No method integrating amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing with clinical assessment for the evaluation of patients with suspected acute heart failure (HF) has been described.
Amino-terminal pro-brain natriuretic peptide results and clinical factors from 599 patients with dyspnea were analyzed. The beta coefficients of the 8 independent predictors of HF were used to assign a weighted integeric score for predictor. The sum of these integers provided a diagnostic HF "score" for each patient. Receiver operating characteristic curve analysis determined the optimal cut point for the diagnosis of acute HF. The performance of the score was evaluated in the development cohort and subsequently in a patient population from a separate clinical trial of patients with dyspnea conducted in Christchurch, New Zealand.
Eight factors comprised the score: elevated NT-proBNP (4 points), interstitial edema on chest x-ray (2 points), orthopnea (2 points), absence of fever (2 points), loop diuretic use, age > 75 years, rales, and absence of cough (all 1 point). Median scores in patients with acute HF were higher than those without acute HF (9 vs 3 points, P < .001). At a cut point of > or = 6 points, the score had a sensitivity of 96% and a specificity of 84% for the diagnosis of acute HF (P < .001). The score improved diagnostic accuracy over NT-proBNP testing alone and retained discriminative capacity in patients in whom clinical uncertainty was present. Lastly, the accuracy of the score was validated in the external data set of patients with suspected acute HF.
We report a simple and accurate scoring system combining NT-proBNP testing and clinical assessment for the diagnosis or exclusion of acute HF in patients with dyspnea.