1060 Cleavage of E-Cadherin is More Specific Than Dilated Intercellular Spaces (DIS) Within Esophageal Epithelium (EE) for the Diagnosis of Gastroesophageal Reflux Disease (GERD)

Abstract

INTRODUCTION: Maintenance of closure of the lower esophageal sphincter (LES) in resting state is central to the prevention of gastroesophageal reflux disease (GERD). There are many factors which contribute to the maintenance/failure of the “reflux barrier” of the LES. Here we present a detailed analysis of the anatomy and corresponding biomechanics of the gastroesophageal junction (GEJ) with the AIM of identifying structural differences, and consequent functional differences, in GEJ between normal subjects and GERD patients. METHODS: Three dimensional (3D) reconstructions of the GEJ from transverse magnetic resonance images (MRI) of 12 healthy volunteers and 12 reflux patients were studied for different breathing and meal phases. The orientation of the GEJ and the proximal stomach (angle φ in fig. 1), and the angle of His (θ in fig. 1) were evaluated with respect to an anatomical reference of the midpoint of the vertebrae. Biomechanical analysis of the GEJ was performed for both groups of subjects using the finite element (FE) methods to assess the mechanical consequences of the structural parameters of the GEJ. RESULTS: The angle of His increased with meal and inspiration in both normals and patients, however it always remained more acute (p=0.002) in volunteers (47.23±1.65°) than patients (54.62±1.66°). Interestingly, the orientation of GEJ and proximal stomach in patients was similar to volunteers during fasting, but became more postero-anterior during subsequent fed states. In addition the span of gastric contact with GEJ increased significantly with meal in volunteers (p=0.002) whereas patients showed no such change. FE simulations based on real geometry of the GEJ from 3D reconstruction showed higher intraluminal pressure in the GEJ with pressurization of the stomach when the angle of His was more acute. CONCLUSIONS: The difference in orientation of the GEJ and proximal stomach is possibly the reason for changes in angle of His between normals and patients. Structural and biomechanical differences in the GEJ between normals and patients indicate existence of a virtual “flap valve” in normals which might be dysfunctional in GERD patients.