Urinary, Plasma, and Serum Biomarkers' Utility for Predicting Acute Kidney Injury Associated With Cardiac Surgery in Adults: A Meta-analysis.
BACKGROUND
Early accurate detection of acute kidney injury (AKI) occurring after cardiac surgery may improve morbidity and mortality. Although several novel biomarkers have been developed for the early detection of AKI, their clinical utility in the critical intraoperative and immediate postoperative period remains unclear.


STUDY DESIGN
Systematic review and meta-analysis.


SETTING & POPULATION
Adult patients having cardiac surgery.


SELECTION CRITERIA FOR STUDIES
EMBASE, CINAHL, Cochrane Library, Scopus, and PubMed from January 1990 until January 2015 were systematically searched for cohort studies reporting the utility of novel biomarkers for the early diagnosis of AKI after adult cardiac surgery. Reviewers extracted data for study design, population, timing of biomarker measurement and AKI occurrence, biomarker performance (area under the receiver operating characteristic curve [AUROC]), and risk of bias.


INDEX TESTS
Novel urine, plasma, and serum AKI biomarkers, measured intraoperatively and in the early postoperative period (<24 hours).


REFERENCE TESTS
AKI was defined according to the RIFLE, AKIN, or 2012 KDIGO criteria.


RESULTS
We found 28 studies reporting intraoperative and/or early postoperative measurement of urine (n=23 studies) or plasma or serum (n=12 studies) biomarkers. Only 4 of these studies measured biomarkers intraoperatively. Overall, intraoperative discrimination by the urine biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury marker 1 (KIM-1) demonstrated AUROCs<0.70, whereas N-acetyl-β-d-glucosaminidase (NAG) and cystatin C had AUROCs<0.75. In the immediate 24-hour postoperative period, the urine biomarkers NGAL (16 studies), KIM-1 (6 studies), and liver-type fatty acid binding protein (6 studies) exhibited composite AUROCs of 0.69 to 0.72. The composite AUROCs for postoperative urine cystatin C, NAG, and interleukin 18 were ≤0.70. Similarly, the composite AUROCs for postoperative plasma NGAL (6 studies) and cystatin-C (5 studies) were <0.70.


LIMITATIONS
Heterogeneous AKI definitions.


CONCLUSIONS
In adults, known urinary, plasma, and serum biomarkers of AKI possess modest discrimination at best when measured within 24 hours of cardiac surgery.
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D000118:Acetylglucosaminidase D058186:Acute Kidney Injury D015415:Biomarkers D006348:Cardiac Surgical Procedures D003404:Creatinine D055316:Cystatin C D050556:Fatty Acid-Binding Proteins D006801:Humans D011183:Postoperative Complications D011237:Predictive Value of Tests
biomarker acute kidney injury intraoperative early postoperative Cardiopulmonary bypass alpha-1-microglobulin (A1M) diagnostic performance hepcidin-25 liver-type fatty acid binding protein (L-FABP) monocyte chemoattractant protein 1 (CCL2) tumor necrosis factor alpha (TNF-α) uric acid