title: Determinants of variations in coronary revascularization practices.
abstract: BACKGROUND
  The ratio of percutaneous coronary interventions to coronary artery bypass graft surgeries (PCI:CABG ratio) varies considerably across hospitals. We conducted a comprehensive study to identify clinical and nonclinical factors associated with variations in the ratio across 17 cardiac centres in the province of Ontario.
  
  
  METHODS
  In this retrospective cohort study, we selected a population-based sample of 8972 patients who underwent an index cardiac catheterization between April 2006 and March 2007 at any of 17 hospitals that perform invasive cardiac procedures in the province. We classified the hospitals into four groups by PCI:CABG ratio (low [< 2.0], low-medium [2.0-2.7], medium-high [2.8-3.2] and high [> 3.2]). We explored the relative contribution of patient, physician and hospital factors to variations in the likelihood of patients receiving PCI or CABG surgery within 90 days after the index catheterization.
  
  
  RESULTS
  The mean PCI:CABG ratio was 2.7 overall. We observed a threefold variation in the ratios across the four hospital ratio groups, from a mean of 1.6 in the lowest ratio group to a mean of 4.6 in the highest ratio group. Patients with single-vessel disease usually received PCI (88.4%-99.0%) and those with left main artery disease usually underwent CABG (80.8%-94.2%), regardless of the hospital's procedure ratio. Variation in the management of patients with non-emergent multivessel disease accounted for most of the variation in the ratios across hospitals. The mode of revascularization largely reflected the recommendation of the physician performing the diagnostic catheterization and was also influenced by the revascularization "culture" at the treating hospital.
  
  
  CONCLUSIONS
  The physician performing the diagnostic catheterization and the treating hospital were strong independent predictors of the mode of revascularization. Opportunities exist to improve transparency and consistency around the decision-making process for coronary revascularization, most notably among patients with non-emergent multivessel disease.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ont. tu@ices.on.ca
authors.forename: Jack V
authors.initials: JV
authors.lastname: Tu
authors.forename: Dennis T
authors.initials: DT
authors.lastname: Ko
authors.forename: Helen
authors.initials: H
authors.lastname: Guo
authors.forename: Janice A
authors.initials: JA
authors.lastname: Richards
authors.forename: Nancy
authors.initials: N
authors.lastname: Walton
authors.forename: Madhu K
authors.initials: MK
authors.lastname: Natarajan
authors.forename: Harindra C
authors.initials: HC
authors.lastname: Wijeysundera
authors.forename: Derek
authors.initials: D
authors.lastname: So
authors.forename: David A
authors.initials: DA
authors.lastname: Latter
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Feindel
authors.forename: Kori
authors.initials: K
authors.lastname: Kingsbury
authors.forename: Eric A
authors.initials: EA
authors.lastname: Cohen
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000706:statistics & numerical data*; D006328:Cardiac Catheterization / Q000706:statistics & numerical data; D016507:Cardiology Service, Hospital / Q000706:statistics & numerical data; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data*; D003327:Coronary Disease / Q000175:diagnosis / Q000601:surgery / Q000628:therapy; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D009864:Ontario; D012189:Retrospective Studies; D012720:Severity of Illness Index