The role of thrombin activatable fibrinolysis inhibitor and factor XI in platelet‐mediated fibrinolysis resistance: a thromboelastographic study in whole blood

Background: The resistance of platelet‐rich thrombi to fibrinolysis is generally attributed to clot retraction and platelet PAI‐1 release. The role of TAFI in platelet‐mediated resistance to lysis is unclear. Objective: We investigated the contribution of TAFI to the antifibrinolytic effect of platelets in whole blood by thromboelastography. Methods: Platelet‐poor (PP‐WB, 400 × 103 μL−1) blood samples were obtained from normal human blood (N‐WB, 150–220 × 103 μL−1). Clot lysis time was measured by thromboelastography in recalcified blood supplemented with t‐PA (100 ng mL−1) and tissue factor (1:1000 Recombiplastin). Results: t‐PA‐induced lysis time increased in parallel with platelet concentration (up to 3‐fold). Neutralization of TAFI, but not of PAI‐1, shortened the lysis time by ∼ 50% in PR‐WB and by