title: Cardiac-surgery associated acute kidney injury requiring renal replacement therapy. A Spanish retrospective case-cohort study.
abstract: BACKGROUND
  Acute kidney injury is among the most serious complications after cardiac surgery and is associated with an impaired outcome. Multiple factors may concur in the development of this disease. Moreover, severe renal failure requiring renal replacement therapy (RRT) presents a high mortality rate. Consequently, we studied a Spanish cohort of patients to assess the risk factors for RRT in cardiac surgery-associated acute kidney injury (CSA-AKI).
  
  
  METHODS
  A retrospective case-cohort study in 24 Spanish hospitals. All cases of RRT after cardiac surgery in 2007 were matched in a crude ratio of 1:4 consecutive patients based on age, sex, treated in the same year, at the same hospital and by the same group of surgeons.
  
  
  RESULTS
  We analyzed the data from 864 patients enrolled in 2007. In multivariate analysis, severe acute kidney injury requiring postoperative RRT was significantly associated with the following variables: lower glomerular filtration rates, less basal haemoglobin, lower left ventricular ejection fraction, diabetes, prior diuretic treatment, urgent surgery, longer aortic cross clamp times, intraoperative administration of aprotinin, and increased number of packed red blood cells (PRBC) transfused. When we conducted a propensity analysis using best-matched of 137 available pairs of patients, prior diuretic treatment, longer aortic cross clamp times and number of PRBC transfused were significantly associated with CSA-AKI.Patients requiring RRT needed longer hospital stays, and suffered higher mortality rates.
  
  
  CONCLUSIONS
  Cardiac-surgery associated acute kidney injury requiring RRT is associated with worse outcomes. For this reason, modifiable risk factors should be optimised and higher risk patients for acute kidney injury should be identified before undertaking cardiac surgery.
authors.affiliation: Department of Anesthesia and Critical Care, Clinica Universidad de Navarra, University of Navarra, Pamplona, Spain. jrpvaldi@unav.es
authors.forename: Jose Ramon
authors.initials: JR
authors.lastname: Perez-Valdivieso
authors.forename: Pablo
authors.initials: P
authors.lastname: Monedero
authors.forename: Marc
authors.initials: M
authors.lastname: Vives
authors.forename: Nuria
authors.initials: N
authors.lastname: Garcia-Fernandez
authors.forename: Maira
authors.initials: M
authors.lastname: Bes-Rastrollo
mesh_terms: D058186:Acute Kidney Injury / Q000401:mortality* / Q000628:therapy*; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D017582:Renal Replacement Therapy / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D015996:Survival Rate