Comparison of three contemporary surgical scores for predicting all-cause mortality of patients undergoing percutaneous mitral valve repair with the MitraClip system (from the multicenter GRASP-IT registry)

The aim of this study was to explore the adaptability of 3 contemporary surgical scores (Logistic EuroSCORE [LES], EuroSCORE II [ESII], and Society of Thoracic Surgeons Predicted Risk of Mortality [STS-PROM]) for prediction of mortality after percutaneous mitral valve repair with the MitraClip system. A total of 304 patients from the multicenter Getting Reduction of mitrAl inSufficiency by Percutaneous clip implantation in ITaly registry (GRASP-IT) were stratified based on LES, ESII, and STS-PROM tertiles and analyzed by different measurements of discrimination, calibration, and global accuracy with focus on 30-day and 1-, 2-, and 3-year mortality. A statistically significant gradient in the distribution of mortality was observed at all time points with ESII, at 2 years with LES, and at 2 and 3 years with STS-PROM. ESII had the best discrimination at 30 days (C-statistic 0.80), which remained acceptable at later follow-up, being significantly superior to that of LES at each time point (p = 0.003 at 30 days, p = 0.005 at 1 year, p = 0.011 at 2 years, and p = 0.029 at 3 years). Compared with STS-PROM, ESII showed better discrimination at 30 days (C-statistic 0.80 vs 0.62, p = 0.023). All scores overpredicted the risk of mortality at 30 days and were miscalibrated at 2 and 3 years. At 1 year, there was a good agreement between the observed and predicted probabilities for ESII and STS-PROM, whereas LES remained overpredictive. ESII showed the best global accuracy at 30 days and 1 year, whereas no notable differences were noted versus LES and STS-PROM at 2 and 3 years. In conclusion, lacking specific tools for risk stratification of patients undergoing MitraClip implantation, ESII holds favorable prognostic characteristics, which makes it a valid surrogate.