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

Abstract

Introduction: Anatomical and functional influences on gastric bypass (GBP) results are often poorly evaluated and not yet fully understood.

Purpose: 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.

Materials and methods: 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).

Results: 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).

Conclusion: 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.

Keywords: Bariatric surgery; Gastric bypass; Gastric emptying; Gastric volumetry; Three-dimensional; Weight loss.