Significance of brain natriuretic peptide measurement as a diagnostic indicator of cardiac function.

Brain natriuretic peptide (BNP) is increased in patients with heart failure due to myocardial infarction and cardiac hypertrophy, in proportion to the severity of left ventricular dysfunction. The aims of this study were to clarify the clinical features of BNP and to determine the diagnostic value of BNP for mass screening. The subjects were 818 office workers (565 males and 253 females; mean age 47 +/- 12 years) who participated in a 1996 routine health check at Kansai University All individuals were examined for blood pressure, serological findings, ECG and plasma BNP level. Thirty-three males underwent 2-D echocardiography. Plasma BNP levels were measured using IRMA (immunoradiometric assay). The results were as follows: (1) BNP levels in females were higher than those in males for healthy subjects (N = 551), in each age group from 20 to 60 years. (2) BNP levels increased with age. (3) There were significant correlations between BNP level and systolic blood pressure and creatinine level. (4) There were significant differences in BNP level between the hypertensive groups with and without hypertensive ECG changes and the age-matched healthy control group. (5) Marked correlations were observed between BNP level and left ventricular wall thickness, fractional shortening, deceleration time and peak early filling velocity. (6) A BNP cut-off-point of 25 pg/ml was best for detecting LV diastolic dysfunction and LV hypertrophy. Measurement of BNP is useful for detecting asymptomatic heart failure in the general population, and is a clinical marker useful in preventing symptomatic heart failure.