Converting enzyme inhibition in coronary artery disease: a randomized, placebo-controlled trial with benazepril.

The antiischemic efficacy of the converting enzyme inhibitor (CEI) benazepril was investigated in a randomized, placebo-controlled double-blind study with intraindividual crossover in 11 normotensive patients with angiographically proven coronary artery disease. Bicycle ergometry and 24-h ambulatory ECG were performed before and after 2-week treatment with placebo and benazepril, respectively. Plasma concentrations of atrial natriuretic peptide (ANP) and plasma renin activity (PRA) were measured before each exercise test. Maximal exercise-induced ST-segment depression was not significantly influenced by benazepril therapy (placebo 2.09 +/- 1.22 mm, benazepril 1.91 +/- 1.00 mm). Systolic blood pressure/heart rate (SBP/HR) product at maximum workload remained almost constant with 253 +/- 43 with placebo and 253 +/- 39 with benazepril treatment. The number of anginal attacks and ischemic episodes detected by ambulatory ECG were not significantly reduced. PRA increased significantly from 2.18 +/- 3.76 to 9.62 +/- 8.49 ng/ml/h after benazepril (p less than 0.005), whereas plasma concentrations of ANP remained unchanged (28.04 +/- 12.39 vs. 26.73 +/- 11.09 pg/ml). Therefore, measurement of ST-segment depression with exercise in 11 normotensive patients with coronary artery disease produced no evidence of an antiischemic action for the CEI benazepril 10 mg twice daily (b.i.d.) for 2 weeks, but an improvement was observed in six patients.