The many faces of the contact pathway and their role in thrombosis.

Understanding inherent differences between thrombosis and hemostasis in the vascular system are critical to developing safe and effective anticoagulants. To this end, constituents of the contact activated and intrinsic pathway of coagulation appear to be involved in pathological thrombus formation, but are not required for normal hemostasis. In addition to coagulation, activation of the contact system is involved in fibrinolytic, inflammatory, and angiogenic processes that can also contribute to the thrombotic environment. This review discusses the role of the contact system in these processes, and highlights the potential of FXII and FXI as safer targets for antithrombotic therapy.