According to the previous studies, aortic surgery, especially thoracic aortic surgery was known to be highly prevalent of AKI, which was considered to be caused by use of total circulatory arrest (TCA), relatively high number of emergency cases, combined malperfusion syndrome before surgery and relatively complicated surgical procedure. However, there has not been many studies of AKI in thoracic aortic surgery because of its low incidence and urgent clinical presentation of aortic pathology, which hinder large randomized controlled study. Moreover, there are conflicting reports of incidence and risk factors of AKI after thoracic aortic surgery, no conclusive result has been made. Therefore, this study was designed to investigate the incidence and risk factors after thoracic aortic surgery only due to dissection.