The Physiology and Pathophysiology of Gastroesophageal Reflux in Patients with Laparoscopic Adjustable Gastric Band.

INTRODUCTION: The effect of the laparoscopic adjustable gastric band (LAGB) on esophageal acid exposure and reflux is poorly understood. Optimal technique and normative values for acid exposure have not been established in this group.

METHODS: High-resolution manometry (HRM) and 24-h ambulatory esophageal pH monitoring were performed in three groups: asymptomatic LAGB, symptomatic LAGB, and pre-operative reflux patients. This technique utilized intraluminal pressure signatures during HRM to guide accurate pH sensor placement.

RESULTS: The LAGB groups were well matched: age 48 vs 51 years (p = 0.249), weight loss 27.3 vs 26.7 kg (p = 0.911). The symptomatic group had a larger gastric pouch (5.2 vs 3.3 cm, p = 0.012), with higher esophageal acid exposure (10.8 vs 0.9%, p < 0.001). Two acidification patterns were observed: irritant and volume acidification, associated with substantial supine acidification. Symptomatic LAGB had altered esophageal motility, with poorer lower esophageal sphincter basal tone (8.0 vs 17.7 mmHg, p = 0.022) and impaired contractility of the lower esophageal segment (90 vs 40%, p = 0.009). Compared to pre-operative reflux patients, symptomatic LAGB patients demonstrated higher total and supine esophageal acid exposure (10.8 vs 7.0%, p = 0.010; 14.9 vs 5.1%, p < 0.001), less symptoms (2 vs 6, p = 0.001) and lower symptom index (0.7 vs 0.9, p = 0.010).

CONCLUSIONS: Ambulatory pH monitoring is an effective technique if the pH sensor is positioned appropriately using HRM. The correctly positioned LAGB appears associated with low esophageal acidification. In contrast, patients with symptoms or pouch dilatation can have markedly elevated esophageal acidification, particularly when supine. This is a different pattern compared to pre-operative patients and importantly can be disproportionate to symptoms.