The Society of Thoracic Surgeons Mitral Repair/Replacement 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 is developing a portfolio of composite performance measures for the most commonly performed procedures in adult cardiac surgery. We now describe the fourth in this series, the STS composite measure for mitral valve repair/replacement (MVRR). Methods We examined all patients undergoing isolated MVRR, with or without concomitant performance of tricuspid valve repair, surgical arrhythmia ablation, or repair of atrial septal defect, between July 1, 2011, and June 30, 2014. In this two-domain model, risk-adjusted mortality and any-or-none major morbidity were combined into a composite score using 3 years of STS data and 95% Bayesian credible intervals to estimate composite scores and star ratings. Results There were 61,201 MVRR patients studied at 867 participant sites. Mitral valve repair was performed in 57.4% (35,114 of 61,201) and mitral valve replacement in 42.6% (26,087 of 61,201). Mortality was 2.9% (1,773 of 61,201), and occurrence of any major morbidity was 17.0% (10,381 of 61,201). The median composite score was 93.2% (interquartile range, 92.3% to 94.2%). Star rating classifications included 23 of 867 (2.6%) 1-star programs (lower-than-expected performance), 795 of 867 (91.7%) 2-star programs (as-expected or average performance), and 49 of 867 (5.7%) 3-star programs (higher-than-expected performance). Conclusions STS has developed an MVRR composite performance measure that will be used for participant feedback, quality performance assessment and improvement, and voluntary public reporting.