Neutrophil Gelatinase-Associated Lipocalin (NGAL) and cystatin C are early biomarkers of acute kidney injury associated with cardiac surgery

Abstract

Acute kidney injury (AKI) is a serious complication in as much as half of the patients undergoing cardiac surgery, and early diagnosis and treatment are of the utmost importance. There is a need for robust biomarkers that can detect cardiac surgery-associated AKI (CSA-AKI) prior to rise in plasma creatinine, which typically occurs at least 48 h postoperatively. We compared pre- and 4, 12 and 48 h postoperative plasma (P) neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, urea and creatinine, and urine (U) NGAL, as markers of AKI, in 49 patients (67% men, median age 65 years) scheduled for elective cardiac surgery (e.g. coronary artery bypass graft and/or valve replacement surgery) with the use of extracorporeal circulation. Patients with preoperative sepsis, renal replacement therapy, or estimated glomerular filtration rate <30 mL/min/1.73m² were excluded. P- and U-NGAL were measured using the Roche Modular P (Roche Diagnostics^®) NGAL immunoassay. According to AKIN/KDIGO criteria, nine patients (18%) were diagnosed with CSA-AKI. Compared to patients without CSA-AKI, these patients had significantly higher P-NGAL and P-cystatin C values 4 h (p-values .002 and <.001) and 12 h (p-values <.001 and <.001) postoperatively. The same differences were not observed for U-NGAL. Patients with AKI also had significantly higher P-creatinine 4 and 12 h postoperatively (p-values .001 and <.001), however the rise in P-creatinine was just above the upper reference limit. In conclusion, plasma NGAL and cystatin C seem to detect CSA-AKI earlier than the more commonly used biomarkers creatinine and urea.

Keywords:

• Acute kidney injury
• cardiac surgery procedures
• biomarker
• neutrophil gelatinase-associated lipocalin
• cystatin C
• creatinine
• urea

Acknowledgements

The authors are very grateful for the initiation of the project by our deceased colleague Jan Frederik Bugge, MD, PhD, from the Department of Anesthesiology, Oslo University Hospital, Oslo, Norway.

Disclosure statement

All authors declare that they have no conflict of interests. The NGAL assay reagents were funded by Gentian (Gentian^®, Moss, Norway), who was otherwise not involved in the data collection and analyses, or drafting, revision and publication of the manuscript.