title: Mechanical thrombectomy in acute stroke: utilization variances and impact of procedural volume on inpatient mortality.
abstract: BACKGROUND
  An increasing number of endovascular mechanical thrombectomy procedures are being performed for the treatment of acute ischemic stroke. This study examines variances in the allocation of these procedures in the United States at the hospital level. We investigate operative volume across centers performing mechanical revascularization and establish that procedural volume is independently associated with inpatient mortality.
  
  
  METHODS
  Data was collected using the Nationwide Inpatient Sample database in the United States for 2008. Medical centers performing mechanical thrombectomy were identified using International Classification of Diseases, 9th revision codes, and procedural volumes were evaluated according to hospital size, location, control/ownership, geographic characteristics, and teaching status. Inpatient mortality was compared for hospitals performing ≥10 mechanical thrombectomy procedures versus those performing<10 procedures annually. After univariate analysis identified the factors that were significantly related to mortality, multivariable logistic regression was performed to compare mortality outcome by hospital procedure volume independent of covariates.
  
  
  RESULTS
  Significant allocation differences existed for mechanical thrombectomy procedures according to hospital size (P<.001), location (P<.0001), control/ownership (P<.0001), geography (P<.05), and teaching status (P<.0001). Substantial procedural volume was independently associated with decreased mortality (P=.0002; odds ratio 0.49) when adjusting for demographic covariates.
  
  
  CONCLUSIONS
  The number of mechanical thrombectomy procedures performed nationally remains relatively low, with a disproportionate distribution of neurointerventional centers in high-volume, urban teaching hospitals. Procedural volume is associated with mortality in facilities performing mechanical thrombectomy for acute ischemic stroke patients. These results suggest a potential benefit for treatment centralization to facilities with substantial operative volume.
authors.affiliation: Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles. Electronic address: peter.adamczyk@med.usc.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Adamczyk
authors.forename: Frank
authors.initials: F
authors.lastname: Attenello
authors.forename: Ge
authors.initials: G
authors.lastname: Wen
authors.forename: Shuhan
authors.initials: S
authors.lastname: He
authors.forename: Jonathan
authors.initials: J
authors.lastname: Russin
authors.forename: Nerses
authors.initials: N
authors.lastname: Sanossian
authors.forename: Arun Paul
authors.initials: AP
authors.lastname: Amar
authors.forename: William J
authors.initials: WJ
authors.lastname: Mack
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000401:mortality / Q000601:surgery*; D002648:Child; D003018:Clot Retraction; D005260:Female; D006276:Health Facility Size / Q000706:statistics & numerical data; D017052:Hospital Mortality; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D010067:Ownership / Q000706:statistics & numerical data; D020521:Stroke / Q000401:mortality / Q000601:surgery*; D017131:Thrombectomy / Q000379:methods* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D055815:Young Adult