Patients who had complete hip replacement surgery, or total hip arthroplasty (THA), had better success at preventing venous thromboembolism if they used extended duration rivaroxaban instead of short-term enoxaparin plus placebo. The results of the full study by Professor Ajay Kakkar (Barts and the London School of Medicine and Dentistry and the Thrombosis Research Institute, London, UK) and colleagues are published in The Lancet.
Venous thromboembolism (VTE) is a potentially fatal blood clot, and its risk of occurrence is greater after THA. Standard preventative treatment includes heparin-based thromboprophylaxis (with enoxaparin) for about 10 to 35 days after surgery, but this clot-preventing treatment is rarely used after the patient has left the hospital. For example, one registry reported that less than 50% of patients received thromboprophylaxis for at least 28 days. To investigate the efficacy of a new orally active antithrombotic drug, Kakkar and colleagues conducted the RECORD2 study.
For patients undergoing THA, the randomized, controlled trial compared 31 to 39 days of the oral antithrombotic drug rivaroxaban with 10 to 14 days of enoxaparin followed by placebo in patients undergoing THA. Specifically, of 2,509 patients scheduled for THA 1,252 were randomly assigned to receive oral rivaroxaban 10mg once daily for 31 to 39 days followed by placebo injection for 10 to 14 days, and 1,257 were randomly assigned to receive enoxaparin 40mg once daily subcutaneously for 10 to 14 days followed by placebo tablet for 31 to 39 days. The researchers focused on deep-vein thrombosis (DVT) measurements as well as non-fatal pulmonary embolism (NFPE) and death from any cause through days 30 to 42.
Complete data were obtained for 864 patients in the rivaroxaban group and 869 in the enoxaparin group. Of key interest were the rates of DVT for each group: 17 patients (2.0%) in the rivaroxaban group and 81 patients (9.3%) in the enoxaparin group. This translates to an absolute risk reduction of 7.3% for those patients in the rivaroxaban group, or a four times greater likelihood that patients in the enoxaparin group suffer DVT, NFPE, or die. There were no significant differences noted, however, in bleeding events during treatment.
“Extended thromboprophylaxis with rivaroxaban was significantly more effective than short-term enoxaparin plus placebo for the prevention of venous thromboembolism, including symptomatic events, in patients undergoing total hip arthroplasty,” conclude the authors.
An accompanying Comment, written by Dr John Eikelboom and Professor Jeffrey Weitz (McMaster University, Hamilton, ON, Canada), maintains that, “With superior efficacy, no compromise in safety, and a convenient once daily regimen, rivaroxaban seems an obvious choice for simplified thromboprophylaxis after hip or knee arthroplasty.”
Extended duration rivaroxaban versus short-term enoxaparin for the prevention of venous thromboembolism after total hip arthroplasty: a double-blind, randomised controlled trial
Ajay K Kakkar, Benjamin Brenner, Ola E Dahl, Bengt I Eriksson, Patrick Mouret, Jim Muntz, Andrea G Soglian, Ákos F Pap, Frank Misselwitz, Sylvia Haas, for the RECORD2 Investigators
The Lancet (2008).
DOI:10.1016/S0140-6736(08)60880-6
Written by: Peter M Crosta