Platelet function and markers of hemostatic activation in plasma donors

Purpose: The aim of this study was to investigate the effects of plasmapher esis procedure on in vivo platelet activation, platelet function, blood coa gulation, and fibrinolysis. Participants and Methods: 16 healthy donors wer e subjected to automated plasma donation using cell separator Autopheresis C(R). 500 ml of plasma were collected per procedure. Samples of donors' blo od for routine hematological measurements and the measurement of P-selectin were obtained immediately before donation as well as 1 min, 24 h, and 48 h after donation. Fibrinogen concentrations, platelet aggregation, thrombin- antithrombin III (TAT) complexes and D dimers were measured before plasmaph eresis as well as 1 min and 48 h after plasmapheresis. Results: Measurement s of CD62-positive platelets and platelet aggregation using ADP, epinephrin e, and arachidonic acid showed no significant differences between pre- and postdonation values (p > 0.05). Mean platelet volume (p < 0.01) as well as fibrinogen concentrations (p < 0.05) and D dimers (p < 0.05) were reduced a fter plasmapheresis. Plasma concentrations of circulating TAT complexes inc reased significantly after plasmapheresis (p < 0.001). Concentrations of fi brinogen and TAT complexes returned to the baseline values within 48 h whil e concentrations of D dimers remained lower 48 h after the completition of the procedure. Conclusion: On the basis of the evaluated testing there was no evidence that plasmapheresis adversely affected platelet-dependent prima ry hemostasis. Decreased concentrations of D dimers after plasmapheresis su ggest no increase in fibrinolytic activity. Nonspecific loss of circulating D dimers during the procedure is a likely explanation. Observed changes of coagulation parameters suggest that plasmapheresis procedure has a transie nt influence on hemostasis, probably without clinical significance.