[Effects of different sulfonylureas on the warm-up phenomenon in diabetes patients with coronary artery disease]

Objective: To explore the different effects of chronic treatment with glibenclamide and gliclazide on the warm-up phenomenon in diabetes patients with coronary artery disease. Methods: A total of seventy-one patients with chronic stable angina and diabetes who were positive for exercise test and was proven that the stenosis degree was 70%-90% in at least one major branch through coronary angiogram were included into the study.They were divided into three groups, diet control group (DMD), glibenclamide group (DMG1) and gliclazide group (DMG2), according to the treatment of diabetes.All of the patients underwent two bicycle exercise tests (EX) at 15-minute interval.Parameters including ischaemic threshold (the rate-pressure product at 1-mm ST-segment depression, RPP), time to ischaemic (the time to 1 mm ST-segment depression, T-STD), the maximum ST-segment depression (STDmax) and exercise duration (ED) were recorded respectively. Results: In group DMD, T-STD and ED were prolonged [(360±83) s vs (409±80) s, P<0.001] and [(518±90) s vs (549±96) s, P=0.001], STDmax were shortened [(1.91±0.43) mm vs (1.60±0.36) mm, P<0.001], and RPP was increased [(180±27) beats·min(-1)·mmHg·10(2) vs (195±28) beats·min(-1)·mmHg·10(2), P<0.001] as the parameters during EX2 were compared with those during EX1. In group DMG1, there was no statistic difference in these indexes except that ED was prolonged [(458±70) s vs (472±66) s, P=0.045] when those of EX2 and EX1were compared. In the group DMG2, all the analyzed variables improved significantly during two sequential exercise tests as the results in the group DMD except that ischaemic threshold was not increased [(199±41) beats·min(-1)·mmHg·10(2) vs (211±39) beats·min(-1)·mmHg·10(2), P=0.071]. Conclutions: Warm-up phenomenon is abolished in diabetic patients with stable angina treated with glibenclamide, partially preserved in gliclazide-treated patients. and the KATP channel may be involved in those different effects. Gliclazide should be the safer choice for the patients with diabetes and chronic stable angina.