Early diagnosis of congestive heart failure: clinical utility of B-type natriuretic peptide testing associated with Doppler echocardiography

Abstract

B-type natriuretic peptide (BNP) has emerged as an important diagnostic serum marker of congestive heart failure (CHF). The aim of this study was to evaluate whether BNP measurement associated with echocardiography could effectively stratify patients with new symptoms as part of a cost-effective heart failure programme based on cooperation between hospital cardiologists and primary care physicians. Patients were referred to the cardiology clinic by general practitioners in case of clinical suspect of CHF. All patients underwent clinical examination, transthoracic echocardiography and plasma determination of BNP. Systolic dysfunction was defined as a left ventricular ejection fraction < 45%; diastolic dysfunction was defined as a preserved systolic function with signs of diastolic impairment. Three hundred and fifty-seven subjects were examined (50% males, mean age 73 years). BNP concentration was 469 +/- 505 pg/ml in the 240 patients diagnosed with CHF, compared with 43 +/- 105 pg/ml in the 117 patients without CHF (P = 0.001). CHF patients were grouped into those with diastolic dysfunction (n = 110; BNP 373 +/- 335 pg/ml), systolic dysfunction (n = 108; BNP 550 +/- 602 pg/ml), and both systolic and diastolic dysfunction (n = 22; BNP 919 +/- 604 pg/ml). At receiver operating characteristic analysis, the optimal BNP cut-off level for diagnosing CHF was 80 pg/ml (sensitivity 84%, specificity 91%). According to cost analysis, this cut-off level might provide a cost saving of 31% without affecting diagnostic accuracy. In patients referred by general practitioners for suspected CHF, plasma BNP levels might help to stratify subjects into different groups of cardiac dysfunction.