Comparison of risk scores for predicting outcomes after isolated tricuspid valve surgery

Background Risk models play important roles in stratification and decision-making towards cardiac surgery. Isolated tricuspid valve surgery is a high risk but increasingly performed the operation, however, the performance of risk models has not been externally evaluated in these patients. We compared the prognostic utility of contemporary risk scores for isolated tricuspid valve surgery. Methods Consecutive patients undergoing isolated tricuspid valve surgery at Cleveland Clinic during 2004-2018 were evaluated in this cohort study. EuroSCORE II, Society of Thoracic Surgeon's tricuspid (STS-TVS) score, and the Model for End-stage Liver Disease (MELD) score were retrospectively calculated, and their performance for predicting operative mortality, postoperative complications, and mortality during follow-up was assessed. Results Amongst 207 patients studied, the mean age was 54.1 +/- 17.9 years, 116 (56.0%) were female, 92 (44.4%) had secondary tricuspid regurgitation, and 151 (72.9%) had a surgical repair. Mean EuroSCORE II, STS-TVS, and MELD scores were 6.3 +/- 6.6%, 5.5 +/- 6.2%, and 9.8 +/- 4.7, respectively. C-statistics (95% confidence intervals) for operative mortality were 0.83 (0.74-0.93) for EuroSCORE II, 0.60 (0.45-0.75) for STS-TVS score, and 0.74 (0.58-0.89) for MELD score, while observed/expected ratios were 0.78 and 0.89 for the first two scores. All three scores were associated with mortality during follow-up and discriminated most postoperative complications. Conclusion EuroSCORE II was superior to STS-tricuspid score for isolated TVS risk assessment. Although surgical risk scores traditionally underestimated operative mortality after isolated tricuspid valve surgery, they did not in our cohort, reflecting the excellent surgical results. The simple MELD score performed similarly to the EuroSCORE II, especially for discriminating morbidities.