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More Data Support Mechanical Thrombectomy in Acute Stroke Treatment

Author profile picture By L.A. McKeown

Adding a stent retriever procedure to medical therapy alone reduces disability and increases functional independence in patients with severe stroke who can be treated early, according to a study presented on April 17, 2015, at the European Stroke Organisation Conference in Glasgow, Scotland. 

The findings, which were simultaneously published in the New England Journal of Medicine, confirm the results of several other recent trials of endovascular therapy for stroke in carefully selected patients. Take Home: More Data Support Mechanical Thrombectomy in Acute Stroke Treatment

For the multicenter REVASCAT trial, Antoni Dávalos, MD, of Universitat Autònoma de Barcelona (Barcelona, Spain), and colleagues enrolled 206 acute ischemic stroke patients with proximal anterior circulation occlusion and the absence of a large infarct on neuroimaging who could be treated within 8 hours after symptom onset. Patients were randomized to receive either medical therapy (including intravenous alteplase when eligible) plus endovascular therapy with the Solitaire stent retriever (Covidien) or medical therapy alone. Treatment occurred at 4 study centers in Spain between November 2012 and December 2014.

All had a prestroke functional ability of 1 or less on the modified Rankin scale (mRS) and a baseline score of at least 6 on the NIH Stroke Scale (NIHSS). Median time from stroke onset to randomization was 225 minutes. Baseline characteristics were similar between the 2 groups.

Outcomes Better With Thrombectomy

At 90 days, there was a greater reduction in severity of disability (primary endpoint) with thrombectomy vs medical therapy alone based on the distribution of mRS scores. After adjustment, the odds ratio for improving 1 mRS point was 1.7 (95% CI 1.05-2.80).

Secondary outcomes, including functional independence, also favored thrombectomy (table 1).

  Table 1. Secondary Outcomes

At 90 days, there were no differences between the thrombectomy and control groups for death (18.4% vs 15.5%; P = .60) or symptomatic intracranial hemorrhage (1.9% in each group; P = 1.00).  

Beneficial Paradigm Shift

REVASCAT was initially intended to enroll 690 patients, but enrollment was stopped due to loss of equipoise in December 2014 after 25% of patients had completed 90-day follow-up. Despite the limitations of the small sample size and early termination, the study authors say the data add strength to already released results (MR CLEAN, ESCAPE, EXTEND IA, and SWIFT PRIME, which also was published online by NEJM on April 17) showing improved clinical outcomes with use of endovascular stroke therapy in patients with proximal large-vessel occlusion.

In an editorial accompanying the study, Anthony J. Furlan, MD, of University Hospitals Case Medical Center (Cleveland, Ohio), says the positive results have been accompanied by heightened awareness of the importance of time. SWIFT PRIME, for example, showed that an emergency department door-to-groin puncture time of 90 minutes was possible, although achieving it “requires stroke-workflow efficiencies not yet in place in many hospitals,” Dr. Furlan notes.   

Combined with better technology and rapid demonstration of large-vessel occlusion as part of the standard evaluation, these improvements have continued a “paradigm shift in stroke therapy” that began with the introduction of intravenous t-PA, he observes.

“Stroke infrastructure must now adapt to endovascular therapy. As with intravenous t-PA, only a small percentage of patients with stroke will require endovascular therapy (estimates are 10%), but this small percentage will drive the reorganization of systems of stroke care,” Dr. Furlan writes, adding that “[n]ot every hospital can or should perform endovascular stroke therapy.”

In REVASCAT, participating comprehensive stroke centers treated more than 500 patients with acute stroke and performed more than 60 mechanical stroke thrombectomy procedures annually. In addition, neurointerventionalists were required to have performed at least 20 thrombectomies with the Solitaire device.

“[E]ndovascular stroke therapy has major implications for triaging decisions by emergency medical services, since in cities or regions with both comprehensive stroke centers and primary stroke centers, candidates for endovascular therapy should now be directly transported to a comprehensive stroke center as rapidly as possible,” Dr. Furlan writes.

This sentiment was echoed by Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), in an email with TCTMD.   

“Taking all stroke patients into account, time remains an important viability measure until more specific metrics of collateral blood supply and tissue viability are validated,” he said. 

Dr. Meyers noted that while several stroke trials addressing additional questions are ongoing and more will be forthcoming, REVASCAT and the other studies like it have answered “yes” to the question of whether there is a role for endovascular therapy in carefully selected patients. He added that the trial data already have led to a change in the standards for stroke care, pointing to the recent publication of a multidisciplinary guideline document.

Sources:
1. Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med. 2015;Epub ahead of print.
2. Furlan AJ. Endovascular therapy for stroke—it’s about time [editorial]. N Engl J Med. 2015;Epub ahead of print. 

 

Disclosures:

  • The study was supported by an unrestricted grant from Covidien; a grant from the Spanish Ministry of Health cofinanced by Fondo Europeo de Desarrollo Regional; and a grant from the Generalitat de Catalunya. 
  • Dr. Davalos reports receiving grants and personal fees from Covidien. 
  • Dr. Furlan reports serving on the steering committee of the DAWN trial, sponsored by Stryker. 
  • Dr. Meyers reports no relevant conflicts of interest. 

 

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