Inhibitors of Coagulation in Terminal Renal Failure and during Hemodialysis

Flemming Knudsen, MD, PhD, Department of Anesthesia, Odense University Hospital, DK-5000 Odense C (Denmark) Dear Sir, The paradoxical occurrence of both bleeding tendency and thrombotic complications in advanced renal failure is still an enigma and, therefore, a problem of continued interest. Hemostatic alterations in renal failure are certainly complex and involve abnormal platelet function [1], increased release of vascular prostacyclin [2], impaired release of plasminogen activator [3], and abnormalities in Factor VΠI-von Willebrand complex [4]. Low levels of circulating antithrombin III (AT III) have also been reported [1]. Recently, Alegre et al. [5] reported a decrease in im-munoreactive protein C during hemodialysis and suggested that this may contribute to the prothrombotic state observed in these patients. As a part of a continued research program dealing with the hemostasis in uremia, we have investigated im-munoreactive protein C and protein C activity in patients with progressive renal failure, patients on hemodialysis, and healthy controls. Protein C antigen was measured by Laurell rocket immunoelectrophoresis, the protein C activity was determined according to Francis and Patch, with a pool of plasma from 30 healthy males used as calibrant in both assays, as previously described in detail [6]. We studied 14 hemodialysis patients and 21 healthy controls. Values before and after hemodialysis were compared with Wil-coxon’s test of paired differences. Values from patients and controls were further compared with the Mann-Whitney test. The results are summarized in table I. Table I. Plasma protein C antigen levels and activity (arbitrary units) in 21 healthy controls and 14 hemodialysis patients before and after dialysis