Essay On Thrombosis

Thrombosis Formation

Thrombosis is the formation of a thrombus within the vascular system. Development of thrombosis after vessel wall injury is characterised by the deposition of platelets, tissue factor and fibrin. A thrombus is a solid or semi-solid mass, which consists of aggregated platelets, that form a platelet plug and a mesh of cross-linked fibrin protein. The formation of a thrombus is a healthy response to blood vessel injury intended to prevent blood loss, and is the first step in restoring haemostasis.

Blood vessel damage can also be caused by the interaction between a foreign material (medical device) and the endothelium lining of the vessel. Exposure of the space under the endothelium initiates platelet activation and the

Under normal conditions, blood contacts an endothelium with anticoagulant and antithrombotic properties. The use of a cardiovascular device represents the introduction of a foreign surface in the circulation, without the properties of the endothelium. Blood– material interactions trigger a complex series of events including protein adsorption, platelet and leukocyte activation/adhesion, and the activation of complement and coagulation processes. A study conducted by Hanson emphasizes that exposure of blood to an artificial surface can induce thrombosis, embolization, and consumption of platelets and plasma coagulation factors, as well as the systemic effects of activated coagulation and complement products, and platelet activation. It is clear that no synthetic or modified biological surface generated by man is as resistant to thrombosis (thromboresistant) as normal unperturbed endothelium (the cellular lining of the circulatory system). Therefore thromboembolic complications are a major cause of mortality and morbidity with cardiovascular devices. However the need for these devices is still evident due to the ever increasing numbers of cardiac episodes per year due to coronary artery disease