Acute kidney injury after cardiac surgery: focus on modifiable risk factors.
BACKGROUND
Acute kidney injury (AKI) after cardiac surgery is a major health issue. Lacking effective therapies, risk factor modification may offer a means of preventing this complication. The objective of the present study was to identify and determine the prognostic importance of such risk factors.


RESULTS
Data from a multicenter cohort of 3500 adult patients who underwent cardiac surgery at 7 hospitals during 2004 were analyzed (using multivariable logistic regression modeling) to determine the independent relationships between 3 thresholds of AKI (>25%, >50%, and >75% decrease in estimated glomerular filtration rate within 1 week of surgery or need for postoperative dialysis) with death rates, as well as to identify modifiable risk factors for AKI. The 3 thresholds of AKI occurred in 24% (n=829), 7% (n=228), and 3% (n=119) of the cohort, respectively. All 3 thresholds were independently associated with a >4-fold increase in the odds of death and could be predicted with several perioperative variables, including preoperative intra-aortic balloon pump use, urgent surgery, and prolonged cardiopulmonary bypass. In particular, 3 potentially modifiable variables were also independently and strongly associated with AKI. These were preoperative anemia, perioperative red blood cell transfusions, and surgical reexploration.


CONCLUSIONS
AKI after cardiac surgery is highly prevalent and prognostically important. Therapies aimed at mitigating preoperative anemia, perioperative red blood cell transfusions, and surgical reexploration may offer protection against this complication.
Karkouti
Keyvan
K
Department of Anesthesia and Health Policy, Management, and Evaluation, Toronto General Hospital, University of Toronto, 200 Elizabeth St, EN 3-402, Toronto, Ontario, Canada M5G 2C4. keyvan.karkouti@uhn.on.ca
Wijeysundera
Duminda N
DN
Yau
Terrence M
TM
Callum
Jeannie L
JL
Cheng
Davy C
DC
Crowther
Mark
M
Dupuis
Jean-Yves
JY
Fremes
Stephen E
SE
Kent
Blaine
B
Laflamme
Claude
C
Lamy
Andre
A
Legare
Jean-Francois
JF
Mazer
C David
CD
McCluskey
Stuart A
SA
Rubens
Fraser D
FD
Sawchuk
Corey
C
Beattie
W Scott
WS
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000401:mortality; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000706:statistics & numerical data*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000706:statistics & numerical data; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000601:surgery*; D017707:Erythrocyte Transfusion / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000209:etiology* / Q000401:mortality*; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality*; D011237:Predictive Value of Tests; D011379:Prognosis; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors