title: Analysis of intersegmental trough and proximal latency of smooth muscle contraction using high-resolution esophageal manometry.
abstract: OBJECTIVE
  Intersegmental troughs (ISTs) between striated and smooth muscle contraction segments on high-resolution manometry (HRM) have been linked to hypomotility disorders. We investigated the relationship between ISTs, latency of initiation of smooth muscle contraction, and motor patterns in symptomatic patients and normal controls.
  
  
  METHODS
  HRM Clouse plots were analyzed in 199 participants (47.2±1.2 y, 112F/87M), categorized into 110 participants with gastroesophageal reflux disease (GERD), 74 symptomatic participants without GERD, and 15 healthy controls. IST length was measured in centimeters and percentage esophageal length, designated extended when ≥20% esophageal length on >30% swallows. Proximal latency was measured as the time interval between onset of skeletal and smooth muscle contraction segments, and designated prolonged when ≥4s in ≥50% of swallows.
  
  
  RESULTS
  ISTs of any length were noted in 74.6% swallows and in 92.5% of participants, with a similar frequency across the 3 groups. ISTs and proximal latency were both longer in the GERD group, especially when Barrett esophagus was present, compared with non-GERD patients or controls (P≤0.03 across groups); extended IST and prolonged proximal latency followed similar trends. On multivariate logistic regression, extended IST predicted GERD [odds ratio (OR), 2.30; 95% confidence intervals (CI) 1.18-4.47], as did lower esophageal sphincter pressure <5 mm Hg (OR, 3.79-3.96; 95% CI 1.77-8.49), after controlling for age and sex; prolonged proximal latency predicted both GERD (OR, 2.03; 95% CI 1.01-4.12) and Barrett esophagus (OR 1.91, 95% CI 1.24-2.94).
  
  
  CONCLUSIONS
  Measurement of IST and proximal latency add value to HRM analysis, and may be markers of esophageal hypomotility.
authors.affiliation: Division of Gastroenterology, Washington University School of Medicine, St Louis, MO 63110, USA.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kumar
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Porter
authors.forename: Jake M
authors.initials: JM
authors.lastname: Chanin
authors.forename: C Prakash
authors.initials: CP
authors.lastname: Gyawali
mesh_terms: D000328:Adult; D001471:Barrett Esophagus / Q000503:physiopathology; D015154:Esophageal Motility Disorders / Q000503:physiopathology*; D004947:Esophagus / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D010528:Peristalsis / Q000502:physiology