The factor VII-Platelet interplay: Effectiveness of recombinant factor VIIa in the treatment of bleeding in severe thrombocytopathia

Recently, high-dose factor VIIa has been used to correct bleeding in patien ts with various thrombocytopathias including Glanzmann's thrombasthenia, Be rnard-Soulier syndrome, and uremia, High-dose factor Wa is postulated to ac t on platelets in the absence of tissue factor to activate factors TX and X and thus enhance thrombin generation, This enhanced thrombin generation mi ght help provide hemostasis in patients with thrombocytopathias through sev eral mechanisms, Enhanced thrombin generation would provide a strong signal for recruitment of other platelets. Also, enhanced fibrin deposition might provide mechanisms for bypassing the specific defect in thrombocytopathias . Thus, platelets from a patient with Bernard-Soulier syndrome might associ ate with fibrin by a glycoprotein IIb-IIIa-mediated mechanism, Also, platel ets from a patient with Glanzmann's thrombasthenia might associate with fib rin through von Willebrand factor-mediated interactions with glycoprotein I b-V-M. Finally, enhanced thrombin generation on platelets would mean that f ewer platelets are required for hemostasis.