B-type natriuretic peptide at presentation and prognosis in patients with ST-segment elevation myocardial infarction: an ENTIRE-TIMI-23 substudy.

OBJECTIVES

We sought to evaluate B-type natriuretic peptide (BNP), alone and in comparison to cardiac troponin I (cTnI) and high-sensitivity C-reactive protein (hs-CRP), for risk assessment at initial presentation with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Elevated levels of BNP drawn two to four days after acute myocardial infarction are associated with higher mortality. Sparse data are available on its use at first presentation with STEMI.

METHODS

We obtained samples from 438 patients presenting within 6 h of STEMI enrolled in the Enoxaparin Tenecteplase-Tissue-Type Plasminogen Activator With or Without Glycoprotein IIb/IIIa Inhibitor as Reperfusion Strategy in ST-Segment Elevation Myocardial Infarction (ENTIRE)-Thrombolysis In Myocardial Infarction (TIMI)-23 trial. Outcomes were assessed through 30 days.

RESULTS

Median BNP was higher in patients who died (89 pg/ml, 25th to 75th percentile: 40 to 192), compared with survivors (15 pg/ml, 25th to 75th percentile: 8.8 to 32, p < 0.0001). Patients with BNP >80 pg/ml were at significantly higher risk of death (17.4% vs. 1.8%, p < 0.0001). Cardiac troponin established a gradient of mortality between the highest and lowest quartile (7.9% vs. 0%, p = 0.007). C-reactive protein was not associated with outcome. After adjustment for cTnI, hs-CRP, and major clinical predictors, including age, heart failure, anterior myocardial infarction location, heart rate, and blood pressure, a BNP level >80 pg/ml was associated with a seven-fold higher mortality risk (odds ratio 7.2, 95% confidence interval 2.1 to 24.5, p = 0.001). Patients with BNP >80 pg/ml were also more likely to have impaired coronary flow (p = 0.049) and incomplete resolution of ST-segment elevation (p = 0.05).

CONCLUSIONS

Increased concentrations of BNP at initial presentation of patients with STEMI are associated with impaired reperfusion after fibrinolysis and higher short-term risk of mortality. These data support the value of combining markers of hemodynamic stress with traditional approaches to risk assessment in acute myocardial infarction.