New Stroke Guidelines Extend Thrombectomy to 24 Hours

Pauline Anderson

January 25, 2018

LOS ANGELES — New guidelines for the management of acute stroke include selection criteria for patients to receive mechanical endovascular thrombectomy up to 24 hours after their stroke.

The guidelines are timely because there has been "a sweeping change" in the management of acute stroke since the last guidelines were released, guideline writing committee chair, William J. Powers, MD, H. Houston Merritt Distinguished Professor and Chair, Department of Neurology, University of North Carolina at Chapel Hill, told Medscape Medical News.

"In 2013, there were no data, no good clinical trial data, that anybody benefited from this procedure, and now there is."

The new guidelines were released here at the International Stroke Conference (ISC) 2018 and published online January 24 in Stroke. The document was endorsed by the American Association of Neurological Surgeons, the Congress of Neurological Surgeons, and the Society for Academic Emergency Medicine.

In 2015, the American Heart Association/American Stroke Association (AHA/ASA) issued a Focused Update of the 2013 guidelines for the early management of patients with acute ischemic stroke. Among other things, the evidence-based guidelines covered the selection of eligible patients for endovascular therapy with a stent retriever (mechanical thrombectomy) within 6 hours from the onset of a stroke.

However, since those guidelines were published, two additional studies have suggested that some patients can benefit from the procedure after 6 hours — possibly up to 24 hours following a stroke.

One of these studies — DEFUSE-3 — was presented at this meeting and published simultaneously in the New England Journal of Medicine (NEJM) just hours before release the updated guidelines. Guideline authors had the chance to review the manuscript for this trial in advance and include the information in their updated guideline.

"When you talk about up-to-date guidelines, it doesn't get any more up-to-date than this," Dr Powers said.

One of the selection criteria for mechanical thrombectomy is having a large clot in one of the large vessels at the base of the brain. "It's not every stroke; it has to be a large clot," said Dr Powers, that typically cause more severe strokes.

According to the updated guidelines, patients should be considered for thrombectomy in under 6 hours after stroke onset if they meet this criterion and these other criteria:

  •  Prestroke modified Rankin Scale (mRS) score of 0 to 1;

  •  Causative occlusion of the internal carotid artery or middle cerebral artery segment 1 (M1);

  •  Age over 18 years;

  •  National Institutes of Health Stroke Scale score of 6 or greater; and

  •  Alberta Stroke Program Early CT Score of 6 or greater.

What's different from previous recommendations is that patients who are ineligible for intravenous (IV) tissue plasminogen activator (tPA) may now be selected for mechanical thrombectomy within 6 hours.

This new recommendation is a level 1A.

In light of the new results from DEFUSE-3, and a second study called DAWN, published January 4 also in NEJM, the new guidelines recommend thrombectomy in eligible patients 6 to 16 hours after a stroke (another level 1A recommendation).

And on the basis of the DAWN results, the procedure is "reasonable" in patients 16 to 24 hours after a stroke (level IIa-B-R).

Dr Powers explained that to garner a level 1A recommendation, two studies are needed. Both DAWN and DEFUSE-3 covered patients for up to 16 hours, but only DAWN covered patients from 16 to 24 hours.

To be eligible for the mechanical clot removal procedure up to 24 hours after a stroke, patients need to meet clear criteria, essentially inclusion criteria for the DAWN trial. "There are certain computed tomography or MRI findings that need to be satisfied," said Dr Powers.  

It's not clear how many patients would benefit from the recommendation extending the time frame for mechanical thrombectomy eligibility to 24 hours, he said.

Care Plan

In light of the broadening selection criteria for this procedure, the new guidelines also recommend that hospitals set up a relevant plan of care.

"We know that this procedure can never be available at every hospital in the country," said Dr Powers. "So it's now really, really important for hospitals in the various regions to start coming up with a system of care."

Such a system would include initially sending patients with symptoms to the closest hospital where staff can determine whether they're having a stroke and whether they're a candidate for IV tPA and, if so, administer it.

But hospitals also need to identify potential candidates for mechanical thrombectomy "and to get them to some place that can do it fast," said Dr Powers.

An increasing number of centers across the country can do this, he added. "There are more and more every day."

The Joint Commission, in collaboration with the AHA/ASA, now offers the Thrombectomy-Capable Stroke Center (TSC) certification program. This new level of stroke certification identifies hospitals that meet rigorous standards for performing mechanical endovascular thrombectomy.

This is the fourth level of stroke center certification offered by the Joint Commission and the AHA/ASA; additional certifications include Acute Stroke Ready, Primary Stroke and Comprehensive Stroke.

Intense Training

The mechanical thrombectomy procedure requires highly skilled professionals, be they radiologists, neurologists, or neurosurgeons. It takes at least 2 years of "intense training" to be skilled enough, said Dr Powers.

"Up until a couple of years ago, there wasn't a huge market for people like that, and now there is."

In addition to recommendations regarding mechanical thrombectomy, the new guidelines broaden the eligibility criteria for IV tPA.

"IV alteplase or thrombolysis remains the cornerstone of stroke therapy," Dr Powers said at a media briefing. "Everyone who is eligible for this should get it, and it should not be delayed to determine if they're eligible for another treatment."

Previous guidelines took a "red light/green light" approach for contraindications and indications. But new information emerging since 2013 allowed the guideline authors to increase the number of indications under the "green light" and reduce the number of absolute contraindications under the "red light," said Dr Powers.

Some of what was absolutely contraindicated before is now subject to the judgment of the treating clinician, he said. For example, a dural puncture within 7 days and nonhead major trauma within 14 days "used to be red lights and now this is a judgment call on the part of the treating physician for weighing the risks and benefits of providing the treatment to the individual patient."

Still, sometimes tPA is all that's needed. "If you're eligible for tPA — if it's been under 4 and a half hours since your stroke — you should still get tPA because sometimes it works and dissolves the clot" and you won't need mechanical clot retrieval, said Dr Powers.

Mechanical thrombectomy and tPA "are not mutually exclusive," and patients can receive both interventions, he said.

Patients with severe strokes who meet criteria for tPA should get this treatment, but physicians should not wait to send them for mechanical thrombectomy. "You don't wait; you basically get them as fast as you can to mechanical thrombectomy," said Dr Powers.

At nearby smaller hospitals, staff will often start tPA on stroke patients, put them in a helicopter, and fly them to Dr Powers' center "with the tPA running," he said.

"When they get here, we check to see if they still have a big clot, and if they do, we will take them to mechanical thrombectomy."

Some patients who are not eligible for tPA — for example, those on blood thinners like warfarin — may still be eligible for mechanical thrombectomy, noted Dr Powers.

This could be tremendously useful, he added. "Before this, we would have to tell those people, 'You're anticoagulated and have had a stroke but I can't give you tPA, so I can't do anything.' But now we can."

Blood Pressure

The guidelines also embrace some changes in blood pressure management.

"Primarily, we have now realized that it's okay for the blood pressure to be high immediately after the stroke," said Dr Powers.

If a patient's blood pressure is at least 220/120 mm Hg and he or she didn't receive tPA or endovascular treatment, and there's no other reason to lower the blood pressure, there's no benefit in bringing it down, he said.

"Before, someone would look at a patient with a blood pressure of 200 over 100 and say, 'This is an emergency; we have to give this patient a medication to bring it down.' Now, we know from studies that this doesn't help. It doesn't hurt; but it just doesn't do anything."

Another recommendation is to use intermittent pneumatic compression on all immobile stroke patients to deep venous thrombosis and possible pulmonary embolism.

The compression sleeves that are wrapped around the calf have inflatable balloons that intermittently blow up and down to squeeze the blood out of the veins in the legs.

Before, there was some debate about whether to use these compression sleeves, anticoagulation, or both, said Dr Powers. "We are saying that this works and with blood thinners, we don't know."

And while anticoagulation may reduce pulmonary embolism, there is risk for bleeding elsewhere in the body.

"The overall benefit of blood thinners is not clear; the overall benefit of these compression cuffs is clear," said Dr Powers.

Another revised recommendation relates to carotid revascularization. When revascularization is indicated for secondary prevention in patients with minor, nondisabling stroke (mRS score of 0 to 2), it is "reasonable," the authors write, to perform the procedure between 48 hours and 7 days of the index event rather than delay treatment if there are no contraindications to early revascularization. 

"You shouldn't wait. You ought to look to see if they have a blockage within 24 hours and if they do have one, between 48 hours and 7 days you ought to operate on it."  Previous guideline didn't give a time frame, he noted.

In light of cost implications, an important new recommendation is ordering only tests that are beneficial.

Pick and Choose

Some doctors think that the more information they can gather through tests, the better, said Dr Powers. "But the idea of having a routine bunch of tests that you do in everybody is not cost-effective. No test should be routinely performed in everybody with a stroke; you really need to pick and choose which tests you do in which person to answer a very specific question."

Dr Powers provided examples of which tests could be skipped. One is brain MRI. While patients typically get computed tomography in the emergency department to determine whether they have an ischemic as opposed to a hemorrhagic stroke, "The question is, does everyone with an ischemic stroke need an MRI?" said Dr Powers.

The same question could be posed for those who routinely undergo echocardiography, even in the absence of heart disease.

Other routinely offered tests that don't seem to add benefit include those for obstructive sleep apnea and hyperhomocysteinemia and prolonged cardiac monitoring. Clinicians should "stop and think, and order only the ones that matter," said Dr Powers.

This approach will save precious healthcare dollars "but still provide really, really good care, so we aren't compromising quality of care," he said.

The guidelines focus on acute stroke, including the management before arrival at the hospital, in the emergency department, and during hospitalization, but they don't "draw the line" between acute treatment and prevention, said Dr Powers.

"Prevention is part of the acute treatment of patients. Prevention literally starts the day the patient comes in; we look to see if they need to be on a statin; we start them on aspirin or a similar drug; we decide if they need to be anticoagulated — all of that."

Dr Powers stressed that at least half of the guideline committee members were not allowed to have ties to industry, and the ones who did have ties were not permitted to vote and were banned from participating in relevant discussions.

This, he said, represented "a little step further" from previous guidelines, where those with industry ties were just prevented from voting on recommendations.

Asked by Medscape Medical News to comment on the new guidelines, Bruce Ovbiagele, MD, professor and chair, Neurology, Medical University of South Carolina, Charleston, praised the new document for being "more comprehensive" and more "user friendly" than previous guidelines.

He commended the authors for recognizing that secondary stroke prevention "starts in the hospital," something, he said, that has not been done before.

Dr Ovbiagele noted that the emphasis on not routinely carrying out a battery of tests on all stroke patients is novel and could contribute to cost savings in the system.

Dr Powers and Dr Ovbiagele have disclosed no relevant financial relationships.

International Stroke Conference (ISC) 2018. Presented January 24, 2018.

Stroke. Published online January 24, 2018. Abstract

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