Plasma levels of BNP primarily reflect the degree of ventricular overload, whereas ANP reflects atrial overload, demonstrating different secretion patterns based on the underlying cardiac disorder.
BACKGROUND: The plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are increased in relation to the severity of congestive heart failure (CHF). This study was designed to examine whether the secretion patterns of ANP and BNP vary with underlying cardiac disorders of CHF with different degrees of overload in atria and ventricles. METHODS AND RESULTS: We measured plasma levels of ANP and BNP in the aorta in 20 patients with mitral stenosis (MS) in whom atria are mainly overloaded, 30 patients with dilated cardiomyopathy (DCM) in whom both atria and ventricles are overloaded, and 20 control subjects during cardiac catheterization. Pulmonary capillary wedge pressure (PCWP) was significantly higher in the MS and DCM groups (16.7 +/- 4.7 mm Hg and 15.1 +/- 7.7 mm Hg, respectively) than in the control group (7.2 +/- 1.1 mm Hg, p < 0.01), whereas there was no significant difference between the MS and DCM groups. Left ventricular end-diastolic pressure (LVEDP) was significantly higher in the DCM group than in the MS group (16.4 +/- 7.8 mm Hg versus 7.6 +/- 2.0 mm Hg, p < 0.01), and the level was comparable between the MS and control groups (7.6 +/- 2.0 mm Hg versus 6.8 +/- 1.2 mm Hg, p = NS). The plasma ANP level was significantly higher in the MS and DCM groups (356 +/- 169 pg/ml and 331 +/- 323 pg/ml, respectively) than in the control group (98 +/- 41 pg/ml, p < 0.01), whereas there was no significant difference between the MS and DCM groups. The plasma BNP level was significantly higher in the DCM group than in the MS group (333 +/- 405 pg/ml versus 147 +/- 54 pg/ml, p < 0.01), and the level was significantly higher in the MS group than in the control group (147 +/- 54 pg/ml versus < 10 pg/ml, p < 0.01). The plasma levels of ANP and BNP had a highly positive correlation with PCWP in the DCM group (p < 0.01). On the other hand, in the MS group, the plasma ANP level had a highly significant correlation with PCWP (p < 0.01) but the plasma BNP level did not. CONCLUSIONS: We conclude that plasma levels of BNP mainly reflect the degree of ventricular overload and that the secretion patterns of ANP and BNP vary with underlying cardiac disorders of CHF with different degrees of overload in atria and ventricles.
Yoshimura et al. (1993) studied this question.