Hemostasis, Thrombosis, Fibrinolysis, and Cardiovascular Disease

Hemostasis requires balancing of the physiologic processes that maintain blood fluidity under normal circumstances and prevent excessive bleeding after vascular injury. Preserving blood fluidity depends on an intact endothelium and complex regulatory pathways that maintain platelets in a quiescent state and keep the coagulation system in check. In contrast, arrest of bleeding requires rapid formation of hemostatic plugs at sites of vascular injury to prevent exsanguination. Perturbation of hemostasis can lead to thrombosis, which is responsible for one in four deaths worldwide. This chapter (a) reviews hemostasis and thrombosis and highlights the processes involved in platelet activation and aggregation, blood coagulation, and fibrinolysis, (b) describes the major components of the hemostatic system: the vascular endothelium, platelets, and coagulation and fibrinolytic systems, and (c) reviews the antiplatelet, anticoagulant, and fibrinolytic drugs in common use.