The Society of Thoracic Surgeons Isolated Aortic Valve Replacement (AVR) Composite Score: A Report of the STS Quality Measurement Task Force

Background Risk-standardized mortality rates provide a valuable but incomplete assessment of provider performance. Consequently, The Society of Thoracic Surgeons (STS) previously developed a multidimensional composite quality measure for coronary artery bypass grafting, the most frequently performed cardiac surgical procedure. The current study creates a similar composite measure for isolated aortic valve replacement (AVR). Methods Because there are few widely accepted process measures for AVR, the STS AVR composite score is based solely on outcomes, including risk-standardized mortality and any-or-none risk-standardized morbidity (occurrence of sternal infection, reoperation, stroke, renal failure, or prolonged ventilation). Isolated AVR is performed less frequently than coronary artery bypass grafting, and 1 year of data provided inadequate sample sizes for profiling. Therefore, we investigated observation periods of 3 years (July 1, 2007, to June 30, 2010: 67,138 records, 2,082 deaths, and 11,962 morbidity events) and 5 years (July 1, 2005, to June 30, 2010: 101,269 records, 3,123 deaths, and 17,514 morbidity events). We also compared results using 90%, 95%, and 98% credible intervals, corresponding to 95%, 97.5%, and 99% Bayesian probabilities, to determine “star ratings.” Results Differences between 3-year and 5-year results were small; the former was chosen because this time frame provides more current and relevant data. Using 3 years of data and 95% credible intervals, adjusted mortality and morbidity rates varied threefold from highest performing (3 stars) to lowest performing (1 star) programs. Approximately 3% of participants were 1-star, 6% were 3-star, and 91% were 2-star programs. Conclusions STS has developed a composite mortality and morbidity outcomes measure for isolated AVR to be used in quality assessment, provider feedback, public reporting, and performance improvement.