At 2 years, the distribution of functional outcomes was superior among those who got endovascular therapy as opposed to standard tPA thrombolysis (median score of 3 versus 4 on the modified Rankin scale [mRS], adjusted common OR 1.68, 95% CI 1.15-2.45), according t0 Yvo B.W.E.M. Roos, MD, PhD, of Academic Medical Center in the Netherlands, and colleagues.
These patients were also more likely to have a good outcome at 2 years (mRS scores 0-2; 37.1% versus 23.9%, adjusted OR 2.21, 95% CI 1.30-3.73), the group reported Wednesday in the New England Journal of Medicine.
That said, there was no differences between groups for the odds of patients achieving excellent outcomes (mRS score 0 or 1; 7.2% versus 6.1%, adjusted OR 1.22, 95% CI 0.53-2.84). On top of that, cumulative 2-year mortality rates were similar between groups: 26.0% for the intervention arm and 31.0% for the control arm (adjusted HR 0.9, 95% CI 0.6-1.2), reported
Average quality-of-life scores did favor thrombectomy recipients, however: 0.48 versus 0.38 based on a European Quality of Life-5 Dimensions questionnaire (P=0.006).
"The results of the extended follow-up evaluation of the MR CLEAN trial showed that endovascular treatment in patients with acute ischemic stroke resulted in functional recovery, as measured on the mRS, that was similar to the originally reported results at 90 days," the authors concluded.
They recalled that the OR for better scores on the mRS in the endovascular group was 1.67 at 90 days, compared with the OR of 1.68 at 2 years.
"The findings of this publication are in line with what would be expected," commented David Liebeskind, MD, of the University of California Los Angeles, who was not involved with MR CLEAN.
"I think the novelty in these findings is that intervention for an acute problem can affect long-term outcomes," he told MedPage Today in a telephone interview. "People do live for years after and free of further disability. You are actually addressing the problem head on at the time."
When asked if the literature on mechanical thrombectomy is sufficient yet to judge its safety and effectiveness, Liebeskind responded: "Absolutely."
"The data collectively over the last several years have demonstrated not just technical success, but clinical success in terms of safety and effectiveness, with an effect size and number-needed-to-treat that is almost more powerful than any other intervention in medicine ... These are sustainable results."
Two-year data were available for 78.2% of the 500 patients randomized to endovascular or standard therapy in the original MR CLEAN trial. The choice of endovascular treatment -- intraarterial thrombolysis and/or mechanical thrombectomy -- was left to the discretion of the interventionist. Ultimately, 83.7% of the endovascular therapy arm got mechanical treatment.
Among other limitations of the study was the fact that Roos' dataset wasn't powered for 2-year analysis. In addition, patients whose data were missing had worse baseline characteristics and were more likely to have been assigned to the control group, indicative of potential selection bias.
Liebeskind noted that his remaining questions regarding mechanical thrombectomy have to do with how different delivery methods compare.
Furthermore, "one of the issues that wasn't addressed in the article is you've achieved certain outcomes in patients at 90 days but from 90 days to 2 years and beyond, it's likely that secondary stroke prevention measures are important as well. Although the focus is on acute intervention, these people have strokes in the first place for different reasons" such as atrial fibrillation, he commented.
"At least in this cohort, there was recognition about cause of stroke and likely effect of preventative measures added as well. There is a preventive benefit hidden in these results -- not because thrombectomy does anything from a prevention standpoint, but the success with these individuals allows physicians to implement prevention practices going forward ... The acute treatment lends itself (under excellent conditions) to rapid prevention measures as well."
"That's important because ultimately what we care about is long-term outcomes, not just putting a band-aid on it," he emphasized.
Roos reported grant support from The Netherlands Organisation for Health Research and Development and the Dutch Heart Foundation.
Several co-authors disclosed relevant relationships with industry.
Liebeskind declared consulting to Medtronic and Stryker.
- Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner
New England Journal of MedicineSource Reference: van den Berg LA, et al "Two-year outcome after endovascular treatment for acute ischemic stroke" New Engl J Med 2017; DOI: 10.1056/NEJMoa1612136.