Validation of EuroSCORE II in a modern cohort of patients undergoing cardiac surgery

Abstract

OBJECTIVE: We aimed to validate the new EuroSCORE II risk model in a contemporary cardiac surgery practice in the United Kingdom (UK). METHODS: The original logistic EuroSCORE was compared to EuroSCORE II with regard to accuracy of predicting in-hospital mortality. Analysis was performed on isolated coronary artery bypass grafts (CABG; n = 2913), aortic valve replacement (AVR; n = 814), mitral valve surgery (MVR; n = 340), combined AVR and CABG (n = 517), aortic (n = 350) and miscellaneous procedures (n = 642), and the above cases combined (n = 5576). RESULTS: In a single-institution experience, EuroSCORE II is a reasonable risk model for in-hospital mortality from isolated CABG (C-statistic 0.79, Hosmer-Lemeshow P = 0.052) and aortic procedures (C-statistic 0.81, Hosmer-Lemeshow P = 0.43), and excellent for mitral valve surgery (C-statistic 0.87, Hosmer-Lemeshow P = 0.6). EuroSCORE II is better than the original EuroSCORE, using contemporaneous data for combined AVR and CABG operations (C-statistic 0.74, Hosmer-Lemeshow P = 0.38). However, EuroSCORE II failed to improve on the original EuroSCORE model for isolated AVR (C-statistic 0.69, Hosmer-Lemeshow P = 0.07) and miscellaneous procedures (C-statistic 0.70, Hosmer-Lemeshow P = 0.99). EuroSCORE II has better calibration than the original EuroSCORE or the Society of Cardiothoracic Surgeons of Great Britain and Ireland (SCTS) modified EuroSCORE for cumulative sum survival (CUSUM) curves. CONCLUSIONS: EuroSCORE II improves on the original logistic EuroSCORE, though mainly for combined AVR and CABG cases. Concerns still exist, however, over its use for isolated AVR procedures, aortic surgery and miscellaneous procedures. There is still room for improvement in risk modelling.