Esophagogastric Junction Contractile Integral (EGJ-CI) Quantifies Changes in EGJ Barrier Function With Surgical Intervention

Abstract

Introduction: Esophagogastric junction contractile integral (EGJ-CI) is a novel high-resolution manometry (HRM) metric to assess EGJ barrier function, taking inspiratory and expiratory pressures, and EGJ length into account. We assessed EGJ-CI values in achalasia and gastroesophageal reflux disease (GERD), and whether postoperative EGJ-CI change reflected surgical intervention in achalasia (Heller myotomy, HM) and GERD (antireflux surgery, ARS). Methods: Patients who underwent HRM both before and after HM and ARS were identified, and compared to controls. EGJ-CI was calculated by forcing the distal contractile integral (DCI) measurement box across the EGJ, for exactly three respiratory cycles. The DCI-like metric was recorded above the gastric baseline, then corrected for respiration by dividing by the duration of the three respiratory cycles, to yield the corrected EGJ-CI (mmHg.cm) (Figure). Pre- and post-surgical EGJ-CI, and conventional lower esophageal sphincter pressure (LESP) metrics were compared within and between groups using non-parametric tests. Correlation between EGJ-CI and conventional LESP metrics was also assessed. Results: 89 patients with pre- and post-operative HRM after surgical intervention to the EGJ were identified: 21 achalasia patients treated with HM (42.8±3.2 yrs, 62% F), and 68 GERD patients who underwent ARS (53.9±1.8 yrs, 66% F). 21 healthy volunteers formed the controls (27.6±0.6 yrs, 52% F). Baseline EGJ-CI was higher in achalasia compared to GERD (p < 0.001) or controls (p=0.03, Table). Values were numerically lower in GERD compared to controls but did not make statistical significance (p=0.18). 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). Only 3 (14%) achalasia patients augmented EGJ-CI following HM, compared to 44 (65%) GERD patients following ARS (p < 0.001). 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. Overall, the EGJ-CI metric correlated well with both end-expiratory and basal LESP (Pearson's r and Spearman coefficients of 0.8 for all). EGJ-CI correlation with the two LESP metrics was comparable in normals (Pearson's r of 0.9, 0.8 respectively) and achalasia (0.9, 0.9), but less robust in GERD (0.7, 0.7). Conclusion: EGJ-CI has clinical utility in assessing EGJ barrier function at baseline and after surgical intervention to the EGJ, and could be more robust than conventional LESP metrics.Table 1: Esophagogastric Junction (EGJ) Metrics by Study GroupFigure 1