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|Issue 60||March 2013|
A Systematic Review: New Oral Anticoagulants vs Standard Anticoagulant Regimens for Thromboprophylaxis Related to Joint Replacement Surgery
Venous thromboembolic (VTE) events are important causes of morbidity in elective total hip replacement (THR) and total knee replacement (TKR) procedures. Current guidelines recommend thromboprophylaxis (measures taken to prevent blood clots) in patients undergoing THR or TKR, although guidelines suggest individual assessment of patients when choosing the specific strategy. Low molecular weight heparin (LMWH) and adjusted-dose warfarin are the most commonly used anticoagulants in the U.S., but a number of other treatment options are available, including unfractionated heparin (UFH), injectable FXa inhibitors, aspirin, mechanical devices, and new oral anticoagulants.
Pharmacological thromboprophylaxis for THR or TKR surgery decreases the risk of VTE by about half, but with the tradeoff of increased bleeding. The risk of bleeding is a concern because it can lead to infections, reoperation, delayed wound healing, and extended hospital stays. New oral anticoagulants were developed with the goal of avoiding the disadvantages of available antithrombotics. The new anticoagulants belong to two drug classes: 1) factor Xa (FXa) inhibitors, and 2) direct thrombin inhibitors (DTIs). Given as fixed oral doses, these drugs have the advantage of a more predictable anticoagulant effect, eliminating the need for the regular monitoring necessary with warfarin. Disadvantages of newer oral anticoagulants include the lack of specific antidotes to reverse their anticoagulant effect in a timely fashion in case of bleeding, and higher drug costs.
Investigators with the VA Evidence-based Synthesis Program, part of the Durham VA Healthcare System, conducted a review of the literature from January 2009 through September 2012, in order to assess emerging data on new oral anticoagulants and compare the effectiveness of the new oral anticoagulants to other classes of antithrombotic agents (i.e., aspirin, warfarin, LMWH, UFH, etc.). Using data from six recently published, high-quality systematic reviews, investigators focused on answering the following questions.
There are no available studies on head-to-head comparisons of these novel anticoagulants. Longer clinical experience and direct drug-drug comparisons are needed to better assess the risk-to-benefit ratio of new oral anticoagulants for surgical thromboprophylaxis. Based on current evidence, new oral anticoagulants--particularly FXa inhibitors--are a reasonable alternative for thromboprophylaxis in patients undergoing THR or TKR surgery. However, only FXa inhibitors rivaroxaban and apixaban are currently FDA-approved and available in the United States. We caution that similar results in standard VA practice will require careful patient monitoring and selection, excluding those with severe renal disease, liver disease, or increased bleeding risk. Because VA patients, on average, have a higher bleeding risk and greater burden of chronic disease than those with private sector insurance, studies in higher risk populations are needed to determine if the comparative effectiveness is similar to published results in these higher risk groups.
Suggested Evidence-Based Guidance
This report is a product of VA/HSR&D's Quality Enhancement Research Initiative's (QUERI) Evidence-Based Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers -- and to disseminate these reports throughout VA.
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This Management eBrief is a product of the HSR&D Evidence Synthesis Program (ESP). ESP is currently soliciting review topics from the broader VA community. Nominations will be accepted electronically using the online Topic Submission Form. If your topic is selected for a synthesis, you will be contacted by an ESP Center to refine the questions and determine a timeline for the report.
This Management e-Brief is provided to inform you about recent HSR&D findings that may be of interest. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs. If you have any questions or comments about this Brief, please email CIDER. The Center for Information Dissemination and Education Resources (CIDER) is a VA HSR&D Resource Center charged with disseminating important HSR&D findings and information to policy makers, managers, clinicians, and researchers working to improve the health and care of Veterans.
This report is a product of the HSR&D Evidence-Based Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers - and to disseminate these reports throughout VA.
See all reports online.