After Hip Replacement Surgery, Rivaroxaban Better Than Enoxaparin For Preventing VTE

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, ГЃkos F Pap, Frank Misselwitz,
Sylvia Haas, for the RECORD2 Investigators

The Lancet (2008).

DOI:10.1016/S0140-6736(08)60880-6

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Written by: Peter M Crosta