A study, called DEFUSE 3, found that performing a endovascular-therapy -- the physical removal of the blockage -- can be removed up to 16 hours after the symptom compared with current approved six hours. Photo courtesy of Greg Albers, Stanford University
Jan. 26 (UPI) -- Patients' outcomes from strokes can be improved by removing brain clots several hours longer after the condition than currently performed, according to a study funded by the National Institute of Neurological Disorders and Stroke.
The institute, which is part of the National Institutes of Health, presented its findings at the International Stroke Conference in Los Angeles on Thursday and published in the New England Journal of Medicine.
The study, called Endovascular Therapy Following Imaging Evaluation for the Ischemic Stroke, or DEFUSE 3, found that performing endovascular therapy -- the physical removal of the blockage -- can be performed up to 16 hours after the symptom compared with the currently approved six hours, because of advanced-imaging technology.
The study was conducted from May 2016 through May 2017 at 38 hospitals across the United States with 192 patients. Ninety patients with a median age of 70 received endovascular-therapy and other therapy while 92 with a median age of 71 only received standard therapy.
Among those who had clots removed, the median time from symptom onset was 10 hours 29 minutes
"These striking results will have an immediate impact and save people from life-long disability or death," said Walter Koroshetz, M.D., director of NINDS, in a NIH release. "I really cannot overstate the size of this effect. The study shows that one out of three stroke patients who present with at-risk brain tissue on their scans improve and some may walk out of the hospital saved from what would otherwise have been a devastating brain injury."
Strokes are the fifth-leading cause of death in the United States with about 140,000 dying each year, according to the Centers for Disease Control and Prevention. More than 795,000 people in the United States have a stroke with about 610,000 of these are first or new strokes.
A ischemic stroke occurs when a cerebral blood vessel is blocked, and oxygen and nutrients to brain tissue are cut off. Although brain tissue near the blockage can't be saved from dying, the nearby areas -- called the ischemic penumbra -- can be salvaged depending on how quickly blood blow is restored.
The study used automated software known as APID to analyze MRI or CT scans involving standard dye.
In imaging technology, standard dye is injected and scanned for a few minutes as it passes through the brain. The process identifies patients most likely to benefit from thrombectomy.
In the study, 45 percent of the patients treated with the clot removal procedure achieved functional independence compared with 17 percent success with only standard treatment. Also, 14 percent of group with clot removal died within 90 days of the study compared to 26 percent in the control group.
NIH ended the trial early on recommendation of the independent Data and Safety and Monitoring Board because of overwhelming evidence of benefit from the clot removal procedure. The intended maximum sample was 400.
"Although stroke is a medical emergency that should be treated as soon as possible, DEFUSE 3 opens the door to treatment even for some patients who wake up with a stroke or arrive at the hospital many hours after their initial symptoms," Albers said.
The NIH study builds on a DAWN trial released last year that showed the time window could be extended from six hours to 24 hours.
Less than one in 10 patients suffering from an ischemic stroke receives thrombectomy, due in part to a lack of scientific evidence supporting treatment beyond six hours, according to Stryker, which makes a tiny stent-shaped medical device used in clot removal.