Plasma concentrations of atrial, brain, and C-type natriuretic peptides and endothelin-1 in patients with chronic respiratory diseases.

We measured plasma concentrations of atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP, respectively) and endothelin-1 in 20 patients with chronic respiratory diseases (CRD) to establish whether these peptides are increased in patient groups with CRD (group A, PaO2 > or = 60 mm Hg; group B, PaO2 < 60 mm Hg) and whether a correlation exists between the levels of natriuretic peptides or endothelin-1, and blood gas variables. In patients receiving long-term oxygen therapy (LTOT), plasma ANP, BNP, and endothelin-1 were compared before and after LTOT. We compared the levels of plasma ANP, BNP, and endothelin-1 in the presence or absence of right heart overloading (RHO) found in the ECG. Plasma ANP and BNP levels in group B patients were higher than those in group A and control subjects, and endothelin-1 in group B patients was higher than in control subjects. Inverse correlations were found between PaO2 and levels of plasma ANP, BNP, and endothelin-1. Plasma ANP, BNP, and endothelin-1 decreased significantly 25.4 days after LTOT. In 10 patients with RHO findings in the ECG, plasma ANP and BNP levels were significantly elevated compared with those in patients without RHO. These findings show that plasma ANP, BNP, and endothelin-1 are elevated according to the degree of hypoxemia, and they suggest that decreases in plasma ANP, BNP, and endothelin-1 may be used as indexes of the improvement by LTOT, and that plasma ANP and BNP may represent markers of RHO.