EFFECT OF ENALAPRIL ON ENDOTHELIAL FUNCTION IN YOUNG INSULIN-DEPENDENT DIABETIC-PATIENTS - A RANDOMIZED, DOUBLE-BLIND-STUDY

Objectives. We sought to determine whether 6 months of treatment with the angiotensin converting enzyme (ACE) inhibitor enalapril can improv e conduit artery endothelial function in young subjects with insulin-d ependent diabetes mellitus (IDDM). Background. Endothelial dysfunction is an early event in atherogenesis and has been demonstrated in young subjects with IDDM. ACE inhibitors have been shown to enhance conduit artery endothelial function in animal experiments and in patients wit h established coronary atherosclerosis, although their effect in IDDM is not known. Methods. Ninety one subjects (mean age 30.9 years, range 18 to 44) with stable IDDM but no clinical evidence of vascular disea se were randomized to receive enalapril (20 mg once daily) (46 subject s) or placebo (45 subjects) in a randomized, double-blind, parallel-gr oup study. Brachial artery flow-mediated dilation (FMD), an endotheliu m-dependent stimulus, and response to glyceryl trinitrate (GTN), which acts directly on vascular smooth muscle, were assessed noninvasively by means of high resolution external vascular ultrasound at baseline a nd after 12 and 24 weeks of treatment. Results. FMD was inversely corr elated with total cholesterol (r = 0.22, p = 0.041) but not with any d iabetic variables. Treatment with enalapril had no significant effect on FMD (p = 0.67) or response to the endothelial-independent dilator G TN (p = 0.45). Conclusions. These data suggest that impairment of endo thelial-dependent dilation in young subjects with IDDM: is not improve d by treatment with the ACE inhibitor enalapril. This lack of improvem ent may reflect the complex nature of vascular disease in IDDM, which can affect both endothelial and smooth muscle function. (C) 1998 by th e American College of Cardiology.