Clinical significance of blood brain natriuretic peptide level measurement in the detection of heart disease in untreated outpatients: comparison of electrocardiography, chest radiography and echocardiography.

The aim of present study was to compare the predictive characteristics and cost-benefit of measuring the concentration of blood brain natriuretic peptide (BNP), compared with electrocardiography (ECG), chest radiography and echocardiography, as a diagnostic test for heart disease. The study group comprised 130 untreated patients who had symptoms suggestive of heart disease. According to the results of additional examinations and follow-up checks, 86 patients were diagnosed as having heart disease and 44 patients were judged free of heart disease. Positive findings in each test suggestive of heart disease were checked in accordance with criteria, and the number of positive and negative cases for each test was calculated. The predictive characteristics, such as specificity, sensitivity, accuracy, positive and negative predictive values, of each test and the cost-benefit value were calculated and analyzed statistically. The sensitivity, specificity and accuracy of blood BNP and echocardiography were significantly greater than those of ECG and chest radiography. Echocardiography had a significantly lower cost-benefit value compared with measuring blood BNP concentration. Thus, the blood BNP concentration had significantly higher predictive characteristics than ECG and chest radiography, and a cost-benefit value significantly greater than that of echocardiography.