title: Mechanical Thrombectomy of M2-Occlusion.
abstract: BACKGROUND
  There is growing evidence for the efficacy of mechanical thrombectomy in acute stroke patients with large-vessel occlusions in the anterior circulation. Although distal occlusions of the middle cerebral artery (MCA) can cause severe clinical symptoms, endovascular therapy is not considered here as the first choice. The aim of our study was to prove the efficacy and safety of mechanical thrombectomy for distal occlusion types in the anterior circulation (M2-segment).
  
  
  METHODS
  Stentretriever-based thrombectomy was performed in 119 patients with acute MCA occlusions between October 2011 and April 2013: 104 (87.4%) were M1- and 15 (12.6%) M2-occlusions. These groups were compared with regard to recanalization success, periprocedural complications, hemorrhage, and modified Rankin Scale (mRS) at 90 days.
  
  
  RESULTS
  Thrombolysis in cerebral infarction 2b/3 reperfusion was more frequent in M2- than in M1-occlusions (93.3% versus 76.0%; P = .186). There was no significant difference in the mean National Institutes of Health Stroke Scale between the M1- and the M2-group both at admission and at discharge (16.18 ± 7.30 versus 13.73 ± 8.30, P = .235; 9.36 ± 8.60 versus 7.43 ± 9.84, P = .446). A good clinical outcome (mRS 0-2) at 3 months was more frequent in the M2-group (60% versus 43.3%; P = .273) and mortality was higher in the M1-group (21.2% versus 6.7%; P = .297). There were 3 periprocedural complications in the M1- and none in the M2-group.
  
  
  CONCLUSIONS
  Endovascular treatment of M2-occlusions in severely affected patients is not associated with a higher procedural risk or postprocedural hemorrhage. Compared with M1-occlusions, there was a greater chance for a good angiographic and clinical result in our case series. Therefore, stentretriever-based thrombectomy should also be considered for patients with severe symptoms because of an acute M2-occlusion.
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany. Electronic address: franziska.dorn@uk-koeln.de.
authors.forename: Franziska
authors.initials: F
authors.lastname: Dorn
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Hannah
authors.initials: H
authors.lastname: Lockau
authors.affiliation: Department of Neurology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Stetefeld
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kabbasch
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Kraus
authors.affiliation: Department of Neurology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Dohmen
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Henning
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Mpotsaris
authors.affiliation: Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Liebig
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D004185:Disability Evaluation; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000503:physiopathology*; D018579:Patient Selection; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015607:Stents; D017131:Thrombectomy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
keywords: M2; MCA; Mechanical thrombectomy; endovascular; stentretriever