Venous thromboembolism prophylaxis for the medical patient: where do we stand?

Acutely ill medical patients are at moderate to high risk of venous thromboembolism: ~10 to 30% of general medical patients may develop deep vein thrombosis or pulmonary embolism, and the latter is a leading contributor to deaths in hospital. Medical conditions associated with a high risk of venous thromboembolism include cardiac disease, cancer, respiratory disease, inflammatory bowel disease, and infectious diseases. Predisposing risk factors in medical patients include a history of venous thromboembolism, history of malignancy, complicating infections, increasing age, thrombophilia, prolonged immobility, and obesity. Heparins, including unfractionated and low molecular weight, as well as fondaparinux have been shown to be effective agents in prevention of VTE in this setting. However, it has not yet been possible to demonstrate a significant effect on mortality rates in this population. In medical patients, unfractionated heparin has a higher rate of bleeding complications than low molecular weight heparin. There is no evidence for the use of aspirin, warfarin, or mechanical methods. We recommend either low molecular weight heparin or fondaparinux as safe and effective agents in the thromboprophylaxis of medical patients.