Usefulness of plasma brain natriuretic peptide levels in predicting dobutamine-induced myocardial ischemia.

Plasma brain natriuretic peptide (BNP) levels have been associated with left ventricular dysfunction and acute myocardial infarction. Although natriuretic peptide responses have been linked to exercise-induced myocardial ischemia, it is not known whether BNP levels predict dobutamine-induced myocardial ischemia. The aim of this study was to determine whether elevations in BNP levels immediately before or after dobutamine-induced stress are associated with echocardiographic myocardial ischemia. Plasma BNP was measured before and after stress during dobutamine-stress echocardiography in 317 patients (aged 68 +/- 11 years; 46% women) who had creatinine <1.5 mg/dl and did not have valvular disease. Ischemia, as assessed by blinded echocardiographic interpretation, was noted in 31 patients (10%). In univariable analyses, prestress BNP was predictive of echocardiographic ischemia (rates of ischemia according to tertiles of BNP 4%, 9%, and 16%, chi-square for trend = 8, p = 0.0059). The change in BNP levels with dobutamine stress was not associated with ischemia. In multivariable analyses, after adjusting for age, gender, and left ventricular ejection fraction, BNP before and after stress remained predictive of ischemia (1 SD increase in the log of resting BNP adjusted odds ratio 2.0, 95% confidence interval 1.3 to 3.0, p = 0.002). In this pilot study, resting BNP was predictive of dobutamine-induced ischemia. Future work is needed to confirm these findings.