title: Acute kidney injury after cardiac surgery according to Risk/Injury/Failure/Loss/End-stage, Acute Kidney Injury Network, and Kidney Disease: Improving Global Outcomes classifications.
abstract: OBJECTIVE
  The epidemiology of acute kidney injury (AKI) after cardiac surgery depends on the definition used. Our aims were to evaluate the Risk/Injury/Failure/Loss/End-stage (RIFLE) criteria, the AKI Network (AKIN) classification, and the Kidney Disease: Improving Global Outcomes (KDIGO) classification for AKI post-cardiac surgery and to compare the outcome of patients on renal replacement therapy (RRT) with historical data.
  
  
  METHODS
  Retrospective analysis of 1881 adults who had cardiac surgery between May 2006 and April 2008 and determination of the maximum AKI stage according to the AKIN, RIFLE, and KDIGO classifications.
  
  
  RESULTS
  The incidence of AKI using the AKIN and RIFLE criteria was 25.9% and 24.9%, respectively, but individual patients were classified differently. The area under the receiver operating characteristic curve for hospital mortality was significantly higher using the AKIN compared with the RIFLE criteria (0.86 vs 0.78, P = .0009). Incidence and outcome of AKI according to the AKIN and KDIGO classification were identical. The percentage of patients who received RRT was 6.2% compared with 2.7% in 1989 to 1990. The associated hospital mortality fell from 82.9% in 1989 to 1990 to 15.6% in 2006 to 2008.
  
  
  CONCLUSIONS
  The AKIN classification correlated better with mortality than did the RIFLE criteria. Mortality of patients needing RRT after cardiac surgery has improved significantly during the last 20 years.
authors.affiliation: Unit of Critical Care, Imperial College, Royal Brompton Hospital, London, SW3 6NP, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Bastin
authors.forename: Marlies
authors.initials: M
authors.lastname: Ostermann
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Slack
authors.forename: Gerhard-Paul
authors.initials: GP
authors.lastname: Diller
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Finney
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Evans
mesh_terms: D058186:Acute Kidney Injury / Q000145:classification* / Q000453:epidemiology* / Q000628:therapy; D000368:Aged; D019540:Area Under Curve; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D007902:Length of Stay / Q000706:statistics & numerical data; D008131:London / Q000453:epidemiology; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D012372:ROC Curve; D017582:Renal Replacement Therapy; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: Acute kidney injury; Cardiac surgery; Cardiopulmonary bypass; Intensive care unit; Renal replacement therapy