The ratio of N-terminal pro-B-type natriuretic peptide to troponin I for differentiating acute coronary syndrome.

INTRODUCTION: It is difficult to differentiate whether coronary or non-coronary causes in patients with elevated troponin I (TnI) in emergency department (ED). The aim of this study was to develop a clinical decision tool for differentiating a coronary cause in the patients with elevated TnI.

METHODS: This was a retrospective observational study that enrolled consecutive ED patients. Patients were included in the study if they were ≥16 years of age, had admitted through ED with a medical illness, and TnI levels at initial evaluation in the ED were ≥0.2 ng/mL. Patients diagnosed with ST elevation myocardial infarction or congestive heart failure were excluded. Coronary angiography, electrocardiogram, laboratory results, echocardiography, and clinical characteristics were analyzed.

RESULTS: Among the included 1441 patients, 603 and 838 patients were categorized into an acute coronary syndrome (ACS) group and non-acute coronary syndrome (non-ACS) group, respectively. The ratio of N-terminal pro-Btype natriuretic peptide (NT-proBNP) to TnI was significantly higher in the non-ACS group compared to the ACS group. The AUC of NT-proBNP/TnI (0.805, 95% CI, 0.784-0.826) was significantly superior to that of NT-proBNP/creatinine kinase-MB, TnI, and NT-proBNP. The patients of the non-ACS group with high levels of TnI and BNP showed more critically ill manifestation at the time of presentation and higher mortality.

CONCLUSION: NT-proBNP/TnI may help to distinguish medical patients with elevated TnI whether the elevated TnIs were caused from ACSs or from conditions other than ACS.