Novel biomarkers early predict the severity of acute kidney injury after cardiac surgery in adults.
BACKGROUND
The purpose of this study was to investigate the ability of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and their combination in predicting the duration and severity of acute kidney injury (AKI) after cardiac surgery in adults.


METHODS
Using data from a prospective observational study of 100 adult cardiac surgical patients, we correlated early postoperative concentrations of plasma NGAL and serum cystatin C with the duration (time during which AKI persisted according to the Acute Kidney Injury Network criteria) and severity of AKI (change in serum creatinine) and with length of stay in intensive care.


RESULTS
We found a mean AKI duration of 67.2 +/- 41.0 hours which was associated with prolonged hospitalization (p < 0.001). NGAL, cystatin C, and their combination on arrival in intensive care correlated with subsequent AKI duration (all p < 0.01) and severity (all p < 0.001). The area under the receiver operating characteristic curve for AKI prediction was 0.77 (95% confidence interval: 0.63 to 0.91) for NGAL and 0.76 (95% confidence interval: 0.61 to 0.91) for cystatin C on arrival in intensive care. Both markers also correlated with length of stay in intensive care (p = 0.037; p = 0.001). Neutrophil gelatinase-associated lipocalin and cystatin C were independent predictors of AKI duration and severity and of length of stay in intensive care (all p < 0.05). The value of cystatin C on arrival in intensive care appeared to be due to a carry-over effect from preoperative values.


CONCLUSIONS
Immediately postoperatively, NGAL and cystatin C correlated with and were independent predictors of duration and severity of AKI and duration of intensive care stay after adult cardiac surgery. The combination of both renal biomarkers did not add predictive value.
Haase
Michael
M
Department of Intensive Care, Austin Health, Melbourne, Australia.
Bellomo
Rinaldo
R
Devarajan
Prasad
P
Ma
Qing
Q
Bennett
Michael R
MR
Möckel
Martin
M
Matalanis
George
G
Dragun
Duska
D
Haase-Fielitz
Anja
A
D058186:Acute Kidney Injury / Q000097:blood* / Q000209:etiology* / Q000401:mortality; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D015331:Cohort Studies; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016019:Survival Analysis
D015415:Biomarkers; D055316:Cystatin C; D054834:Lipocalins