Major bleeding during oral anticoagulant therapy associated with factor V activation by factor Xa

Plasma thrombin generation (TG) provides important information on coagulation status; however, current TG output parameters do not predict major bleeding of patients on anticoagulants. We recently reported that factor V (FV) activation by factor X (FX)a contributes importantly to the initiation phase of TG. Here we investigated how this pathway varies in the normal population and whether FXa‐mediated activation of FV is associated with major bleeding in patients on anticoagulant therapy.