New guidelines give physicians added response time for strokes

New technology helps doctors save brain tissue

New stroke-treatment guidelines were issued Wednesday that will significantly extend the time during which doctors can remove blood clots that are choking off circulation to the brain.

The American Stroke Association’s guidelines, published in the journal Stroke and released at an international meeting of the group, are based on two studies that show brain cells can still be rescued by a procedure to remove the clot up to 16 hours in selected patients. Old guidelines held doctors have just six hours to save threatened tissue when a major vessel to the brain is blocked.

“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 is also starved for blood and oxygen, giving doctors many more hours to save that tissue than they previously believed, Albers 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.”

“These guidelines are more than just an evolution,” said Dr. John Volpi, a stroke neurologist at Houston Methodist Hospital. “They’re a real revolution in the way we’ll be able to treat stroke.”

Volpi said the guidelines will benefit everyone coming in for an evaluation after a stroke “because we’ll no longer be bound by a time window of a few hours.” He said “we’ll be able to image all patients and select the right treatment.”

Volpi characterized stroke doctors at Methodist as very excited about the new guidelines.

Volpi said that in Houston, more than half of stroke patients are evaluated in an ER environment. Stroke is the No. 4 killer in Texas, claiming the lives of more than 9,000 a year.

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 lifelong disability or death.”

Strokes were the fifthleading 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.

Doctors can respond with clot-dissolving medication within the first few hours and within six hours have been reaching into the blood vessel with clotremoving devices such as stents.

But the studies show that they may have more time to save brain tissue where the blood supply is being choked off but the tissue has not yet died.

The key is the imaging technology developed at Stanford, Albers said. When a CT scan that uses a dye shows a larger area of damaged tissue surrounding the dead tissue, doctors can respond by removing the clot as long as 16 hours after the patient was last known to be well.

This is especially important for people who have strokes in their sleep, which may make it impossible to pinpoint when the blockage occurred, or people who live far medical centers where the clots can be removed.

The diagnostic test can be read on a cellphone, with pink and green areas denoting the dead and damaged tissue, Albers said.