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Stanford stroke expert Greg Albers

Stanford-led clinical trial extends time window of intensive treatment for acute stroke to 16 hours

The study's finding is likely to translate into an increase in the number of acute-stroke patients receiving thrombectomies -- and likely save lives.

To understand the importance of an extremely promising study on stroke treatment just published in the New England Journal of Medicine, consider the experience of Cindi Dodd.

As I write in the news release:

On the night of April 23, 2017, Cindi Dodd, a 46-year-old graphic designer who lives in Salinas, California, went to bed around 10:30 p.m., anticipating a 5 a.m. wake-up by her husband, as she was scheduled for outpatient surgery at Stanford. She did arrive at Stanford the next morning — not as an outpatient but as the victim of a massive ischemic stroke.

Ischemic strokes account for about 85 percent of the roughly 750,000 strokes suffered annually in the United States, Stanford neurologist Greg Albers, MD, who led the study, told me. They happen when blood supply to part of the brain is cut off by a clot in a cerebral blood vessel. The resulting lack of oxygen and glucose quickly kills brain tissue in the immediate area, and the affected area continues to expand until blood supply is restored.

Thrombectomy, the current state-of-the-art treatment for a stroke that's just occurred, involves guiding a cage-like stent through the circulatory system to the site of an acute-stroke patient’s brain clot, where the stent then encases the clot and physically extracts it. This procedure is now made available only to patients who reach a treatment center within six hours of a stroke, because there's been no solid reason to think it would do any good after that point.

The short time window of thrombectomies' reputed therapeutic efficacy severely limits the number who can get them. Some 35 to 40 percent of all strokes occur during sleep, for example -- and the clock starts ticking beginning when the patient was last seen to be well -- which, if the stroke comes during sleep, means when that patient went to bed.

That's what happened to Cindi Dodd. From our release:

'My husband woke me up at 5 o’clock as planned, and when I started to speak to him I knew what I was trying to say in my mind, but it had nothing to do with the sounds that were coming out of my mouth,' Dodd said. Her left side was paralyzed.

An ambulance rushed Dodd to a local hospital. But it was already too late for aggressive clot-removal treatment, the attending physicians explained.

Fortunately, within 45 minutes a helicopter operated by Stanford Health Care whisked Dodd to Stanford, where a clinical trial was determining whether brain-imaging-analysis software developed by Albers and a couple of peers could accurately determine which patients arriving between six and 16 hours of their stroke had enough salvageable brain tissue to make a thrombectomy worthwhile. Dodd, it turned out, fell into that category.

By the time her husband and son, driving up from Salinas, had arrived at Stanford, she was already out of surgery. Today, she's not only talking and walking but driving and about to return to her full-time job as a graphic designer.

As Dodd's experience showed, it's not the amount of time elapsed since a stroke but the amount of at-risk but still salveagable brain tissue that should determine the decision to thrombectomize or not. The study clearly proved that about half of patients arriving as late as 16 hours afterward could benefit strongly from the procedure -- a finding that's likely to translate into an almost doubling in the number of acute-stroke patients receiving thrombectomies.

“These astounding results will have an immediate impact in the clinic and will help us save many lives,” said National Institute of Neurological Disorders and Stroke director Walter Koroshetz, MD, in a related NIH news release. “I really cannot overstate the size of this effect.”

Photo by Stanford Health Care

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