BNP Identifies High Risk ACS But Its Clinical Utility Is Unclear

B-type natriuretic peptide (BNP) is released in response to ventricular wall stress. Elevated levels are correlated with congestive heart failure and with outcomes after acute MI. The value of BNP in risk-stratifying patients with non-ST-segment elevation (NSTE), MI, and unstable angina is not clear. These authors assessed the predictive value of BNP in 1676 patients enrolled in the TACTICS-TIMI 18 trial, which compared an invasive strategy and a noninvasive strategy in patients with high-risk NSTE acute coronary syndromes (ACSs) who were treated with tirofiban.

A total of 320 patients had elevated BNP levels, defined as higher than 80 mg/mL. Patients with elevated BNP levels had increased risks for death at 7 days (2.5% vs. 0.7%; P=0.006), death at 6 months (8.4% vs. 1.8%; P<0.0001), and death or CHF at 6 months (16.3% vs. 3.6%; P<0.001). BNP levels predicted outcomes independently of troponin I levels. Elevated BNP levels did not discriminate between patients who did and did not benefit from the invasive strategy.

Comment: It is clear that extremely sick patients with ACS are more likely to have elevated BNP levels, probably as a result of their high ischemic burden and related ventricular dysfunction. It is unclear from this study how BNP might be used to define a subgroup of patients with diagnosed NSTE ACS who require different therapy. The clinical utility of BNP has yet to be determined in this population.

James M. Christenson, MD, FRCPC

Published in Journal Watch Emergency Medicine May 27, 2003

Source

Morrow DA et al. Evaluation of B-type natriuretic peptide for risk assessment in unstable angina/non-ST-elevation myocardial infarction: B-type natriuretic peptide and prognosis in TACTICS-TIMI 18. J Am Coll Cardiol 2003 Apr 16; 41:1264-72.