Updated Stroke Guidelines Back the Use of Stent Retrievers in Select Patients
A new recommendation favoring stent retrievers after IV fibrinolysis to treat ischemic stroke in well-defined settings is the centerpiece of a focused update of the 2013 American Heart Association (AHA)/American Stroke Association (ASA) acute stroke guidelines, which were published online June 29, 2015, ahead of print in Stroke.
An expert task force analyzed 8 randomized clinical trials of endovascular treatment and other relevant data published since 2013, zeroing in on what it called “pivotal new evidence” that warrants changes in current guidelines. They underline that rapid administration of IV tPA to appropriate patients “remains the mainstay of early treatment of acute ischemic stroke.”
“What we have learned in the last 8 months, from 6 new trials, is that some people will benefit from additional treatment with a stent retrieval device if a clot continues to obstruct 1 of the big vessels after tPA is given,” said writing committee chair William J. Powers, MD, of the University of North Carolina Hospitals (Chapel Hill, NC), in a press release.
According to the new recommendation—which is designated class I, level of evidence A—a stent retriever should be used in cases in which all of the following criteria are met:
- Prestroke modified Rankin Scale score of 0-1
- Culprit occlusion located in the internal carotid artery or proximal middle cerebral artery
- Patient at least 18 years of age
- NIH Stroke Scale score of at least 6
- Substantial portion of brain tissue on the side of the stroke is not permanently damaged
- Treatment can be initiated within 6 hours of symptom onset
The guidelines underline that endovascular therapy should be performed at “an experienced stroke center with rapid access to cerebral angiography and qualified neurointerventionalists.” In addition, they outline a variety of scenarios in which use of a stent retriever “may be reasonable,” meaning benefit is uncertain due to sparse or no randomized evidence.
Choice to Fast-Track Justified
In a telephone interview with TCTMD, Tudor G. Jovin, MD, of the University of Pittsburgh Medical Center (Pittsburgh, PA), observed that positive trials reported in the last few months, which included MR CLEAN and 3 others, “shook the world of acute stroke treatment to its foundations, leaving the whole stroke community hungry for new guidelines.”
Indeed, the AHA chose to fast-track the update, reported Joseph Broderick, MD, of the University of Cincinnati Medical Center (Cincinnati, OH), who is chair of the AHA Stroke Council. Aware that clinicians were already starting to shape their practice based on recent data, “AHA wanted to provide guidance as to what is backed by solid evidence and what needs more analysis and data,” he told TCTMD in a telephone interview.
What About Aspiration Devices?
According to Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), 1 point about which “some [experts] have raised a concern is the strong recommendation for use of a stent retriever” because potential benefits have also been seen with aspiration devices.
“However, the great majority of the procedures in the published positive trials were performed with stent retrievers, and there has never been a direct comparison between the suction systems and the stent retrievers, so stent retrievers are primarily recommended in these guidelines,” he commented in a telephone interview with TCTMD.
In fact, noted Dr. Broderick, many operators currently use aspiration devices first then follow up with a stent retriever if necessary.
“The reason,” he said, “is you may be able to pull the clot out right away, and if you do it right you may not get the fragmentation potentially [triggered] by a stent retriever.” Recent results of the THERAPY trial testing the Penumbra aspiration system (Penumbra; Alameda, CA)—which were not included in the evidence reviewed by the guidelines task force—showed a strong trend toward benefit over fibrinolysis alone, he reported.
Dr. Broderick suggested that clot removal technology appears to be evolving toward a combination of the best features of the 2 types of devices.
Room for Clinical Judgment
Beyond the strong recommendation for stent retrievers, the guidelines also outline settings in which endovascular therapy may be “reasonable” even though they do not meet the high bar of level A evidence.
Prime examples in which clinical judgment may come into play, Dr. Jovin said, are endovascular treatment of basilar artery occlusions or of large strokes in patients who do not qualify for tPA. Signals of benefit from the recent trials as well as the logic of early reperfusion deserved greater attention in the guidelines document, he suggested.
Another important area of uncertainty is the value of endovascular treatment at more than 6 hours after stroke onset, said Dr. Broderick. “We don’t have much data to say whether it adds benefit or what imaging criteria should be used to select patients, but trials are starting to look at longer time windows.”
Changes Affect Overall Stroke Management
The updated guidelines also address broader stroke management, Dr. Broderick noted. For example, now all patients with more than a mild stroke will likely undergo noninvasive imaging of the intracranial arteries to help determine whether they are candidates for endovascular therapy, he said.
As in the 2013 version, the guidelines recommend that stroke patients be transported rapidly to the closest available certified primary stroke center or comprehensive stroke center. The update specifically advocates development of a 2-tiered regional system of stroke care, with the higher-level center being capable of performing endovascular therapy.
But the guidelines “came up short of recommending that all patients with suspected large-vessel strokes be delivered directly to an endovascular center, which in my mind is a natural conclusion of the recent trials,” Dr. Jovin said. “We also need to develop systems that will allow us to triage patients in the field.” Strategies that reduce time to treatment are “where you get the biggest bang for your buck,” he commented.
“Of course, the evidence will continue to evolve, and new studies are already addressing outstanding questions where evidence is limited,” Dr. Meyers said, so “this particular guideline may require further updates and at more frequent intervals than some other guideline documents. But my sense is they’re moving in the right direction.”
Dr. Broderick agreed but described this update as “the Big One,” stressing that “use of clot retrieval devices is the second biggest step in acute stroke treatment after use of tPA.”
Powers WJ, Derdeyn CP, Biller J, et al. 2015 AHA/ASA focused update of the 2013 guidelines for the early management of patients with acute stroke regarding endovascular treatment: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2015;Epub ahead of print.
- Outcomes of Endovascular Therapy for Acute Ischemic Stroke Getting Better Over Time
- Endovascular Treatment Shows Dramatic Benefits for Large Strokes in 3 Trials
- MR CLEAN Appears to Redeem Endovascular Therapy for Acute Stroke
- Drs. Powers and Meyers report no relevant conflicts of interest.
- Dr. Broderick reports serving as principal investigator for the IMS-III trial and receiving research grants from Genentech for the PRISMS study.
- Dr. Jovin reports serving as principal investigator for the REVASCAT and DAWN trials and as an unpaid consultant to Covidien and Stryker.