title: Effect of operator and institutional volume on clinical outcomes after percutaneous coronary interventions performed in Canada and the United States: a brief report from the Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) study.
abstract: BACKGROUND
  The Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial compared the use of eptifibatide with placebo in 2064 coronary intervention patients. It was previously reported that Canadian patients had reduced rates of 30-day and one-year death, myocardial infarction (MI) or target vessel revascularization (TVR) compared with patients in the United States (US).
  
  
  OBJECTIVE
  To examine whether operator or institutional volume differences explain the regional variation in clinical outcome.
  
  
  RESULTS
  Each site received an operator and institutional volume survey. Fifty-seven sites (62%) returned complete data on 1338 patients. In this smaller cohort, Canadian patients had reduced rates of 30-day and one-year death, MI or TVR compared with US patients (6.3% versus 10.3% and 14.9% versus 20.1%, respectively; P<0.05 for both comparisons). Among 176 physicians with a median of 13 years experience, the median operator volume was 200 cases per year. Operators with fewer than 100 cases per year had higher rates of 30-day death, MI or TVR (13.2% versus 8.7%; P=0.18) and large MI (7.7% versus 3.3%; P=0.06) than those with 100 or more cases per year. The median institutional volume was 1064 cases per year. Canadian and US centres had similar operator and institutional volumes. By multivariate modelling, operator volume was not predictive of adverse clinical events. However, the rates of 30-day and one-year death, MI or TVR fell by 3% for every 100 patients treated by the institution (OR 0.97; P=0.058 and P=0.002, respectively). Enrollment in Canada was associated with improved outcomes at 30 days (OR 0.50; P=0.001) and one year (OR 0.66; P=0.001) despite inclusion of volume variables in the models.
  
  
  CONCLUSIONS
  In the ESPRIT study, institutional volume was associated with a modest reduction in risk of death, MI or TVR over short- and long-term follow-up periods. The Canadian and US investigators and institutions selected in ESPRIT had similar annual procedural volumes. Therefore, volume variables did not explain the differential risk of clinical events observed for patients enrolled in the two countries.
authors: Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. mina.madan@sunnybrook.ca
authors: Mina
authors: M
authors: Madan
authors: Janarthan
authors: J
authors: Nikhil
authors: Anne S
authors: AS
authors: Hellkamp
authors: Karen S
authors: KS
authors: Pieper
authors: Marino
authors: M
authors: Labinaz
authors: E A
authors: EA
authors: Cohen
authors: Christopher E
authors: CE
authors: Buller
authors: Warren J
authors: WJ
authors: Cantor
authors: Peter
authors: P
authors: Seidelin
authors: John
authors: J
authors: Ducas
authors: Ronald G
authors: RG
authors: Carere
authors: Madhu K
authors: MK
authors: Natarajan
authors: J Conor
authors: JC
authors: O'Shea
authors: James E
authors: JE
authors: Tcheng
mesh_terms: D000328:Adult; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects* / Q000706:statistics & numerical data*; D002170:Canada; D003324:Coronary Artery Disease / Q000628:therapy*; D000077542:Eptifibatide; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000627:therapeutic use; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States
chemical_list: D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D000077542:Eptifibatide