Renal Biomarkers in the Early Detection of Acute Kidney Injury After Off-Pump Coronary Artery Bypass Grafting

Background: Cardiac surgery -associated (CSA) acute kidney injury (AKI) is a severe postoperative complication in patients undergoing off -pump coronary artery bypass grafting (OPCAB). Early detection of postoperative CSA-AKI may be key to improving patient outcomes. This study explored the use of renal biomarkers measured immediately after surgery for the early detection of CSA-AKI in patients undergoing OPCAB. Methods and Results: In all, 111 patients who underwent OPCAB at Kumamoto University Hospital between June 2020 and October 2022 were included in this study. Urinary neutrophil gelatinase-associated lipocalin, liver -type fatty acid -binding protein, and N -acetyl-beta-D-glucosaminidase (NAG) were measured upon arrival in the intensive care unit (ICU) after surgery. AKI was diagnosed using KDIGO criteria. Of the 111 patients, 32 (28.8%) developed postoperative AKI. Regarding AKI staging, 19 (59.4%), 11 (34.4%), and 2 (6.3%) patients had Stage 1, 2, and 3 AKI, respectively. There were significant differences in chronic kidney disease, preoperative estimated glomerular filtration rate (eGFR), and NAG between the AKI and non-AKI groups. Multivariate analysis showed that preoperative eGFR (odds ratio [OR] for 5-mL/min/1.73 m 2 increase in eGFR 0.75; 95% confidence interval [CI] 0.63-0.89) and increasing urinary NAG concentrations at ICU admission (OR 2.44; 95% CI 1.30-4.60) were significant risk factors for CSA-AKI in OPCAB patients. Conclusions: NAG and eGFR may be valuable biomarkers for the early detection of CSA-AKI in patients undergoing OPCAB.