Plasma von Willebrand factor and thrombomodulin as markers of vascular disorders in patients undergoing regular hemodialysis therapy.

Increased plasma levels of von Willebrand factor antigen (vWF:Ag) are regarded as reflecting the release reaction by vascular endothelial cells and/or endothelial cell injury, and increased levels of thrombomodulin (TM) antigen as reflecting damage to endothelial cells. We investigated changes in plasma vWF:Ag and TM antigen levels during the course of regular hemodialysis treatment (RDT) in 14 patients undergoing RDT in order to evaluate the effect of hemodialysis (HD) on endothelial cells. vWF:Ag and TM were both measured by the sandwich EIA method. Predialysis levels of vWF:Ag and TM in RDT patients were both significantly higher than normal control values. Neither patient age nor blood pressure was not correlated with predialysis vWF:Ag and TM levels. Both vWF:Ag and TM levels significantly increased during a single HD session. There was a positive correlation between predialysis TM levels and duration of HD and an inverse correlation between the amount of vWF:Ag released during HD and duration of HD. It appears that HD procedures induce stimulation and damage of endothelial cells and that long-term, recurrent HD treatment may predispose to vascular disorders.