Correlation of the EuroSCORE with the onset of postoperative acute kidney injury in cardiac surgery

OBJECTIVE The objective of this study was to assess the correlation between the European System for Cardiac Operative Risk Evaluation (EuroSCORE) score and the risk of developing acute kidney injury in cardiac surgery patients. METHODS This retrospective study was conducted at a tertiary hospital on consecutive cardiac surgery patients (e.g., valvular, ischemic and congenital heart diseases) between October 2010 and July 2011. RESULTS One hundred patients were assessed. Among the 100 patients, six were excluded, including five because of prior kidney disease or dialysis therapy and one because of incomplete medical records. The primary surgical indications were myocardial revascularization in 55 patients (58.5% of cases) and valve replacement in 28 patients (29.8%). According to the EuroSCORE, 55 patients were classified as high risk (58.5%), 27 patients as medium risk (28.7%) and 12 patients as low risk (12.8%). In the postoperative period, patients were classified with the Risk, Injury, Failure, Loss and End-stage kidney disease (RIFLE) score. Among the 31 patients (33%) who displayed an increase in serum creatinine, 18 patients (19.1%) were classified as RIFLE "R" (risk), seven patients (7.4%) were classified as RIFLE "I" (injury) and six patients (6.5%) were classified as RIFLE "F" (failure). Among the patients who were considered to be high risk according to the EuroSCORE criteria, 24 patients (43.6%) showed acute kidney injury. Among the patients who were classified as medium or low risk, acute kidney injury occurred in 18.5 and 16.6% of the cases, respectively. The correlations between risk stratification (low, medium and high) and the EuroSCORE and postoperative RIFLE scores were statistically significant (p=0.03). CONCLUSION In the studied population, there was a statistically significant correlation between the EuroSCORE and the risk of developing acute kidney injury in the postoperative period after cardiac surgery.