Aims: Experience with amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing for evaluation of dyspnoeic patients with suspected acute heart failure (HF) is limited to single-centre studies. We wished to establish broader standards for NT-proBNP testing in a study involving four sites in three continents.
Methods and results: Differences in NT-proBNP levels among 1256 patients with and without acute HF and the relationship between NT-proBNP levels and HF symptoms were examined. Optimal cut-points for diagnosis and prognosis were identified and verified using bootstrapping and multi-variable logistic regression techniques. Seven hundred and twenty subjects (57.3%) had acute HF, whose median NT-proBNP was considerably higher than those without (4639 vs. 108 pg/mL, P<0.001), and levels of NT-proBNP correlated with HF symptom severity (P=0.008). An optimal strategy to identify acute HF was to use age-related cut-points of 450, 900, and 1800 pg/mL for ages <50, 50-75, and >75, which yielded 90% sensitivity and 84% specificity for acute HF. An age-independent cut-point of 300 pg/mL had 98% negative predictive value to exclude acute HF. Among those with acute HF, a presenting NT-proBNP concentration >5180 pg/mL was strongly predictive of death by 76 days [odds ratio=5.2, 95% confidence interval (CI)=2.2-8.1, P<0.001].
Conclusion: In this multi-centre, international study, NT-proBNP testing was valuable for diagnostic evaluation and short-term prognosis estimation in dyspnoeic subjects with suspected or confirmed acute HF and should establish broader standards for use of the NT-proBNP in dyspnoeic patients.