Procedural volume as a marker of quality for CABG surgery.

CONTEXT There have been recent calls for using hospital procedural volume as a quality indicator for coronary artery bypass graft (CABG) surgery, but further research into analysis and policy implication is needed before hospital procedural volume is accepted as a standard quality metric. OBJECTIVE To examine the contemporary association between hospital CABG procedure volume and outcome in a large national clinical database. DESIGN, SETTING, AND PARTICIPANTS Observational analysis of 267 089 isolated CABG procedures performed at 439 US hospitals participating in the Society of Thoracic Surgeons National Cardiac Database between January 1, 2000, and December 31, 2001. MAIN OUTCOME MEASURE Association between hospital CABG procedural volume and all-cause operative mortality (in-hospital or 30-day, whichever was longer). RESULTS The median (interquartile range) annual hospital-isolated CABG volume was 253 (165-417) procedures, with 82% of centers performing fewer than 500 procedures per year. The overall operative mortality was 2.66%. After adjusting for patient risk and clustering effects, rates of operative mortality decreased with increasing hospital CABG volume (0.07% for every 100 additional CABG procedures; adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.96-0.99; P =.004). While the association between volume and outcome was statistically significant overall, this association was not observed in patients younger than 65 years or in those at low operative risk and was confounded by surgeon volume. The ability of hospital volume to discriminate those centers with significantly better or worse mortality was limited due to the wide variability in risk-adjusted mortality among hospitals with similar volume. Closure of up to 100 of the lowest-volume centers (ie, those performing < or =150 CABG procedures/year) was estimated to avert fewer than 50 of 7110 (<1% of total) CABG-related deaths. CONCLUSION In contemporary practice, hospital procedural volume is only modestly associated with CABG outcomes and therefore may not be an adequate quality metric for CABG surgery.

[1]  R. Brook,et al.  Regionalization of cardiac surgery in the United States and Canada. Geographic access, choice, and outcomes. , 1995, JAMA.

[2]  H S Luft,et al.  Association of volume with outcome of coronary artery bypass graft surgery —scheduled vs nonscheduled operations , 1987, JAMA.

[3]  A. Sanabria,et al.  Randomized controlled trial. , 2005, World journal of surgery.

[4]  F J Hellinger,et al.  Physician and Hospital Factors Associated With Mortality of Surgical Patients , 1986, Medical care.

[5]  H S Luft,et al.  Effects of Surgeon Volume and Hospital Volume on Quality of Care in Hospitals , 1987, Medical care.

[6]  R. E. Clark,et al.  Practical considerations in the management of large multiinstitutional databases. , 1994, The Annals of thoracic surgery.

[7]  A. Enthoven,et al.  Should operations be regionalized? The empirical relation between surgical volume and mortality. , 1980, The New England journal of medicine.

[8]  Edwards Fh.  Evolution of the Society of Thoracic Surgeons National Cardiac Surgery Database. , 1998 .

[9]  Harold S. Luft,et al.  Association of volume with outcome of coronary artery bypass graft surgery —scheduled vs nonscheduled operations , 1987, JAMA.

[10]  Edwards.  Evolution of the Society of Thoracic Surgeons National Cardiac Surgery Database. , 1998, The Journal of invasive cardiology.

[11]  A. Moskowitz,et al.  Volume-outcome relationships in cardiovascular operations: New York State, 1990-1995. , 1999, The Journal of thoracic and cardiovascular surgery.

[12]  G. Marshall,et al.  No continuous relationship between Veterans Affairs hospital coronary artery bypass grafting surgical volume and operative mortality. , 1996, The Annals of thoracic surgery.

[13]  A L Shroyer,et al.  The STS National Database: current changes and challenges for the new millennium. Committee to Establish a National Database in Cardiothoracic Surgery, The Society of Thoracic Surgeons. , 2000, The Annals of thoracic surgery.

[14]  Laura P Coombs,et al.  The Society of Thoracic Surgeons: 30-day operative mortality and morbidity risk models. , 2003, The Annals of thoracic surgery.

[15]  E. Peterson,et al.  Validity of the Society of Thoracic Surgeons National Adult Cardiac Surgery Database. , 2004, The Annals of thoracic surgery.

[16]  A. Epstein.  Volume and outcome--it is time to move ahead. , 2002, The New England journal of medicine.

[17]  M. Chassin.  Assessing strategies for quality improvement. , 1997, Health affairs.

[18]  N. Draper,et al.  Applied Regression Analysis , 1966 .

[19]  J. Birkmeyer,et al.  Hospital volume and surgical mortality in the United States. , 2002, The New England journal of medicine.

[20]  J. Daley,et al.  Invited commentary: quality of care and the volume-outcome relationship--what's next for surgery? , 2002, Surgery.

[21]  A Milstein,et al.  Selective referral to high-volume hospitals: estimating potentially avoidable deaths. , 2000, JAMA.

[22]  H S Luft,et al.  Selecting Categories of Patients for Regionalization: Implications of the Relationship Between Volume and Outcome , 1986, Medical care.

[23]  J. Lubitz,et al.  Outcomes of surgery among the Medicare aged: Mortality after surgery , 1985, Health care financing review.

[24]  J. Birkmeyer,et al.  Should Volume Standards for Cardiovascular Surgery Focus Only on High-Risk Patients? , 2003, Circulation.

[25]  E. Hannan,et al.  Investigation of the relationship between volume and mortality for surgical procedures performed in New York State hospitals. , 1990, JAMA.

[26]  Chuntao Wu,et al.  Do Hospitals and Surgeons With Higher Coronary Artery Bypass Graft Surgery Volumes Still Have Lower Risk-Adjusted Mortality Rates? , 2003, Circulation.

[27]  M. Chassin.  Assessing Strategics For Quality Improvement , 1997 .

[28]  A. Flood,et al.  Does Practice Make Perfect?: Part II: The Relation Between Volume and and Outcomes and Other Hospital Characteristics , 1984, Medical care.

[29]  E. Hannan,et al.  The decline in coronary artery bypass graft surgery mortality in New York State. The role of surgeon volume. , 1995, JAMA.

[30]  K A Eagle,et al.  The role of hospital volume in coronary artery bypass grafting: is more always better? , 2001, Journal of the American College of Cardiology.

[31]  Clark Re.  Outcome as a function of annual coronary artery bypass graft volume , 1996 .

[32]  J. Birkmeyer,et al.  Volume standards for high-risk surgical procedures: potential benefits of the Leapfrog initiative. , 2001, Surgery.

[33]  J. Lubitz,et al.  Outcomes of surgery among the Medicare aged: Surgical volume and mortality , 1985, Health care financing review.

[34]  Laura P Coombs,et al.  Use of continuous quality improvement to increase use of process measures in patients undergoing coronary artery bypass graft surgery: a randomized controlled trial. , 2003, JAMA.