VASODILATORY EFFECTS OF B-TYPE NATRIURETIC PEPTIDE ARE IMPAIRED IN PATIENTS WITH CHRONIC HEART-FAILURE

Background B-type natriuretic peptide (BNP) and atrial natriuretic pep tide (ANP) are secreted from the heart and are thought to be equally i mportant factors in the regulation of vascular tone in health and in c ongestive heart failure (CHF). However, no studies directly compare va sodilator effects of these peptides in healthy subjects and in patient s with CHF. Methods Plethysmography was used to determine the vasodila tory effects of BNP and to compare these to the effects of ANP in pati ents with CHF (n = 15) and age-matched healthy subjects (n = 16). Grad ed doses of ANP and BNP (8, 16, 32, and 48 pmol/min per 100 ml of tiss ue volume for both) were administered randomly into the brachial arter y. Forearm blood flow (FBF) was measured, and cyclic GMP (cGMP) spillo ver was calculated. Results Responses in FBF to both peptides in CHF w ere significantly lower than those of healthy subjects (BNP p < 0.05;. ANP p < 0.01). Similarly, forearm spillover of cGMP was significantly lower in CHF than in healthy subjects (BNP p < 0.05; ANP p < 0.01), W hen vascular responses in healthy subjects were compared between BNP a nd ANP, BN P-induced changes in FBF (p < 0.05) and forearm cGMP spillo ver (p < 0.01) were significantly less than changes induced by ANP. In CHF, though, FBF change and cGMP spillover induced by the two peptide s were not significantly different. Conclusions These results suggest that the metabolism and action of these natriuretic peptides in CHF ma y differ from the healthy state.