MR CLEAN trial published - a positive randomized trial of intraarterial treatment for acute ischemic stroke

Today the New England Journal of Medicine published online first the results of the MR CLEAN trial from the Netherlands. Results. 500 patients were enrolled in the Netherlands (233 assigned to intraarterial treatment and 267 to usual care alone). The authors found an absolute difference of 13.5 percentage points in the rate of functional independence (modified Rankin score, 0 to 2) in favor of the intervention (32.6% vs. 19.1%). There were no significant differences in mortality or the occurrence of symptomatic intracerebral hemorrhage.

This marks for the first time that a trial incorporated the lessons from previous studies where detailed analysis suggested 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.

While encouraging it is important to remember that several similar trials are ongoing which will not only aid to confirm or reject the results of MR CLEAN but also allow us to examine subgroups for which most single trials are underpowered. Nevertheless MR CLEAN is an important result and undoubtedly for most endovascular neurosurgeons an important step in the right direction.