Comparison of Endovascular Treatment with Intravenous Thrombolysis for Isolated M2 Segment of Middle Cerebral Artery Occlusion in Acute Ischemic Stroke.

Background: The benefit of endovascular treatment for distal large artery ischemic occlusions such as M2 segment of middle cerebral artery is not clear.

Methods: We retrospectively analyzed data from 51 subjects who had an isolated M2 segment occlusion on baseline computed tomographic (CT) angiogram who were randomized to either intravenous (IV) recombinant tissue plasminogen activator (rt-PA) followed by endovascular treatment or IV rt-PA alone in a multicenter trial. We determined the effect of endovascular treatment on occurrence of excellent [mRS (modified Rankin scale) scores of 0-1] functional outcomes at three months and any death within 3 and 12 months. We also performed proportional odds logistic regression analysis to compare the distribution of mRS scores between the two groups. Each of the analyses was adjusted for age, baseline Alberta stroke program early CT score strata, and baseline National Institutes of Health Stroke scale score strata.

Results: At three months, the rate of excellent functional outcome (38.2% versus 17.6%, unadjusted odds ratio 2.9; 95% confidence interval ; 0.7-12.1;  p  = 0.15) was non-significantly higher among subjects with M2 segment occlusion who were randomized to endovascular treatment. In multivariate analysis, the odds of excellent functional outcome at three months were non-significantly higher among subjects who were randomized to endovascular treatment at three months (OR 2.7; 95% CI; 0.6-13.6;  p = 0.22). There was a trend toward lower disability grades in subject randomized to endovascular treatment when distribution of the mRS score at three months were compared (common OR 2.6; p = 0.084), adjusting for potential confounders. The rates of any death within 3 (adjusted OR 0.1; 95% CI; 0.1-0.8; p = 0.031) and within 12 months (adjusted OR 0.1; 95% CI; 0.1-0.7; p = 0.022) were significantly lower among those who were randomized to endovascular treatment.

Conclusion: In this post-hoc analysis, acute ischemic stroke subjects who had isolated M2 segment occlusion randomized to endovascular treatment appeared to have lower mortality and a trend toward lower grades of disability.