RESPONSES OF PLASMA-CONCENTRATIONS OF A TYPE NATRIURETIC PEPTIDE AND B-TYPE NATRIURETIC PEPTIDE TO ALACEPRIL, AN ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR, IN PATIENTS WITH CONGESTIVE-HEART-FAILURE

Background-Plasma concentrations of A type or atrial natriuretic pepti de (ANP) and B type or brain natriuretic peptide (BNP) are increased i n patients with congestive heart failure (CHF). Objective-To examine t he haemodynamic and hormonal responses, especially of ANP and BNP, to oral administration of an angiotensin-converting enzyme (ACE) inhibito r in patients with CHF and in controls. Patients-12 patients with CHF and 11 controls. Methods-Haemodynamic variables and plasma concentrati ons of ANP, BNP, and other hormones were serially measured for 24 hour s after alacepril (37.5 mg) was given by mouth. Results-Pulmonary capi llary wedge pressure and systemic vascular resistance decreased signif icantly in both groups. The cardiac index increased only in the CHF gr oup. In patients with CHF pulmonary capillary wedge pressure, systemic vascular resistance, and cardiac index were significantly changed fro m 1 to 12 hours after alacepril administration. Plasma ANP and BNP dec reased significantly after alacepril was given to the CHF group: neith er concentration changed in the control group. In the CHF group plasma ANP was significantly lower between 1 and 6 hours and was highly sign ificantly correlated with pulmonary capillary wedge pressure. Plasma B NP, however, was significantly lower between 6 and 24 hours after alac epril and was not correlated with pulmonary capillary wedge pressure. Conclusions-The response of plasma BNP after alacepril administration occurred later and lasted longer than the plasma ANP response. This ma y indicate that the mechanisms of synthesis, secretion, or degradation of the two peptides are different.