Effects of bariatric surgery on gastroesophageal motor function

Abstract

The prevalence of gastroesophageal reflux disease (GERD) is increasing and this is thought to be linked to the global rise in obesity. In morbidly obese individuals, bariatric surgery is nowadays a popular and effective therapy to induce weight loss. This thesis focuses on the consequences of this strategy on the gastroesophageal function.

It has been suggested that GERD symptoms may be improved by weight reduction. We reviewed the literature on the effect of various weight-reducing modalities on manifestations of GERD in obese patients. In conclusion, dietary and lifestyle intervention may improve GERD in obese patients; however, the most favorable effect is likely to be found after bariatric surgery, especially after a Roux-en-Y gastric bypass procedure.

We studied the association between BMI and esophageal acid exposure in a cohort of patients. Overweight and obesity were associated with increased reflux, especially in the supine position. The most important factors that contribute to reflux are the presence of a hiatal hernia and a lower LES pressure in overweight patients and an increased IGP in obese patients.

We assessed the effects of gastric band placement and stepwise adjustment on esophageal motility. In conclusion, gastric band adjustment leads to immediate enforcement of esophageal peristalsis associated with an increase in intrabolus pressure and with pronounced esophageal shortening. We speculated that subjects without these responses to outflow obstruction may be more prone to dysphagia after band placement.

We studied the effect of the laparoscopic sleeve gastrectomy (LSG) procedure, a relatively new bariatric procedure. Some patients develop gastroesophageal reflux symptoms postoperatively. Using esophageal function tests like 24-hour pH-impedance monitoring) before and three months after LSG, we concluded that patients have significantly higher esophageal acid exposure after LSG, which may well be due to a decrease in LES resting pressure following the procedure.

Postprandial symptoms can compromise the beneficial effect of LSG. It is has been suggested that these symptoms may be due to an altered pattern of gastric emptying. A gastric emptying study with a solid and liquid meal component was performed in the second year after LSG. We concluded that pre-test symptomatic patients after LSG reported more symptoms during the gastric emptying study than patients without these symptoms. However, there was no difference between gastric emptying characteristics between both groups, suggesting that abnormal gastric emptying is not a major determinant of postprandial symptoms after LSG.

In the last chapter of the thesis, we studied the changes in belching before and after LSG, as measured with impedance monitoring. In conclusion, subjectively (as reported by patients) and objectively (as measured by impedance monitoring), an increase in gastric belches is seen after LSG, while the number of (air) swallows tends to decrease after the procedure and the incidence of supragastric belches remains constant. The altered anatomy as well as increased gastroesophageal reflux after LSG may play a role in the increased rate of belching.