HYPERCOAGULABILITY IN VENOUS AND ARTERIAL THROMBOSIS

The term ''hypercoagulability'' is used to describe patients who are a t increased risk far thrombosis because of inherited defects in their anticoagulant pathways or because of various predisposing causes. Abou t one in five patients of European descent who present with venous thr omboembolism have a specific genetic defect in their anticoagulant pat hway. In these patients, anticoagulant prophylaxis is indicated at rim es of high risk, such as after surgery. Prolonged anticoagulant therap y may be required in patients with recurrent or life-threatening throm boemboli, but decisions about this are best made on an individual basi s. Patients who present with arterial thrombosis usually develop their disease as a complication of atherosclerosis. However, these patients also have a form of hypercoagulability, manifested primarily by high fibrinogen levels and elevated factor VII activity. Evidence increasin gly indicates that these and other hemostatic markers may help in the assessment of patients at risk for coronary heart disease.