Saturday, April 21, 2007

Enoxaparin Outdoes Heparin for Post-Stroke Venous Thromboembolism

SAN ANTONIO, Tex., April 20 -- Enoxaparin (Lovenox), a low molecular-weight heparin, proved more effective than unfractionated heparin for preventing potentially fatal leg and lung clots after acute ischemic stroke, researchers reported.
In a head-to-head study of 1,762 stroke patients unable to walk unassisted, enoxaparin was 43% more effective at preventing venous thromboembolism than unfractionated heparin, David G. Sherman, M.D., of the University of Texas here, and colleagues reported in the Apil 21 issue of The Lancet.
The results of this study, Dr. Sherman concluded, suggest that for patients with acute ischemic stroke, enoxaparin is preferable to unfractionated heparin for venous thromboembolism prophylaxis in view of its better clinical benefits-to-risk ratio and convenience of once daily administration.
Venous thrombembolism with either low-molecular-weight heparin or unfractionated heparin is recommended for acute ischemic stroke, but because large studies are lacking, it has been uncertain which is the better regimen, Dr. Sherman said.
To compare the efficacy and safety of the drugs, the researchers undertook a large, 15-nation multinational randomized study (PREVAIL), sponsored by Sanofi-Aventis, maker of enoxaparin.
Within 48 hours of symptoms, 666 patients were given enoxaparin (40 mg subcutaneously) once daily for 10 days, while 669 got unfractionated heparin (5,000 U subcutaneously) every 12 hours, for 10 days (range for all, six to 14 days).
The patients were stratified by the National Institutes of Health Stroke Scale (NIHSS) (severe stroke ≥14, less severe stroke <14).
Enoxaparin reduced the risk of venous thromboembolism by 43% compared with unfractionated heparin (68 [10%] versus 121 [18%]; relative risk 0.57, 95% CI 0.44-0.76, P=0.0001; difference -7.9%, -11.6 to -4.2).
The greater reduction with enoxaparin was consistent for patients with an NIHSS score of 14 or more (26 [16%] versus 52 [30%]; P=0.0036) or less than 14 (42 [8%] versus 69 [14%]; P=0.0044).

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