Gastric emptying rate after gastric bypass and gastroplasty.

Fifty-seven morbidly obese patients were randomized into two surgical treatment groups, gastric bypass (n = 29) and gastroplasty (n = 28). Studies of the gastric emptying with radionuclide-labelled food were performed preoperatively (12 patients) and postoperatively at 2 months (28 patients) and 12 months (49 patients). Pouch emptying after gastric bypass was slower at 2 months than at 12 months. After gastroplasty the emptying rate was the same at 2 and 12 months and the same as that of gastric bypass at 12 months. A statistically significant correlation between stoma diameter and emptying rate was seen 1 year after gastroplasty but not after gastric bypass. No correlation between emptying rate and weight loss was shown in either group. Differences in the mechanisms of action between these two methods are apparent and are discussed.