Prospective validation of EuroSCORE II in patients undergoing cardiac surgery in Argentinean centres

Abstract

Objectives: The European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) is an updated version of the original EuroSCORE that must be extensively validated. The objective was to prospectively evaluate the efficacy of EuroSCORE II in predicting the immediate results of cardiac surgery in Argentinean centres.

Methods: A prospective consecutive series of 503 adults who underwent cardiac surgery between January 2012 and April 2013 was studied. EuroSCORE II discrimination and accuracy were assessed in the overall cohort and in two surgically defined subgroups: isolated coronary artery bypass graft (CABG) surgery and non-CABG surgery. Additionally, a risk-adjusted cumulative sum control chart analysis was performed.

Results: In-hospital overall mortality rate was 4.17%, while the mortality rate predicted by the EuroSCORE II was 3.18% (P = 0.402). Receiver operating characteristic curve analysis demonstrated a good overall (area 0.856) and non-CABG subgroup (area 0.857) discrimination (P = 0.0001), while discrimination in the CABG subgroup was poorer (area 0.794, P = 0.014). The model showed good calibration in predicting in-hospital mortality, both overall (Hosmer-Lemeshow, P = 0.082) and for each subgroup (non-CABG, P = 0.308, and CABG, P = 0.150).

Conclusions: EuroSCORE II reflects a better current surgical performance and offers a new quality standard to evaluate local outcomes. EuroSCORE showed an overall good discriminative capacity and calibration in this local population; nevertheless, the model performed optimally in non-CABG surgery and in highest-risk patients, underestimating in-hospital mortality in lowest-risk cases. The latter finding may be interpreted as an inadequate behaviour of the model, as a poor performance of surgeons or both. Larger prospective studies will elucidate this hypothesis.

Keywords: Argentina; Cardiac surgery; European System for Cardiac Operative Risk Evaluation II; Operative risk; Validation.