Intraarterial Treatment May Be Successful Against Acute Ischemic Stroke Six Hours After Onset

For patients suffering from acute ischemic stroke caused by a proximal intracranial occlusion of the anterior circulation, intraarterial treatment administered within six hours after the stroke’s onset may be effective and safe, according to a study published Dec. 17 in the New England Journal of Medicine.

Despite demonstrating highly effective outcomes for emergency revascularization, intraarterial therapy has encountered a number of neutral results in recent randomized, controlled trials, contributing to uncertainty in regards to its true efficacy. Attempting to prove the procedure’s true beneficial effect on functional outcome, Olvert Berkhemer, MD, Department of Radiology, Sint Lucas Andreas Hospital, Amsterdam, and his co-authors launched the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) overseeing the enrollment of 500 patients at 16 medical centers in the Netherlands, and randomly assigning subjects to either intraarterial treatment plus usual care or usual care alone (n=233 and 267, respectively). With a mean age of 65 years (range, 23 to 96), 445 patients (89 percent) were treated with intravenous alteplase before randomization and retrievable stents were utilized in 190 of the 233 patients (81.5 percent) assigned to intraarterial treatment.

With an adjusted odds ratio of 1.67 (95 percent confidence interval [CI], 1.21 to 2.30), results showed there to be an absolute difference of 13.5 percentage points (95 percent CI, 5.9 to 21.2) in the rate of functional independence (modified Rankin score, 0 to 2) in favor of the intervention (32.6 percent vs. 19.1 percent). The data also showed there to be no significant differences in mortality or the occurrence of symptomatic intracerebral hemorrhage.

The authors conclude that their results show that “patients with acute ischemic stroke caused by a proximal intracranial arterial occlusion of the anterior circulation have a benefit with respect to functional recovery when intraarterial treatment is administered within six hours after stroke onset. This treatment leads to a clinically significant increase in functional independence in daily life by three months, without an increase in mortality.”

In a commenting editorial analysis of the study, Werner Hacke, MD, PhD, writes “what 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 six hours after stroke onset? Several similar trials are ongoing; it is premature to conclude that there is no longer equipoise regarding thrombectomy. 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.”

Keywords: Cerebral Hemorrhage, Infusions, Intra-Arterial, Stents, Stroke, Thrombectomy, Time-to-Treatment, Tissue Plasminogen Activator

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