Abstract
BACKGROUND: Dysphagia and reflux are frequently experienced by individuals with hiatus hernia (HH), but the underlying mechanisms are not fully defined in radiological or manometric studies. This study explores the impact of HH on propulsive esophageal peristalsis and investigates the biomechanical underpinnings of HH-concurrent-related dysphagia in affected individuals. METHODS: High-resolution manometry with impedance (HRM-I) studies compared the biomechanics of 195 gastroesophageal reflux disease (GERD) patients (excluding large HH and motility disorders) and 20 normal healthy volunteers. Assessments included dysphagia severity, esophageal pH monitoring, and HRM-I with 5-mL liquid and viscous swallows. Bolus distension pressures during bolus transport and esophageal emptying parameters were assessed in conjunction with standard pressure topography metrics. Data grouped by EGJ morphology type were analyzed by a mixed-effects statistical model. KEY RESULTS: Patients with unequivocal HH exhibited altered bolus transport through the mid-distal esophageal body, indicated by increased intrabolus distension pressure during bolus transport (p < 0.01 for liquid and viscous swallows) and shorter bolus flow time through the EGJ (p ≤ 0.005 for liquid and viscous swallows). Increased HH size during swallows also correlated with increased intrabolus distension pressure (liquid r 0.243, p < 0.001) and shorter EGJ flow time (liquid r - 0.191, p < 0.005). Patients with confirmed GERD without HH showed a different pattern of altered bolus transport in the more proximal esophagus. CONCLUSION: In the presence of a HH, esophageal biomechanics are altered, with elevated bolus distension pressure revealing resistance to bolus transport occurring in the mid-lower esophageal body for liquid and viscous boluses, contributing to dysphagia symptoms.