title: Impact of hospital volume on long-term neurological outcome in patients undergoing carotid artery stenting.
abstract: BACKGROUND
  The impact of hospital volume on long-term outcome after carotid artery stenting (CAS) remains unknown.
  
  
  OBJECTIVE
  We designed a nationwide cohort study to elucidate the impact of hospital volume on the incidence of stroke after CAS.
  
  
  METHODS
  The Taiwan National Health Insurance Research database was used to identify all patients admitted for CAS from 2008 to 2012. We defined high-volume hospitals as those performing more than 20 CAS per year. The primary outcome was new ischemic stroke after discharging from the index CAS. Propensity score-matching was performed to create two matched groups for comparison.
  
  
  RESULTS
  A total of 3,248 patients underwent 3,576 CAS procedures were enrolled. There were 56 hospitals performing CAS during the study period. Among these 3,248 patients, 2,226 (68.5%) were performed in high-volume hospitals. A propensity score-matching created two groups with 1,000 patients in each group. During a median of 2.06 years follow-up, 35 (3.5%) and 52 (5.2%) patients in high-volume hospitals and low-volume hospitals developed new ischemic stroke 30 days after discharging from the index CAS, respectively (for low-volume hospitals, HR 1.50, 95%CI 1.06-2.12, P = 0.023). The use of embolic protection device did not result in different periprocedural or postdischarge strokes. The periprocedural (within 30 days after CAS) ischemic stroke or all-cause mortality rates during follow-up period were similar between two groups.
  
  
  CONCLUSIONS
  CAS performed in high-volume hospitals was associated with less new ischemic stroke after discharging from the index CAS, compared to those in low-volume hospitals. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chi-Sheng
authors.initials: CS
authors.lastname: Hung
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chih-Fan
authors.initials: CF
authors.lastname: Yeh
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Mao-Shin
authors.initials: MS
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ying-Hsien
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ching-Chang
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hung-Yuan
authors.initials: HY
authors.lastname: Li
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hsien-Li
authors.initials: HL
authors.lastname: Kao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D002545:Brain Ischemia / Q000175:diagnosis / Q000401:mortality; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D016009:Chi-Square Distribution; D016208:Databases, Factual; D005260:Female; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D016016:Proportional Hazards Models; D012307:Risk Factors; D015607:Stents; D020521:Stroke / Q000175:diagnosis / Q000401:mortality; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome
keywords: carotid artery disease; cerebrovascular disease; health care outcomes; intervention