Intermittent spatial separation of diaphragm and lower esophageal sphincter favors acidic and weakly acidic reflux.

BACKGROUND & AIMS: In small hiatal hernias, the size of the hernia is variable. Intermittent complete reduction can be observed with high-resolution manometry as a transition from a double-peak (hernia) to a single-peak (reduced) high-pressure zone. The aim of this study was to investigate whether intermittent separation of the diaphragm and lower esophageal sphincter (LES) favors the occurrence of gastroesophageal reflux.

METHODS

In 16 patients with a small hiatal hernia (3 cm), prolonged high-resolution manometry was performed. Acid and weakly acidic reflux episodes were detected with pH-impedance monitoring.

RESULTS

The single pressure peak profile (reduced hernia) was present for 814 minutes (56.5% of total time), and the double peak profile (unreduced hernia) was present for 626 minutes (43.5% of total time). In all patients, both pressure profiles were observed. The transition rate between the 2 profiles was 7.5 +/- 0.9 per hour. More reflux occurred when the LES and diaphragm were separated versus the reduced hernia state (23.1 +/- 5.1 vs 12.2 +/- 2.4 episodes per hour, respectively; P < .05). The proportions of acidic reflux episodes during the single and double pressure peaks were similar (70% and 67%, respectively). In the two-pressure-zone state, there was an increase in all reflux mechanisms except transient LES relaxation.

CONCLUSIONS

In patients with a small hiatal hernia, intermittent reduction of the hernia occurs frequently. Spatial separation of the diaphragm and LES in the nonreduced state results in a 2-fold increase in acidic and weakly acidic reflux due to mechanisms other than transient LES relaxation.