Background: Acute kidney injury (AKI) develops in 10% of patients after surgical abdominal aortic aneurysm
(AAA) repair. Neutrophil gelatinase-associated lipocalin (NGAL) is a predictor of AKI and Endothelial Progenitor Cells
(EPCs) represent a potential repair mechanism for vascular lesions. We evaluated the diagnostic power of serum (s) and
urine (u) NGAL in detecting a possible event of AKI in patients undergoing surgical treatment for AAA repair. We also
investigated the influence of vascular injury on EPCs.
Methods: We examined 50 patients who underwent open AAA repair. Blood and urine was collected preoperatively and
every hour after surgery until 8 h to quantify sNGAL, uNGAL and circulating EPCs. AKI, was defined as a 25% decrease
in eGFR compared with baseline values.
Results: There was an inverse correlation between eGFR, sNGAL and uNGAL, while a direct correlation between
sNGAL APACHE II Score and EPCs was found. At receiver operating characteristic (ROC) analysis, sNGAL and uNGAL
showed a very good diagnostic profile. Kaplan Meier curves showed that NGAL is a highly sensitive predictor of
incidence of AKI. Univariate followed by multivariate Cox proportional hazard regression analysis showed that uNGAL
and sNGAL predicted AKI independently of other potential confounders, including eGFR and APACHE II Score. Patients
had at baseline and after surgical stress a significantly higher number of EPCs than control group.
Conclusions: NGAL represents an independent renal predictor of incidence of AKI. EPCs reflect the degree of vascular
damage and could be considered as an indicator of disease with a reparative-regenerative vascular-endothelial function.