Effect of selective proximal vagotomy and truncal vagotomy on gastric acid and serum gastrin responses to a meal in duodenal ulcer patients.

To assess the effectiveness of selective proximal vagotomy (SPV) in reducing the acid response to food, we have compared pre- and postoperative gastric acid and serum gastrin responses to a meal in 11 duodenal ulcer patients with intractable pain treated by SPV, with those of seven ulcer patients with gastric outlet obstruction treated by truncal vagotomy and drainage (TV + D). Acid secretion was measured by an intragastric titration method which measures acid response to food within the stomach (5% amino acid meal) adjusted to various pH levels (5.5, 2.5, and 1.5). Studies were performed before and two to six weeks after operation. The preoperative intragastric acid output (IGAO) was about 50% of maximal acid response to Histalog. The mean preoperative IGAO at pH 5.5 For 11 SPV patients was 17.4 +/- 3.1 mEq/hour; this was decreased by 72% to 4.3 +/- 1.1 mEq/hour after operation. The mean IGAO at pH 5.5 in nine patients treated by TV + D was 21.6 +/- 3.4 mEq/hour; this was decreased by 67% to 7.3 +/- 2.1 mEq/hour. Gastrin levels were significantly higher in postop than in preop SPV PATIENTS EVEN THOUGH PH values were constant. Gastrin levels were higher in postop TV + D patients than in postop SPV patients. This study demonstrates that acid reduction achieved by SPV is reliable and at least comparable with that achieved by turncal vagotomy. Postoperative elevation of gastrin in the SPV patients suggests that the vagus may release a humoral inhibitor of gastrin release from the gastric fundus; there may also be a further direct vagal inhibitor of antral gastrin release.