Contraction Reserve With Ineffective Esophageal Motility on Esophageal High-Resolution Manometry is Associated With Lower Acid Exposure Times Compared With Absent Contraction Reserve

INTRODUCTION:Ineffective esophageal motility (IEM) is a minor motor disorder with potential reflux implications. Contraction reserve, manifested as augmentation of esophageal body contraction after multiple rapid swallows (MRS), may affect esophageal acid exposure time (AET) in IEM.METHODS:Esophageal high-resolution manometry (HRM) and ambulatory reflux monitoring studies were reviewed over 2 years to identify patients with normal HRM, IEM (≥50% ineffective swallows), and absent contractility (100% failed swallows). Single swallows and MRS were analyzed using HRM software tools (distal contractile integral, DCI) to determine contraction reserve (mean MRS DCI to mean single swallow DCI ratio >1). Univariate analysis and multivariable regression analyses were performed to determine motor predictors of abnormal AET in the context of contraction reserve.RESULTS:Of 191 eligible patients, 57.1% had normal HRM, 37.2% had IEM, and 5.8% had absent contractility. Contraction reserve had no affect on AET in normal HRM. Nonsevere IEM (5-7 ineffective swallows) demonstrated significantly lower proportions with abnormal AET in the presence of contraction reserve (30.4%) compared with severe IEM (8-10 ineffective swallows) (75.0%, P = 0.03). Abnormal AET proportions in nonsevere IEM with contraction reserve (32.7%) resembled normal HRM (33.0%, P = 0.96), whereas that in severe IEM with (46.2%) or without contraction reserve (50.0%) resembled absent contractility (54.5%, P ≥ 0.6). Multivariable analysis demonstrated contraction reserve to be an independent predictor of lower upright AET in nonsevere (odds ratio 0.44, 95% confidence interval 0.23-0.88) but not severe IEM.DISCUSSION:Contraction reserve affects esophageal reflux burden in nonsevere IEM. Segregating IEM into severe and nonsevere cohorts has clinical value.