Immediate postoperative plasma neutrophil gelatinase-associated lipocalin to predict acute kidney injury after major open abdominal aortic surgery: A prospective observational study

Abstract

Introduction: Plasma neutrophil gelatinase-associated lipocalin (pNGAL) has been used as a biomarker in acute kidney injury (AKI). AKI is a common postoperative complication of aortic surgery. We sought to evaluate the performance of the immediately postoperative pNGAL level in comparison with the serum creatinine (SCr) level in predicting AKI and the need for renal replacement therapy (RRT).

Patients and methods: Prospective non-interventional study in a university hospital. Fifty patients undergoing elective or emergent major intra-abdominal aortic surgery were included. Comparisons between groups of patients with or without postoperative AKI, according to KDIGO staging, were made. Performance of NGAL was determined by examining the area under receiver operating characteristic (AUROC) curve.

Results: The incidence of AKI was 36%. At H+2, pNGAL values in AKI and non-AKI patients, respectively, were 221 [133-278] versus 50 [50-90] ng/mL (P<0.0001), and SCr values were 115 [96-178] versus 90 [72-99] μmol/L (P<0.0008). The AUROC of pNGAL for prediction of AKI was 0.90 (95% CI: 0.81-0.98) with an optimal cutoff of 112ng/mL, a sensitivity of 83%, specificity of 84%, and positive and negative predictive values of 75% and 90%, respectively. SCr produced an AUROC curve of 0.79 (0.65-0.92) at a cutoff of 110μmol/L. The diagnostic performance of pNGAL was significantly better than that of SCr (P=0.039). PNGAL at H+2 better predicted the RRT requirement [0.96 (0.90-1.0)] compared to SCr [0.86 (0.73-0.98)], but this difference was not statistically significant.

Conclusions: A 2-hour postoperative determination of pNGAL outperformed SCr level in predicting postoperative AKI after major aortic surgery.

Keywords: AKI predictor; E-PASS; NGAL; Preoperative risk score; Vascular surgery; v-POSSUM.