The paradox of the pouch: prompt emptying predicts improved weight loss after laparoscopic Roux-Y gastric bypass

The utility of routine upper gastrointestinal (UGI) evaluations after laparoscopic Roux-Y gastric bypass (LRYGB) has yet to be determined, primarily being used to rule out a gastrojejunal leak. Additional information can be assessed with these studies, including the rate of contrast emptying from the pouch; some patients show no or very slow emptying while others show a faster rate of emptying. No or slow emptying is likely due to anastomotic edema and/or a small initial stomal diameter. The aim of this study is to ascertain whether initial pouch emptying (or lack thereof) predicts postoperative weight loss. Between August 2002 and July 2006, 405 LRYGB were performed by a single surgeon using a linear stapler technique. Patient demographics were entered into a longitudinal, prospective database. All patients had an UGI study on postoperative day 1. At 1-year follow-up, 304 patients were available for analysis. The patients were divided into two groups: group A, 188 patients with normal gastric emptying, and group B, 116 patients with very slow or no emptying of contrast. Analysis of covariance (ANCOVA) was used to compare weight loss between the two groups. The following covariates were considered in all analyses: age, sex, length of stay, and operative time. There was a statistically significant difference in weight loss between the two gastric emptying groups adjusting for age, sex, and operative time (p = 0.007). Subjects with prompt gastric emptying (group A) showed more weight loss (50.6 kg versus 47.3 kg) and greater body mass index (BMI) loss (mean loss of 18.1 versus mean loss of 16.6 kg/m(2)) when compared with group B patients with slow or no emptying of the gastric pouch. Many factors (psychosocial, behavioral, hormonal, and anatomical) influence weight loss after LRYGB. Although we are uncertain of the mechanism, patients with normal initial pouch emptying tend to lose more weight than patients who initially exhibit slow or no emptying of the gastric pouch.