Atrial and brain natriuretic peptides as markers of cardiac load and volume retention in primary aldosteronism

Background Atrial and brain natriuretic peptides (ANP and BNP, respectively) are cardiac hormones with natriuretic and vasodilator actions. The present study was carried out to determine the natriuretic peptide that is closely related to cardiac load and volume retention in patients with primary aldosteronism (PA). Methods We examined 11 patients with PA due to aldosterone-producing adrenal adenoma before and after surgical resection. Plasma levels of ANP and BNP were measured by specific immunoradiometric assays, and total blood volume was determined by a plasma tracer method with 131I-human albumin. Results Plasma levels of ANP and BNP were elevated in the PA patients compared with normotensive control subjects (P< .01), and the elevated ANP and BNP levels were reduced (P< .01) after adenoma resection. When analyzed with the pre- and postoperative data, a significant relationship was observed between mean blood pressure and plasma levels of ANP (r = 0.64, P< .01) and BNP (r = 0.58, P< .01). The BNP was significantly correlated with the SV1 + RV5 voltage (r = 0.65, P< .01) and with total blood volume (r = 0.57, P< .01), but this was not the case for ANP. Conclusion The present results suggest that the plasma level of BNP is more closely related to cardiac load or volume status than ANP is, in patients with PA due to adrenal adenoma.