Advanced brain imaging technology may give doctors an additional 10 hours or more to respond to some strokes, researchers said on Wednesday, a development that may soon bring major changes to the way hospitals treat one of the leading causes of disability and death.
The research is upending doctors’ long-held belief that they have just six hours to save threatened brain tissue from lack of blood flow when a major vessel to the brain is blocked. The new findings suggest they may have as long as 16 hours in many cases; a study published three weeks ago with a different group of stroke victims put the outer limit at 24 hours for some.
Together, the two studies are expected to be responsible for new stroke treatment guidelines to be released later on Wednesday. Both studies showed such dramatic results that they were cut short to speed up reporting of the information to physicians.
“The big news is that we were all wrong in how we were thinking about how strokes evolve,” said Gregory Albers, a professor of neurology at Stanford University Medical Center and lead author of the new paper. While some brain tissue dies in a stroke, collateral blood vessels temporarily take over feeding a larger area that also is starved for blood and oxygen, giving doctors many more hours to save that tissue than they previously believed, Albers said.
So the age-old medical belief that “time is brain” — that millions of neurons die each minute after a stroke — must be reconsidered, he said. “We are quadrupling the stroke treatment window today,” Albers said. “It’s going to have a massive impact on how stroke is triaged and assessed.”
Walter Koroshetz, director of the National Institute of Neurological Disorders and Stroke, which funded the new study, said in a news release: “These striking results will have an immediate impact and save people from life-long disability or death. I really cannot overstate the size of this effect.”
Strokes were the fifth-leading cause of death in the United States in 2016, when they killed 142,142 people. About 800,000 people have strokes every year, most of which are first-time events.
The vast majority of strokes are ischemic — a clot or mass blocks a vessel, cutting off the flow of blood to a portion of the brain. Those strokes kill some brain tissue and threaten more in many people.