Conference Coverage

Three trials cement embolectomy for acute ischemic stroke

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Results warrant embolectomy scale-up

Many U.S. centers have interventionalists who already perform endovascular treatments within intracerebral arteries, but the issue is can they do this form of embolectomy in the high-quality, highly-reliable, rapid way that it was done in these trials? Stent-retriever catheters are relatively straightforward to use by operators who are experienced doing vascular procedures in the brain, but they don’t deliver this treatment by themselves. You need a team that is focused on doing it quickly, and that will be the kind of training we’ll need to roll out this treatment broadly. We achieved it for stroke thrombolytic treatment through the Target Stroke program (JAMA 2014;311:1632-40), so we know that we can achieve this sort of goal. Delivering embolectomy requires more people and more technology than thrombolysis, but it is not rocket science; it just needs a system.

Dr. Lee H. Schwamm

Embolectomy will not replace routine thrombolysis treatment; it will piggyback on top of it. The percentage of patients with a proximal occlusion in a large artery is relatively small. The results we have seen suggest that using embolectomy plus thrombolysis has no adverse-effect downside, compared with thrombolysis alone. Once routine use of embolectomy becomes established, we can directly compare catheter treatment only against combined embolectomy and thrombolysis. My impression today is that what we’d compare is transporting stroke patients directly to a center that can perform embolectomy against taking patients to the closest center that can treat them with thrombolysis and then transporting them to the center that performs embolectomy.

The results of these three new studies plus the previously-reported results from MR CLEAN are not exactly a game changer, because many centers were already performing embolectomy but in a limited way. Now we have the data to give us confidence to do it routinely and to know which patients to select for embolectomy. Because many centers are already doing this, it will not take 5 years to diffuse the technology.

Embolectomy is already a treatment cited in the guidelines, but now it will be a level 1A recommendation.
The significance of the new reports is that they will have a dramatic impact on public health systems and in the triage of patients with stroke. It will affect how patients get triaged, and will allow us to identify which patients should go to which centers. I believe we will soon develop clinical examination tools that will allow prehospital providers to discern patients with mild strokes who can go to the nearest center that can administer thrombolysis and which patients need to go to comprehensive centers that can perform embolectomy. We now need to do what we did for thrombolysis, and help centers develop the expertise to do embolectomy as a team and to shave minutes off the delivery at every step of the process. It’s clear that it is the time from stroke onset to getting the artery open that is the key to improved patient outcomes.

If I have my way, we will launch later this year a big effort to focus on improving embolectomy delivery. Now that we know for certain that it works we need to turn the crank and make sure that as many patients as possible who qualify get this treatment.

Dr. Lee H. Schwamm is professor of neurology at Harvard Medical School, and director of acute stroke services at Massachusetts General Hospital, both in Boston. He is a consultant to Penumbra and has received research support from Genentech. He made these comments in an interview.


 

AT THE INTERNATIONAL STROKE CONFERENCE

References

The trial led by Dr. Saver, SWIFT-PRIME (SOLITAIRE™ FR With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke), enrolled 195 patients at 39 sites in the United States and in Europe. At 90 days after treatment, 59 patients (60%) among those treated with thrombolysis plus embolectomy had a modified Rankin Scale score of 0-2, compared with 33 patients (36%) among those treated only with thrombolysis (in this trial intravenous treatment with tissue plasminogen activator), a highly significant difference for the study’s primary endpoint.

Dr. Kyra J. Becker Mitchel L. Zoler/Frontline Medical News

Dr. Kyra J. Becker

“For every two and half patients treated, one more patient had a better disability outcome, and for every four patients treated, one more patient was independent at long-term follow-up,” Dr. Saver said. Safety measures were similar among patients in the study’s two arms.

The EXTEND-IA results showed a 90-day modified Rankin Scale score of 0-2 in 52% of the embolectomy patients, compared with 28% of those treated only with thrombolysis. The study’s co–primary endpoints were median level of reperfusion at 24 hours after treatment, 100% with embolectomy and 37% with thrombolysis only, and early neurologic recovery, defined as at least an 8-point drop from the baseline in the National Institutes of Health Stroke Scale score or a score of 0 or 1 when assessed 3 days after treatment. Patients met this second endpoint at an 80% rate with embolectomy and a 37% rate with thrombolysis only. Results of EXTEND-IA appeared in an article published online concurrently with the meeting report (N. Engl J. Med. 2015 Feb. 11 [doi:10.1056/NEJMoa1414792]).

The third, and largest, of the three studies presented at the conference, ESCAPE (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times), enrolled 316 patients at 11 centers in Canada, 6 in the United States, 3 in South Korea, and 1 in Ireland. After 90 days, 53% of patients in the embolectomy arm had achieved a modified Rankin Scale score of 0-2, this study’s primary endpoint, compared with 29% of patients in the thrombolysis-only arm (treatment with alteplase). These results also appeared in an article published online concurrently with the conference report (N. Engl. J. Med. 2015 Feb. 11 [doi:10.1056/NEJMoa1414905]).

SWIFT PRIME was sponsored by Covidien, which markets the stent retriever used in the study. Dr. Saver and Dr. Goyal are consultants to Covidien. EXTEND-IA used stent retrievers provided by Covidien. ESCAPE received a grant from Covidien. Dr. Becker had no relevant disclosures.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

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