Activation of coagulation during hemodialysis

20 subjects in chronic dialytic treatment by chronic renal failure were studied. Plasma protein C activity (PCA:chromogenic assay) factor VII and factor X coagulant activity (FVIIc,FXc:coagulant method) and serum lipoprotein(a) (Lp(a):immunonephelometric assay) were evaluated before and after hemodialysis (Hd) session. Hd was performed for 3 hours during continous heparinization. Results Despite heparinization PCA,FVIIc,FXc and Lp(a) were increased after Hd. The pathway protein C/protein S/thrombomodulin system is triggered when thrombin binds to the endothelial cell receptor thrombomodulin. Coagulant activity of FVII is linked to Tissue Factor (TF), produced by endothelial cells. FVII activation leads to FX activation that can directely produce thrombinogenesis. The increase of Lp(a) may deprime fibrinolysis and enhance smooth cell proliferation. The activation of coagulation during hemodialysis contributes to the pre-thrombotic state of uremia.