Obesity and gastro-esophageal acid reflux: physiopathological mechanisms and role of gastric bariatric surgery.

Background: Controversial findings about the relationships between obesity and gastro-esophageal reflux have been reported, as well as about the effects of weight loss and bariatric surgery on reflux. The aims of this study were to evaluate esophageal motility and gastro-esophageal acid circadian patterns in obese patients and to test the effects of vertical banded gastroplasty (VBG) on these parameters. Methods: 14 obese subjects (BMI 36-53 kg/m2), 4 men, 10 women, 27-61 years old, admitted for elective bariatric surgery, underwent clinical evaluation, upper endoscopy, esophageal manometry and gastroesophageal pH monitoring. Evaluations were repeated 6 to 12 months after gastric surgery that consisted of a VBG (7 patients), accompanied in the other 7 patients with an anti-reflux procedure (fundoplication). Manometric and pH-metric findings in the obese patients were compared with a normal-weight control group before and after the two different surgical treatments. Results: Gastro-esophageal reflux was significantly more frequent in obese (57.1%) than in control group (7.1%). Esophageal motility in obese subjects was not different from controls. After VBG alone, we found a reduction in basal lower esophageal sphincter (LES) pressure and an increase of acid reflux. When VBG was accompanied by fundoplication, basal LES pressure increased and acid reflux frequency decreased. Conclusions: Obesity is associated with gastroesophageal reflux. VBG reduced weight, but not gastro-esophageal acid reflux. Therefore, in our population, this operation cannot be considered as an antireflux procedure.