Background: The aim of this study was to evaluate the usefulness of brain natriuretic peptide (BNP) in diagnosing congestive heart failure (CHF), in an unselected population.
Methods: Eighty-three patients (47 men, 36 women, mean age 70 +/- 10 years) were referred to our hospital ambulatory from their general practitioners, with a diagnosis of CHF.
Results: Clinical-instrumental evaluation confirmed diagnosis in 45 patients (54%) (group A), and excluded it in the remaining 38 (46%) (group B). There were no differences between groups regarding age, weight, height, heart rate, blood pressure. Statistically significant differences between groups were found regarding ejection fraction (44 +/- 10% group A vs 60 +/- 7% group B, p < 0.01), and BNP blood concentration (162 +/- 226 pg/ml group A vs 73 +/- 23 pg/ml group B, p < 0.01). Forty-two patients in group A (93%) and 25 in group B (65%) had a BNP value > 20 pg/ml (p < 0.05). Using this cut-off value, sensitivity was 93%, specificity 34%, negative predictive value 81% and positive predictive value 62%. Forty-two patients in group A (93%) and 14 in group B (36%) had an "abnormal" electrocardiogram (p < 0.01). The presence of electrocardiographic abnormalities showed a sensitivity for the diagnosis of CHF of 93%, specificity of 63%, negative predictive value of 89% and positive predictive value of 77%.
Conclusions: In our population BNP dosage confirms the high negative predictive value reported in the literature and may be useful to exclude diagnosis of CHF in patients with suspect signs and symptoms.