Diagnosis of Congestive Heart Failure in Acute Dyspneic Patients with N-terminal Probrain Natriuretic Peptide (NT-proBNP)

ABSTRACT

PURPOSE: Misdiagnosis of congestive heart failure (CHF) is common in the emergency care setting uses clinical diagnostic tests. The utility of N-terminal probrain natriuretic peptide (NT-(pro)BNP) testing in the emergency department for differentiating between the causes of acute dyspnea and optimal cut-off points for its use are not well established. METHODS: One-hundred-nine consecutive patients with acute dyspnea, who visited our emergency medical center from December 2005 to February 2006, were prospectively recruited. Patients with acute coronary syndrome and chronic renal failure were excluded from study enrollment. The diagnosis of CHF was based on echocardiographic evidence of systolic or diastolic dysfunction. The diagnostic accuracy of NT-(pro)BNP was assessed by receiver operating characteristic curve analysis. RESULTS: The mean age was 69+/-15 years, and 41% of the patients were men. The diagnosis made in the emergency setting was incorrect in 29% of cases. The median NT(pro)BNP level among 45 patients (41%) who had acute CHF was 7739 versus 982 pg/ml for those 64 patients (59%) who did not have acute CHF(p<0.001). The area under the receiver operating characteristic curve was 0.88 (95% CI of 0.83-0.95). At a cutoff of 700pg/ml, NT-(pro)BNP had a sensitivity of 91%, a specificity of 70%, and an overall accuracy of 79% for acute CHF(p<0.001). An NT-(pro)BNP level <400pg/ml was optimal for ruling out acute CHF, which was a negative predictive value of 97%. Increased NT-(pro)BNP was the strongest independent predictor of acute CHF (odds ratio 21, 95% CI 6.1-70.0, p<0.001). CONCLUSION: NT-(pro)BNP appears to be useful as an aid in the diagnosis of CHF in acute dyspnea patients to the emergency department, however, an understanding of the cut-off points is helpful in accurate diagnosis of congestive heart failure.