Acute kidney injury (AKI) is a frequent complication after cardiac surgery. AKI has been reported as 7-40% depending on the type of surgery, and is known to increase to about 50% when there are risk factors. Cardiac surgery-associated AKI (CSA-AKI) requires cardiac replacement therapy in 1-5% of patients and increases mortality to 1,4%, but the treatment is still unknown. Therefore prevention of occurrence is very important.

Known factors related to the development of CSA-AKI include hemodynamic, inflammatory, metabolic, and nephrotoxic factors, and since there is a close connection between hypotension due to deterioration of cardiac function, preventive measures to prevent hypotension in juicing It is only possible.

To date, strategies to protect kidneys with drugs are very limited. Urinary trypsin inhibitor, ulistine, has anti-inflammatory and antioxidant effects, so it has been reported to protect against renal ischemia/reperfusion injury. Various studies have been attempted to prevent CSA-AKI, but most of them are inflammatory reactions during surgery. It was performed only for surgery with extracorporeal circulation that causes severely.

Therefore, this study would like to verify the effectiveness of ulistine's medicine in the prevention of CSA-AKI in patients undergoing coronary artery bypass surgery without extracorporeal circulation.

Inclusion Criteria:

• From January 2015 to June 2020, a retrospective study will be conducted on patients undergoing extracorporeal circulatory coronary artery bypass surgery at Ajou University Hospital.

Exclusion Criteria:

• Patients who were undergoing renal replacement therapy prior to surgery due to end-stage renal failure are excluded from the study.