HORMONAL AND CARDIORENAL RESPONSES TO ACUTE SALINE LOADING IN MILD CONGESTIVE-HEART-FAILURE - THE EFFECT OF ANGIOTENSIN-CONVERTING ENZYME-INHIBITION

We investigated cardiorenal responses to acute saline loading in patie nts with mild congestive heart failure (CHF) with and without angioten sin-converting enzyme (ACE) inhibition. Saline loading (infusion of 25 0 ml of normal saline) was performed on 10 patients with mild CHF and 10 control subjects. Although saline loading reduced plasma renin acti vity and plasma angiotensin II to a similar extent in both groups, it increased cardiac output, renal blood flow, and the ratio of renal blo od flow to cardiac output in the mild CHF group but not in the control group, After saline loading, urinary sodium excretion was higher in t he control than in the mild CHF group, In the mild CHF group, saline l oading was performed again after an ACE inhibitor (delapril) had been administered for 5 days. Although delapril increased cardiac output an d renal blood flow under basal conditions, saline loading did not affe ct these variables. Delapril improved urinary sodium excretion after s aline loading. Thus, the renin-angiotensin-aldosterone axis may contri bute to cardiorenal hemodynamics and renal sodium handling in patients with mild CHF. This effect may attenuate the natriuretic response to acute saline loading, and administration of an ACE inhibitor improves this attenuation.