NT-proBNP Cut-off Values for Risk Stratification in Acute MI and Comparison with Other Risk Assessment Scores

Abstract

Background: N-terminal pro-brain natriuretic peptide (NT-proBNP) provides prognostic information regarding the risk of death, acute heart failure and the development of AF in patients with acute coronary syndrome. While there are established cut-off values for the association between clinical risk assessment scores and in-hospital mortality, there is no clear cut-off value for NT-proBNP to guide risk stratification in patients with acute MI (AMI). Our study sought to evaluate the cut-off values of NT-proBNP in all-cause mortality post AMI and to compare with other available risk assessment scores. Methods: We conducted a multi-centre, prospective, observational study involving 411 patients admitted for AMI. Plasma NT-proBNP was assessed within 24 hours of admission. Results: One-year all-cause mortality occurred in 31 (7.6%) of 411 patients. NT-proBNP ≥404 pg/ml had an area under the curve of 0.66 (95% CI [0.54–0.77]; p=0.004) to predict all-cause mortality at 1 year (sensitivity: 80.6%; specificity: 36.9%; positive predictive value: 9.47%; negative predictive value: 95.89%). Using the Youden index, an NT-proBNP level ≥1,995 pg/ml was an independent predictor of all-cause mortality at 1 year (adjusted HR 2.6; 95% CI [1.3–5.5]; p=0.010), regardless of cardiovascular disease risk factors or revascularisation status. There were no significant differences among the predictive values of NT-proBNP, Thrombolysis in MI risk score, Global Registry of Acute Coronary Events risk score and left ventricular ejection fraction in predicting all-cause mortality at 1 year (p>0.05). Conclusion: NT-proBNP level ≥1,995 pg/ml measured within 24 hours of admission for AMI was associated with higher all-cause mortality at 1 year. Randomised controlled trials are needed to further validate the usefulness of NT-proBNP for risk stratification in patients with AMI.