The Society of Thoracic Surgeons Mitral Valve Repair/Replacement Plus Coronary Artery Bypass Grafting Composite Score: A Report of The Society of Thoracic Surgeons Quality Measurement Task Force

Background The Society of Thoracic Surgeons (STS) Quality Measurement Task Force has developed a composite performance measure for mitral repair/replacement (MVRR) with concomitant coronary artery bypass grafting (CABG). Methods Data were acquired from the STS Adult Cardiac Surgery Database for 26,463 patients undergoing MVRR + CABG operations between July 1, 2011, and June 30, 2014. Established STS risk models were applied, along with modifications enabling the inclusion of patients with concomitant closures of atrial septal defects and patent foramen ovale, surgical ablation for atrial fibrillation, and tricuspid valve repair (TVR). Participants with fewer than 10 eligible cases over 3 years were excluded. The MVRR + CABG composite consisted of two domains: risk-adjusted mortality and the any-or-none occurrence of major morbidity (prolonged ventilation, deep sternal infection, permanent stroke, renal failure, and reoperation). Composite performance scores were calculated with the use of hierarchic regression models, and high-performing and low-performing outliers were determined with the use of 95% Bayesian credible intervals. Results There were 24,740 patients at 703 participant sites after exclusions. Two percent (14/703) of programs were classified as 1-star (lower than expected performance), 95% (666/703) were classified as 2-star (as-expected performance), and 3% (23/703) were classified as 3-star (higher than expected performance). The average unadjusted operative mortality was 6.2% (1,532/24,740), and a monotonic decline in both mortality and morbidity was observed as star rating scores increased. Conclusions An STS composite performance measure was developed for MVRR + CABG operations. This measure may be useful for outcome assessment, quality improvement, patient counseling, clinical research, and public reporting.