The determinants of B-type natriuretic peptide release in acute, non-ST-segment elevation myocardial infarction

B-type natriuretic peptide (BNP) is used to predict the clinical outcome of acute coronary syndromes, even in the absence of signs of cardiac failure. The triggers for BNP release have yet to be identified.

Eighty-three patients with an acute, non-ST-segment elevation myocardial infarction (NSTEMI) underwent invasive evaluation within 72 hours of admission. Patients with signs of cardiac failure or with a left ventricular ejection fraction (LVEF) <30% were excluded. BNP samples were taken at the time of the invasive evaluation and were correlated with systolic left ventricular function (LVEF), diastolic function (left ventricular end diastolic pressure (LVEDP)), the characteristics of the infarct-related artery (% vessel stenosis and TIMI flow), the extent of myocardial ischaemia (troponin level, amount of jeopardized myocardium, number of diseased vessels), and the clinical parameters of the patients, such as gender and TIMI risk score.

Median BNP level was 93 pg/ml (43-226, 25th and 75th percentiles). Stepwise regression analysis identified that TIMI risk score, gender, and LVEDP were independent variables of BNP. The BNP levels in patients with LVEDPs < or = 15 mm Hg and LVEDPs > 15 mm Hg were 52 (29-102) pg/ml and 128 (51-315) pg/ml, respectively (P = 0.0013). No correlation existed between LVEDP and the extent of ischaemia (troponin level or the amount of jeopardized myocardium).

In this study of NSTEMI and preserved left ventricular function, BNP release was primarily determined by diastolic dysfunction (defined as an LVEDP > 15 mm Hg) and by the risk profile of the patient.