In vitro evaluation of the hemostatic effectiveness of cryopreserved platelets.

Abstract

Cryopreserved platelet (CPP) concentrates exhibit a variety of morphologic and functional alterations that may affect the action of CPP with accelerated platelet (PLT) response and clotting. The objective of this study was to compare the in vitro hemostatic effect of CPP with fresh whole blood (WB) and standard 5-day PLT concentrates (PCs). WB collected from eight healthy donors was used to prepare fresh WB, PLT-depleted WB (TPN), and PLT-restored TPN using CPP (TPN-CPP) or PC (TPN-PC). Clot properties were evaluated with thromboelastometry (ROTEM); adhesion and aggregate formation under high shear (Impact-R); and PLT adhesion, aggregate formation, fibrin formation, and prothrombin activation under medium shear in a perfusion system. TPN-CPP had faster clot initiation (ROTEM clot time--TPN-CPP 115 sec, WB 194 sec, TPN-PC 161 sec), and CPP contributes to a strong clot with PLT involvement (maximum clot firmness--TPN-CPP 32 mm, WB 62 mm, TPN-PC 59 mm). The Impact-R PLT-covered area with TPN-CPP was less than those of WB and PCs, but aggregate size was the same as WB. PLT coverage in perfusion studies was observed with TPN-CPP, although generally less than both WB and PC. Fibrin was deposited with CPP-restored samples, but did not exceed the level of WB. CPPs present a phenotype supporting a moderate increase in the rate of clot formation, form stable PLT clots, and do not present a hypercoagulable phenotype during in vitro functional tests.