Sutherland L, et al. - In this retrospective analysis, researchers investigated which definition of acute kidney injury (AKI) among Acute Kidney Injury Network (AKIN), Kidney Disease: Improving Global Outcomes (KDIGO) or risk, injury, failure, loss, end-stage kidney disease (RIFLE) would be the best to apply after cardiac surgery to define AKI and exert the largest influence on the outcome in cardiac surgery patients. They compared these definitions with respect to their incidence as well as influence on the outcome (90-day and 1-year mortality). Overall 1,551 patients were included. Among these, the development of AKI defined by AKIN criteria, by KDIGO, and by RIFLE-Risk criteria was detected in 410 patients, 449, and 217 patients, respectively. The best definition of AKI was risk, injury, failure, loss, end-stage kidney disease-risk as it best predicted short-term mortality. Only after 48 hours, the development of AKI was evident in a substantial number of patients, and the use of AKIN criteria missed these. They noted that AKIN criteria lacked sufficient sensitivity to capture all episodes of AKI in this population.