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Prevention of venous thromboembolism in medical patients and outpatients


The majority of fatal cases of pulmonary embolism in hospitalized patients occur in acutely ill, medically treated patients. Current guidelines, based on a large number of prospective, randomized, controlled trials evaluating the safety and efficacy of pharmacologic venous thromboembolism (VTE) prophylaxis in medical patients, now recommend using VTE prophylaxis in this population. Unfortunately, prophylaxis rates in medical patients are unacceptably low, despite efforts to develop strategies for improving implementation of prophylaxis regimens. Studies indicate that a substantial proportion of patients with VTE present after hospital discharge, but no clinical trials evaluating VTE prophylaxis for medical outpatients have yet been published. In this Review, we examine the literature on VTE prophylaxis in hospitalized medical patients, and evaluate the available data for the outpatient setting.

Key Points

  • Patients should be assessed for their risk of venous thromboembolism (VTE) at hospital admission

  • Anticoagulant medication should be given to patients at risk of VTE unless contraindications exist, in which case mechanical prophylaxis should be used

  • American College of Chest Physicians guidelines recommend the use of low-molecular-weight heparin, low-dose unfractionated heparin, or fondaparinux for VTE prophylaxis in at-risk medical patients

  • Data from observational studies indicate that rates of VTE prophylaxis need to be improved

  • A large proportion of outpatient cases of VTE occur within 3 months of hospitalization

  • Most medical patients do not receive the duration of VTE prophylaxis given in clinical trials, owing to shorter hospital stays

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Charles P Vega, University of California, Irvine, CA, is the author of and is solely responsible for the content of the learning objectives, questions and answers of the Medscape-accredited continuing medical education activity associated with this article.

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Correspondence to Gregg J. Stashenko.

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Competing interests

V. F. Tapson has acted as a consultant for Genentech. He has also acted as a consultant and received research support from Sanofi-Aventis. G. J. Stashenko declared no competing interests.

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Stashenko, G., Tapson, V. Prevention of venous thromboembolism in medical patients and outpatients. Nat Rev Cardiol 6, 356–363 (2009).

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