title: Case load and valve surgery outcome in Australia.
abstract: BACKGROUND
  In Australia it has been suggested that heart valve surgery, particularly for rheumatic heart disease (RHD), should be consolidated in higher volume centres. International studies of cardiac surgery suggest large volume centres have superior outcomes. However the effect of site and surgeon case load on longer term outcomes for valve surgery has not been investigated.
  
  
  METHODS
  The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed. The adjusted association between both average annual site and surgeon case load on short term complications and short and long-term survival was determined.
  
  
  RESULTS
  Outcomes associated with 20,116 valve procedures at 25 surgical sites and by 93 surgeons were analysed. Overall adjusted analysis showed increasing site and surgeon case load was associated with longer ventilation, less reoperation and more anticoagulant complications. Increasing surgeon case load was also associated with less acute kidney injury. Adjusted 30-day mortality was not associated with site or surgeon case load. There was no consistent relationship between increasing site case load and long term survival. The association between surgeon case load and outcome demonstrated poorer adjusted survival in the highest volume surgeon group.
  
  
  CONCLUSIONS
  In this Australian study, the adjusted association between surgeon and site case load was not simple or consistent. Overall larger volume sites or surgeons did not have superior outcomes. Mandating a particular site case load level for valve surgery or a minimum number of procedures for individual surgeons, in an Australian context, cannot be supported by these findings.
authors.affiliation: Baker IDI, Melbourne, Victoria, Australia. Electronic address: anne.russell@monash.edu.
authors.forename: E Anne
authors.initials: EA
authors.lastname: Russell
authors.affiliation: School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA. Electronic address: Rob.Baker@health.sa.gov.au.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Baker
authors.affiliation: Department of Surgery, School of Medicine, Flinders University, Adelaide, SA, Australia; Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA, Australia. Electronic address: Jayme.Bennetts@health.sa.gov.au.
authors.forename: Jayme S
authors.initials: JS
authors.lastname: Bennetts
authors.affiliation: Wardliparingga Aboriginal Research Unit, South Australia Health and Medical Research Institute, Adelaide, SA, Australia; School of Population Health, University of South Australia, Adelaide, SA, Australia. Electronic address: alex.brown@sahmri.com.
authors.forename: Alex
authors.initials: A
authors.lastname: Brown
authors.affiliation: School of Public Health, Curtin University, Perth, WA, Australia; School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address: christopher.reid@curtin.edu.au.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Reid
authors.affiliation: Department of Cardiothoracic Surgery, Townsville, Hospital, Queensland, Australia. Electronic address: robert.tam@health.qld.gov.au.
authors.forename: Robert
authors.initials: R
authors.lastname: Tam
authors.affiliation: School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Lavinia
authors.initials: L
authors.lastname: Tran
authors.affiliation: Prince of Wales Hospital, Randwick, NSW. Australia. Electronic address: warren.walsh@ehc.com.au.
authors.forename: Warren F
authors.initials: WF
authors.lastname: Walsh
authors.affiliation: Baker IDI, Melbourne, Victoria, Australia; School of Medicine, James Cook University, Cairns, Queensland, Australia; School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address: graeme.maguire@bakeridi.edu.au.
authors.forename: Graeme P
authors.initials: GP
authors.lastname: Maguire
mesh_terms: D000328:Adult; D000367:Age Factors; D001315:Australia / Q000453:epidemiology; D016208:Databases, Factual; D005260:Female; D006349:Heart Valve Diseases / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D000069451:Long Term Adverse Effects / Q000175:diagnosis / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D010043:Outcome and Process Assessment, Health Care; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology; D012307:Risk Factors; D016019:Survival Analysis; D013903:Thoracic Surgery / Q000379:methods / Q000706:statistics & numerical data
keywords: Cardiac surgery; Hospital performance; Indigenous health; Outcome indicators; Rheumatic valve surgery; Volume–outcome relationship