Neutrophil Gelatinase-Associated Lipocalin as a Predictor of Complications and Mortality in Patients Undergoing Non-Cardiac Major Surgery

Introduction: We tested the hypothesis that urinary and serum neutrophil gelatinase-associated lipocalins (NGAL) early after non-cardiac major surgery predict postoperative acute kidney injury (AKI), complications and mortality. Methods: We studied 74 patients undergoing orthopedic, vascular and abdominal surgery lasting 6 2 h. NGAL was measured in preoperative, as well as 2and 6-hour postoperative samples. The primary outcome was AKI. Secondary outcome was postoperative infection and death. Results: 10 patients (13.5%) developed AKI, 19 (26%) reached secondary outcomes, of whom 5 (7%) died. Serum NGAL was significantly higher in patients with diabetes and chronic kidney disease (CKD). No significant correlation was detected between serum or urine NGAL and subsequent development of AKI. Urine NGAL at 6 h and serum NGAL at 2 and 6 h were strongly correlated with postoperative infection and death (p = 0.004, p = 0.013 and p = 0.001, respectively). Conclusions: Our data suggest that in the general surgical population, NGAL could serve as a potent early biomarker for postoperaReceived: August 2, 2010 Accepted: December 23, 2010 Published online: February 11, 2011 Linda Shavit, MD Adult Nephrology Unit Shaare Zedek Medical Center, PO Box 3235 Jerusalem 91031 (Israel) E-Mail lshavit @ szmc.org.il © 2011 S. Karger AG, Basel 1420–4096/11/0342–0116$38.00/0 Accessible online at: www.karger.com/kbr NGAL as a Predictor of Complications and Mortality Kidney Blood Press Res 2011;34:116–124 117 Neutrophil gelatinase-associated lipocalin (NGAL) belongs to the lipocalin family of proteins and was originally isolated from the supernatant of activated human neutrophils [5] , but it is also expressed at low levels in other human tissues including the kidney, prostate and epithelia of the respiratory and alimentary tracts [6] . NGAL expression has been studied in ischemic and nephrotoxic acute tubular necrosis, chronic kidney disease (CKD) and proteinuria, kidney transplantation, and other conditions [7–9] . It is apparent that a large variety of renal disorders are associated with raised plasma and urinary levels of NGAL. Patients with CKD are at increased risk of developing AKI following any acute insults. Elevated urinary and serum NGAL levels have been observed in patients with CKD as well as in malignant diseases and ongoing infection. However, NGAL levels after AKI in this high-risk population have not been studied previously. We might predict that urinary and serum NGAL levels would increase significantly from baseline levels after ischemic renal injury severe enough to result in AKI in patients with underlying CKD. Our study evaluated urinary and serum NGAL levels before, during and after surgery and tested the hypothesis that NGAL predicts subsequent development of AKI and in-hospital morbidity and mortality in a large spectrum of patients including those with CKD and other comorbidities.