Stroke: Clot-Busting Drug Window May Be Expanded
Giving stroke patients a clot-busting drug within three hours of the start of symptoms is a long-established guideline, and recent research demonstrates that extending that treatment window by an hour-and-a-half could still benefit some patients, according to a new American Heart Association/American Stroke Association advisory.
The scientific advisory, published in Stroke: Journal of the American Heart Association, reinforces immediately seeking and initiating care for a stroke because the opportunity to minimize brain damage is greater with earlier treatment.
The clot-buster recombinant tissue-plasminogen activator (rt-PA) is approved by the U.S. Food and Drug Administration for use within three hours of symptom onset in eligible patients and the scientific advisory reaffirms this guideline. Not every stroke patient is eligible for rt-PA. Patients with a hemorrhagic (bleeding) stroke, people with certain medical conditions (such as bleeding disorders), or those patients who take medications that make the blood less likely to clot (e.g. warfarin) are unable to receive rt-PA.
The advisory notes that some patients were treated successfully up to 4.5 hours after symptoms began in the 2008 European Cooperative Acute Stroke Study (ECASS)-3, a multi-center, randomized, placebo-controlled trial. The advisory updates the current guidelines to recommend treatment in select patients in the three to four and a half hour window, but urges confirmation of the trial’s results with further analyses.
“The results of ECASS 3 study confirm the need to treat patients within the three-hour window – according to the guidelines – to reduce disability from ischemic stroke, the kind caused by blood clots in the brain,” said Gregory J. del Zoppo, M.D., chair of the advisory writing committee and professor of medicine and adjunct professor of neurology at the University of Washington School of Medicine in Seattle.
In addition, trial reinforces a pooled analyses of earlier trials providing confirmatory evidence that intravenous rt-PA can safely benefit carefully selected patients when used between three and 4.5 hours after stroke symptoms. However, based on the ECASS-3 study, some patients that could be treated within three hours should not be treated during the wider treatment window, including those:
• Older than 80 years
• Having a severe stroke
• With a history of stroke and diabetes
• Taking oral anticoagulants (anti-clotting drugs)
“Every second counts with ischemic stroke because the likelihood of permanent damage increases with each passing moment,” del Zoppo said, adding that once stroke patients arrive at a hospital they must undergo imaging tests to rule out hemorrhagic stroke (caused by bleeding in the brain) so that clot dissolvers can be given if appropriate.
“There has always been a notion that there are patients who could be successfully treated outside the three-hour window, but there has been no confirmation of that, although we seem to be getting closer to the answer,” del Zoppo said.