Case complexity scores in congenital heart surgery: A comparative study of the Aristotle Basic Complexity score and the Risk Adjustment in Congenital Heart Surgery (RACHS-1) system

Al-Radi, Osman O.; Harrell, Frank E.; Caldarone, Christopher A.; McCrindle, Brian W.; Jacobs, Jeffrey P.; Williams, M. Gail; Van Arsdell, Glen S.; Williams, William G.

doi:10.1016/j.jtcvs.2006.05.071

« Previous Next »The Journal of Thoracic and Cardiovascular Surgery
Volume 133, Issue 4 , Pages 865-875, April 2007

Case complexity scores in congenital heart surgery: A comparative study of the Aristotle Basic Complexity score and the Risk Adjustment in Congenital Heart Surgery (RACHS-1) system

Read at the Eighty-fifth Annual Meeting of The American Association for Thoracic Surgery, San Francisco, Calif, April 10-13, 2005.

Osman O. Al-Radi, MD, MSc
- Hospital for Sick Children, University of Toronto, Toronto, Canada
Frank E. Harrell Jr, PhD
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tenn.
Christopher A. Caldarone, MD
- Hospital for Sick Children, University of Toronto, Toronto, Canada
Brian W. McCrindle, MD, MPH
- Hospital for Sick Children, University of Toronto, Toronto, Canada
Jeffrey P. Jacobs, MD
- The Congenital Heart Institute of Florida, University of South Florida, Saint Petersburg, Fla.
M. Gail Williams
- Hospital for Sick Children, University of Toronto, Toronto, Canada
Glen S. Van Arsdell, MD
- Hospital for Sick Children, University of Toronto, Toronto, Canada
William G. Williams, MD
- Hospital for Sick Children, University of Toronto, Toronto, Canada
- Address for reprints: William G. Williams, MD, 555 University Avenue, Room 1525, Toronto, ON, M5G 1X8, Canada.

Received 20 April 2005; received in revised form 26 April 2006; accepted 17 May 2006. published online 10 March 2007.

Objective

The Aristotle Basic Complexity score and the Risk Adjustment in Congenital Heart Surgery system were developed by consensus to compare outcomes of congenital cardiac surgery. We compared the predictive value of the 2 systems.

Methods

Of all index congenital cardiac operations at our institution from 1982 to 2004 (n = 13,675), we were able to assign an Aristotle Basic Complexity score, a Risk Adjustment in Congenital Heart Surgery score, and both scores to 13,138 (96%), 11,533 (84%), and 11,438 (84%) operations, respectively. Models of in-hospital mortality and length of stay were generated for Aristotle Basic Complexity and Risk Adjustment in Congenital Heart Surgery using an identical data set in which both Aristotle Basic Complexity and Risk Adjustment in Congenital Heart Surgery scores were assigned. The likelihood ratio test for nested models and paired concordance statistics were used.

Results

After adjustment for year of operation, the odds ratios for Aristotle Basic Complexity score 3 versus 6, 9 versus 6, 12 versus 6, and 15 versus 6 were 0.29, 2.22, 7.62, and 26.54 (P < .0001). Similarly, odds ratios for Risk Adjustment in Congenital Heart Surgery categories 1 versus 2, 3 versus 2, 4 versus 2, and 5/6 versus 2 were 0.23, 1.98, 5.80, and 20.71 (P < .0001). Risk Adjustment in Congenital Heart Surgery added significant predictive value over Aristotle Basic Complexity (likelihood ratio χ² = 162, P < .0001), whereas Aristotle Basic Complexity contributed much less predictive value over Risk Adjustment in Congenital Heart Surgery (likelihood ratio χ² = 13.4, P = .009). Neither system fully adjusted for the child’s age. The Risk Adjustment in Congenital Heart Surgery scores were more concordant with length of stay compared with Aristotle Basic Complexity scores (P < .0001).

Conclusions

The predictive value of Risk Adjustment in Congenital Heart Surgery is higher than that of Aristotle Basic Complexity. The use of Aristotle Basic Complexity or Risk Adjustment in Congenital Heart Surgery as risk stratification and trending tools to monitor outcomes over time and to guide risk-adjusted comparisons may be valuable.

CTSNet classification: 20, 21

Abbreviations and Acronyms: ABC, Aristotle Basic Complexity, CI, confidence interval, CVSDB, cardiovascular surgery database, LR, likelihood ratio, OR, odds ratio, RACHS-1, Risk Adjustment in Congenital Heart Surgery, ROC, receiver operator characteristics