Traditionally stroke is treated with medications that stabilize or diminish blood clots in the brain. In select patients surgical intervention to remove the clot may be possible to mitigate effects of the stroke.
This study could affect the current guidelines on treating stroke patients, according to Dr. Cathy Sila, Director of the Comprehensive Stroke Center at University Hospitals Cleveland Medical Center. She said there is "compelling rationale to move that window a little bit."
As a result of having lost blood flow to the brain for an extended time, stroke victims often suffer physical disabilities and lose varying degrees of their independence. They often require longer-term care and therapies.
"Long-term disability of stroke is more expensive than cost of hospitalization," Sila told ABC News today.
Authors from multiple institutions including the University of Calgary, pooled data from five studies on stroke treatments to see if providing endovascular thrombectomy in addition to standard medical treatment past six hours would help patients. They analyzed those studies for patients who have had large blood vessel strokes, seeking to understand how much of an effect blood clot removal surgery performed after six hours would have on their longer-term recovery. They used a benchmark of three months after the stroke to assess patients' level of disability.
In total, 1,287 patients were enrolled in the five trials studied. The researchers examined clinical data and brain imaging in addition to the patients’ physical function. They found that the patients who received standard medical therapy along with an endovascular thrombectomy up to 7.3 hours after developing stroke symptoms were less likely than patients who were treated with only medications to report disability three months later.
When they examined the patients three months after the stroke, each hour delay in receiving the treatment corresponded in worse outcomes for the patients, including more severe disability and less functional independence.
This meant that even the patients who received the treatment outside of the generally accepted 6 hours cut off up to the 7.3 hours point tended to report less disability during their recovery. However, if people received the treatment after 7.3 hours from onset of symptoms there was no statistical improvement.
Dr. Mayank Goyal, a co-author of the study and professor of Radiology, University of Calgary, said he hopes the study will help raise awareness about the importance of getting prompt treatment for a stroke and having an efficient system to provide this procedure.
"Time is brain," Goyal told ABC News. "The faster we can re-establish blood flow to brain, the higher the likelihood of the patients having a good outcome and going back to independent living."
"We need to have this kind of data so third party payers would have it to base [costs] on," she said.
Dr. Lei Lynn is an internal medicine resident at George Washington University Hospital and a resident in the ABC News Medical Unit.