December 31, 2014
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MR CLEAN: Intra-arterial therapy safe, effective for certain acute ischemic strokes

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Intra-arterial treatment plus usual care within 6 hours of stroke onset was safe and effective in patients with acute ischemic stroke caused by a proximal intracranial arterial occlusion of the anterior circulation.

This finding is in contrast to results of other recent randomized controlled trials that did not report a benefit of intra-arterial treatment, researchers wrote in The New England Journal of Medicine.

The phase 3, multicenter, open-label MR CLEAN study included 500 patients with acute ischemic stroke caused by an intracranial occlusion in the anterior circulation artery that was treatable within 6 hours of symptom onset. The mean age of the patients was 65 years and 58.4% were men. All patients underwent random assignment to usual care (control group, n=267) or usual care plus intra-arterial treatment (intervention group, n=233) from December 2010 to March 2014 at 16 centers in the Netherlands. Intra-arterial treatment included intra-arterial thrombolysis, mechanical therapy or both.

The primary outcome was modified Rankin score at 90 days. Secondary outcomes included NIH Stroke Scale at 24 hours and after 5 to 7 days or discharge, whichever came first, and health-related quality of life at 90 days.

Acute intra-arterial therapy with or without mechanical thrombectomy was performed in 84.1% of the intervention group. Mechanical treatment was performed in 83.7% of the interventional group. Retrievable stents were used in 81.5% of patients. Across the entire cohort, 89% of patients received IV alteplase before randomization.

Overall, the researchers observed significantly better modified Rankin scores in the intervention group (adjusted common OR=1.67; 95% CI, 1.21-2.3). “The shift toward better outcomes in favor of the intervention was consistent for all categories of the modified Rankin scale, except for death,” the researchers wrote. They calculated an absolute between-group difference in the proportion of patients who were functionally independent, as indicated by a modified Rankin score of 0 to 2, of 13.5 percentage points in favor of the intervention group (32.6% vs. 19.1%).

Analysis of all evaluated secondary outcomes favored the intervention, the researchers wrote. NIH Stroke Scale score was an average of 2.9 points lower at 5 to 7 days in the intervention group compared with the control group. Residual occlusion at the target site was also less common (75.4% vs. 32.9%) and infarct volume was lower (between-group difference, 19 mL) in the intervention group among patients with evaluable data.

The two groups had similar rates of serious adverse events during 90 days of follow-up (P=.31). The researchers noted that 5.6% of patients in the intervention group exhibited signs of new ischemic stroke in a different vascular territory compared with 0.4% of the control group. In addition, mortality at 7, 30 or 90 days of follow-up was not significantly different between the two groups.

István Szikora, MD, PhD

István Szikora

“Intra-arterial treatment in patients with acute ischemic stroke caused by a proximal intracranial occlusion of the anterior circulation was effective and safe when administered within 6 hours after stroke onset,” the researchers concluded.

István Szikora, MD, PhD, president of the European Society of Minimally Invasive Neurological Therapy, said in a press release that these findings may “change the practice of acute stroke treatment in this special group of patients.” However, he added, physicians “must make sure that this delicate technique is being used in proper conditions and delivered by properly trained physicians.”

Disclosure: The study was supported by the Dutch Heart Foundation and by unrestricted grants from AngioCare Covidien/ev3, Medac/Lamepro and Penumbra.