DVT prophylaxis: better living through chemistry: affirms.

Venous thromboembolism remains the most common cause of hospital readmission and death after total joint arthroplasty. The 2008 American College of Chest Physicians (ACCP) guidelines, based on prospective randomized clinical trials with a venography endpoint, endorse the use of low-molecular-weight heparin, fondaparinux, or adjusted dose warfarin (target international normalized ratio, 2.5; range, 2-3) for up to 35 days after total hip arthroplasty (THA) and total knee arthroplasty (TKA). In the past, the ACCP has recommended against the use of aspirin, graduated compression stockings, or venous compression devices as the sole means of prophylaxis, but in 2008 they first recommended the "optimal use of mechanical thromboprophylaxis with venous foot pumps or intermittent pneumatic compression devices" in patients undergoing total joint arthroplasty who "have a high risk of bleeding." When the high risk subsides, pharmacologic thromboprophylaxis is substituted for, or added to, mechanical methods. Fractionated heparins and pentasaccharide are the most effective agents in reducing venographic deep venous thrombosis (DVT) after total joint arthroplasty with residual clot rates <5% after THA and 20% after TKA, but major or clinically meaningful bleeding occurs in 3% to 5% of patients. Newer Xa and thrombin inhibitors enjoy greater efficacy with equal or higher bleeding rates. Low-intensity warfarin (target international normalized ratio, 2.0) combines safety (bleeding rates <1%) with efficacy (readmission for clinical DVT or pulmonary embolism 0.2%) after total joint arthroplasty. Warfarin represents a therapeutic compromise by preventing clinical events in exchange for a lower bleeding rate; genetic testing will likely simplify warfarin use and reduce outlier responders.