The 1996 coronary artery bypass risk model: The society of thoracic surgeons adult cardiac national database

Background. The Society of Thoracic Surgeons Adult Cardiac National Database has recently completed the update for the 1996 risk model to be used to estimate the risk of operative death for isolated coronary artery bypass graft (CABG) procedures. Methods. We placed emphasis on clinical relevance, data quality, data completeness, and univariate analyses. A logistic regression approach was used to develop the 1996 CABG-only risk model. Results. Odds ratios for the factors with highest risk are multiple reoperations (OR = 4.3), emergent salvage status (OR = 3.7), and first reoperation (OR = 2.7). Standard performance measures indicated the model had high predictive power and an acceptable level of calibration after adjustment for a large sample size effect. Conclusion. The most current STS risk model of CABG operative mortality is a reliable and statistically valid tool. The 1996 CABG-only model has been approved for use by The Society of Thoracic Surgeons. (Ann Thorac Surg 1999;67:1205-8) (C) 1999 by The Society of Thoracic Surgeons.