Neutrophil Gelatinase-associated Lipocalin as a Biomarker for Predicting Acute Kidney Injury during Off-pump Coronary Artery Bypass Grafting

BACKGROUND Acute kidney injury (AKI) following cardiac surgery is a major complication resulting in increased morbidity, mortality, and economic burden. In this study, we assessed the usefulness of estimating serum neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker in predicting AKI in patients with stable chronic kidney disease (CKD) and undergoing off-pump coronary artery bypass grafting (OP-CABG). PATIENTS AND METHODS We prospectively studied sixty nondialysis-dependent CKD patients with estimated glomerular filtration rate <60 ml/min/1.73 m2 who required elective OP-CABG. Patients were randomized into two groups, Group D received dopamine infusion at 2 μg/kg/min following anesthesia induction till the end of the surgery and Group P did not receive any intervention. Serum creatinine, NGAL, brain natriuretic peptide, and troponin-I were estimated at specified intervals before, during, and after surgery. The results of the study patients were also compared to a simultaneous matched cohort control of thirty patients (Group A) without renal dysfunction who underwent OP-CABG. RESULTS No patient required renal replacement therapy, and no mortality was observed during perioperative and hospitalization period. Six patients from control group (n = 30), ten patients from placebo group (n = 30), and 12 patients from dopamine group (n = 30) developed stage 1 AKI. However, we did not observe any stage 2 and stage 3 AKI among all the groups. There was a significant increase in serum NGAL levels at the end of surgery and 24 h postoperatively in placebo and dopamine groups as compared to the control. CONCLUSION The measurement of NGAL appears to predict the occurrence of AKI after OP-CAB surgery. However, large multicentric studies may be required to confirm the findings of this study.