[Skip to Content]
[Skip to Content Landing]
Original Investigation
November 2016

Endovascular Therapy for Acute Ischemic Stroke With Occlusion of the Middle Cerebral Artery M2 Segment

Author Affiliations
  • 1University of Texas at Houston Stroke Center, University of Texas Health Foundation, University of Texas Health Science Center, Houston
  • 2Department of Neurology, Kaiser Permanente, Los Angeles, California
  • 3Department of Neurology, Cleveland Clinic Health Foundation, Cleveland, Ohio
  • 4Department of Neurology, Ohio Health Methodist Riverside Hospital, Columbus
  • 5Department of Neurology, University of Tennessee, Memphis
  • 6Department of Neurology, University of Kansas Medical Center, Kansas City
  • 7Department of Neurology, Texas Stroke Institute, Plano
  • 8Department of Neurology, WellStar Hospital, Marietta, Georgia
  • 9Department of Neurology, Saint Louis University Hospital, Saint Louis, Missouri
  • 10Department of Neurosurgery, University of Texas Health Science Center, Houston
  • 11Department of Neurology, Tulane University, New Orleans, Louisiana
JAMA Neurol. 2016;73(11):1291-1296. doi:10.1001/jamaneurol.2016.2773
Key Points

Question  Is endovascular therapy (EVT) superior to best medical management of occlusions of the second (M2) segment of the middle cerebral artery?

Findings  In this retrospective pooled analysis of 522 patients, higher proportions of patients treated with EVT achieved good clinical outcomes measured as independence at 90 days (62.8%) than did those treated with best medical management (35.4%), a statistically significant difference.

Meaning  Endovascular therapy is effective and may be superior to best medical management in occlusions of the M2 segment of the middle cerebral artery.


Importance  Randomized clinical trials have shown the superiority of endovascular therapy (EVT) compared with best medical management for acute ischemic strokes with large vessel occlusion (LVO) in the anterior circulation. However, of 1287 patients enrolled in 5 trials, 94 with isolated second (M2) segment occlusions were randomized and 51 of these received EVT, thereby limiting evidence for treating isolated M2 segment occlusions as reflected in American Heart Association guidelines.

Objective  To evaluate EVT safety and effectiveness in M2 occlusions in a cohort of patients with acute ischemic stroke.

Design, Setting, and Participants  This multicenter retrospective cohort study pooled patients with acute ischemic strokes and LVO isolated to M2 segments from 10 US centers. Patients with acute ischemic strokes and LVO in M2 segments presenting within 8 hours from their last known normal clinical status (LKN) from January 1, 2012, to April 30, 2015, were divided based on their treatment into EVT and medical management groups. Logistic regression was used to compare the 2 groups. Univariate and multivariate analyses evaluated associations with good outcome in the EVT group.

Main Outcomes and Measures  The primary outcome was the 90-day modified Rankin Scale score (range, 0-6; scores of 0-2 indicate a good outcome); the secondary outcome was symptomatic intracerebral hemorrhage.

Results  A total of 522 patients (256 men [49%]; 266 women [51%]; mean [SD] age, 68 [14.3] years) were identified, of whom 288 received EVT and 234 received best medical management. Patients in the medical management group were older (median [interquartile range] age, 73 [60-81] vs 68 [56-78] years) and had higher rates of intravenous tissue plasminogen activator treatment (174 [74.4%] vs 172 [59.7%]); otherwise the 2 groups were balanced. The rate of good outcomes was higher for EVT (181 [62.8%]) than for medical management (83 [35.4%]). The EVT group had 3 times the odds of a good outcome as the medical management group (odds ratio [OR], 3.1; 95% CI, 2.1-4.4; P < .001) even after adjustment for age, National Institute of Health Stroke Scale (NIHSS) score, Alberta Stroke Program Early Computed Tomographic Score (ASPECTS), intravenous tissue plasminogen activator treatment, and time from LKN to arrival in the emergency department (OR, 3.2; 95% CI, 2-5.2; P < .001). No statistical difference in symptomatic intracerebral hemorrhage was found (5.6% vs 2.1% for the EVT group vs the medical management group; P = .10). The treatment effect did not change after adjusting for center (OR, 3.3; 95% CI, 1.9-5.8; P < .001). Age, NIHSS score, ASPECTS, time from LKN to reperfusion, and successful reperfusion score of at least 2b (range, 0 [no perfusion] to 3 [full perfusion with filling of all distal branches]) were independently associated with good outcome of EVT. A linear association was found between good outcome and time from LKN to reperfusion.

Conclusions and Relevance  Although a randomized clinical trial is needed to confirm these findings, available data suggest that EVT is reasonable, safe, and effective for LVO of the M2 segment relative to best medical management.