N-Terminal pro-B-Type Natriuretic Peptide in Risk Stratification after Acute Myocardial Infarction in Patients on Long-Term Beta-Adrenergic Receptor Blocker Therapy

Abstract

Background: N-terminal pro-B-type natriuretic peptide (NT-proBNP) appears to be a strong risk marker of mortality in patients with acute coronary syndrome. However, little information is available on NT-proBNP as a predictor of long-term serious cardiovascular events beyond that of left ventricular ejection fraction in patients with acute myocardial infarction (AMI), most of them treated with an early invasive strategy and on a uniform optimal secondary preventive medication including long-term beta-adrenergic receptor blockade. Objective: To assess the prognostic impact of plasma NT-proBNP in patients with AMI who received optimal medical treatment including long-term beta-adrenergic receptor blockade. Methods: Plasma NT-proBNP was measured in 219 patients (age range 31–80 years) with AMI at baseline, and then followed for a median duration of 1.63 years. The first occurrences of a serious cardiovascular event including cardiac mortality, nonfatal MI, and congestive heart failure were registered. Results: Ninety serious cardiovascular events occurred. Left ventricular ejection fraction and reperfusion therapy with thrombolysis or percutaneous coronary intervention were identified as confounders. When adjusting for these factors in multivariate analysis, NT-proBNP was a strong predictor of serious cardiovascular events in patients with a plasma NT-proBNP of >162.2 pmol/l and aged <60 years (p = 0.001). The incidence rate was related to increasing NT-proBNP (p = 0.0017). The risk of serious cardiovascular events was higher in patients with NT-proBNP levels in the highest quartile (≧162.2 pmol/l) than in those with levels in the three lowest quartiles (rate ratio = 2.5, 95% confidence interval = 1.6–3.9, p = 0.0001). Conclusion: AMI patients with high plasma NT-proBNP seem to be at an increased risk of serious cardiovascular events, but only those ≤60 years of age.