Controlled trial of captopril in chronic heart failure: a rest and exercise hemodynamic study.

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Abstract
Although many studies have shown acute hemodynamic improvement in patients with congestive heart failure treated with vasodilating drugs, long-term controlled studies with both hemodynamic and exercise capacity measurements are not available. The [angiotensin] converting-enzyme inhibitor captopril were studied in 16 ambulatory patients in New York Heart Association functional class II-IV heart failure who were clinically stable on digoxin and diuretics. The acute response to open-label captopril was quantified by blood pool scintigraphy, right-heart catheterization at rest and during exercise and measurements of exercise capacity. The patients were then randomized to maintenance therapy with captopril or matching placebo and were restudied after 3 mo. The 2 groups were similar in their clinical characteristics and pretreatment rest and exercise hemodynamic measurements. Both displayed similar acute beneficial responses to captopril at rest, with a mean reduction in left ventricular filling pressure from 24 .+-. 9 to 14 .+-. 6 mm Hg (P < 0.001) and increases in cardiac index, from 2.1 .+-. 0.5 to 2.5 .+-. 0.61/min per m2 (P < 0.01), and stroke index, from 25 .+-. 8 to 34 .+-. 8 ml/m2 (P < 0.001). Directionally similar hemodynamic improvement was noted during exercise. After 3 mo., these beneficial hemodynamic changes were sustained only in the patients randomized to captopril. Concomitantly, the captopril patients increased their exercise capacity as measured by the duration of bicycle exercise (9.0 .+-. 2.2 vs. 11.7 .+-. 1.4 min, P < 0.01), maximal work load (360 .+-. 80 vs. 460 .+-. 50 kpm[kilopound meters]/min, P < 0.005) and O2 consumption (12.9 .+-. 2.3 vs. 15 .+-. 1.8 ml/kg per min). The placebo group showed either no change or a worsening over the 3 mo. compared to their pretreatment measurements. Captopril is evidently an effective adjunctive agent for the treatment of chronic heart failure, and it produces long-term hemodynamic improvement together with an increase in exercise capacity.