title: Recanalization rates decrease with increasing thrombectomy attempts.
abstract: OBJECTIVE
  Use of the Merci retriever is increasing as a means to reopen large intracranial arterial occlusions. We sought to determine whether there is an optimum number of retrieval attempts that yields the highest recanalization rates and after which the probability of success decreases.
  
  
  METHODS
  All consecutive patients undergoing Merci retrieval for large cerebral artery occlusions were prospectively tracked at a comprehensive stroke center. We analyzed ICA, M1 segment of the MCA, and vertebrobasilar occlusions. We compared the revascularization of the primary AOL with the number of documented retrieval attempts used to achieve that AOL score. For tandem lesions, each target lesion was compared separately on the basis of where the device was deployed.
  
  
  RESULTS
  We identified a total of 97 patients with 115 arterial occlusions. The median number of attempts per target vessel was 3, while the median final AOL score was 2. Up to 3 retrieval attempts correlated with good revascularization (AOL 2 or 3). When >or=4 attempts were performed, the end result was more often failed revascularization (AOL 0 or 1) and procedural complications (P = .006).
  
  
  CONCLUSIONS
  In our experience, 3 may be the optimum number of Merci retrieval attempts per target vessel occlusion. Four or more attempts may not improve the chances of recanalization, while increasing the risk of complications.
authors.affiliation: Division of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. yincer@yahoo.com
authors.forename: Y
authors.initials: Y
authors.lastname: Loh
authors.forename: R
authors.initials: R
authors.lastname: Jahan
authors.forename: D L
authors.initials: DL
authors.lastname: McArthur
authors.forename: Z-S
authors.initials: ZS
authors.lastname: Shi
authors.forename: N R
authors.initials: NR
authors.lastname: Gonzalez
authors.forename: G R
authors.initials: GR
authors.lastname: Duckwiler
authors.forename: P M
authors.initials: PM
authors.lastname: Vespa
authors.forename: S
authors.initials: S
authors.lastname: Starkman
authors.forename: J L
authors.initials: JL
authors.lastname: Saver
authors.forename: S
authors.initials: S
authors.lastname: Tateshima
authors.forename: D S
authors.initials: DS
authors.lastname: Liebeskind
authors.forename: F
authors.initials: F
authors.lastname: Viñuela
mesh_terms: D000328:Adult; D000368:Aged; D002140:California / Q000453:epidemiology; D002539:Cerebral Arterial Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D017131:Thrombectomy / Q000295:instrumentation* / Q000706:statistics & numerical data*; D016896:Treatment Outcome