Prognostic impact of b-type natriuretic peptide on long-term clinical outcomes in patients with non-st-segment elevation acute myocardial infarction without creatine kinase elevation

Although B-type natriuretic peptide (BNP) has gradually gained recognition as an indicator in risk stratification for patients with acute myocardial infarction (AMI), the prognostic impact on long-term clinical outcomes in patients with non-ST-segment elevation acute myocardial infarction (NSTEMI) without creatine kinase (CK) elevation remains unclear. This prospective multicenter study assessed 3,283 consecutive patients with AMI admitted to 28 institutions in Japan between 2012 and 2014. We analyzed 218 patients with NSTEMI without CK elevation (NSTEMI-CK) for whom BNP was available. In the NSTEMI-CK group, patients were assigned to high-and low-BNP groups according to BNP values (cut-off BNP, 100 pg/mL). The primary endpoint was defined as a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, cardiac failure, and urgent revascularization for unstable angina up to 3 years. Primary endpoints were observed in 60 (33.3%) events among patients with NSTEMI-CK. Kaplan-Meier analysis revealed a significantly higher event rate for primary endpoints among patients with high BNP (log-rank P < 0.001). After adjusting for covariates, a higher BNP level was significantly associated with long-term clinical outcomes in NSTEMI-CK (adjusted hazard ratio, 4.86; 95% confidence interval, 2.18-12.44; P < 0.001). The BNP concentration is associated with adverse long-term clinical outcomes among patients with NSTEMI-CK who are considered low risk. Careful clinical management may be warranted for secondary prevention in patients with NSTEMI-CK with high BNP levels.