Venous Thromboembolic Risk and Its Prevention in Hospitalized Medical Patients

In medical patients, the risk of venous thromboembolism (VTE) is substantially underestimated and prophylaxis is used far less than in surgical patients, reflecting the scarcity of evidence supporting antithrombotic therapy in nonsurgical settings. However, current consensus documents recommend assessment of all medical, as well as surgical, patients for thromboembolic risk and provide prophylaxis recommendations according to the risk level, determined by the presence of different clinical and molecular risk factors. Although long-term, underlying clinical and molecular risk factors also have a major impact on overall risk in medical patients; risk clearly varies with the type of medical condition. Myocardial infarction, stroke, and malignant disease are linked to a high rate of VTE; recent evidence highlights patients with cardiopulmonary disease as a distinct risk group. Despite skepticism in some quarters, high-quality evidence confirms the efficacy of unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH) in reducing asymptomatic deep vein thrombosis (DVT) in a broad spectrum of medical patients; further studies are required to clarify the effect on fatal pulmonary embolism (PE). Emerging data from the recent PRINCE and MEDENOX studies demonstrate that the LMWH enoxaparin provides effective and well-tolerated VTE prevention in patients with severe cardiopulmonary disease. Emerging evidence has led to a grade 1A recommendation for the use of thromboprophylaxis in these patients in the most recent consensus conference on thromboprophylaxis. Further studies, however, are required to clarify the optimal duration of prophylaxis in medical patients and to evaluate the potential role of outpatient prophylaxis. Accurate risk assessment and prompt implementation of appropriate prophylaxis, selected on the basis of evidence from well-designed controlled clinical trials, may reduce the future morbidity and mortality due to VTE in medical patients.