[Role of the renin-angiotensin-aldosterone system in the pathogenesis of edema formation in chronic obstructive pulmonary disease].

The pathogenesis of edema in COPD patients is poorly understood. In 50 COPD patients without cor pulmonale, we measured water sodium and potassium excretion in 24 hours, concentration of sodium and potassium in plasma as well as PRA, ATII and aldosterone levels. We found that PRA, ATII, and aldosterone levels in COPD patients with edema are much higher than those in patients without edema and sodium and water excretion decreased significantly in edematous COPD patients. Elevation of PRA, ATII, and aldosterone correlated with inability to excrete sodium and water. These data suggest that, in conjunction with hypercapnia-hypoxia-mediated disturbance in renal function, stimulation of RAAS, especially the resulting increase of aldosterone may contribute to edema formation in COPD patients.