Serum angiotensin-converting enzyme increases during hemodialysis. Evidence for injury of the pulmonary vascular endothelium?

In 19 patients hemodialysis was associated with significant decreases in arterial oxygen tension and leukocyte count. After 240 min of dialysis serum angiotensin-converting enzyme (ACE) corrected for hemoconcentration increased 14.3% (p less than 0.001) indicating injury of the vascular endothelium during hemodialysis. It is suggested that the increase in serum ACE is due to a complement-mediated sequestration of leukocytes in the pulmonary vasculature leading to injury of the vascular endothelium with interstitial edema and pulmonary dysfunction. Furthermore, it is suggested that serum ACE analysis may prove a new method to assess biocompatibility of materials used in devices for extracorporeal circulation.