New ischaemic stroke guidelines widen mechanical thrombectomy window to 24 hours in selected patients


The American Heart Association and American Stroke Association released updated ischaemic stroke guidelines that were published in Stroke, and released during the International Stroke Conference 2018 (ISC; 24–26 January 2018, Los Angeles, USA).

A major new recommendation increases the time window to 24 hours for selected acute ischaemic stroke patients to receive mechanical thrombectomy, a procedure only advisable in clots that block large vessels. The new recommendation will likely result in more patients becoming eligible for thrombectomy since more patients will be treated based on clinical presentation rather than a time cut-off alone.

The new guideline, based on the most recent science available, recommends that large vessel strokes can safely be treated with mechanical thrombectomy up to 16 hours after a stroke in selected patients. The expanded treatment window from six to 16 hours is based on clinical evidence from the DAWN and DEFUSE 3 trials. Under certain conditions, based on advanced brain imaging, some patients may have up to 24 hours for treatment with mechanical thrombectomy, based on the DAWN Trial criteria. The previous time limit was six hours.

The purpose and scope of 2018 American Heart Association/American Stroke Association guidelines were presented by William J Powers, Chapel Hill, USA at ISC.

“The purpose of these guidelines is to provide an up-to-date comprehensive set of recommendations for clinicians caring for adult patients with acute arterial ischaemic stroke in a single document. They address prehospital care; urgent and emergency evaluation; treatment with intravenous and intra-arterial therapies; and in-hospital management including secondary prevention measures that are appropriately instituted within the first two weeks,” said Powers, the guideline writing group chair and professor of neurology, University of North Carolina.

Explaining two of the new recommendations, Powers said: “In selected patients with acute ischaemic stroke within six to 16 hours of last known normal who have large vessel occlusion in the anterior circulation and meet other DAWN or DEFUSE-3 eligibility criteria, mechanical thrombectomy is recommended. In selected patients patients with acute ischaemic stroke within 16 to 24 hours of last known normal who have large vessel occlusion in the anterior circulation and meet other DAWN eligibility criteria, mechanical thrombectomy is reasonable.

“The expanded time window for mechanical thrombectomy for appropriate patients will allow us to help more patients lower their risk of disability from stroke,” he noted, saying “that is a big deal. That is potentially a lot more people who could benefit, and it has completely changed the landscape of acute stroke treatment.”

Another new recommendation broadens the eligibility for administering intravenous alteplase, the only US FDA-approved clot-dissolving treatment for ischaemic stroke. Previously, patients with mild strokes were not eligible for clot-busting treatment, but new research suggests it could help some of these patients. The guideline says doctors should weigh the risks and benefits in individual patients, because the drug can decrease disability when given promptly and appropriately.

The guideline is based on a review of over 400 peer-reviewed published studies. The studies were examined by a group of experts in stroke care and are the most comprehensive recommendations for treating ischemic stroke issued since 2013.



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