By Ric Susman
ORLANDO, Fla -- November 19, 2009 -- Patients who have undergone hip and knee replacement surgery can better avoid deep vein thrombosis in they are treated with the investigative oral drug rivaroxaban, rather than enoxaparin, according to a meta-analysis presented here at the American Heart Association (AHA) Scientific Sessions 2009.
After reviewing studies that included more than 13,000 patients, the researchers determined that a statistically significant (P = .001) relative risk reduction of 50.7% was achieved when patients were receiving rivaroxaban rather than enoxaparin.
In those trials, 229 patients undergoing treatment with rivaroxaban experience deep vein thromboses -- either symptomatic or detected with a venogram -- while 464 patients experienced deep vein thromboses while being treated with enoxaparin.
"We did not see a similar reduction in pulmonary embolism between the groups, but that was because the numbers of patients actually experiencing these events were very low," said Umesh Tamhane, MD, University of Michigan, Ann Arbor, Michigan, on November 17.
The studies documented 13 pulmonary embolism events with rivaroxaban compared with 17 such events among patients receiving enoxaparin. Five of the studies involved hip replacement surgery; 3 looked at knee replacement procedures.
In the meta-analysis, the risk of major bleeding incidents occurring with rivaroxaban was about 50% higher than among patients receiving enoxaparin, but that difference did not reach statistical significance (P = .172) because the number of bleeding events were small. There were 30 major bleeds with rivaroxaban compared with 20 for enoxaparin.
Dr. Tamhane found no significant difference in mortality in the meta-analysis: 14 people who underwent the procedures and were assigned to rivaroxaban died compared with 24 patients who were assigned to receive enoxaparin (P = .433).
Dr. Tamhane said the drug should undergo further testing among diverse groups of patients. "Among patients undergoing major orthopaedic surgery, rivaroxaban may be a more effective agent for thromboprophylaxis than enoxaparin without increasing major bleeding," he said.
[Presentation title: Safety and Efficacy of Rivaroxaban in Prevention of Venous Thromboembolism in Patients Undergoing Elective Major Orthopedic Surgery: A Meta-Analysis of Randomized Controlled Trials. Abstract 5582]
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