Effects of captopril on cardiorenal hemodynamics in patients with severe chronic congestive heart failure.

The effects of captopril on cardiorenal function were studied in patients with chronic congestive heart failure. A single oral dose of captopril in 16 patients significantly increased cardiac indices and decreased total systemic vascular resistance. These changes were greater in subjects with higher baseline plasma renin activity (PRA). The increase in PRA and decrease in plasma aldosterone were also greater in this group. During 7 days of captopril therapy, renal plasma flow distinctly increased in 10 patients in whom renal function was followed. The increase in renal blood flow was greater in subjects with higher PRA. Simultaneous infusion of aprotinin in eight of these subjects did not affect the captopril-induced increase in renal plasma flow: these responses were the same in both PRA subgroups. The results suggest that captopril reduces total systemic vascular resistance in patients with chronic congestive heart failure through the inhibition of the renin-angiotensin system and the preferential renal vasodilating effect of captopril seems exclusively to be the sole result of this inhibition, with the kallikrein-kinin system or kinin-mediated prostaglandins not playing a major role.