Anatomical and functional deficiencies of the crural diaphragm in patients with esophagitis

Background Inspiratory esophagogastric junction (EGJ) pressure is lower in gastroesophageal reflux disease (GERD) and patients fail to increase EGJ pressure during the inspiratory effort. The aim of this study was to assess the EGJ activity during inspiratory maneuvers (high‐resolution manometry, HRM) and the crural diaphragm (CD) thickness (endoscopic ultrasound, EUS) in GERD. Methods Twenty esophagitis patients (average age 45 years, 7 grade A, 13 grade B) had HRM and EUS. Forty‐three controls were recruited; 30 had HRM (average age 33 years), and 13 had EUS (average age 40 years). The EGJ contractility index (EGJ‐CI) (mm Hg×cm) was measured during normal respiration and two inspiratory maneuvers: without and with inspiratory loads of 12, 24, and 48 cmH2O (TH‐maneuvers). A composite metric for TH‐maneuvers (“EGJ total activity”) was defined as the product of the maximal EGJ pressure and the length of its aboral excursion during the maneuver (mm Hg×cm). The CD thickness (cm) was measured during expiration (12 MHz). Key Results Expiratory lower esophageal sphincter pressure and integrated relaxation pressure were lower in GERD. The EGJ‐CI and the “EGJ total activity” were lower in GERD during TH‐maneuvers (48‐cmH2O load: 168.4 ± 13.8 vs 114.8 ± 9.6, P=.006). Patients failed to sustain the inspiratory CD activity across the 12 and 48‐cmH2O efforts. The CD was thinner in GERD patients (0.37 ± 0.03 vs 0.49 ± 0.04, P=.02). The CD thickness correlated with the increment in the “EGJ total activity” in GERD without a hiatal hernia (r=.702, P=.016, n=11). Conclusions & Inferences There are anatomical changes and functional failure of the CD in esophagitis patients supporting the possibility of a skeletal muscle deficiency in GERD. This study shows that the CD right crus is thinner in esophagitis patients compared to healthy subjects. Additionally, esophagitis patients failed to keep the EGJ‐CI and the “EGJ total activity” at high levels as the inspiratory load increased. This phenomenon did not occur in healthy subjects.