SAN FRANCISCO, February 9 /PRNewswire/ -- A 1,700-patient study comparing anticoagulation therapies found that enoxaparin, one of a class of compounds called low-molecular-weight heparins, is significantly more effective than an older therapy at preventing a dangerous and common ischemic stroke complication called venous thromboembolism (VTE).
Importantly, patients benefited even when the treatment was not initiated for up to two days following the onset of ischemic stroke symptoms. “These results are extremely useful for practitioners to know that they have a relatively long therapeutic window to start prophylaxis following the diagnosis of ischemic stroke,” said neurologist David Sherman, M.D., professor of medicine at The University of Texas Health Science Center at San Antonio.
Dr. Sherman is principal investigator for the international PREVAIL study (Prevention of VTE after Acute Ischemic Stroke with Low-Molecular-Weight Heparin Enoxaparin). He presented the findings today at the 2007 International Stroke Conference in San Francisco. The research was sponsored by Sanofi-Aventis, maker of Lovenox(R), brand name for enoxaparin.
Ischemic stroke, caused by a blood vessel blockage, is by far the most common type of stroke (about 85 percent of cases). VTE, a general term used to describe the formation of a blood clot (thrombus) that blocks a vessel, is diagnosed for the first time in an estimated 300,000 Americans each year.
The PREVAIL study enrolled 1,762 patients in 15 countries who suffered ischemic stroke. Participants were enrolled within 48 hours of the onset of ischemic stroke symptoms. They were randomly assigned to be treated with either enoxaparin or the older class of agent, unfractionated heparin, for 10 days and were followed for 90 days.
Enoxaparin reduced the relative risk for developing VTE after an acute ischemic stroke by 43 percent versus unfractionated heparin (10.2 percent of participants in the enoxaparin arm of the study developed VTE, versus 18.1 percent of participants in the unfractionated heparin arm).
Results showed that this significant reduction of VTE risk with enoxaparin versus unfractionated heparin was maintained whether the treatment was initiated within 24 hours of stroke symptom onset or whether it was initiated 24 to 48 hours after symptom onset.
Among participants receiving enoxaparin within 24 hours of symptom onset, 8.1 percent suffered VTE. Among those receiving unfractionated heparin within 24 hours, the figure was 18.5 percent. Among participants receiving enoxaparin after 24 to 48 hours, 11.3 percent suffered VTE. Among those receiving unfractionated heparin after that duration, the figure was 17.8 percent.
This relative risk reduction was associated with a comparable safety profile as assessed by no significant difference in clinically important bleeding, whatever the time of initiation (within 48 hours after stroke onset).
Furthermore, the clinical benefit of enoxaparin on VTE prevention did not affect stroke patient outcomes at three months as compared to unfractionated heparin. Rate of stroke progression and stroke recurrence were comparable in both groups.
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