Acute venous thromboembolism.

Abstract

OBJECTIVE: To review the recent advances in management of acute venous thromboembolism. DATA SOURCES: Articles and published reviews on venous thromboembolism, pulmonary embolism and deep vein thrombosis. SUMMARY OF REVIEW: Acute venous thromboembolism describes a group of disorders that include venous thrombosis (usually deep vein thrombosis) and pulmonary thromboembolism. Ultrasound supplemented by Doppler flow detection imaging has become the investigation of choice in the diagnosis of deep vein thrombosis and spiral volumetric computed tomography or ventilation perfusion scan (if the patient is haemodynamically stable) or bedside echocardiography (if the patient is hypotensive) are often the initial investigations in a patient who has a suspected pulmonary thromboembolism. Magnetic resonance venography has only recently been evaluated and may prove in future to be a valuable diagnostic test for both deep vein thrombosis and pulmonary thromboembolism. Treatment requires immediate anticoagulation using either subcutaneous low molecular weight heparin (e.g. enoxaparin 1 mg/kg 12-hourly or dalteparin 100 IU anti Xa/kg twice daily) or intravenous unfractionated heparin (80 U/kg as a bolus then 18 U/kg/hr and adjusted to keep the APTT 1.5-2x the control value). Oral anticoagulation using warfarin is started simultaneously with heparin. Fibrinolytic therapy is considered in all patients with pulmonary thromboembolism in whom there are no contraindications, as the improvement in right ventricular function is greater and the pulmonary artery perfusion defect is less compared with patients treated by anticoagulation alone. Fibrinolytic therapy is usually only considered in patients with deep vein thrombosis if severe limb oedema is present. While streptokinase, urokinase and alteplase have been recommended, alteplase (100 mg over two hours with heparinisation) may be the treatment of choice as alteplase has a shorter half life, has a more rapid effect and may be more effective in lysing older clots, when compared with streptokinase or urokinase. Reteplase (10 U over 2 minutes followed by 10 U 30 minutes later) may be as effective as alteplase. CONCLUSIONS: Acute venous thromboembolism is a disorder that carries a high morbidity and mortality. Anticoagulation with or without fibrinolysis is the treatment of choice.