Physiology of haemostasis

Haemostasis is a complex process that ensures the maintenance of blood flow under normal physiological conditions and prevents major blood loss following vascular injury. The process is tightly regulated to prevent pathological thrombosis. Normal haemostasis relies on the delicate balance of prothrombotic and anticoagulant processes, where five components play a significant role inmaintaining the haemostasis, these include: (1) endothelial cells; (2) platelets which are key to platelet plug formation; (3) coagulation factors that are essential to formation of insoluble fibrin clot; (4) coagulation inhibitors; and (5) fibrinolysis. This article will provide an overview of the current concepts of haemostasis, and through this we will explain how antiplatelets and antithrombotic drugs work, as well as provide a basic understanding of how to interpret clotting tests used to measure coagulation disorders.