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

Abstract

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