Achalasia subtypes can be identified with functional luminal imaging probe (FLIP) panometry using a supervised machine learning process

Effects of Cholecystokinin on Esophageal Motor Response to Distension in Asymptomatic Volunteers

Background/Aims

Cholecystokinin (CCK) administration has been shown to reduce lower esophageal sphincter (LES) pressure in normal subjects in manometric studies. Functional luminal imaging probe (FLIP) panometry offers a method to assess esophageal motility in response to sustained distension though mechanisms related to this response remain unexplored. The aim of this study is to evaluate the effect of CCK-8 on the esophageal response to distension in asymptomatic volunteers using FLIP.

Methods

Esophageal response to distension was studied in 7 asymptomatic volunteers (mean age ± SD [27 ± 2]; 86% female) before and after CCK-8 administration in a crossover study design. During sedated endoscopy, FLIP was performed twice with CCK-8 administered via intravenous push in one of 2 protocols: during filling (n = 4) or during emptying (n = 3). Esophagogastric junction distensibility index (EGJ-DI) at 60 mL fill volume and esophageal body contractile response patterns were analyzed.

Results

During the baseline FLIP study, all subjects had a contractile response with repetitive antegrade contractions both before and after CCK-8 administration. However, a sustained LES contraction or a sustained occluding contraction with esophageal shortening was observed in all subjects in the filling protocol, but in none during the emptying protocol. EGJ-DI was similar before and after CCK-8 during both filling (4.7 ± 1.9 mm2/mmHg vs 4.3 ± 1.8 mm2/mmHg) and emptying protocol (7.5 ± 1.4 mm2/mmHg vs 6.9 ± 0.6 mm2/mmHg).

Conclusion

While EGJ-DI appeared unaffected by CCK-8 administration in asymptomatic volunteers, CCK induced spastic-reactive contractions of the LES during distention suggesting that exogenous CCK interferes with normal LES relaxation during secondary peristalsis.

Artificial Intelligence Tools for Improving Manometric Diagnosis of Esophageal Dysmotility

PURPOSE OF REVIEW

Artificial intelligence (AI) is a broad term that pertains to a computer's ability to mimic and sometimes surpass human intelligence in interpretation of large datasets. The adoption of AI in gastrointestinal motility has been slower compared to other areas such as polyp detection and interpretation of histopathology.

RECENT FINDINGS

Within esophageal physiologic testing, AI can automate interpretation of image-based tests, especially high resolution manometry (HRM) and functional luminal imaging probe (FLIP) studies. Basic tasks such as identification of landmarks, determining adequacy of the HRM study and identification from achalasia from non-achalasia patterns are achieved with good accuracy. However, existing AI systems compare AI interpretation to expert analysis rather than to clinical outcome from management based on AI diagnosis. The use of AI methods is much less advanced within the field of ambulatory reflux monitoring, where challenges exist in assimilation of data from multiple impedance and pH channels. There remains potential for replication of the AI successes within esophageal physiologic testing to HRM of the anorectum, and to innovative and novel methods of evaluating gastric electrical activity and motor function. The use of AI has tremendous potential to improve detection of dysmotility within the esophagus using esophageal physiologic testing, as well as in other regions of the gastrointestinal tract. Eventually, integration of patient presentation, demographics and alternate test results to individual motility test interpretation will improve diagnostic precision and prognostication using AI tools.

Modern Achalasia: Diagnosis, Classification, and Treatment

Achalasia is a major esophageal motor disorder featured by the altered relaxation of the esophagogastric junction in the absence of effective peristaltic activity. As a consequence of the esophageal outflow obstruction, achalasia patients present with clinical symptoms of dysphagia, chest pain, weight loss, and regurgitation of indigested food. Other less specific symptoms can also present including heartburn, chronic cough, and aspiration pneumonia. The delay in diagnosis, particularly when the presenting symptoms mimic those of gastroesophageal reflux disease, may be as long as several years. The widespread use of high-resolution manometry has permitted earlier detection and uncovered achalasia phenotypes which can have prognostic and therapeutic implications. Other tools have also emerged to help define achalasia severity and which can be used as objective measures of response to therapy including the timed barium esophagogram and the functional lumen imaging probe. Such diagnostic innovations, along with the increased awareness by clinicians and patients due to the availability of alternative therapeutic approaches (laparoscopic and robotic Heller myotomy, and peroral endoscopic myotomy) have radically changed the natural history of the disorder. Herein, we report the most recent advances in the diagnosis, classification, and management of esophageal achalasia and underline the still-grey areas that needs to be addressed by future research to reach the goal of personalizing treatment.

An artificial intelligence platform provides an accurate interpretation of esophageal motility from Functional Lumen Imaging Probe Panometry studies

BACKGROUND

Functional lumen imaging probe (FLIP) Panometry is performed at the time of sedated endoscopy and evaluates esophageal motility in response to distension. This study aimed to develop and test an automated artificial intelligence (AI) platform that could interpret FLIP Panometry studies.

METHODS

The study cohort included 678 consecutive patients and 35 asymptomatic controls that completed FLIP Panometry during endoscopy and high-resolution manometry (HRM). "True" study labels for model training and testing were assigned by experienced esophagologists per a hierarchical classification scheme. The supervised, deep learning, AI model generated FLIP Panometry heatmaps from raw FLIP data and based on convolutional neural networks assigned esophageal motility labels using a two-stage prediction model. Model performance was tested on a 15% held-out test set (n = 103); the remainder of the studies were utilized for model training (n = 610).

KEY RESULTS

"True" FLIP labels across the entire cohort included 190 (27%) "normal," 265 (37%) "not normal/not achalasia," and 258 (36%) "achalasia." On the test set, both the Normal/Not normal and the achalasia/not achalasia models achieved an accuracy of 89% (with 89%/88% recall, 90%/89% precision, respectively). Of 28 patients with achalasia (per HRM) in the test set, 0 were predicted as "normal" and 93% as "achalasia" by the AI model.

CONCLUSIONS

An AI platform provided accurate interpretation of FLIP Panometry esophageal motility studies from a single center compared with the impression of experienced FLIP Panometry interpreters. This platform may provide useful clinical decision support for esophageal motility diagnosis from FLIP Panometry studies performed at the time of endoscopy.

Pediatric Neurogastroenterology and Motility Disorders: What Role Does Endoscopy Play?

Although pediatric neurogastroenterology and motility (PNGM) disorders are prevalent, often debilitating, and remain challenging to diagnose and treat, this field has made remarkable progress in the last decade. Diagnostic and therapeutic gastrointestinal endoscopy emerged as a valuable tool in the management of PNGM disorders. Novel modalities such as functional lumen imaging probe, per-oral endoscopic myotomy, gastric-POEM, and electrocautery incisional therapy have changed the diagnostic and therapeutic landscape of PNGM. In this review, the authors highlight the emerging role of therapeutic and diagnostic endoscopy in esophageal, gastric, small bowel, colonic, and anorectal disorders and disorders of gut and brain axis interaction.

Type II achalasia with focal elevated pressures: A distinct manometric and clinical sub-group

BACKGROUND

Type II achalasia (Ach2) is distinguished from other achalasia sub-types by the presence of panesophageal pressurization (PEP) of ≥30 mmHg in ≥20% swallows on high-resolution manometry (HRM). Variable manometric features in Ach2 have been observed, characterized by focal elevated pressures (FEPs) (focal/segmental pressures ≥70 mmHg within the PEP band) and/or high compression pressures (PEP ≥70 mmHg). This study aimed to examine clinical and physiologic variables among sub-groups of Ach2.

METHODS

This retrospective single center study performed over 3 years (1/2019-1/2022) included adults with Ach2 on HRM who underwent endoscopic ultrasound (EUS), functional lumen imaging probe (FLIP), and/or barium esophagram (BE) prior to therapy. Patients were categorized into two overarching sub-groups: Ach2 without FEPs and Ach2 with FEPs. Demographic, clinical, and physiologic data were compared between these sub-groups utilizing unpaired univariate analyses.

KEY RESULTS

Of 53 patients with Ach2, 40 (75%) were without FEPs and 13 (25%) had FEPs. Compared with the Ach2 sub-group without FEPs, the Ach2 sub-group with FEPs demonstrated a significantly thickened distal esophageal circular muscle on EUS (1.4 mm [SD 0.9] vs. 2.1 [0.7]; p = 0.02), higher prevalence of tertiary contractions on BE (46% vs. 100%; p = 0.0006), lower esophagogastric junction distensibility index (2.2mm2 /mmHg [0.9] vs 0.9 [0.4]; p = 0.0008) as well as higher distensive pressure (31.0 mmHg [9.8] vs. 55.4 [18.8]; p = 0.01) at 60 cc fill on FLIP, and higher prevalence of chest pain on Eckardt score (p = 0.03).

CONCLUSIONS AND INFERENCES

We identified a distinct sub-group of type II achalasia on HRM, defined as type II achalasia with focal elevated pressures. This sub-group uniquely exhibits spastic features and may benefit from personalized treatment approaches.

Advances and horizons for artificial intelligence of endoscopic screening and surveillance of gastric and esophageal disease

The development of artificial intelligence in endoscopic assessment of the gastrointestinal tract has shown progressive enhancement in diagnostic acuity. This review discusses the expanding applications for gastric and esophageal diseases. The gastric section covers the utility of AI in detecting and characterizing gastric polyps and further explores prevention, detection, and classification of gastric cancer. The esophageal discussion highlights applications for use in screening and surveillance in Barrett's esophagus and in high-risk conditions for esophageal squamous cell carcinoma. Additionally, these discussions highlight applications for use in assessing eosinophilic esophagitis and future potential in assessing esophageal microbiome changes.

Validation of secondary peristalsis classification using FLIP panometry in 741 subjects undergoing manometry

BACKGROUND AND AIMS

This study aimed to systematically evaluate a classification scheme of secondary peristalsis using functional luminal imaging probe (FLIP) panometry through comparison with primary peristalsis on high-resolution manometry (HRM).

METHODS

706 adult patients that completed FLIP and HRM for primary esophageal motility evaluation and 35 asymptomatic volunteers ("controls") were included. Secondary peristalsis, that is, contractile responses (CRs), was classified on FLIP panometry by the presence and pattern of contractility as normal (NCR), borderline (BCR), impaired/disordered (IDCR), absent (ACR), or spastic-reactive (SRCR). Primary peristalsis on HRM was assessed according to the Chicago Classification.

RESULTS

All 35 of the controls had antegrade contractions on FLIP panometry with either NCR (89%) or BCR (11%). The average percentages of normal swallows on HRM varied across contractile response patterns from 84% in NCR, 68% in BCR, 39% in IDCR, to 11% in ACR, as did the percentage of failed swallows on HRM: 4% in NCR, 12% in BCR, 36% in IDCR, and 79% in ACR. SRCR on FLIP panometry was observed in 18/57 (32%) patients with type III achalasia, 4/15 (27%) with distal esophageal spasm, and 7/15 (47%) with hypercontractile esophagus on HRM.

CONCLUSIONS

The FLIP panometry contractile response patterns reflect a pathophysiologic transition from normal to abnormal esophageal peristaltic function with shared features with primary peristaltic function/dysfunction on HRM. Thus, these patterns of the contractile response to distension can facilitate the evaluation of esophageal motility using FLIP panometry.

Dysphagia: Novel and Emerging Diagnostic Modalities

Among recent advances in diagnostics for dysphagia and esophageal motility disorders is the update to the Chicago Classification (version 4.0) for interpretation of high-resolution manometry (HRM) and diagnosis of esophageal motility disorders. The update incorporates application of complementary testing strategies during HRM, such as provocative HRM maneuvers, and recommendation for barium esophagram or functional luminal imaging probe (FLIP) panometry to help clarify inconclusive HRM findings. FLIP panometry also represents an emerging technology for evaluation of esophageal distensibility and motility at the time of endoscopy.

Classifying Esophageal Motility by FLIP Panometry: A Study of 722 Subjects With Manometry

INTRODUCTION

Functional luminal imaging probe (FLIP) panometry can evaluate esophageal motility in response to sustained esophageal distension at the time of sedated endoscopy. This study aimed to describe a classification of esophageal motility using FLIP panometry and evaluate it against high-resolution manometry (HRM) and Chicago Classification v4.0 (CCv4.0).

METHODS

Five hundred thirty-nine adult patients who completed FLIP and HRM with a conclusive CCv4.0 diagnosis were included in the primary analysis. Thirty-five asymptomatic volunteers ("controls") and 148 patients with an inconclusive CCv4.0 diagnosis or systemic sclerosis were also described. Esophagogastric junction (EGJ) opening and the contractile response (CR) to distension (i.e., secondary peristalsis) were evaluated with a 16-cm FLIP during sedated endoscopy and analyzed using a customized software program. HRM was classified according to CCv4.0.

RESULTS

In the primary analysis, 156 patients (29%) had normal motility on FLIP panometry, defined by normal EGJ opening and a normal or borderline CR; 95% of these patients had normal motility or ineffective esophageal motility on HRM. Two hundred two patients (37%) had obstruction with weak CR, defined as reduced EGJ opening and absent CR or impaired/disordered CR, on FLIP panometry; 92% of these patients had a disorder of EGJ outflow per CCv4.0.

DISCUSSION

Classifying esophageal motility in response to sustained distension with FLIP panometry parallels the swallow-associated motility evaluation provided with HRM and CCv4.0. Thus, FLIP panometry serves as a well-tolerated method that can complement, or in some cases be an alternative to HRM, for evaluating esophageal motility disorders.

The Outcomes of Performing Partial Fundoplication Based on Endoflip Versus Manometric Findings

BACKGROUND

The surgical management of gastroesophageal reflux disease (GERD) involves extensive diagnostic studies and sophisticated surgical techniques. The workup should be comprehensive and purposeful. High resolution impedance manometry (HRIM) provides valuable information regarding peristalsis and lower esophageal sphincter relaxation. The disadvantages of HRIM such as intolerance or inability to pass the catheter led to its selective use or even omission especially in laparoscopic hiatal hernia repair with partial fundoplication. This pragmatic approach risks missing motility disorders in patients with secondary reflux symptoms related to achalasia or scleroderma. Endolumenal functional lumen imaging probe (endoFLIP) can fill this void as it evaluates the dynamics of the esophagogastric junction under sedation. This study aims to compare the outcomes of preoperative use of HRIM vs endoFLIP for laparoscopic repair of hiatal hernia with partial fundoplication.

METHODS

This is a retrospective cohort study for consecutive patients who underwent antireflux surgery with partial fundoplication between July 2018 and February 2021. Preoperative and postoperative outcomes were compared between two cohorts of patients: those with preoperative HRIM and those with preoperative endoFLIP.

RESULTS

A total of 72 patients were evaluated, 41 had preoperative HRIM and 31 had endoFLIP. There was no statistically significant difference in their age, sex, BMI, duration of GERD symptoms, or proton pump inhibitors use. The endoscopic findings of esophagitis, hiatal hernia, and Hill's grade were comparable. There was no difference in the American Society of Anesthesiology classification or the choice of antireflux surgery. The improvement of postoperative GERD scores and dysphagia subscore was similar between the two groups.

CONCLUSION

Performing partial fundoplication based on endoFLIP evaluation of the dynamics of the esophagogastric junction is safe and does not increase postoperative dysphagia compared to preoperative manometric use. Randomized prospective studies are needed to confirm the findings of this study.

Evaluating esophageal motility beyond primary peristalsis: Assessing esophagogastric junction opening mechanics and secondary peristalsis in patients with normal manometry

BACKGROUND

Functional luminal imaging probe (FLIP) Panometry assesses the esophageal response to distention and may complement the assessment of primary peristalsis on high-resolution manometry (HRM). We aimed to investigate whether FLIP Panometry provides complementary information in patients with normal esophageal motility on HRM.

METHODS

Adult patients that completed FLIP and had an HRM classification of normal motility were retrospectively identified for inclusion. 16-cm FLIP studies performed during endoscopy were evaluated to assess EGJ distensibility, secondary peristalsis, and identify an abnormal response to distention involving sustained LES contraction (sLESC). Clinical characteristics and esophagram were assessed when available.

KEY RESULTS

Of 164 patients included (mean(SD) age 48(16) years, 75% female), 111 (68%) had normal Panometry with EGJ-distensibility index (DI) ≥2.0 mm2 /mmHg, maximum EGJ diameter ≥16mm and antegrade contractions. Abnormal EGJ distensibility was observed in 44/164 (27%), and 38/164 (23%) had an abnormal contractile response to distension. sLESC was observed in 11/164 (7%). Among 68 patients that completed esophagram, abnormal EGJ distensibility was more frequently observed with an abnormal esophagram than normal EGJ opening: 14/23 (61%) vs 10/45 (22%); P=0.003. Epiphrenic diverticula were present in 3/164 patients: 2/3 had sLESC.

CONCLUSIONS & INFERENCES

Symptomatic patients with normal esophageal motility on HRM predominantly have normal FLIP Panometry; however, abnormal FLIP findings can be observed. While abnormal Panometry findings appear clinically relevant via an association with abnormal bolus retention, complementary tests, such as provocative maneuvers with HRM and timed barium esophagram, are useful to determine clinical context.