PREVENTION AND TREATMENT OF VENOUS THROMBOEMBOLISM

All patients at moderate to high risk for the development of venous th romboembolism should receive prophylaxis. The approaches of proven val ue include low-dose heparin, low molecular weight heparin, oral antico agulants and intermittent pneumatic compression. The use of one of the cited heparin nomograms will ensure that all patients are rapidly bro ught within the therapeutic range. Because of the varying sensitivitie s of thromboplastins, each laboratory should establish a therapeutic r ange using the activated partial thromboplastin time (APTT) which will correspond to 0.2 to 0.4 U/ml of heparin. Constant vigilance and a hi gh level of suspicion are necessary to establish the clinical diagnosi s of heparin-induced thrombocytopenia, and to institute appropriate th erapy. Physicians should be aware of the sensitivity of the thrombopla stin being used in the performance of the international Normalised Rat io (INR). Care must be taken to ensure that patients an maintained wit hin the target therapeutic range for INR (in most cases 2 to 3) by fre quent determination of the INR and appropriate adjustments of warfarin dosage. Low molecular weight heparin is the recommended approach to t he initial management of venous thromboembolism where these agents are available. Patients with an acute episode of venous thromboembolism s hould receive warfarin therapy for at least 3 months. At the present t ime it is reasonable to treat the first recurrence with oral anticoagu lants for a period of 12 months and indefinitely for more than 1 recur rence. For selected patients with acute massive pulmonary embolism, th rombolytic therapy with one of the available agents is recommended. Ho wever, the role of thrombolytic therapy in patients with proximal veno us thrombosis remains unclear. In selected patients with acute venous thromboembolism who have contra-indications to anticoagulant therapy o r who have objectively documented recurrent disease while on adequate therapy, the insertion of an inferior vena cava filter is recommended.