麻豆传媒

LOS ANGELES -- In a radical move for the typically glacial pace of comprehensive guideline overhaul, the American Heart Association/American Stroke Association expanded the treatment window for endovascular thrombectomy within hours of release of supporting trial data.

The guideline, released here at the International Stroke Conference (ISC) and online in Stroke, moved from a 6-hour time frame for stent retriever use to up to 24 hours after patients with acute ischemic stroke were last known to be well.

The recommendation was class Ia for the period from 6 to 16 hours as both the DAWN trial and the DEFUSE 3 trial, released the same day here at ISC, confirmed better outcomes than medical therapy alone; it was a IIa recommendation out to 24 hours, reflecting that only a single trial for this window (DAWN) was available.

"This will be perhaps a once in a lifetime situation where a study gets published [and] within 2 hours is incorporated into new guidelines," DEFUSE 3 presenter Gregory Albers, MD, of Stanford University in Stanford, California, said at a press conference. He noted that this was made possible by provision of an embargoed copy of the trial to the guideline-writing group.

The guidelines recommend physicians use either DAWN or DEFUSE 3 criteria for determining which large vessel occlusions are candidates for clot removal. DEFUSE 3 used broader inclusion characteristics (mainly in allowing a larger ischemic core and less severe strokes), with about 40% of participants not fitting DAWN criteria.

Basically, that comes down to being as generous as possible in inclusion to reach "anybody who is eligible based on either one" before the 16-hour window, but follow DAWN criteria from past 16 hours to 24 hours, guideline writing committee chair William Powers, MD, of the University of Chapel Hill in North Carolina, told 麻豆传媒 at the press conference.

While Mark Alberts, MD, of Hartford HealthCare in Hartford, Connecticut, noted that his center had already adopted the 24-hour strategy based on DAWN, they will consider the two in resetting criteria. "Our stroke staff will meet and we'll discuss them. I think that's what's going to go on in most systems; they'll come up with a happy medium."

That also necessitated a shift to the guidelines recommending more sophisticated imaging, specifically diffusion weighted MRI or MRI perfusion to aid in patient selection for mechanical thrombectomy.

In practical terms, these changes are likely to increase the thrombectomy-eligible population by 20% nationwide, commented Jeffrey Saver, MD, of the University of California Los Angeles.

"Now ... it doesn't matter where you are, there's nowhere in the country that you can't get to a [thrombectomy] center in 24 hours," Albers noted.

However, "there's a lot of work to be done," toward the class Ia recommendation for development of regional systems of care that remained unchanged from the 2015 update, Powers noted. Each individual region has many issues to work out with "no easy recipe" that all can follow, he said.

Now adding the complexities of thrombectomy scans and transfers, "it's a new world," agreed Albers.

Thrombolytics, too, saw some changes in the guidelines. Overall, the recommendations for IV thrombolysis were broadened, with an increase in indications and reduction in absolute contraindications, such as recent dural puncture or non-major head trauma. Use in otherwise eligible patients with mild stroke even in 3 to 4.5 hour windows was also deemed reasonable.

Other changes included:

• Prevention of deep vein thrombosis for immobile patients during the hospital stay should focus on intermittent pneumatic compression (upgraded to class I) instead of heparin, which was downgraded from a Ia to IIb recommendation
• Candidates for carotid endarterectomy should be evaluated for that within 24 hours and surgery should occur within 7 days after
• Acute blood pressure management recommendations got downgraded to reflect increasingly equivocal evidence of benefit

The guidelines were also endorsed by the American Association of Neurological Surgeons, Congress of Neurological Surgeons, and the Society for Academic Emergency Medicine.

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