The value of NT-proBNP in early risk stratification of acute coronary syndromes.

INTRODUCTION: The N-terminal portion of brain natriuretic peptide (NT-proBNP) has been identified as an indicator of prognosis in different cardiovascular diseases. Its role in risk stratification in patients with acute coronary syndromes (ACS) is still under evaluation.

OBJECTIVE: We aimed to evaluate the prognostic value of NT-proBNP measured in the first 48 hours after admission due to an acute coronary syndrome.

METHODS: Our study included 142 patients (aged 62.7 +/- 12.0 years, 70.4% males) admitted to a cardiology unit with an ACS. All laboratory evaluations were performed in the first 48 hours after admission. The mean follow-up was 200 days. Death from any cause or hospitalization because of a major acute cardiovascular event (whichever occurred first) was defined as the end-point.

RESULTS: Cardiovascular risk factors were found in a significant proportion of our sample (hypertension in 56.3%, diabetes mellitus in 38.0%, current or previous smoking in 51.4%, dyslipidemia in 67.6%). Fifty-eight patients had left ventricular systolic dysfunction (LVSD). Serum levels of NT-proBNP were 2174 +/- 4801 pg/ml. Variables associated with event-free survival in univariate analysis were: NT-proBNP (HR 1.007, 95% CI 1.003-1.011, for each 100 pg/ml increment), serum glucose (hazard ratio [HR] 1.007, 95% CI 1.001-1.012, for each 1 mg/dl increment) and maximum cardiac troponin I (cTnI) level (HR 1.005, 95% CI 1.001-1.009, for each 1 ng/ml increment). The white blood count (WBC) was marginally associated with a poor prognosis (HR 1.152, 95% CI 0.994-1.335, for each 1000/mm3 increment). After adjustment for the above variables, age, sex, left ventricular systolic dysfunction, diabetes, coronary anatomy and coronary revascularization using a forward likelihood ratio Cox regression model, NT-proBNP remained the only variable with significant prognostic value (HR 1.007, 95% CI 1.003-1.011, for each 100 pg/ml increment).

CONCLUSIONS: These data suggest that NT-proBNP is a strong clinical predictor of prognosis in acute coronary syndromes. Its early measurement should be included in the risk stratification strategy in this setting.