December 17th, 2014
Dutch Trial Gives Support to Thrombectomy for Ischemic Stroke
A large new trial provides the first substantial evidence that thrombectomy may be beneficial in patients with acute ischemic stroke. Previous thromboectomy trials have been disappointing; some experts have speculated this may be due to the use of early-generation devices, long treatment delays, and difficulties in recruiting suitable patients into the trials.
The Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN), published in the New England Journal of Medicine, was designed to address the limitations of previous trials. Some 500 patients with ischemic stroke were randomized to usual care or the addition of intraarterial treatment within 6 hours of symptom onset. Ninety percent of patients in both groups received intravenous alteplase before randomization. More than 80% of patients in the intraarterial treatment group were treated with a contemporary retrievable stent. Treatment was open label but the endpoint evaluation was blinded.
There were significant differences between the groups in outcomes. For the primary outcome measure, there was a one-point reduction in the modified Rankin scale at 90 days, from 4 in the control group to 3 in the treatment group. Some 32% of patients in the treatment group and 19% of patients in the control group were functionally independent (modified Rankin score, 0-2). The results were consistent across all prespecified subgroups.
There was no difference in mortality between the groups. More patients in the treatment group had clinical signs of a second ischemic stroke in a different vascular territory (5.6% versus 0.4%).
In addition to the use of retrievable stents, the authors speculated that a key factor in the success of intraarterial therapy in their trial was that all patients had a radiologically proven intracranial occlusion.
In an accompanying editorial, Werner Hacke praises the trial as a “first step in the right direction” but believes that it is too early to proclaim thrombectomy “the new standard treatment for severe stroke with proximal large-vessel occlusion up to 6 hours after stroke onset.” Several ongoing trials are still needed, he writes.