title: Institutional volumes and coronary angioplasty outcomes before and after the introduction of stenting.
abstract: BACKGROUND
  An increasing number of patients undergoing percutaneous transluminal coronary angioplasty (PTCA) are receiving coronary stents.
  
  
  OBJECTIVE
  To assess whether the introduction of coronary stenting has changed hospital mortality or same-admission coronary artery bypass grafting (CABG) and whether the hospital's procedure volume affects these outcomes.
  
  
  METHODS
  Observational study using hospital claims.
  
  
  METHODS
  Nonfederal hospitals that performed PTCA in California in 1993 and 1996.
  
  
  METHODS
  35,350 patients who underwent PTCA in 1993 (before the introduction of stenting) and 43,040 patients who had PTCA in 1996 (43% of whom received stents).
  
  
  METHODS
  Hospital stenting volumes for 1996 were divided into terciles; total PTCA procedures per year were categorized as low (< or = 200), medium (201 to 400), or high (> 400). Outcome variables included hospital death and coronary artery bypass grafting (CABG) performed during the same admission. Patients with a principal diagnosis of acute myocardial infarction (AMI) were analyzed separately from those without such a diagnosis.
  
  
  RESULTS
  From 1993 to 1996, the characteristics of patients undergoing PTCA did not change substantially. The use of same-admission CABG decreased by 13% (from 6.0% to 5.2%; P = 0.008) in the AMI group and by 30% (from 3.7% to 2.6%; P < 0.001) in the no-AMI group. Hospital mortality did not change significantly in either group. Procedure volume was not related to hospital mortality. However, rates of same-admission CABG were significantly lower at hospitals with high annual stenting volumes than at low-volume centers (1.3% vs. 2.3% among patients in the no-AMI group; P < 0.001).
  
  
  CONCLUSIONS
  Hospital mortality rates after PTCA have not changed considerably since the introduction and diffusion of coronary stenting. However, rates of same-admission CABG have decreased in recent years and are lowest at hospitals with high procedure volumes.
authors.affiliation: Department of Veterans Affairs and Department of Health Services, University of Washington, USA.
authors.forename: C
authors.initials: C
authors.lastname: Maynard
authors.forename: N R
authors.initials: NR
authors.lastname: Every
authors.forename: M K
authors.initials: MK
authors.lastname: Chapko
authors.forename: J L
authors.initials: JL
authors.lastname: Ritchie
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000706:statistics & numerical data*; D002140:California / Q000453:epidemiology; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data*; D003327:Coronary Disease / Q000401:mortality / Q000601:surgery; D017050:Episode of Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care / Q000706:statistics & numerical data*; D015607:Stents / Q000706:statistics & numerical data*; D013503:Surgery Department, Hospital