Fragmented and failed swallows on esophageal high-resolution manometry associate with abnormal reflux burden better than weak swallows

Background: Association between proportions of hypomotile swallows on esophageal high-resolution manometry (HRM) and esophageal reflux burden remains incompletely understood. We investigated relationships between hypomotility, acid exposure time (AET), and mean nocturnal baseline impedance (MNBI) on ambulatory reflux monitoring. Methods: Clinical data, HRM, and ambulatory pH-impedance studies (performed off acid suppression) from patients with persisting reflux symptoms were reviewed from five international centers. AET (abnormal > 6%) and MNBI (abnormal < 2292 ohms) were extracted from pH-impedance studies. Distal contractile integral (DCI) designated esophageal peristalsis into normal (DCI > 450 mmHg.cm.s), fragmented (DCI > 450 mmHg.cm.s with breaks > 5 cm), weak (DCI 100-450 mmHg.cm.s), and failed (DCI < 100 mm mmHg.cm.s) sequences. Univariate and multivariate analyses were performed to identify motor associations of abnormal reflux burden. Key results: Of 351 patients (52.1 ± 0.8 years, 67%F), 29.3% had AET > 6% and 61.8% had MNBI < 2292 ohms. On univariate analysis, both fragmented peristalsis and IEM associated with abnormal AET (P ≤ .01) and MNBI (P ≤ .03); reflux burden was more profound with >70% fragmented as well as ineffective sequences compared to ≤70% for each (P < .05 for each comparison). When weak and failed sequences within IEM were separately analyzed, ≥50% failed sequences predicted abnormal AET (P ≤ .009), and ≥50% weak sequences did not (P = .14). On multivariate regression, ≥50% failed sequences predicted abnormal AET (P = .02), and >70% ineffective sequences trended strongly (P = .069); >70% ineffective sequences predicted abnormal MNBI (P = .046), and >70% fragmented sequences trended strongly (P = .076). Conclusions and inferences: Breaks in esophageal peristaltic integrity seen with fragmented and failed sequences are more relevant to abnormal esophageal acid burden than weak sequences.