Fragmented esophageal smooth muscle contraction segments on high resolution manometry: a marker of esophageal hypomotility

Background  Esophageal peristalsis consists of a chain of contracting striated and smooth muscle segments on high resolution manometry (HRM). We compared smooth muscle contraction segments in symptomatic subjects with reflux disease to healthy controls. Methods  High resolution manometry Clouse plots were analyzed in 110 subjects with reflux disease (50 ± 1.4 years, 51.5% women) and 15 controls (27 ± 2.1 years, 60.0% women). Using the 30 mmHg isobaric contour tool, sequences were designated fragmented if either smooth muscle contraction segment was absent or if the two smooth muscle segments were separated by a pressure trough, and failed if both smooth muscle contraction segments were absent. The discriminative value of contraction segment analysis was assessed. Key Results  A total of 1115 swallows were analyzed (reflux group: 965, controls: 150). Reflux subjects had lower peak and averaged contraction amplitudes compared with controls ( P  < 0.0001 for all comparisons). Fragmented sequences followed 18.4% wet swallows in the reflux group, compared with 7.5% in controls ( P  < 0.0001), and were seen more frequently than failed sequences (7.9% and 2.5%, respectively). Using a threshold of 30% in individual subjects, a composite of failed and/or fragmented sequences was effective in segregating reflux subjects from control subjects ( P  = 0.04). Conclusions & Inferences  Evaluation of smooth muscle contraction segments adds value to HRM analysis. Specifically, fragmented smooth muscle contraction segments may be a marker of esophageal hypomotility.