Antiplatelet Agents In Diabetic Lower Extremity Vascular Disease. A Va Cooperative Study

Abstract

Peripheral vascular disease is a devastating complication of diabetes mellitus. Post-operative vascular death rates are 10% or more following amputation for gangrene in diabetic patients, and three year mortality approaches 30%. An additional 20-30% of patients require subsequent amputation for diabetic gangrene. In view of these statistics, and because of the postulated role of the blood platelet in diabetic vascular disease, a collaborative study on antiplatelet agents was begun in 10 VA medical centers in 1977. In a double-blinded study, aspirin (325 mg tid) plus dipyridamole (75 mg tid) or placebos are given to adult diabetic males who had suffered a recent amputation for diabetic lower extremity vascular disease. End points are major vascular events after at least 3 years of follow-up.Recruitment of 231 subjects was completed by May, 1980. Baseline characteristics are well matched in both groups. Mean age is 59.6 years, duration of diabetes 12.7 years, smoking history 33.3 pack years, and treatment with insulin 68%. Previous myocardial infarction, congestive heart failure, and/or cerebrovascular disease is present in 17-18% and retinopathy is present in 40% at entry. About 43% have more than one vascular complication at baseline.Mean duration of follow-up is now 18 months. Major vascular events in separate patients are: 40 amputations, 31 deaths, 5 myocardial infarctions. Numerous less serious vascular events have also occurred, as have multiple events in single patients. Therapy has been stopped in 17% of patients, but rarely due to drug side effects. Compliance with therapy has been good.We conclude that this study will provide important new information on the natural history of lower extremity vascular disease in diabetes. It will also provide definitive data about the efficacy of antiplatelet agents in diabetic vascular disease.