Serial Insulin Tests Over a Five-Year Period After Highly Selective Vagotomy for Duodenal Ulcer

Twenty-one patients underwent serial insulin testing, approximately 1 week, 1 year, 3 years, and 5 years after highly selective vagotomy (HSV) for duodenal ulcer (DU). They were thought to be representative of the much larger number of patients who have undergone HSV for DU in Leeds. The results obtained were compared with the responses to insulin of 40 other DU patients who were tested before HSV. Before operation, all tests were positive in the 1st hr after insulin (“early-positive”) by Hollander’s criteria and the mean peak acid response to insulin after subtraction of basal acid output (PAO1) was 33 mEq per hr. One week after HSV, all 21 tests were negative and mean PAO1 was 0.05 mEq per hr. One year after HSV, 62% of 21 tests were Hollander-positive and PAO1 had increased significantly (P < 0.001) to a mean of 2.3 mEq per hr. Three years after HSV, 15 of 17 tests (94%) were Hollander-positive and mean PAO1 was 3.1 mEq per hr (0.1 > P > 0.05, compared with PAO1 at 1 year). Five years after HSV, 65% of 20 tests were positive and mean PAO1 was 3.5 mEq per hr, a significant increase (P < 0.05) compared with PAO1 at 1 year. Only 2 patients (10%) had consistently negative insulin tests over the 5-year period and neither of them was tested 3 years after operation. Thus, HSV was found to abolish consistently the acid response to insulin soon after operation, but on serial testing 90% of the patients eventually developed positive responses to insulin by Hollander’s criteria. Most of the acid responses to insulin after HSV were small and the mean reduction in PAO1 5 years after operation compared with PAO1 before operation is approximately 90%. The positive responses to insulin in the long term after HSV could be due to vagal nerve regeneration or to other causes. After a mean period of follow-up of 5 years (range 31/2 U to 61/2 years), only 1 of the first 100 patients who were treated by HSV for DU in Leeds has so far developed recurrent ulceration. The finding of a positive response to insulin by Hollander’s criteria more than 1 year after HSV appears to have no prognostic significance.