Relationship between changes in F1+2 and TAT levels and blood coagulation early after prosthetic valve replacement

Prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III complex (TAT), D-dimer and other coagulation-related factors were measured over time in 48 patients who underwent prosthetic valve replacement and subsequent anticoagulant therapy, in order to evaluate the dynamics of thrombin generation. Before surgery, levels of both F1 + 2 and TAT were high, indicating enhanced thrombin generation. On the 7th day after initiation of postoperative administration of warfarin, F1 + 2 was significantly lower than preoperatively, while TAT tended to be increased. Even on the 21st day, levels of both F1 + 2 and TAT were still high. Despite the administration of warfarin, thrombin generation increased in these patients. After surgery, D-dimer level was increased, indicating hyperfibrinolysis. On the 21st day after initiation of warfarin administration, abnormally high levels of F1 + 2 were observed in 4 of the 48 patients. In these 4 patients, thrombin generation was markedly increased, suggesting that they were in a preliminary stage of thrombogenesis. Antiplatelet therapy did not affect the levels of F1 + 2 or TAT. Our findings suggest that both F1 + 2 and TAT levels are useful for evaluation of enhanced coagulability. D-dimer is also considered to be useful as a parameter of fibrinolysis. F1 + 2 is less affected by surgical invasion than TAT, and therefore appeared to reflect coagulability more accurately.