Clinical trials of deep vein thrombosis prophylaxis in medical patients.

Autopsies and clinical studies have shown that venous thromboembolism (VTE) is a common cause of morbidity and mortality in medical patients. Prophylaxis of VTE has been less extensively studied in medical patients than in surgical patients, and the results of recent practice audits indicate that the use of thromboprophylaxis is uncommon in medical patients. In the past few years, 3 large randomized clinical trials have demonstrated the efficacy and safety of prophylaxis of VTE in the medical setting. The prophylaxis in MEDical patients with ENOXaparin (MEDENOX), Prospective Evaluation of Dalteparin Efficacy for PREVENTion of VTE in Immobilized Patients Trial (PREVENT), and ARixta for ThromboEmbolism Prevention in a Medical Indications Study (ARTEMIS) studies have compared the low-molecular-weight heparins enoxaparin and dalteparin, and the specific factor Xa inhibitor fondaparinux, respectively, with placebo in acutely ill medical patients hospitalized with heart failure, respiratory failure, infectious disease, or inflammatory disease. All studies showed both a statistically significant reduction in the rate of venous thromboembolic events (as assessed by venography or compression ultrasonography) and a rate of major bleeding events that were comparable to placebo. The results of these studies support the evidence-based recommendations for systematic use of thromboprophylaxis in this setting.