Rapid determination of brain natriuretic peptide in patients with acute myocardial infarction

We evaluated a rapid brain natriuretic peptide (BNP) assay (Triage BNP, Biosite Diagnostics) as indicator of infarct size, left ventricular (LV) dysfunction, and longterm survival in patients with acute myocardial infarction (AMI) during the coronary care unit stay. We studied 64 AMI patients in whom infarct size was estimated by creatine kinase isoenzyme MB (CK-MB) peak concentrations and single-photon emission computed tomography (SPECT) myocardial perfusion using technetium-99m sestamibi, and LV function by gated SPECT imaging. Measurements of BNP and SPECT were performed approximately 3 days after admission. SPECT was also repeated 3 months later. We found a significant correlation between BNP and both the peak CK-MB concentrations (r = 0.40, p = 0.001) and the perfusion defect size at SPECT (r = 0.38, p = 0.002). BNP was weakly related to LV ejection fraction (LVEF) assessed both early and 3 months after AMI (r = -0.29, p = 0.02; and r = -0.27, p = 0.04, respectively). The sensitivity and specificity of BNP for predicting survival of patients over 1 year of follow-up was 100% and 43%, respectively, with a negative predictive value of 100%. The positive predictive power of BNP was very modest (12%). Considering our results, the measurement of BNP did not look nearly as promising when tested in the setting of our cardiological intensive care.