B-type natriuretic peptide as an integrated risk marker in non-ST elevation acute coronary syndromes

Elevated B-type natriuretic peptide (BNP) levels show prognostic significance in patients with non-ST elevation acute coronary syndromes, but the underlying pathophysiology remains unclear.

Two hundred and eighteen consecutive patients with non-ST elevation acute coronary syndromes were studied retrospectively. We compared clinical characteristics between groups with plasma BNP levels above or below the median value, and performed multiple logistic regression analysis to identify independent predictors of supramedian BNP levels.

Patients with supramedian BNP (>or=134 pg/ml) were more likely to be elderly (>or=75 years) with diabetes, prior myocardial infarction, and a history of coronary artery bypass grafting. They also had higher cardiac marker levels, a higher Killip class, a lower left ventricular ejection fraction, renal insufficiency (creatinine>or=1.5 mg/dl), and more 3-vessel disease. In multivariate analysis, the strongest independent predictor of supramedian BNP levels was 3-vessel disease (chi(2)=12.1), followed by old age (chi(2)=10.3), renal insufficiency (chi(2)=5.0), higher Killip class (chi(2)=4.2), and lower left ventricular ejection fraction (chi(2)=4.1). All 11 patients dying in hospital had supramedian BNP levels. Its elevation reflected the risk of 3-vessel disease and coronary artery bypass grafting regardless of troponin status.

In unselected patients with non-ST elevation acute coronary syndromes, an increase of BNP is correlated with the extent of myocardial ischemia, age, renal insufficiency, and ventricular dysfunction. It may be a useful biomarker integrating conventional risk factors for risk stratification in this population.