Rapid point-of-care NT-proBNP optimal cut-off point for heart failure diagnosis in primary care.

INTRODUCTION AND OBJECTIVES Measurement of natriuretic peptides may be recommended prior to echocardiography in patients with suspected heart failure. Cut-off point for heart failure diagnosis in primary care is not well established. We aimed to assess the optimal diagnostic cut-off value of N-terminal pro-B-type natriuretic peptide on a community population attended in primary care. METHODS Prospective diagnostic accuracy study of a rapid point-of-care N-terminal pro-B-type natriuretic peptide test in a primary healthcare centre. Consecutive patients referred by their general practitioners to echocardiography due to suspected heart failure were included. Clinical history and physical examination based on Framingham criteria, electrocardiogram, chest X-ray, N-terminal pro-B-type natriuretic peptide measurement and echocardiogram were performed. Heart failure diagnosis was made by a cardiologist blinded to N-terminal pro-B-type natriuretic peptide value, using the European Society of Cardiology diagnosis criteria (clinical and echocardiographic data). RESULTS Of 220 patients evaluated (65.5% women; median 74 years [interquartile range 67-81]). Heart failure diagnosis was confirmed in 52 patients (23.6%), 16 (30.8%) with left ventricular ejection fraction <50% (39.6 [5.1]%). Median values of N-terminal pro-B-type natriuretic peptide were 715 pg/mL [interquartile range 510.5-1575] and 77.5 pg/mL [interquartile range 58-179.75] for patients with and without heart failure respectively. The best cut-off point was 280 pg/mL, with a receiver operating characteristic curve of 0.94 (95% confidence interval, 0.91-0.97). Six patients with heart failure diagnosis (11.5%) had N-terminal pro-B-type natriuretic peptide values <400 pg/mL. Measurement of natriuretic peptides would avoid 67% of requested echocardiograms. CONCLUSIONS In a community population attended in primary care, the best cut-off point of N-terminal pro-B-type natriuretic peptide to rule out heart failure was 280 pg/mL. N-terminal pro-B-type natriuretic peptide measurement improve work-out diagnoses and could be cost-effectiveness.