Excess gastroesophageal reflux in patients with hiatus hernia is caused by mechanisms other than transient LES relaxations

BACKGROUND & AIMS: Esophageal acid exposure is higher in gastroesophageal reflux disease (GERD) patients with hiatus hernia than in those without. We investigated the effect of a sliding hiatus hernia on the mechanisms underlying spontaneous gastroesophageal reflux over 24 hours. METHODS: Twelve GERD patients with and 10 GERD patients without hiatus hernia were studied for 24 hours. Combined esophageal pH and manometric recordings of the pharynx, lower esophageal sphincter (LES), and stomach were performed using a multiple-lumen assembly incorporating a Dent sleeve connected to a portable water-perfused manometric system and a pH glass electrode. RESULTS: Patients with hiatus hernia had greater esophageal acid exposure (7.6% vs. 3.3%; P < 0.01) and more reflux episodes (3.1 vs. 1.8/h; P < 0.001) than those without. LES pressure, the incidence of transient LES relaxations (TLESRs), and the proportion of TLESRs associated with acid reflux were comparable in both groups. Both groups had equal numbers of reflux episodes associated with TLESRs and swallow-associated prolonged LES relaxations. Patients with hiatus hernia had more reflux associated with low LES pressure, swallow-associated normal LES relaxations, and straining during periods with low LES pressure. CONCLUSIONS: The excess reflux in GERD patients with hiatus hernia compared with those without is caused by malfunction of the gastroesophageal barrier during low LES pressure, swallow-associated normal LES relaxations, deep inspiration, and straining.