NT-proBNP in the differential diagnosis of acute dyspnea in the emergency department

Objectives: The purpose of this study was to verify the usefulness of NT-proBNP in the differential diagnosis of dyspnea in a population of patients presenting in the ER with breathlessness. Design and methods: In samples from 122 patients presenting in the ER with acute-severe dyspnea and from 25 subjects enrolled as a “comparison group” (NORM), NT-proBNP levels were measured. Patients have been classified on the basis of discharge diagnosis: pulmonary disease (PD, n = 23), pulmonary concomitant to cardiac disease (MIXED, n = 17), pulmonary embolism (EMB, n = 8), cardiac disease (CARD, n = 56), acute myocardial infarction (AMI, n = 11) and other disease (OTHER, n = 7). Results: A significant difference in NT-proBNP values (P ≤ 0.05) was found in CARD vs. PD as well as vs. NORM and OTHER groups. 1760 ng/L was the best cut-off value calculated from ROC analysis (AUC ± SE 0.815 ± 0.041). Comparing NT-proBNP values and ER diagnosis, a disagreement in 24 patients was observed. Using the discharge diagnosis as the “gold standard,” four cases (17%) were found to be FP and 11 cases (46%) were FN according to ER diagnosis, while 2 patients showed false positive and 7 false negative NT-proBNP values. Conclusions: NT-proBNP measurement represents a useful biochemical tool helping the ER physician in the rapid and reliable recognition of cardiac involvement in patients presenting in the ER with acute-severe dyspnea.