Dutch study shows major functional benefit among stroke patients from clot removal or dissolution

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cerebral circulationA new report in the New England Journal of Medicine from The Netherlands shows that rapid intra-arterial intervention, using either a recoverable stent (mechanical removal) or dissolution via a clot-busting drug, yielded significant functional improvement compared to usual care in a large group of patients with a severe type of stroke.

The Dutch investigators of the MR CLEAN trial Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands recruited 500 patients from 15 Dutch medical centers who had suffered from an anterior circulation stroke - the type of stroke that occurs when a major artery that carries blood to the brain is blocked. To be involved in this study, the blocked artery would have to be one of the internal carotid, the middle cerebral, or the anterior cerebral artery. All patients received intravenous clot-busting drug, alteplase, as part of usual care; somewhat over half (267 out of 500) were randomly assigned to also get intra-arterial intervention: these comprised the study group, while the 233 patients who got only usual care were the controls. The average age of the entire group was 65; to be eligible, they had to receive the initial intravenous (IV) treatment within 4 ½ hours of symptom onset, and to be acceptable for the intra-arterial (IA) treatment within 6 hours, if they were randomized to that arm of the study.

The outcome measure was functional abilities 90 days post-stroke. The study group (who received both the IV and IA treatments) had a significantly better functional status almost twice as improved by the authors measurement criteria at that point than the control group did.

An editorial accompanying the study, by Werner Hacke, M.D., Ph.D. of the Heidelberg University Hospital Neurology Dept., had this comment: The lessons of these [prior, equivocal] studies were that trials of intraarterial treatment should enroll patients with severe strokes, have proof of proximal vessel occlusion, initiate treatment as early as possible, and use modern thrombectomy devices. The results of the first such trial now appear in the Journal ¦[W]hat does this first positive thrombectomy trial mean for interventional treatment? Is there any doubt left, or should thrombectomy now become the new standard treatment for severe stroke with proximal large-vessel occlusion up to 6 hours after stroke onset?....We need and will get results from other well-designed trials, not only to confirm or refute the results of MR CLEAN but also to look at effects in subgroups (according to stroke severity, occlusion site, or time to treatment initiation), for which most single trials are underpowered. MR CLEAN is the first step in the right direction.