The Transdiaphragmatic Pressure Gradient and the Lower Esophageal Sphincter in the Pathophysiology of Gastroesophageal Reflux Disease: an Analysis of 500 Esophageal Function Tests.

backgroundGastroesophageal reflux disease (GERD) pathophysiology is multifactorial. Greater importance has been attributed to a defective lower esophageal sphincter (LES) in comparison to an altered transdiaphragmatic pressure gradient (TPG). This study aims to evaluate the role of the TPG and LES disfunction in GERD pathogenesis.

methodsFive hundred consecutive esophageal function tests from patients with clinically suspected GERD were reviewed. Patients were classified according to the pH monitoring in GERD positive or GERD negative. Abdominal pressure, thoracic pressure, TPG (abdominal-thoracic pressures), LES resting pressure (mid-respiratory, expiratory, and EGJ-CI), and LES retention pressure (LES resting pressure-TPG) were determined.

resultsGERD was present in 296 (59%) individuals. GERD-positive patients were mostly males. LES resting pressure (by all parameters) and thoracic pressure were not different between groups. Abdominal pressure and TPG were higher in GERD-positive patients. LES retention pressure (by all parameters) was lower in GERD-positive patients. DeMeester score had a positive correlation with LES resting pressure, TPG, and LES retention pressure (by all parameters) but not with abdominal pressure and thoracic pressure.

conclusionsLES valvular competency as measured by absolute resting pressure was not reliable to predict GERD; however, it was associated with GERD severity. Relative LES pressure (LES retention pressure) predicted GERD presence and severity, but no parameter showed superiority. TPG plays an important role in the pathophysiology of GERD since it is related to GERD presence and severity; still TPG is altered mostly based on a higher abdominal pressure.