Predictors of mitral valve repair: clinical and surgeon factors

Background: Mitral valve repair is acknowledged as desirable and superior to replacement for virtually all mitral pathology. Utilizing The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD), a multivariable model was created that included patient clinical characteristics and surgeon-specific mitral volume to predict the likelihood of mitral valve repair.

Methods: Between January 2005 and December 2007, 28,507 patients undergoing isolated mitral valve surgery (with or without tricuspid valve surgery, with or without atrial fibrillation surgery) by 1,088 surgeons at 639 hospitals in the STS ACSD were identified. Patient characteristics independently associated with mitral valve repair were identified using a generalized estimating equations logistic regression model. Observed mitral valve repair rates were plotted against surgeon-specific annual mitral volume, and predicted probabilities of mitral repair by surgeon volume were calculated after adjusting for patient baseline covariates.

Results: On average, patients undergoing mitral valve surgery were 62 years old, with 51% female and 82% Caucasian. Among surgeons performing mitral procedures, the mean rate of mitral valve repair was 41% (range, 0% to 100%) and the median number of mitral valve operations per year was 5 (range, 1 to 166). Several patient characteristics were independently associated with a decreased odds of mitral repair (versus replacement), including mitral stenosis (odds ratio 0.09; 95% confidence interval: 0.08 to 0.11) and active endocarditis (odds ratio 0.21; 95% confidence interval: 0.17 to 0.25). While substantial variability in repair rates was observed among low-volume surgeons, increased surgeon-level mitral volume was independently associated with an increased probability of mitral repair.

Conclusions: This analysis demonstrates marked variability in the frequency of mitral valve repair, and the influence of both patient- and surgeon-level factors on the likelihood of mitral valve repair. Increasing surgeon-specific annual mitral valve volume is associated with a higher probability of mitral repair. Identification of these predictors of mitral valve repair creates substantial opportunity for quality improvement in patient outcomes in mitral valve surgery, potentially through education, adoption of best practices, and improved mitral repair enabling technology.