Hypercoagulable states and venous thrombosis.

Many factors predispose patients to thromboembolic disease. A young person presenting with idiopathic deep venous thrombosis may never have its etiology elucidated, despite exhaustive testing. On the other hand, hypercoagulability is no mystery in an obese, bedridden, postoperative patient with a malignancy. Invasive or noninvasive testing should be performed in all suspicious cases. Patients with positive results should be treated promptly; those with negative findings should not be subjected to anticoagulation. The length of anticoagulation depends on the length of time the patient remains at risk of thrombosis and may vary from months to a lifetime. Patients over 40 should receive prophylactic minidose heparin for abdominal and thoracic surgery. Patients undergoing hip surgery require some form of anticoagulation--be it heparin, warfarin, aspirin, or dihydroergotamine-heparin. Because of lower morbidity and superior long-term efficacy, transvenous devices are favored over surgical techniques for inferior vena caval interruption.