Abstract: 【Abstract】 Objective The purpose of present study was to validate externally AKICS score for acute kidney injury (AKI) after cardiac surgery in Chinese elderly patients. Method We conducted a retrospective research in patients undergoing coronary artery bypass grafting surgery and (or) valve replacement at our center between January 1, 2007 and December 31, 2009. The primary outcome was AKI according to RIFLE criteria. The baseline serum creatinine was defined as the latest serum creatinine before surgery. For evaluation of the performance of model, the discrimination and calibration of AKICS score were measured in elderly patients undergoing surgery and patients who did not expose contrast media less than 7 days prior to surgery. Results Among 227 patients included in present study, 141 patients did not expose contrast media less than 7 days before surgery. The incidences of AKI between total elderly patients and patients who did not expose contrast media less than 7 days before surgery were 63.9% (145/227) and 66.7% (94/141), respectively. In total elderly patients, the discrimination of score using the area under the receiver operating characteristic (ROC) curve was 0.702 (95%CI 0.631-0.772); the calibration using Hosmer- Lemeshow goodness- of-fit test was 0.704. And in patients who did not expose contrast media less than 7 days before surgery, the area under ROC was 0.764 (95%CI 0.684-0.844) ; the calibration was 0.906. Conclusion AKICS score offers good performance, accurately predicting AKI according to RIFLE criteria, in elderly patients undergoing cardiac surgery. And this score is more suitable to be used in elderly patients who did not expose contrast media 7 days before cardiac surgery.

Key words: AKICS score, Cardiac surgery, Acute kidney injury, Elderly