January 24, 2018
5 min read

Mechanical thrombectomy, IV alteplase recommendations updated in new stroke guidelines

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William J. Powers, MD, FAHA
William J. Powers

IV alteplase may benefit patients with mild strokes, and mechanical thrombectomy may be performed up to 24 hours after the onset of an acute ischemic stroke, according to newly released guidelines published by the American Heart Association and American Stroke Association in Stroke.

“The purpose of these guidelines is very broad,” William J. Powers, MD, FAHA, chair of the department of neurology and H. Houston Merritt distinguished professor at University of North Carolina at Chapel Hill and chair of the guidelines writing group, said during a press conference. “They’re not just for physicians. They’re for any health care provider who cares for patients with acute ischemic stroke.”

Pre-hospital management

According to the guidelines, regional systems of stroke care should be created and include health care facilities for initial emergency care and centers that can perform endovascular stroke treatment. This remains unchanged from the 2015 endovascular guidelines.

Leaders of emergency medical services should develop triage protocols and paradigms to identify and assess patients with a known or suspected stroke. Screening should be done with instruments such as the Los Angeles Prehospital Stroke Screen, FAST scale or Cincinnati Prehospital Stroke Scale.
“We want the patients who do have stroke to get to the hospital as fast as possible,” Powers said. “This means some kind of
screening in the field by emergency medical services and … they need to go to the closest hospital that can adequately evaluate them and give them intravenous alteplase if they are eligible for it.”

Patients should receive mechanical thrombectomy with a stent retriever if they are aged at least 18 years, have a pre-stroke modified Rankin scale between 0 and 1, have a NIH Stroke Scale score of 6 or greater, have causative occlusion of the internal carotid artery or middle cerebral artery segment 1, have an ASPECTS score of at least 6 and if treatment can start within 6 hours of symptom onset. The guidelines now include those who are ineligible for IV alteplase (Activase, Genentech), as they may benefit from this treatment.

A previous guideline restricted use of mechanical thrombectomy to within 6 hours of ischemic stroke onset, but the new guidelines expand the time window for use depending on certain criteria.

Mechanical thrombectomy is also recommended for patients with acute ischemic stroke with large vessel occlusion in the anterior circulation within 6 to 16 hours of symptom onset and who meet DEFUSE-3 or DAWN trial eligibility criteria. It is reasonable for patients to receive this treatment within 16 to 24 hours if they meet DAWN eligibility criteria.

“The eligibility criteria in these studies were very specific, and it doesn’t mean you can use other criteria to select these patients and see the same benefit that were seen in these studies,” Powers said.

Patients should be identified as having an acute ischemic stroke between 6 to 24 hours and then undergo brain imaging such as diffusion-weighted MRI, CT perfusion or MRI perfusion. This allows health care providers to identify those who would benefit from mechanical thrombectomy based on the DAWN or DEFUSE 3 criteria.

Treatment of ischemic stroke with IV alteplase up to 4.5 hours of symptom onset remains recommended, but the new guideline adds that IV alteplase can be useful in patients with mild stroke within the 3- to 4.5-hour window. Health care providers should weigh treatment risks against possible benefits, the authors wrote.

The guidelines feature updated indications, contraindications and additional recommendations for IV alteplase.

“Previous guidelines have sort of been red light, green light, this is an indication, this is a contraindication” Powers said. “A lot of new experience with this drug has come out since the guidelines in 2013, which has allowed us to increase the number of indications that is green light, reduce the number absolute contraindications that is red light and a lot of things now which were said if the person has this, they cannot get the drug under any circumstances whatsoever now become judgment calls.”

Some of the criteria that have become judgment calls include arterial puncture within 7 days, dural puncture within 7 days and non-head major trauma within 14 days.

BP control

The guidelines have been updated to recognize that there is little evidence on BP management in patients having a stroke. Restarting hypertension treatment within the first 48 to 72 hours after an acute ischemic stroke is not effective in preventing dependency or death in patients with BP less than 220 mm Hg/120 mm Hg who did not receive endovascular treatment or IV alteplase and have no comorbidities. For those with a BP of at least 220/120 mm Hg, it is uncertain whether initiating or reinitiating hypertension treatment is beneficial, although it may be reasonable to lower BP by 15% within 24 hours after stroke onset.

Intermittent pneumatic compression with routine care such as hydration and aspirin is recommended in patients without contraindications who had a stroke and are immobile. Compared with routine care, this approach reduces the risk for deep vein thrombosis.

Recommendations for prophylactic-dose subcutaneous heparin have been downgraded from the 2013 guidelines. The benefit of this treatment in patients with acute ischemic stroke who are immobile has not been well established.

“A very careful review of the available information indicates that this is a two-edged sword,” Powers said. “It reduces the risk of blood clots in the legs going to the lungs, but it also increases the risk of bleeding elsewhere in your body. The overall benefit of this seems to be a wash, and the overall efficacy is uncertain.”

Within 24 hours of hospital admission, those with nondisabling acute ischemic stroke who are candidates for stenting or carotid endarterectomy should undergo noninvasive imaging of the cervical vessels, and it is reasonable to perform revascularization between 48 hours and 7 days for secondary prevention.

Evidence has not supported the routine use of numerous diagnostic tests in patients with acute ischemic stroke, such as echocardiography, brain MRI, screening for obstructive sleep apnea and blood cholesterol while not on a statin. Decisions on these tests should be individualized, as they may be reasonable in certain patients.

“We took a very close look at the cost-benefit of doing diagnostic tests to decide what was the best treatment for patients to prevent them from having another stroke,” Powers said. “It is often assumed that just doing a whole bunch of tests is valuable in every patient. … It turns out that is actually not good medical practice. It’s expensive. It leads to studies that provide no information that will be used to improve patient outcome and actually can lead to adverse patient outcomes.”

“There has been a palpable shift toward more focused cost-effective recommendations for laboratory and cardiac testing,” Karen L. Furie, MD, MPH, Samuel I. Kennison, MD, and Bertha S. Kennison professor of clinical neuroscience, professor of neurology and chair of neurology at Brown University in Providence, Rhode Island, and Mahesh V. Jayaraman, MD, associate professor of diagnostic imaging, neurology and neurosurgery at Brown University Warren Alpert Medical School and director of the neurovascular center at Rhode Island Hospital in Providence, wrote in a related editorial. “The message is clear: More is not necessarily better. The new guideline emphasizes a targeted approach to the diagnostic evaluation and the institution of secondary stroke preventive interventions. Although the role of antiplatelet agents and statins remains relatively unchanged in this update, consideration of dual antiplatelet agents has been added as a new recommendation, albeit with limited evidence.” – by Darlene Dobkowski


Powers WJ, et al. Acute Ischemic Stroke Guidelines. Presented at: International Stroke Conference; Jan. 23-26, 2018; Los Angeles.

Furie KL, et al. Stroke. 2018;doi:10.1161/STROKEAHA.118.020176.

Powers WJ, et al. Stroke. 2018;doi:10.1161/STR.0000000000000158.

Disclosures: Powers, Furie and Jayaraman report no relevant financial disclosures. Please see the guidelines for all other authors’ relevant financial disclosures.