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 m2, 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.