Neutrophil gelatinase-associated lipocalin as a biomarker for acute kidney injury in patients undergoing coronary artery bypass grafting.

Background/objective: The development of acute renal injury (ARI) is an important indicator of clinical outcomes after cardiac surgery. Neutrophil gelatinase-associated lipocalin (NGAL) has been certified as a predictive biomarker of hypoxic ARI. The present study aimed to determine the predictive role of NGAL in coronary bypass graft (CABG) surgery.

Method: A total of 72 consecutive patients undergoing elective CABG were enrolled in the study. NGAL levels were determined preoperatively and postoperatively after 6 h, 24 h and 72 h for all participants. The participants were then divided into two groups according to their preoperative creatinine levels (group I, creatinine 111.38 μmol/L to 361.55 μmol/L; group II, creatinine <111.38 μmol/L).

Results: There was no statistically significant difference between the groups according to their NGAL values (P>0.05), except at 6 h (P=0.045). Three patients required continuous hemodialysis. Comparison of the NGAL levels of these three patients with those of the other participants did not reveal any correlation with serum creatinine levels. In contrast, the NGAL levels were significantly lower in the continuous hemodialysis patients (1.9±1 ng/mL) compared with those of the other participants (22.6±12.8 ng/mL; P=0.001).

Conclusion: NGAL is one of the most frequently used biomarkers for ARI after cardiac operations, especially in younger patients. The participants in the present study were coronary artery disease patients and were, therefore, older than patients in previous reports. These results support the view that NGAL is not a relevant predictive factor for ARI in patients with CABG, including older patients.