagnosed. Performing a proper gastric emptying study which adheres to standard protocol, and accurately interpreting the results in the context of the individual patient, are critical to making an accurate diagnosis of GP. The treatment paradigm needs to shift from simply aiming to accelerate gastric emptying to treating global symptoms of a chronic syndrome that may represent gut-brain dysfunction in many patients.

Imaging in Gastroparesis: Exploring Innovative Diagnostic Approaches, Symptoms, and Treatment

Gastroparesis (GP) is a chronic disease characterized by upper gastrointestinal symptoms, primarily nausea and vomiting, and delayed gastric emptying (GE), in the absence of mechanical GI obstruction. The underlying pathophysiology of GP remains unclear, but factors contributing to the condition include vagal nerve dysfunction, impaired gastric fundic accommodation, antral hypomotility, gastric dysrhythmias, and pyloric dysfunction. Currently, gastric emptying scintigraphy (GES) is considered the gold standard for GP diagnosis. However, the overall delay in GE weakly correlates with GP symptoms and their severity. Recent research efforts have focused on developing treatments that address the presumed underlying pathophysiological mechanisms of GP, such as pyloric hypertonicity, with Gastric Peroral Endoscopic Myotomy (G-POEM) one of these procedures. New promising diagnostic tools for gastroparesis include wireless motility capsule (WMC), the 13 carbon-GE breath test, high-resolution electrogastrography, and the Endoluminal Functional Lumen Imaging Probe (EndoFLIP). Some of these tools assess alterations beyond GE, such as muscular electrical activity and pyloric tone. These modalities have the potential to characterize the pathophysiology of gastroparesis, identifying patients who may benefit from targeted therapies. The aim of this review is to provide an overview of the current knowledge on diagnostic pathways in GP, with a focus on the association between diagnosis, symptoms, and treatment.

Experience with Impedance Planimetry for Surgical Foregut Disease in 1,097 Cases

BACKGROUND

The geometry and compliance of gastrointestinal sphincters may be assessed by impedance planimetry using a functional lumen imaging probe (FLIP). We describe our institutional foregut surgeon experience using FLIP in 1,097 cases, highlighting instances where FLIP changed operative decision making.

STUDY DESIGN

A retrospective review of an IRB-approved prospective quality database was performed. This included operative and endoscopic suite foregut procedures using FLIP between February 2013 and May 2022.

RESULTS

During the study period, FLIP was used a total of 1,097 times in 919 unique patients by 2 foregut surgeons. Intraoperative FLIP was used during 573 antireflux procedures and 272 endoscopic myotomies. FLIP was also used during 252 endoscopic suite procedures. For those undergoing preoperative workup of GERD, starting in 2021, esophageal panometry was performed in addition to standard FLIP measurements at the lower esophageal sphincter. In 77 cases, intraoperative FLIP changed operative decision making. During antireflux procedures, changes included adding or removing crural sutures, adjusting a fundoplication tightness, choice of full vs partial wrap, and magnetic sphincter augmentation sizing. For endoscopic procedures, changes included aborting peroral endoscopic myotomy or Zenker's peroral endoscopic myotomy, performing a myotomy when preoperative diagnosis was unclear, or performing additional myotomy.

CONCLUSIONS

FLIP is a useful tool for assessing the upper esophageal sphincter, lower esophageal sphincter, pylorus, and secondary esophageal peristalsis that can be used in a wide variety of clinical situations within a foregut surgeon's practice. It can also function as an adjunct in intraoperative decision making.

Paradoxical association between dyspepsia and autoimmune chronic atrophic gastritis: Insights into mechanisms, pathophysiology, and treatment options

BACKGROUND

Autoimmune gastritis (AIG) is a progressive, chronic, immune-mediated inflammatory disease characterized by the destruction of gastric parietal cells leading to hypo/anacidity and loss of intrinsic factor. Gastrointestinal symptoms such as dyspepsia and early satiety are very common, being second in terms of frequency only to anemia, which is the most typical feature of AIG.

AIM

To address both well-established and more innovative information and knowledge about this challenging disorder.

METHODS

An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published in the last 10 years.

RESULTS

A total of 125 records were reviewed and 80 were defined as fulfilling the criteria.

CONCLUSION

AIG can cause a range of clinical manifestations, including dyspepsia. The pathophysiology of dyspepsia in AIG is complex and involves changes in acid secretion, gastric motility, hormone signaling, and gut microbiota, among other factors. Managing dyspeptic symptoms of AIG is challenging and there are no specific therapies targeting dyspepsia in AIG. While proton pump inhibitors are commonly used to treat dyspepsia and gastroesophageal reflux disease, they may not be appropriate for AIG. Prokinetic agents, antidepressant drugs, and non-pharmacological treatments may be of help, even if not adequately evidence-based supported. A multidisciplinary approach for the management of dyspepsia in AIG is recommended, and further research is needed to develop and validate more effective therapies for dyspepsia.

A Systematic Review of the Long-Term Clinical Success of Gastric Peroral Endoscopic Myotomy for Refractory Gastroparesis

Gastroparesis is a chronic and debilitating gastrointestinal disorder with few medical treatment options. Traditional surgical management has involved laparoscopic pyloromyotomy or gastric stimulation. In recent years, gastric peroral endoscopic myotomy (GPOEM) has become an attractive, less invasive option for patients with refractory gastroparesis. There is little information on the long-term clinical success of GPOEM in patients with refractory gastroparesis. This systematic review aims to evaluate the data on this procedure's long-term clinical efficacy and safety. A comprehensive literature review was done in PubMed, EMBASE, Ovid, and Google Scholar databases from the date of earliest entry in May 2017 up to August 15, 2022. The Gastroparesis Cardinal Symptom Index (GCSI) score, adverse reaction, and length of stay were analyzed. Eleven studies were eligible for inclusion (900 patients), seven of the studies were retrospective, while four were prospective. The GCSI is a 6-point Likert scale questionnaire that assesses improvement in gastroparesis. An average decrease of GCSI by 1 point compared to baseline GCSI for all patients (described as clinical success) was found in 662 patients out of 713 (92.8%) at one-year follow-up, 421 out of 460 (91.5%) at two-year follow-up, 270 out of 270 (100%) at three-year follow-up, and 102 out of 102 (100%) at four-year follow-up. Adverse events occurred in 62 out of 835 patients (in nine studies), with two of the most frequent being bleeding and mucosal tears. GPOEM is an effective and safe treatment option for patients with refractory gastroparesis, with symptom improvement noted up to four years postoperatively.

AGA Clinical Practice Update on Gastric Peroral Endoscopic Myotomy for Gastroparesis: Commentary

DESCRIPTION

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) is to review the available evidence and provide expert advice regarding cognitive, procedural, and post-procedural aspects of performing gastric peroral endoscopic myotomy for the treatment of refractory gastroparesis.

METHODS

This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. This expert commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors who are advanced endoscopists with expertise in treating patients by performing third-space endoscopy and gastric peroral endoscopic myotomy.

Prospective study on the efficacy of endoscopic through-the-scope tack and suture system for gastric peroral endoscopic myotomy mucosal incision site closure

Background and study aims  Mucosal closure after gastric per-oral endoscopic myotomy (G-POEM) can be difficult due to the thick gastric mucosa. We evaluated the use of a novel through-the-scope (TTS) suture system for G-POEM mucosotomy closure. Patients and methods  This was a single-center prospective study on consecutive patients who underwent G-POEM with TTS suture closure between February 2022 and August 2022. Technical success was defined as complete mucosotomy closure with TTS suture alone. On subgroup analysis, we compared performance on TTS suturing between the advanced endoscopist and the advanced endoscopy fellow (AEF) under supervision. Results  Thirty-six consecutive patients (median age 60 years, interquartile range [IQR] 48.5-67], 72 % women) underwent G-POEM with TTS suture of the mucosotomy. Median mucosal incision length was 2 cm (IQR: 2-2.5). Mean mucosal closure and total procedure time were 17.5 ± 10.8 and 48.4 ± 16.8 minutes, respectively. Technical success was achieved in 24 patients (66.7 %) and 100 % of the cases were adequately closed with a combination of TTS suture and clips. When compared to the advanced endoscopist, the AEF required > 1 TTS suture system for complete closure significantly more frequently (66.7 % vs. 8.3 %, P  = 0.009) and more time for mucosal closure (20.4 ± 12.1 vs. 11.9 ± 4.9 minutes, P  = 0.03). Conclusions  TTS suturing is effective and safe for G-POEM mucosal incision closure. With experience, technical success is high, and most closures may be achieved using a single TTS suture system alone, which has important cost and time implications. Additional comparative trials with other closure devices are need1ed.

Response to botulinum toxin may predict response to peroral pyloromyotomy in patients with gastroparesis

BACKGROUND : Patients with gastroparesis who have undergone prior intrapyloric botulinum toxin injection (BTI) may seek an opinion regarding peroral pyloromyotomy (POP). There are only two small reports assessing the role of BTI as a predictor for successful treatment with POP.

METHODS

 We performed a retrospective cohort study to assess whether symptomatic improvement after BTI predicts a response to POP. We included 119 patients who had undergone both BTI and POP at Cleveland Clinic Ohio or Cleveland Clinic Florida from January 2016 to September 2019.

RESULTS

 65.5 % of patients had symptomatic improvement after BTI. Gastroparesis Cardinal Symptom Index (GCSI) scores were available for 74 patients, with 64 % achieving a response to POP, defined as a decrease in mean GCSI ≥ 1. In multivariable analysis, response to BTI (odds ratio [OR] 7.7 [95 %CI 2.2-26.1]) and higher pre-POP GCSI score (OR 2.3 [95 %CI 1.2-4.6]) were independent predictors of response to POP.

CONCLUSIONS

 Clinical improvement after BTI is a predictor of response to POP in patients with gastroparesis. This information may aid in improving patient selection for POP.

Targeting the pylorus in gastroparesis: From physiology to endoscopic pyloromyotomy

BACKGROUND

The pylorus plays a key role in the control of gastric content outflow. Impairment of pyloric physiology has been observed in gastroparesis, particularly when associated with diabetes mellitus or opioid intake or after antireflux surgery. New tools have been developed to identify pyloric dysfunction in routine care, including functional luminal impedance planimetry (FLIP). As such, a new therapeutic strategy targeting the pylorus, namely endoscopic pyloromyotomy (G-POEM), has received increasing attention and emerged as a promising treatment for gastroparesis.

PURPOSE

The present review details the involvement of the pyloric pathophysiology in gastroparesis, as well as clinical results of G-POEM according to the current literature.

Endoscopic findings do not predict per-oral pyloromyotomy (POP) response

INTRODUCTION

Gastroparesis is a life-altering diagnosis caused by the stomach's inability to function in the absence of a mechanical obstruction. The primary causes are idiopathic, diabetic, and postoperative. Our first-line treatment for medical refractory gastroparesis is the endoscopic per-oral pyloromyotomy (POP) procedure. Predicting clinical response cost effectively remains elusive.

METHODS

All patients who underwent a POP procedure at our institution by a single surgical endoscopist from January 1, 2019 to June 30, 2020 were retrospectively reviewed. All endoscopic data were prospectively collected. The patients were followed by a survey including the Gastroparesis Cardinal Symptom Index (GCSI) and other relevant postoperative measures. The primary endpoint was clinical response defined as ≥ 1.0 decrease in the GCSI from preoperative to the time of survey. Secondary outcome was normalization of the gastric emptying study (GES).

RESULTS

Our patient population is 85% female and has an average age of 44.8 years. The diagnosis of gastroparesis is 71% iatrogenic, 19% postoperative, and 10% diabetic. On endoscopy, 30% had bile in the stomach and 65% had any degree of pylorospasm. The primary outcome measure of clinical response was 39% at an average of 697 ± 151 days post-POP, but 66% of patients attested to an improvement in their symptoms. Of 68 postoperative gastric emptying studies 50% normalized at an average of 145 ± 98 days. Following univariate and multivariate analyses of preoperative data and endoscopic findings, there were no significant predictors of clinical response. A preoperative GCSI ≥ 2.6 trends toward significance (OR 6.87, p = 0.058).

CONCLUSION

Endoscopic findings at the time of POP do not correlate with clinical response. The GCSI model currently used to measure clinical response may not accurately capture the full clinical picture. The long-term durability of endoscopic myotomy to treat medical refractory gastroparesis needs to be studied further to improve patient selection.

Gastric peroral endoscopic pyloromyotomy (G-POEM) in patients with refractory gastroparesis: a review

Gastric peroral endoscopic pyloromyotomy (G-POEM or POP) is an endoscopic therapeutic modality for treatment of refractory gastroparesis. Since the first case reported in 2013, there are more than 200 papers published on G-POEM. In this narrative review, we summarize the short-term and long-term outcomes and review other important studies. The technical success rate is 100% and the short-term (within 1 year) success rate is about 50-80%. The procedure time is between 50 and 70 min while the average length of hospital stay was 2-3 days. The adverse event rate was around 10%. Few patients need further intervention. Three studies showed that at the 4-year follow-up, the response to G-POEM was durable, but there was a yearly recurrence rate of 13% or more. Redo G-POEM is feasible and can be of benefit for some patients. Most of the studies showed that long duration of illness is associated with poor outcomes. However, reliable predictors for successful outcomes are still unknown. Current literature indicates G-POEM is superior to gastric electric stimulator and surgical pyloroplasty. Endoflip has been used at G-POEM to predict the outcome, but the result is very preliminary. A recent sham study confirms the short-term efficacy of G-POEM. G-POEM is safe and about 50% of patients can be discharged to home on the same day. G-POEM allows for direct biopsy of the gastric muscle, which is the location of the pacemaker cells, the interstitial cells of Cajal; therefore, G-POEM may provide a new path for further research on the pathogenesis of gastroparesis.

Submucosal endoscopy: the present and future

Submucosal endoscopy or third-space endoscopy utilizes the potential space between the mucosal and muscularis layers of the gastrointestinal tract to execute therapeutic interventions for various diseases. Over the last decade, endoscopic access to the submucosal space has revolutionized the field of therapeutic endoscopy. Submucosal endoscopy was originally used to perform endoscopic myotomy in patients with achalasia cardia, and its use has grown exponentially since. Currently, submucosal endoscopy is widely used to resect subepithelial tumors and to manage refractory gastroparesis and Zenker's diverticulum. While the utility of submucosal endoscopy has stood the test of time in esophageal motility disorders and subepithelial tumors, its durability remains to be established in conditions such as Zenker's diverticulum and refractory gastroparesis. Other emerging indications for submucosal endoscopy include esophageal epiphrenic diverticulum, Hirschsprung's disease, and esophageal strictures not amenable to conventional endoscopic treatment. The potential of submucosal endoscopy to provide easy and safe access to the mediastinum and peritoneal spaces may open doors to novel indications and rejuvenate the interest of endoscopists in natural orifice transluminal endoscopic surgery in the future. This review focuses on the current spectrum, recent updates, and future direction of submucosal endoscopy in the gastrointestinal tract.

Evolving field of third-space endoscopy: Derivatives of peroral endoscopic myotomy

Third-space endoscopy, also known as submucosal endoscopy, allows for a wide range of therapeutic interventions within the submucosal layer and even into the muscular or subserosal layers of the gastrointestinal lumen. The technical development of peroral endoscopic myotomy (POEM) for achalasia has revolutionized the field of therapeutic endoscopy and the method has been continuously refined and modified. Although POEM has been applied to treat primary achalasia, it shows a favorable clinical response in other esophageal motility disorders and as a salvage treatment after previously failed intervention. Gastroesophageal reflux after POEM has drawn considerable attention and there have been major advancements in its prevention and management. POEM has led to advantageous derivatives such as peroral endoscopic tumor resection or submucosal tunneling endoscopic resection for resection of subepithelial lesions, Zenker POEM for hypopharyngeal diverticula, diverticular POEM for epiphrenic esophageal diverticula, and gastric POEM for refractory gastroparesis. These techniques have a similar concept, which constitutes submucosal tunneling with a mucosal flap valve and secure mucosal incision closure. The submucosal tunneling technique is widely accepted and continues to evolve. This study aimed to review in detail the indications, outcomes, and technical variations in POEM and explore several emerging submucosal tunneling procedures. This review will benefit future studies by providing a summary of recent developments in this field.

A New Paradigm Shift in Gastroparesis Management

Gastroparesis, once regarded as a rare disease, is difficult to diagnose and challenging to treat; there were many breakthrough advances in the 2010s, shifting the paradigm of the understanding of this complex entity and its management. Similar to diabetes, its increasing prevalence reflects increased accessibility to diagnostic modalities and suggests that gastroparesis was underacknowledged in the past. Major developments in the three main aspects of the disease include the discovery of smooth muscle cells, interstitial cells of Cajal, PDGFRα+ cells syncytium, rather than interstitial cells of Cajal alone, as the main gastric pacemaker unit; the development of validated point-of-care diagnostic modalities such as a wireless motility capsule, the carbon 13-labeled breath test, and impedance planimetry; and the introduction of novel minimally invasive therapeutic options such as newer pharmacologic agents and gastric peroral endoscopic pyloromyotomy. All aspects of these advances will be discussed further in this review.

Endoscopic pyloromyotomy for the treatment of severe and refractory gastroparesis: a pilot, randomised, sham-controlled trial

OBJECTIVE

Endoscopic pyloromyotomy (G-POEM) is a minimally invasive treatment option with promising uncontrolled outcome results in patients with gastroparesis.

DESIGN

In this prospective randomised trial, we compared G-POEM with a sham procedure in patients with severe gastroparesis. The primary outcome was the proportion of patients with treatment success (defined as a decrease in the Gastroparesis Cardinal Symptom Index (GCSI) by at least 50%) at 6 months. Patients randomised to the sham group with persistent symptoms were offered cross-over G-POEM.

RESULTS

The enrolment was stopped after the interim analysis by the Data and Safety Monitoring Board prior to reaching the planned sample of 86 patients. A total of 41 patients (17 diabetic, 13 postsurgical, 11 idiopathic; 46% male) were randomised (21 G-POEM, 20-sham). Treatment success rate was 71% (95% CI 50 to 86) after G-POEM versus 22% (8-47) after sham (p=0.005). Treatment success in patients with diabetic, postsurgical and idiopathic gastroparesis was 89% (95% CI 56 to 98), 50% (18-82) and 67% (30-90) after G-POEM; the corresponding rates in the sham group were 17% (3-57), 29% (7-67) and 20% (3-67).Median gastric retention at 4 hours decreased from 22% (95% CI 17 to 31) to 12% (5-22) after G-POEM and did not change after sham: 26% (18-39) versus 24% (11-35). Twelve patients crossed over to G-POEM with 9 of them (75%) achieving treatment success.

CONCLUSION

In severe gastroparesis, G-POEM is superior to a sham procedure for improving both symptoms and gastric emptying 6 months after the procedure. These results are not entirely conclusive in patients with idiopathic and postsurgical aetiologies.

TRIAL REGISTRATION NUMBER

NCT03356067; ClinicalTrials.gov.

Fasting pyloric diameter and distensibility by functional endoluminal imaging probe in unsedated healthy volunteers

BACKGROUND

Recent studies with functional endoluminal imaging probe (EndoFLIP® ) measure physiologic characteristics of the pylorus. EndoFLIP® has the potential to select optimal candidates for gastric peroral endoscopic myotomy (G-POEM). Normative values of the pylorus using EndoFLIP® have not been established.

METHODS

Twenty-four healthy volunteers (20-56 years old; 15 females) underwent unsedated, transoral EndoFLIP® measurements of the pylorus after 8 h of fasting. Measurements of diameter (DM), balloon pressure, and distensibility index (DI) of the pylorus were obtained twice over 5 min at 40, 50, and 60 ml balloon distensions.

KEY RESULTS

Pyloric DM at 40, 50, and 60 ml balloon distensions were 13.0 ± 2.5, 14.3 ± 1.8, and 17.2 ± 2.0 mm, respectively. DM with 60 ml distension was notably higher than with 40 and 50 ml distensions. Pyloric DI at 40, 50, and 60 ml distensions were 10.9 ± 4.8, 11.3 ± 5.8, and 11.1 ± 4.3 mm2 /mm Hg, respectively (p = 0.86). Linear regression and Bland-Altman plots showed similar distribution of the DM and DI during the second minute compared with the full 5-min measurements at 50 ml distension, as well as between two sequential measurements using 50 ml distension. With 50 ml balloon distension, intraindividual coefficients of variation (COVintra ) for DM and DI were 13.8% and 29.6%, respectively, and interindividual COV (COVinter ) were 12.6% and 51.3%, respectively. Similar reproducibility was obtained with 40 ml balloon distension.

CONCLUSIONS AND INFERENCES

Unsedated EndoFLIP® can be used to characterize human fasting pyloric diameter and distensibility, with best performance observed with 40 ml and 50 ml distensions and data collection during the second minute. Normative values reported serve as reference values for future studies.

Gastric peroral endoscopic myotomy outcomes after 4 years of follow-up in a large cohort of patients with refractory gastroparesis (with video)

BACKGROUND AND AIMS

Gastric peroral endoscopic myotomy (G-POEM) is used for refractory gastroparesis (RG) with good early-term but variable mid- and long-term outcomes. Limited data exist about candidates and long-term clinical and predictive factors. Our aim was to evaluate the 4-year follow-up efficacy and predictive factors in patients with RG.

METHODS

Confirmed RG patients were included and evaluated between April 2017 and December 2021. Gastroparesis Cardinal Symptom Index (GCSI) score, retention percentage at 4 hours (RP4H), mean half-emptying time (MHET), and the 36-item short-form survey (SF-36) were performed at 1, 6, 12, 18, 24, 30, 36, 42, and 48 months.

RESULTS

After G-POEM, 374 patients with RG were included: 141 patients (37.7%) had diabetic gastroparesis (DG), 115 (30.7%) had idiopathic gastroparesis (IG), 102 (27.3%) had postsurgical gastroparesis (PSG), and 16 (4.3%) had other etiologies. After the 48-month evaluation, 102 patients completed follow-up (DG, 58; IG, 22; PSG, 18; other, 4). Before G-POEM, GCSI score, RP4H, and MHET were 3.84 ± .53, 44% (interquartile range [IQR], 11-68), and 246 minutes (IQR, 150-368), respectively, and after the 48-month evaluation improved to 2.1 ± .70 (P < .001), 15.5% (IQR, 0-36; P = .021), and 135 minutes (IQR, 67-290; P = .045), respectively. At the 48-month evaluation, clinical success was 77.5%. DG showed the best outcomes (DG vs IG vs PSG vs other: 86.5% vs 72.5% [P = .001] vs 72.1% [P = .003] vs 68.8% [P < .001]). Long-term success predictors were DG (odds ratio [OR], 5.113; 95% confidence interval [CI], 1.643-5.981; P = .035), early diagnosis (OR, 2.455; 95% CI, 1.129-3.522; P = .042), nausea/vomiting (OR, 3.541; 95% CI, 1.881-5.511; P = .012), GCSI score at 6 months (1.5-2) (OR, 3.612; 95% CI, 2.122-5.317; P = .022), and RP4H <10% at 6 months (OR, 2.188; 95% CI, 1.435-4.233; P = .039).

CONCLUSIONS

G-POEM is an effective 4-year treatment in patients with RG, especially in DG, establishing a potential first-line therapy in these patients. However, randomized controlled clinical trials are needed to confirm these results. (Clinical trial registration number: NTC03126513.).

Gastric peroral endoscopic myotomy in refractory gastroparesis: long-term outcomes and predictive score to improve patient selection

BACKGROUND AND AIMS

Limited data exist concerning the long-term efficiency of gastric peroral endoscopic myotomy (G-POEM) as a treatment of refractory gastroparesis. This study evaluated the 3-year results of G-POEM in patients with refractory gastroparesis.

METHODS

This was a prospective multicenter study of all G-POEM operations performed in 2 expert French centers for 46 patients with refractory gastroparesis with at least 3 years of follow-up.

RESULTS

Clinical success was 65.2% at 36 months. There was significant improvement in symptom severity. Median Gastroparesis Cardinal Symptom Index decreased from 3.33 to 1.80 (P < .0001), with improvement in all subscales. We created a predictive score concerning G-POEM success (G-POEM predictive score) to which points were assigned as follows: nausea subscale <2: predictive of success, 1 point; satiety subscale >4: predictive of success, 1 point; bloating subscale >3.5: predictive of success, 1 point; percentage of gastric retention at 4 hours on scintigraphy >50%: 1 point. A threshold of 2 was identified by receiver operating characteristic curve analysis with an area under the curve of .825 that predicted clinical success with a sensitivity of 93.3% (95% confidence interval [CI], .77-.99), specificity of 56.3% (95% CI, .33-.77), positive predictive value of 80% (95% CI, .67-.93), negative predictive value of 81.8% (95% CI, .59-1.00), and accuracy of 80.4% (95% CI, .69-.92). Patients with a score ≥2 were significantly more likely to be responders at 3 years than were patients with a score <2 (80% and 18%, respectively; P = .0004).

CONCLUSIONS

The clinical success of G-POEM for refractory gastroparesis was 65.2% at 36 months. Our predictive score offers an easy tool that needs to be confirmed in other studies.

Systematic review with meta-analysis: one-year outcomes of gastric peroral endoscopic myotomy for refractory gastroparesis

BACKGROUND

Several studies have examined the efficacy of gastric peroral endoscopic myotomy (G-POEM) for gastroparesis.

AIM

To evaluate the mid-term efficacy of G-POEM by meta-analysis of studies with a minimum 1 year of follow-up.

METHODS

We reviewed several databases from inception to 10 June 2021 to identify studies that evaluated the efficacy of G-POEM in refractory gastroparesis, and had at least 1 year of follow-up. Our outcomes of interest were clinical success at 1 year, adverse events, difference in mean pre- and 1 year post-procedure Gastroparesis Cardinal Symptom Index (GCSI) score, and difference in mean pre- and post-procedure EndoFLIP measurements. We analysed data using a random-effects model and assessed heterogeneity by I2 statistic.

RESULTS

We included 10 studies comprising 482 patients. Pooled rates (95% CI) of clinical success at 1 year and adverse events were 61% (49%, 71%) and 8% (6%, 11%), respectively. Mean GCSI at 1 year post-procedure was significantly lower than pre-procedure; mean difference (MD) (95% CI) -1.4 (-1.9, -0.9). Mean post-procedure distensibility index was significantly higher than pre-procedure in the clinical success group at 40 and 50 mL volume distension; standardised mean difference (95% CI) 0.82 (0.07, 1.64) and 0.91 (0.32, 1.49), respectively. In the clinical failure group, there was no significant difference between mean pre- and post-procedure EndoFLIP measurements.

CONCLUSIONS

G-POEM is associated with modest clinical success at 1 year. Additional studies with longer follow-up are required to evaluate its longer-term efficacy.

Third-Space Endoscopy: Recent Updates

Third space or submucosal space is a potential space which on expansion allows the endoscopist to execute a multitude of therapeutic procedures for various gastrointestinal diseases like achalasia, subepithelial tumors, Zenker’s diverticulum, and refractory gastroparesis. Third space was first utilized for performing endoscopic myotomy in cases with achalasia cardia about a decade ago. Since then, the field of submucosal endoscopy has witnessed an exponential growth. The present review focuses on recent advances in the field of third-space endoscopy. With regard to per-oral endoscopic myotomy (POEM) in achalasia cardia, several recent studies have evaluated the long-term outcomes of POEM, compared endoscopic myotomy with pneumatic dilatation (PD) and surgical myotomy, and evaluated the outcomes of short- versus long-esophageal myotomy. In addition, the utility of multiple dose antibiotic prophylaxis to prevent infections after POEM has been questioned. Overall, the results from these studies indicate that POEM is a durable treatment modality, equally effective to Heller’s myotomy and superior to PD. With regard to gastric-POEM (G-POEM), recent studies suggest only modest efficacy in cases with refractory gastroparesis. Therefore, quality studies are required to identify predictors of response to optimize the outcomes of G-POEM in these cases. Another third-space endoscopy procedure that has gained popularity is endoscopic division of septum in cases with esophageal diverticula including Zenker’s POEM and epiphrenic diverticula POEM (Z-POEM and D-POEM, respectively). The technique of diverticulotomy using the principles of submucosal endoscopy appears safe and effective in short term. Data on term outcomes are awaited and comparative trials with flexible endoscopic myotomy required. Per-rectal endoscopic myotomy (PREM) is the most recent addition to third space endoscopy procedures for the management of short-segment Hirschsprung’s disease. Limited data suggest that PREM may be a promising alternative surgery in these cases. However, quality studies with long-term follow-up are required to validate the outcomes of PREM.

Gastroparesis

PURPOSE OF REVIEW

This review highlights recent research advances regarding the pathophysiology and treatment of gastroparesis.

RECENT FINDINGS

Differences in brain activity have been identified on functional MRI imaging in gastroparesis patients with nausea. Abdominal pain is common in patients with gastroparesis and does not correlate with the severity of gastric emptying delay, though may be associated with depression and anxiety. Autonomic dysfunction may play an important role in the pathophysiology of gastroparesis. There is increasing sentiment that gastroparesis should be considered a part of the same spectrum of gastric neuromuscular disorders. The risk of tardive dyskinesia with metoclopramide has likely been significantly overestimated historically. Endoscopic BoTox injection of the pylorus and gastric electrical stimulation remain controversial treatments for gastroparesis. New, highly selective 5-hydroxytryptamine 4 (5-HT4) agonists appear safe and may be effective in improving symptoms of gastric emptying. Long-term data assessing the use of gastric peroral endoscopic myotomy (G-POEM) for the treatment of refractory gastroparesis suggest durable clinical improvement.

SUMMARY

Altered central processing and autonomic dysfunction may be important factors in the pathogenesis of gastroparesis. While the risk of tardive dyskinesia appears much lower than historically advertised, there is increasing hope for novel therapeutics with the advent of new 5-HT4 agonists, neurokinin-1 receptor (N1KR) antagonists, and G-POEM.