Oral anticoagulation is highly effective prophylaxis for patients who have experienced or are at risk of thrombosis. They have been associated with unexplained venous thromboembolism in younger patients. Possible hereditary fibrinolytic abnormalities should be investigated in a research setting. In vitro clotting tests are prolonged. Patients with symptomatic atherosclerosis are at significant risk of stroke, MI, and peripheral artery occlusion, which primarily develop at sites of preexisting stenosis.
Atherosclerotic plaques rupture and expose tissue factor-rich plaque contents to blood.
Increases in fibrinogen levels correlate with thrombotic events. High levels may be an independent risk factor for arterial thromboembolism or a nonspecific inflammatory marker of ruptured plaques. However, in the absence of vascular disruption, there is little relationship between arterial thrombosis and thrombocytosis, even if peripheral platelet counts are very high, especially in young asymptomatic persons. Other Predisposing Factors Stasis is associated with increased venous thromboembolism in surgery, orthopedic or paralytic immobilization, congestive heart failure, pregnancy, varicosities, and obesity. Tissue injury from trauma and surgery increases the frequency of venous thromboembolism.