But endovascular strategies have shown a better rate of "recanalization," or opening the artery up, Benesch said.
"The difficult challenge has been trying to establish that recanalization is clearly associated with improved clinical outcome," he added.
For this study, Ciccone and his colleagues randomly assigned 362 patients with acute ischemic stroke to undergo endovascular therapy or standard tPA administered intravenously.
Endovascular therapy given in the study included administering tPA through the artery directly into the clot or retrieving or breaking up the clot mechanically, or a combination of both.
All treatments occurred with 4.5 hours of the beginning of the stroke.
After three months, about a third of patients in each group were alive and without disability. In other words, there was no difference in outcomes.
A number of reasons might account for the results, including the extra time it takes to perform endovascular therapy, said Dr. Daniel Labovitz, director of the Stern Stroke Center at Montefiore Medical Center, in New York City.
In this study, endovascular treatment delayed initiation of treatment by one hour, study author Ciccone said.
But another explanation for the finding is possible and may be good reason not to write off endovascular strategies entirely, experts said.
In particular, devices called stent retrievers "seem to be more effective and safe than their predecessors," Ciccone said. But they are so new that they were only used in the last phase of this study, which ran from 2008 through 2012.
"We do not know if the extensive use of these devices could have produced more favorable results for endovascular therapy," Ciccone said.
For his part, Labovitz said that stent retrievers "have been a game changer."
It's also possible that different patients would benefit from different treatments but doctors don't yet know which patients fall into which
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