Thrombin generation in prothrombin-complex-preparations; its effect on a chromogenic substrate, fibrinogen and platelets.

The kinetics of thrombin generation in various prothrombin-complex-preparations (PCC) were investigated using a chromogenic substrate assay. The rate of thrombin formation and the total activity of thrombin generated varied considerably among different preparations. The thrombin generation velocity influenced the rate of fibrinogen to fibrin conversion, measured as plasma viscosity alteration per unit of time. It also influenced thrombin induced platelet aggregation with regard to maximum aggregation and aggregation velocity. The kinetic parameters measured photometrically and coagulometrically showed reduced generation velocities and less thrombin effects with thrombin formed in PCCs than with thrombin generated in plasma. The quantitative differences between thrombin effects in various PCCs on platelet aggregation did not correlate with the data of the amidolytic and fibrinogenolytic measurements. The significance of the results is discussed with regard to the question of whether, or to what extent, PCCs could cause or accelerate a disseminated intravascular coagulation.