Plasma neutrophil gelatinase-associated lipocalin protein and cystatin C as predictive biomarkers for acute kidney injury following cardiopulmonary bypass surgery: a prospective study

To investigate the predictive values of plasma levels of cystatin C (CysC), cytokines, and neutrophil gelatinase-associated lipocalin protein (NGAL) for acute kidney injury (AKI) development following cardiopulmonary bypass (CPB) surgery. Clinical data were collected from cardiopulmonary bypass patients at Suzhou Municipal Hospital between May 2022 and April 2024. Plasma NGAL and CysC levels were measured at 12 h and 36 h postoperatively, while Cytokines were measured at 12 h postoperatively. AKI was assessed using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Receiver operating characteristic (ROC) curves were used to evaluate the predictive value of NGAL and CysC for AKI, and binary logistic regression was used to identify risk factors for postoperative AKI. Among 95 enrolled patients, 42 (44.21%) developed AKI. The area under the ROC curve (AUC) for plasma NGAL was 0.65 (95% CI 0.54-0.77) at 12 h and 0.76 (95% CI 0.67-0.86) at 36 h, with corresponding sensitivities and specificities of 58%/73% and 51%/94%, respectively. The AUCs for plasma CysC at 12 h and 36 h were both 0.77 (95% CI 0.67-0.86 and 0.67-0.87, respectively), with sensitivities/specificities of 56%/88% and 68%/80%. Logistic regression analysis identified CysC-12 h, CysC-36 h, NGAL-12 h, NGAL-36 h, cTnI-36 h, age, and CPB duration as risk factors for postoperative AKI, with hazard ratios (HRs) for CysC-12 h and CysC-36 h of 8.2 (95% CI 2.74-24.55) and 9.51 (95% CI 2.97-30.50). Elevated plasma NGAL and CysC levels are significantly associated with the development of AKI after CPB surgery. These biomarkers may facilitate early identification of patients at high risk for postoperative AKI.