Small-Volume, Fast-Emptying Gastric Pouch Leads to Better Long-Term Weight Loss and Food Tolerance After Roux-en-Y Gastric Bypass

Anatomical and functional influences on gastric bypass (GBP) results are often poorly evaluated and not yet fully understood. The purpose of this study is to evaluate the influence of the gastric pouch volume and its emptying rate on long-term weight loss and food tolerance after GBP. Weight loss, food tolerance, pouch volumetry (V) by three-dimensional reconstruction, and pouch emptying rate by 4 h scintigraphy were evaluated in 67 patients. Cutoffs were identified for V and retention percentage (%Ret) at 1 h (%Ret1). From these parameters, the sample was categorized, looking for associations between V, %Ret, weight loss, and food tolerance, assessed by a questionnaire for quick assessment of food tolerance (SS). PO median follow-up time was 47 months; median V was 28 mL; %Ret at 1, 2, and 4 h were 8, 2, and 1%, respectively. There were associations between V <= 40 mL and higher emptying rates up to 2 h (V <= 40 mL: %Ret1 = 6, %Ret2 = 2, p = 0.009; V > 40 mL: %Ret1 = 44, %Ret2 = 13.5, p = 0.045). An association was found between higher emptying speed in 1 h and higher late weight loss (WL), represented by lower percentage of excess weight loss (%EWL) regain (p = 0.036) and higher %EWL (p = 0.033) in the group with %Ret1 <= 12%, compared to the group %Ret1 >= 25%. Better food tolerance (SS > 24), was associated with lower %Ret1 (p = 0.003). Smaller pouch size is associated with a faster gastric emptying, greater WL maintenance, and better food tolerance. These data suggest that a small pouch with rapid emptying rate is an important technical parameter for good outcomes in GBP.