Transpulmonary angiotensin II formation in patients with chronic stable cor pulmonale.

The activity of the renin-angiotensin (RA) system and the ability of the lungs to generate angiotensin II (AII) were studied in 11 patients with stable cor pulmonale and respiratory failure caused by chronic obstructive bronchitis and emphysema. Angiotensin I concentrations (18.7 +/- 8.3 pmol/L) were normal, and transpulmonary AII formation rates (TRAIIFR) (14.2 +/- 18.1 pmol/min) were not significantly different from those recorded in nonedematous cardiac subjects (19.9 +/- 20.1 pmol/min), matched for sex, age, and diuretic therapy. The main determinant of TPAIIFR was the mixed venous AI concentration. Administration of oxygen for 30 min led to a small increase in TPAIIFR in the majority of patients. This increase could not be accounted for by changes in mixed venous AI. There was no correlation between serum angiotensin-converting enzyme levels and either the TPAIIFR or the systemic arterial AII concentrations.