Introduction: Achalasia is an esophageal motility disorder that results from a disruption of the neuromodulatory responses of the esophagus and lower esophageal sphincter (LES). A common consequence of treating the hypercontractile LES is worsened gastroesophageal reflux (GER). It is well-established that peroral endoscopic myotomy (POEM) leads to a higher absolute rate of GER than Laparoscopic Heller Myotomy with Dor fundoplication (LHM); however, the exact patterns of reflux have not been well-described.
Methods: The charts of patients who underwent LHM or POEM between 2017 and 2019 at our institution were reviewed, and patients who had completed a 2-month post-treatment esophageal pH study off acid-lower agents were included. We also included patients who underwent EGD but did not undergo pH monitoring due to finding erosive esophagitis. Patients with a history of prior myotomy or who underwent Heller without Dor fundoplication were excluded.
Results: Of the 236 patients included, 85 (36%) had undergone POEM while 151 (64%) had undergone LHM. Overall, 45% of POEM patients experienced more than 30 reflux episodes per day compared to 12% for LHM, p< 0.001. POEM patients had more GER in all positions compared to LHM, identified by a mean total % time spent in reflux of 9.3% vs 3.2%, upright 7.8% vs 2.6%, and supine 10.1% vs 3.5%, p< 0.001 for all. POEM patients also developed significantly more long refluxes (episodes > 5 minutes) per day (4.0 vs 1.7, p< 0.001). 47% of POEM patients experienced at least one reflux episode longer than 30 minutes, compared to 19% of LHM patients (p< 0.001). POEM patients who developed relatively more reflux in the supine position than upright comprised 41.1% compared to 21.7% of LHM, p=0.007.
Discussion: This study sheds light on the pattern of reflux in POEM as compared to LHM. POEM patients had evidence of significantly more esophageal acid exposure across all indices. POEM patients on average spent 9.3% of their day in reflux as compared to 3.2% for LHM. POEM patients had higher supine to upright ratios of reflux exposure. The finding of abnormal reflux in both the upright and supine position, with relative skew towards supine reflux after POEM may help to better tailor anti-reflux therapies in this population.
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