March 6, 2013 – A recent study led by a Georgetown researcher shows that a mechanical procedure to remove blood clots from the brains of stroke victims works no better than non-invasive standard medications.
The study, led by Dr. Chelsea Kidwell, professor of neurology and director of the Stroke Center at Georgetown’s Medical Center, was published online Feb. 8 in the New England Journal of Medicine.
“The hope was, and to some degree still is, that if you pull out the clot within a certain period of time and there is salvageable brain tissue, there will be better outcomes,” said Kidwell, who presented the research at the International Stroke Conference Feb. 6-8 in Hawaii. “But the fact is that we found no greater overall benefit in patients who had their clot removed using the first generation clot retrieval devices when compared to standard medicines.”
She says the study showed that the level of disability 90 days after stroke was no different in patients who received standard care versus clot removal and that the rates of death (21 percent) and symptomatic brain bleeds (4 percent) were no different between the two treatment groups.
Also, the response to clot removal was no better in the 58 percent of patients whose favorable imaging pattern suggested salvageable brain tissue.
“The study also found that imaging techniques were not helpful in identifying patients who potentially would benefit most from clot removal,” Kidwell says. “While this is disappointing, it is as important to know what is not working as it is to know what is working well.”
The only proven effective treatment for a stroke caused by a blood clot is tPA (tissue plasminogen activator).
The treatment, administered in the hospital, must be given within the first few hours after stroke symptoms appear.
For patients who don’t meet the timeline for treatment or whose clots do not respond to tPA, an interventional procedure to remove the clot is another option.
Researchers conducted the study was conducted at 22 institutions in the United States, evaluating outcomes in 118 patients with an average age of 65.5 who had suffered a severe ischemic stroke in one of the large blood vessels carrying blood to the front of the brain.
By removing the clot within the first eight hours of having the stroke, researchers hoped that the procedure would restore blood flow to the affected area of the brain.
Positive Safety Data
Prior to conducting the procedure, the patients received advanced MRI or CT scans of the brain, including a blood flow study, to help identify those with viable brain tissue who presumably would benefit if the clot was removed and blood flow restored.
Patients in the study received either standard medications or clot removal with a special device.
Those who received tPA were allowed to enroll in the study if the treatment failed.
Hope for Future
“The findings may not apply to the newer clot removal tools that can open vessels better and faster,” Kidwell says. “The safety data for the tools examined in this study are encouraging, which is important as we move forward to evaluate newer and possibly better devices.”
Dr. Reza Jahan, associate professor of interventional neuroradiology at the University of California, Los Angeles, is co-principal investigator of the study.
The National Institutes of Health’s National Institute of Neurological Disorders and Stroke grant No. P50 NS044378 supported the research.