Abstract
Background: The aim of the present study was to interpret B-type natriuretic peptide (BNP) level in outpatients with stable chronic heart failure (CHF); it is important to clarify whether the change in BNP represents disease progression or a range of biological variation. Methods and Results: To compare biological variation in BNP and biological variation in factors of the renin-angiotensin-aldosterone system (RAS) in stable CHF patients with dilated cardiomyopathy (DCM), the BNP plasma levels and RAS factors were measured in 115 stable outpatients with DCM. According to stepwise multivariate analysis, plasma BNP at baseline (P=0.005), presence of atrial fibrillation (P=0.015), and a high biological variation in plasma renin concentration (PRC; P=0.002) were significant independent dominant factors related to a high biological variation in BNP. Although there was no change in body weight or blood pressure during the 2-month study period, the % change in hematocrit was negatively correlated with % change in BNP (r=-0.327, P=0.0008), and positively correlated with % change in PRC (r=0.671, P=0.001). Conclusions: There was a significant relationship between biological variation in BNP and biological variation in PRC, suggesting that the physiological interaction between the natriuretic peptide system and RAS may contribute to the biological variation in plasma BNP in stable outpatients with DCM. (Circ J 2011; 75: 1897-1904)
