title: Exploring the volume-outcome relationship for off-pump coronary artery bypass graft procedures.
abstract: BACKGROUND
  The relationship between the surgical case volume and risk-adjusted clinical outcomes has been examined for different surgical specialties. The purpose of this study was to explore the relationship between the off-pump coronary artery bypass graft procedure volumes (OPCABG) with risk-adjusted outcomes within the Department of Veterans Affairs (VA) 44 cardiac surgery programs.
  
  
  METHODS
  Based on VA Continuous Improvement in Cardiac Surgery Program data, the results of 5,076 OPCABG surgical procedures performed between October 1998 and September 2003 were analyzed. Hierarchical logistic regression models evaluated the relationship between OPCABG procedure volume with risk-adjusted 30-day operative mortality, perioperative morbidity, and 180-day mortality. Both a hospital's average OPCABG volume per 6-month period and the hospital's most recent 6-month OPCABG volume were examined.
  
  
  RESULTS
  Hospital OPCABG average volume in a 6-month period ranged from 0.2 to 47.4 procedures; whereas the most recent 6-month OPCABG hospital volume ranged from 0 to 76 OPCABG per site. No relationship between the volume measures and the outcome variables was found.
  
  
  CONCLUSIONS
  We did not find an association between OPCABG volume with short-term mortality, perioperative morbidity, or intermediate-term (180-day) mortality.
authors.affiliation: Eastern Colorado Health Care System, Department of Veterans Affairs Medical Center, Denver, Colorado 80220, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Plomondon
authors.forename: Adrianne W
authors.initials: AW
authors.lastname: Casebeer
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Schooley
authors.forename: Brandie D
authors.initials: BD
authors.lastname: Wagner
authors.forename: Gary K
authors.initials: GK
authors.lastname: Grunwald
authors.forename: Gerald O
authors.initials: GO
authors.lastname: McDonald
authors.forename: Frederick L
authors.initials: FL
authors.lastname: Grover
authors.forename: A Laurie W
authors.initials: AL
authors.lastname: Shroyer
mesh_terms: D000368:Aged; D047549:Coronary Artery Bypass, Off-Pump / Q000401:mortality* / Q000706:statistics & numerical data*; D005260:Female; D006787:Hospitals, Veterans / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012044:Regression Analysis; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome