B-type natriuretic peptide infusions in acute myocardial infarction

Background: Natriuretic peptides have actions likely to ameliorate cardiac dysfunction. B-type natriuretic peptide (BNP) is indicated as treatment for decompensated cardiac failure. Objective: To determine the utility of BNP in acute myocardial infarction (MI). Design: Double-blind randomised placebo-controlled trial. Setting: Tertiary hospital coronary care unit. Patients: 28 patients with acute MI with delayed or failed reperfusion and moderate left ventricular dysfunction. Interventions: Infusion of BNP or placebo for 60 hours after MI. Main outcome measures: Neurohormonal activation and renal function in response to BNP infusion, secondary end points of echocardiographic measures of left ventricular function and dimension. Results: BNP infusion resulted in a significant rise in BNP (276 pg/l vs 86 pg/l, p=0.001). NT-proBNP levels were suppressed by BNP infusion (p= 0.002). Atrial natriuretic peptide (ANP) and NT-proANP levels fell with a significant difference in the pattern between BNP infusion and placebo during the first 5 days (p < 0.005). C-type natriuretic peptide (CNP) and NT-proCNP levels rose during the infusion with higher levels than placebo at all measurements during the first 3 days (p < 0.01). Cyclic guanosine monophosphate (cGMP) was raised during the infusion period showing a peak of 23 pmol/l on day 2 (placebo 8.9 pmol/l, p= 0.002), with a correlation between BNP and cGMP levels (p < 0.001). Glomerular filtration rate (GFR) fell with BNP infusion but was not significantly lower than with placebo (71.0 (5.6) vs 75.8 (5.4) ml/min/1.73 m(2), p=0.62). Patients receiving nesiritide exhibited favourable trends in left ventricular remodelling. Conclusions: Nesiritide, given soon after MI, induced increments in plasma cGMP and CNP and decrements in other endogenous cardiac peptides with a neutral effect on renal function and a trend towards favourable ventricular remodelling.