IDENTIFICATION OF OBSTRUCTIVE PHENOTYPES WITHIN ABSENT CONTRACTILITY ON ESOPHAGEAL HIGH-RESOLUTION MANOMETRY

Background: Esophageal peristalsis comprises of an initial inhibition/relaxation followed by the excitation/contraction. The high-resolution esophageal manometry (HRM) measures only the contraction phase of peristalsis. From the impedance part of HRMZ recordings, we have developed a technique to measure the intraluminal cross section area (distension) of esophagus during peristalsis, as bolus travels through the esophagus. Distension is an indirect marker of the inhibitory phase of peristalsis. Using a protocol that comprised of 10ml swallows of 0.5N saline in -15⁰ Trendelenburg position, our studies show that, as compared to normal subjects, patients with functional dysphagia (dysphagia but normal HRM study) show following; 1) bolus travels through the esophagus at a faster velocity and, 2) the amplitude of distal esophageal distension is smaller in patients¹. The clinical protocol of HRM testing utilize a 5ml bolus of 0.5N saline in the supine position during HRMZ studies to record esophageal peristalsis. Aims: to determine if there are differences in the distension contraction profile of esophageal peristalsis in patients with functional dysphagia (FD), as compared to normal subjects using the standard clinical protocol. Method: The HRMZ studies of 20 asymptomatic subjects and 20 patients with FD (brief esophageal dysphagia score of > 10, and normal HRMZ study) were analyzed. Studies in both groups were performed using the standard clinical protocol, i.e., 5ml swallows of 0.5N saline in the supine position. Several distension contraction parameters were extracted from the recordings using a custom developed software (Dplots, Motilityviz, LaJolla, CA). Results: T1 (the time difference between the onset of swallow to peak distension in the distal esophagus) is smaller and velocity of bolus flow faster in FD patients as compared to normal subjects. The peak luminal cross section area (esophageal distension) of the distal esophagus is smaller in FD patients as compared to normal subjects. On the other hand, there is no difference in the peak contraction pressure (contraction amplitude) and the area under the curve of contraction pressures between the two groups, (Figure 1). Conclusion: Based on the Poiseuille law of fluid flow, differences in the bolus flow velocity, a shorter time to travel to distal esophagus and smaller luminal cross-sectional area of the esophagus suggest a narrower lumen of the esophagus during peristalsis in FD patients. Using routine current clinical HRMZ protocol, distension contraction plots can distinguish patients with “functional dysphagia” from normal subjects and it should be the standard of esophageal motor function assessment in future studies.
1) Mittal RK et al. Abnormal Esophageal Distension Profiles in Patients With Functional Dysphagia: A Possible Mechanism of Dysphagia. Gastroenterology, 2021;160 (5):1847-1849

Background: Absent contractility on high-resolution manometry (HRM) defines severe hypomotility but needs distinction from achalasia. We characterized esophagogastric junction (EGJ) obstruction suggestive of achalasia within absent contractility using HRM provocative maneuvers, barium esophagraphy, and functional lumen imaging probe (FLIP).
Methods: Adult patients with absent contractility (distal contractile integral, DCI<100 mmHg.cm.s on 100% swallows, supine integrated relaxation pressure, IRP<15 mmHg) diagnosed between 4/2016-3/2020 were eligible for inclusion. Inadequate or incomplete studies, achalasia after therapy, or history of prior foregut surgery were exclusions. On multiple rapid swallows (MRS; five 2-mL rapid swallows) and rapid drink challenge (RDC; free drinking of 100-200 mL), panesophageal pressurization, and/or elevated IRP (MRS:≥15 mmHg; RDC >16.7 mmHg) defined HRM obstruction. On barium studies and FLIP, objective obstruction consisted of esophageal barium retention, abnormal EGJ distensibility index (EGJ DI<2.0) on FLIP, or borderline EGJ DI (2.0-3.0) with abnormal barium. Clinical, endoscopic and motor characteristics of patients with obstructive features on testing were compared to those without obstruction.
Results: Inclusion criteria were met by 165 patients (Table) undergoing HRM for dysphagia (33.8%) or prior to foregut surgery (37.0%); a minority presented with heartburn (12.1%), and half had weight loss. The majority were on antisecretory therapy prior to testing (128/158, 81.0%). Erosive esophagitis (LA grades B, C, or D esophagitis) was identified in 9.0%. Objective evidence of EGJ obstruction on barium/FLIP was identified in 32 patients (19.4%). While median supine IRP and RDC IRP were higher in patients with objective obstruction (p=0.02), IRP values were rarely abnormal (Table). In contrast, RDC pressurization and overall HRM evidence of obstruction on provocative testing were both higher with objective obstruction on adjunctive testing (p≤0.02, Figure). Of note, patients without adjunctive investigation for obstruction were more likely to experience heartburn (17, 18.7%, p=0.008 across groups compared to those without obstruction on adjunctive testing) and 24/86 (27.9%) had esophagitis on endoscopy; however, supine median IRP was 4.9 (IQR 2.6-7.8) mmHg, no different from patients without obstruction on adjunctive testing (p=0.633).
Conclusions: Despite HRM diagnosis of absent contractility, objective obstruction on adjunctive testing is identified in as many as a fifth of patients. Rather than IRP at any position or with any maneuver, pressurization on RDC was seen most often with objective obstruction. Presentation with dysphagia rather than heartburn, no reflux esophagitis, and pressurization on provocative testing may raise suspicion of EGJ obstruction in absent contractility, with management implications.