Extended prophylaxis comparing low molecular weight heparin (LMWH) to aspirin in total hip arthroplasty (EPCAT study)

Venous thromboembolism (legs and/or lung blood clots) is a common complication following orthopedic surgery. In the past, hip replacement patients were treated with blood thinners (anticoagulants) for the duration of their hospital stay (average 14 days). Presently, patients having total hip arthroplasty (THA) are often discharged within days of surgery at a time when the risk of developing a blood clot still remains. Some research supports the theory that extending anticoagulant prophylaxis beyond hospital discharge is effective and safe. However, due to uncertainty about clinical importance of this intervention, only about two-thirds of Canadian orthopedic surgeons prescribe anticoagulant prophylaxis beyond hospital discharge after THA and there is no consensus about which is the best drug to use. Low Molecular Weight Heparin (LMWH) is an effective anticoagulant for preventing post-operative venous thromboembolism. This agent has been the most extensively studied agent for prophylaxis beyond hospital discharge. Although safe and effective LMWH is very expensive and it must be given by injection. We hypothesize that extending antithrombotic prophylaxis with aspirin for 28 days following hospital discharge after THA will be as safe and effective as extended prophylaxis with LWMH. If proven correct, there could be significant savings to the health care system, and more patients could have a much more convenient and affordable medication to take for this indication.