Gastric peroral endoscopic pyloromyotomy for decompensated gastroparesis: comprehensive motility analysis in relation to treatment outcomes

Endoscopic pyloromyotomy for treatment of gastroparesis: A new standard or still an experimental approach?

Gastroparesis (GP) can be a severe and debilitating disease. Its pathophysiology is complex and not completely understood. Two principal mechanisms are responsible for the development of symptoms - gastric hypomotility and pylorospasm. Pylorus targeted therapies aim to decrease presumably elevated pyloric tone - pylorospasm. There is a growing body of evidence about their role in the treatment algorithm of GP. G-POEM (endoscopic pyloromyotomy) is an extensively studied pylorus targeted therapy. Its efficacy ranges between 56 and 80% and the number of recurrences among those with treatment effect seems low. G-POEM is a safe procedure with very low frequency of severe adverse events. At present, G-POEM should not be considered as an experimental approach and may be offered to all patients with refractory and severe GP. Nevertheless, G-POEM is not a first line treatment. Conservative measures such as diet modification and pharmacotherapy should always be tried before G-POEM is considered. Further research must focus on better patient selection as at present there are no standardized criteria. Functional imaging such as impedance planimetry (EndoFlip) may hold promise in this regard.

Do antro-duodenal manometry parameters predict clinical response after gastric peroral endoscopic pyloromyotomy in refractory gastroparesis?

BACKGROUND

Gastric peroral endoscopic pyloromyotomy (G-POEM) is a promising therapeutic modality for refractory gastroparesis (GP). However, as characteristics of suitable patients for G-POEM remain unclear, antro-duodenal manometry (ADM) has been suggested to provide objective parameters for patient selection. The aim of the present study was to identify ADM parameters as predictors for treatment response after G-POEM in refractory GP.

METHODS

Refractory GP patients who underwent a G-POEM between 2017 and 2022 were included. The following ADM parameters were mainly scored: antral hypomotility, pylorospasm, and the presence of neuropathic enteric patterns. Treatment response was defined as a GCSI-score decrease of ≥1 point 12 months after G-POEM. Explorative analyses were performed on potential predictors of response using logistic regression analysis.

KEY RESULTS

Sixty patients (52 women, mean age 52 ± 14 years.) with refractory GP (33 idiopathic, 16 diabetic, 11 postsurgical) were included. Clinical response data were available for 52 patients. In 8 out of 60 patients, it was not feasible to advance the catheter beyond the pylorus. Abnormal ADM was found in 46/60 patients (77%). Antral hypomotility and pylorospasm were found in respectively 33% and 12% of patients. At least one neuropathic enteric dysmotility pattern was found in 58% of patients. No differences were found when comparing baseline ADM parameters between clinical response groups at 12 months follow-up. Following explorative analyses, no ADM parameters were identified to predict clinical response 12 months after G-POEM.

CONCLUSIONS AND INFERENCES

No ADM parameters were identified as predictors of clinical response after G-POEM in refractory GP patients. Additionally, a high percentage of abnormal ADM tracings was found, in particular with relation to enteric dysmotility, while only a low percentage of patients showed antral hypomotility or pylorospasm.

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.

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.

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.

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.

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.

Antroduodenal motility recording identifies characteristic patterns in gastroparesis related to underlying etiology

BACKGROUND

Gastroparesis (GP) is a gastrointestinal disorder associated with significant morbidity and healthcare costs. GP patients form a heterogeneous population with diverse etiology, and treatment is often challenging due to a poorly understood underlying pathophysiology. The aim of the present study was to assess antroduodenal motility patterns among the different GP etiologies.

METHODS

We reviewed antroduodenal manometry (ADM) recordings of patients with confirmed GP between 2009 and 2019. ADM measurements were evaluated for fed period duration, number of phase III contractions and migrating motor complexes (MMCs), motility index (MI), and presence of neuropathic patterns.

KEY RESULTS

A total of 167 GP patients (142 women, median age 45 [31-57]) were included. The following etiologies were identified: idiopathic n = 101; post-surgery n = 36; and diabetes n = 30. Fed period duration was significantly longer in idiopathic (p < 0.01) and diabetic GP patients (p < 0.05) compared with post-surgery GP patients. Furthermore, the number and duration of phase III contractions and the number of MMCs were significantly lower in idiopathic and diabetic patients compared with post-surgery GP patients (p < 0.01). Likewise, absence of MMCs during 6-h recording was more often observed in idiopathic and diabetes GP patients compared with post-surgery GP patients (resp. p < 0.01 and p < 0.05).

CONCLUSIONS AND INFERENCES

Antroduodenal motility patterns are different among GP etiologies. A dysmotility spectrum was identified with different patterns ranging from post-surgery GP to idiopathic and diabetic GP.

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.

Comprehensive characterization of antral and pyloric contractions by high resolution manometry: applied physiology in suspected gastroparesis

Delayed gastric emptying may result from diverse pathophysiological mechanisms including antral hypomotility and pylorospasm. With increasing use of gastric peroral endoscopic myotomy and preliminary evidence of efficacy, our aim was to assess the motor functions of the distal antrum and pylorus in patients with symptoms of gastroparesis using high-resolution antropyloroduodenal manometry (HR-ADM). Sixteen patients with symptoms suggestive of gastroparesis underwent HR-ADM with 13 sensors, 1 cm apart, placed across the antropyloroduodenal (APD) junction and 2 sensors, 10 cm apart, in descending and distal duodenum. The 1-h postprandial motility was quantitated as contraction frequency/minute, average amplitude, and motility index (MI). Six healthy volunteers served as controls. In the patient group, the HR-ADM identified postprandial antral hypomotility, isolated pyloric pressure waves, and tonic elevation of baseline pressure in pylorus. Patients had significantly reduced frequency of the full-hour postprandial antral contractions/minute compared with healthy volunteers [1.52 (0.97, 1.67) vs. 2.04 (1.70, 2.67), P = 0.005], as well as reduced MI [9.65 (8.29, 10.31) vs. 11.04 (10.65, 11.63), P = 0.002]. The average contraction amplitude was numerically, but not significantly reduced [51.9 (21.9, 74.9) vs. 73.0 (59.8, 82.7), P = 0.14]. Bland-Altman plots showed similar distribution of antral contraction frequency and MI during the first and second postprandial 30-min periods for both patients and controls. High-resolution ADM can characterize a variety of postprandial antral contractile and pyloric motility dysfunctions. This technique shows promise to provide guidance for the selection of optimal treatment of patients with gastroparesis.NEW & NOTEWORTHY Current selection of different treatments for patients with gastroparesis is empiric or based on trial and error, though pyloric distensibility and diameter may predict response to pyloric interventions. High-resolution antropyloroduodenal manometry (HR-ADM) can characterize a variety of postprandial antral contractile and pyloric motility dysfunctions in patients with suspected gastroparesis. HR-ADM shows promise to provide guidance for selection and individualization of treatments such as prokinetic agents or pyloric interventions for patients with gastroparesis based on documented pathophysiology.

Gastric per-oral endoscopic myotomy: Indications, technique, results and comparison with surgical approach

Gastroparesis is a chronic disease of the stomach that causes a delayed gastric emptying, without the presence of a stenosis. For 30 years the authors identified pylorospasm as one of the most important pathophysiological mechanisms determining gastroparesis. Studies with EndoFLIP, a device that assesses pyloric distensibility, increased the knowledge about pylorospasm. Based on this data, several pyloric-targeted therapies were developed to treat refractory gastroparesis: Surgical pyloroplasty and endoscopic approach, such as pyloric injection of botulinum and pyloric stenting. Notwithstanding, the success of most of these techniques is still not complete. In 2013, the first human gastric per-oral endoscopic myotomy (GPOEM) was performed. It was inspired by the POEM technique, with a similar dissection method, that allows pyloromyotomy. Therapeutical results of GPOEM are similar to surgical approach in term of clinical success, adverse events and post-surgical pain. In the last 8 years GPOEM has gained the attention of the scientific community, as a minimally invasive technique with high rate of clinical success, quickly prevailing as a promising therapy for gastroparesis. Not surprisingly, in referral centers, its technical success rate is 100%. One of the main goals of recent studies is to identify those patients that will respond better to the therapies targeted on pylorus and to choose the better approach for each patient.

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.

Gastroparesis

Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.

Devices for esophageal function testing

BACKGROUND AND AIMS

Esophageal function testing is an integral component of the evaluation of refractory GERD and esophageal motility disorders. This review summarizes the current technologies available for esophageal function testing, including the functional luminal imaging probe (FLIP), high-resolution esophageal manometry (HRM), and multichannel intraluminal impedance (MII) and pH monitoring.

METHODS

We performed a MEDLINE, PubMed, and MAUDE database literature search to identify pertinent clinical studies through March 2021 using the following key words: esophageal manometry, HRM, esophageal impedance, FLIP, MII, and esophageal pH testing. Technical data were gathered from traditional and web-based publications, proprietary publications, and informal communications with pertinent vendors. The report was drafted, reviewed, and edited by the American Society for Gastrointestinal Endoscopy Technology Committee and approved by the Governing Board of the American Society for Gastrointestinal Endoscopy.

RESULTS

FLIP is a high-resolution impedance planimetry system used for pressure and dimension measurement in the esophagus, pylorus, and anal sphincter. FLIP provides complementary information to HRM for esophageal motility disorders, especially achalasia. The Chicago classification, based on HRM data, is a widely adopted algorithmic scheme used to diagnose esophageal motility disorders. MII detects intraluminal bolus movement and, combined with pH measurement or manometry, provides information on acid and non-acid gastroesophageal reflux and bolus transit in patients with refractory GERD and for preoperative evaluation for anti-reflux procedures.

CONCLUSIONS

Esophageal function testing techniques (FLIP, HRM, and MII-pH) have diagnostic and prognostic value in the evaluation of esophageal motility disorders and refractory GERD. Newer technologies and classification systems have enabled an increased understanding of these diseases.

[Endoscopic tunneling procedures in achalasia and gastroparesis]

Since the first publication of peroral endoscopic myotomy (POEM) by Haruhiro Inoue et al. in 2008 in Japan, various novel endoscopic procedures have been established, which are performed after iatrogenic creation of a submucosal tunnel as a "new space" 1. Through the artificially formed access in the tela submucosa, interventions in the muscular layer of the esophagus and stomach can be performed while carefully sparing the mucosal layer 2. These include, peroral myotomy of the esophageal muscle layer in patients with achalasia (POEM) and myotomy of the pylorus in patients with gastroparesis (antropyloromyotomy, G-POEM). Further indications include splitting of Zenker diverticulum in POEM technique ("Z-POEM") as well as the removal of subepithelial tumors (STER: submucosal tunneling, endoscopic resection). The long-term therapeutic success (with > 80 % response) of these innovative procedures has now been proven by controlled studies, especially in achalasia 2 3 4 5 6.