Background Mean nocturnal baseline impedance (MNBI), a novel pH-impedance metric, may be a surrogate marker of reflux burden. Aim To assess the predictive value of MNBI on symptomatic outcomes after antireflux therapy. Methods In this prospective observational cohort study, pH-impedance studies performed over a 5-year period were reviewed. Baseline impedance was extracted from 6 channels at three stable nocturnal 10-min time periods, and averaged to yield MNBI. Distal and proximal esophageal MNBI values were calculated by averaging MNBI values at 3, 5, 7, and 9 cm, and 15 and 17 cm, respectively. Symptomatic outcomes were measured as changes in global symptom severity (GSS, rated on 100-mm visual analog scales) on prospective follow-up after medical or surgical antireflux therapy. Univariate and multivariate analyses assessed the predictive value of MNBI on symptomatic outcomes. Results Of 266 patients, 135 (50.8%) were tested off PPI therapy and formed the study cohort (52.1±1.1 yrs, 63.7% F). The 59 with elevated acid exposure time (AET) had lower composite and distal MNBI values than those with physiologic AET (p<0.0001), but similar proximal MNBI (p=0.62). Linear AET negatively correlated with distal MNBI, both individually and collectively (Pearson's r=−0.5, p<0.001), but not proximal MNBI (Pearson's r=0, p=0.72). After prospective follow-up (94 patients followed for 3.1±0.2 yrs), univariate and multivariate regression models showed that distal MNBI, but not proximal MNBI, was independently predictive of linear GSS improvement. Conclusions Distal esophageal MNBI negatively correlates with AET and, when assessed off PPI therapy, is independently predictive of symptomatic improvement following antireflux therapy.

While abnormal EGJ and esophageal body metrics are collectively associated with elevated esophageal reflux burden, increasing proportions of failed swallows are better predictors of reflux burden and outcome compared to the current IEM definition.

Background Esophagogastric junction contractile integral (EGJ-CI) assesses EGJ barrier function on esophageal high resolution manometry (HRM). We assessed EGJ-CI values in achalasia and gastroesophageal reflux disease (GERD) to determine if postoperative EGJ-CI changes reflected surgical intervention. Methods 21 achalasia patients (42.8±3.2 yrs, 62% F) with HRM before and after Heller myotomy (HM) and 68 GERD patients (53.9±1.8 yrs, 66% F) undergoing anti-reflux surgery (ARS) were compared to 21 healthy controls (27.6±0.6 yrs, 52% F). EGJ-CI (mmHg.cm) was calculated using the distal contractile integral (DCI) measurement across the EGJ, measured above the gastric baseline and corrected for respiration. Pre- and post-surgical EGJ-CI and conventional lower esophageal sphincter pressure (LESP) metrics were compared within and between these groups using non-parametric tests. Correlation between EGJ-CI and conventional LESP metrics was assessed. Results Baseline EGJ-CI was higher in achalasia compared to GERD (p<0.001) or controls (p=0.03). EGJ-CI declined by 59.2% after HM in achalasia (p=0.001), and increased by 26.3% after ARS in GERD (p=0.005). End-expiratory and basal LESP decreased by 74.5% and 64.5% with HM, but increased by only 17.8% and 4.3% with ARS. Differences were noted between Dor vs. Toupet fundoplication in achalasia (p=0.007), and partial vs. complete ARS in GERD (p=0.03). EGJ-CI correlated modestly with both end-expiratory and basal LESP (Pearson’s r of 0.8 for all), but was less robust in GERD (0.7). Conclusions EGJ-CI has clinical utility in assessing EGJ barrier function at baseline and after surgical intervention to the EGJ, and could complement conventional EGJ metrics.

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SUMMARY Background The Chicago Classification (CC) uses high-resolution manometry (HRM) software tools to designate esophageal motor diagnoses. We evaluated changes in diagnostic designations between two CC versions, and determined motor patterns not identified by either version. Methods In this observational cohort study of consecutive patients undergoing esophageal HRM over a 6-year period, proportions meeting CC 2.0 and 3.0 criteria were segregated into esophageal outflow obstruction, hypermotility, and hypomotility disorders. Contraction wave abnormalities (CWA), and ‘normal’ cohorts were recorded. Symptom burden was characterized using dominant symptom intensity and global symptom severity. Motor diagnoses, presenting symptoms, and symptom burden were compared between CC 2.0 and 3.0, and in cohorts not meeting CC diagnoses. Results Of 2569 eligible studies, 49.9% met CC 2.0 criteria, but only 40.3% met CC 3.0 criteria (p<0.0001). Between CC 2.0 and 3.0, 82.8% of diagnoses were concordant. Discordance resulted from decreasing proportions of hypermotility (4.4%) and hypomotility (9.0%) disorders, and increase in ‘normal’ designations (13.0%); esophageal outflow obstruction showed the least variation between CC versions. Symptom burden was higher with CC 3.0 diagnoses (p≤0.005) but not with CC 2.0 diagnoses (p≥0.1). Within ‘normal’ cohorts for both CC versions, CWA were associated with higher likelihood of esophageal symptoms, especially dysphagia, regurgitation, and heartburn, compared to truly normal studies (p≤0.02 for each comparison). Conclusions Despite lower sensitivity, CC 3.0 identifies esophageal motor disorders with higher symptom burden compared to CC 2.0. CWA, which are associated with both transit and perceptive symptoms, are not well identified by either version.