MR CLEAN Results a Game Changer for Stroke Treatment

Ischemic stroke
Ischemic stroke
Intra-arterial treatment for ischemic stroke produced a significant improvement in functional independence in patients.

The results of the MR CLEAN study are in, and they’re significant. 

Researchers published the results of the highly-anticipated Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands in the New England Journal of Medicine and concluded that intra-arterial treatment is safe and effective for the treatment of ischemic stroke, leaving patients with a significant increase in functional independence three months after treatment.

Treatment with thrombolysis is often ineffective for patients with an occluded major cerebral artery, and so the intra-arterial endovascular approach is an exciting advancement in treatment that can help limit disability in the most serious types of stroke.

The results, first announced at the World Stroke Congress in October, have been extremely well-received by the health-care community. Previous studies on endovascular therapy produced neutral results; however four recent studies with similar endpoints have stopped early because of positive results in endovascular groups.

500 participants were enrolled in the study — 233 patients were assigned to the intra-arterial intervention group and 267 were assigned to the control group, which received usual care, reported Diederik W. J. Dippel, MD, PhD, of Erasmus University Medical Center in Rotterdam, Netherlands, and colleagues.

Actual intra-arterial therapy, with or without mechanical thrombectomy, was performed in 196 of the 233 patients in the intervention group. Retrievable stents were used in 190 patients, and acute cervical carotid stenting was simultaneously performed in 30 patients in the group. The researchers reported a 13.5 percentage-point difference (95% 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% vs. 19.1%). However, there were no significant differences in mortality or the occurrence of symptomatic intracerebral hemorrhage.

Additionally, data on recanalization and infarct volume favored the intervention group and there was no significant group difference in the occurrence of adverse events across the 90-day follow-up period. However, 13 patients in the intervention group showed clinical signs of a new ischemic stroke in a different vascular territory within the follow-up period compared to only 1 patient in the control group.

Medical professionals credit the study’s stringent criteria and advanced technology for its success, including radiological evidence of an occlusion in a major cerebral artery, treatment with endovascular therapy within six hours of symptom onset, and the use of the latest stent retrievers. 


  1. Berkhemer OA et al. N Engl J Med. 2014; doi:10.1056/NEJMoa1411587.