Elevated Factor VIII Levels and the Risk of Thrombosis

I n vivo, a delicate balance exists between fibrin formation and fibrinolysis. Reduced blood flow, changes in the vessel wall, and changes in blood composition (hypercoagulability) 1 may all result in a disturbance of this balance, which favors fibrin formation and ultimately may lead to the formation of occlusive thrombi. Venous thromboembolism is the result of clot formation in a vein at sites of reduced blood flow. Arterial thrombosis involves the formation of platelet aggregates at high shear rates at sites of vessel-wall injury.