Performance of the EuroSCORE in coronary artery bypass graft in Colombia, a middle-income country: A retrospective cohort

BACKGROUND The EuroSCORE II is a globally accepted tool for predicting mortality in patients undergoing cardiac surgery. However, the discriminative ability of this tool in non-European populations may be inadequate, limiting its use in other regions. AIM To evaluate the performance of EuroSCORE II in patients undergoing coronary artery bypass graft (CABG) surgery at a hospital in Bogotá, Colombia. METHODS An observational, analytical study of a retrospective cohort was designed. All patients admitted to Hospital Universitario Mayor Méderi who underwent CABG between December 2015 and May 2020 were included. In-hospital mortality was the primary outcome evaluated. Furthermore, the performance of EuroSCORE II was assessed in this population. RESULTS A total of 1009 patients were included [median age 66 years IQR = 59-72, 78.2% men]. The overall in-hospital mortality was 5.5% (n = 56). The median mortality predicted using EuroSCORE II was 1.29 (IQR = 0.92-2.11). Non-ST-segment elevation myocardial infarction was the most common preoperative diagnosis (54.1%), followed by ST-segment elevation myocardial infarction (19.1%) and unstable angina (14.3%). Urgent surgery was performed in 87.3% of the patients (n = 881). Mortality rates in each group were as follows: Low risk 6.0% (n = 45, observed-to-expected (O/E) ratio, 5.6), moderate risk 3.0% (n = 5, O/E ratio 1.17), high risk 5.0% (n = 4, O/E ratio 0.94), and very high risk 7.6% (n = 2, O/E ratio 0.71). The overall O/E ratio was 4.2. The area under the curve of EuroSCORE II was 0.55 [95% confidence interval: 0.48-0.63] CONCLUSION EuroSCORE II exhibited poor performance in this population owing to its low discriminative ability. This finding may be explained by the fact that the population comprised older individuals with higher ventricular function impairment. Moreover, unlike the population in which this tool was originally developed, most patients were not electively admitted for the surgery.