EuroScore II is the best predictive model for the off pump coronary artery bypass graft surgery

Abstract

Abstract Background Coronary artery bypass graft surgery (CABG) is the most common cardiac surgery performed in the world and a significant part of these surgeries are performed without cardiopulmonary bypass (off pump). Although none of the main surgical risk scores include pump use in their prediction model, the scores are widely used in risk stratification, including for patients who will be submitted to off pump CABG. Purpose To analyse and compare the predictive accuracy of EuroScore I, EuroScore II and STS Score for 30-day mortality after off pump CABG. Methods Single-centre cohort with 943 patients consecutively submitted to off pump CABG between January 2010 and December 2020. 31 baseline and operative variables were analysed. The primary outcome was the occurrence of death in the first 30 days after the surgery. Descriptive analysis, normality for quantitative data and univariate inference were performed to compare proportions and means between the survival group (n=930) and death group (n=13). Next, three logistic regression models were performed. Each of them had 30-day mortality as a dependent variable and one of the scores as an independent variable. The probabilities generated by the three models were saved and analysed by ROC curves. Thus, it was possible to assess the predictive accuracy of each of the scores. Finally, the values of the areas under the curves were compared using the DeLong test. The level of significance was 5% and the analysis was performed using the Python 3.0 programming language. Results The mean age of the general group was 63 years old and there was a predominance of male patients (68.4%). The means of the three evaluated risk scores were significantly higher in the Death group (p<0,05). This pattern confirmed the findings of higher prevalence of several comorbidities in the death group. The 30-day mortality rate was 1.37%. Through the analysis of regressions and the probabilities generated through them, it was possible to verify that the predictive accuracy of EuroScore II was significantly higher than that of the other two scores. While the predictive accuracy of EuroScore II was 77.3%, the accuracy of two other scores was in the range of 69% (AUC EsI: 0.697; AUC EsII: 0.773; AUC STS: 0.695; p=0.029). Conclusion EuroScore II seems to be the most adequate surgical risk score for the assessment of mortality risk of patients who will undergoing to off pump CABG. The score had a predictive accuracy of 77.3%, almost 8% more than the other two scores. Therefore, although EuroScore II does not include in its model the use of cardiopulmonary bypass, it has a satisfactory accuracy to be used in clinical-surgical practice. On the other hand, the EuroScore I and the STS Score showed predictive accuracy not adequate for this type of surgery. Funding Acknowledgement Type of funding sources: None. Predictive accuracies of risk scores