Platelet Function and Factor VIII in Uremia(*)

We studied platelet function and plasma factor VIII in 15 healthy individuals and 41 uremic patients to evaluate the effect of dialysis on the hemostatic defect in uremia. Platelet counts and bleeding times were normal in all subjects. Platelet retention on glass beads was significantly reduced in all uremic patients. Platelet aggregation induced by collagen and ADP were significantly reduced in uremic patients on conservative therapy. ADP-induced platelet aggregation was normal but collagen-induced aggregation remained abnormal in hemodialysis (HD) patients. Both ADP- and collagen-induced aggregation were normal in patients on continuous ambulatory peritoneal dialysis (CAPD). FVIII: C was normal in all uremic patients. Both FVIII:vWF and FVIII R:Ag were significantly elevated in all uremic patients. In conclusion, platelet function was significantly defective and FVIII:vWF and FVIII R:Ag significantly elevated in uremia. HD and CAPD did not influence factor VIII levels or function nor did they improve platelet retention. Platelet aggregation improved partially on HD and completely on CAPD.