[Therapeutic indications for acute venous thromboembolism. Current status and future perspectives]

Except for selected patients requiring aggressive therapies, the large majority of patients with acute venous thromboembolism are currently treated with full doses of unfractionated or low-molecular-weight heparins (LMWH) followed by oral anticoagulants for variable periods of time. LMWHs present a number of potential advantages over unfractionated heparin: a longer plasma half-life, improved subcutaneous bioavailability, and a more predictable dose-response relationship. As a result of these pharmacokinetic properties, these compounds have the potential to greatly simplify the initial treatment of venous thromboembolism, making the treatment of suitable patients feasible in an outpatient setting with considerable saving in costs and improvement in patients' quality of life. The use of unfractionated heparin is still desirable in the initial treatment of acute pulmonary embolism in non-critically ill patients. The use of heparin protocols assures that virtually all patients will promptly achieve the therapeutic range for the activated partial thromboplastin time. Although the optimal duration of anticoagulation in patients suffering an episode of venous thromboembolism is presently unknown, it seems reasonable to administer a short-term course of coumarin drugs to patients with thrombosis associated with transient risk factors, while a longer course should be considered in patients with idiopathic thrombosis and in those with permanent risk factors. At present, indefinite anticoagulant therapy remains a clinical judgment in the individual patient. The efficacy and safety of emerging drugs (pentasaccharide, ximelagatran) in the treatment and secondary prevention of venous thromboembolic disorders is currently under investigation.