Defining "true acid reflux" after peroral endoscopic myotomy for achalasia: a prospective cohort study.

ABSTRACT

BACKGROUND AND AIMS: The symptoms of reflux in achalasia patients undergoing peroral endoscopic myotomy (POEM) are believed to result from gastroesophageal reflux, and the current treatment primarily focuses on acid suppression. Nevertheless, other factors such as nonreflux acidification caused by fermentation or stasis might play a role. This study aimed to identify patients with "true acid reflux" who actually require acid suppression and fundoplication. METHODS: In this prospective large cohort study, the primary objective was to assess the incidence and risk factors for true acid reflux in achalasia patients undergoing POEM. Acid reflux with normal and delayed clearance defined true acid reflux, whereas other patterns were labeled as nonreflux acidification patterns on manual analysis of pH tracings. These findings were corroborated with a symptom questionnaire, esophagogastroscopy, esophageal manometry, and timed barium esophagogram at 3 months after the POEM procedure. RESULTS: Fifty-four achalasia patients aged 18 to 80 years (mean age, 41.1 ± 12.8 years; 59.3% men; 90.7% with type II achalasia) underwent POEM, which resulted in a significant mean Eckardt score improvement (6.7 to 1.6, P < .05). True acid reflux was noted in 29.6% of patients as compared with 64.8% on automated analysis. Acid fermentation was the predominant acidification pattern seen in 42.7% of patients. On multivariable logistic regression analysis, increasing age (odds ratio, 1.12; 95% confidence interval, 1.02-1.27; P = .04) and preprocedural integrated relaxation pressure (IRP; odds ratio, 1.13; 95% confidence interval, 1.04-1.30; P = .02) were significantly associated with true acid reflux in patients after undergoing POEM. CONCLUSIONS: A manual review of pH tracings helps to identify true acid reflux in patients with achalasia after undergoing POEM. Preprocedural IRP can be a predictive factor in determining patients at risk for this outcome. (Clinical trial registration number NCT04951739.).