Accuracy of Urinary Neutrophil Gelatinase-Associated Lipocalin in Quantifying Acute Kidney Injury after Partial Nephrectomy in Patients with Normal Contralateral Kidney

BACKGROUND To evaluate the efficacy of urinary neutrophil gelatinase-associated lipocalin (uNGAL) for predicting the degree of acute kidney injury (AKI) in patients following partial nephrectomy (PN). METHODS This prospective study included 176 patients who underwent open or laparoscopic PN for solid renal tumors between June 2013 and May 2014. Urine samples were collected preoperatively and at 3, 24, and 48 h after renal pedicle clamp removal. Changes in uNGAL levels were analyzed for all patients and between subgroups that were dichotomized based on preoperative eGFR values of <60 and ≥60 mL/min/1.73m2, open and laparoscopic surgery, and according to the onset of AKI. Linear mixed models were used to investigate preoperative and perioperative features associated with postoperative uNGAL and eGFR changes at 6 months postoperatively. RESULTS Among 146 patients included in the final analysis, 10 (6.8%) patients had preoperative eGFR <60 mL/min/1.73m2. In the overall group, uNGAL levels increased following PN. However, all subgroups demonstrated comparable changes in uNGAL levels over time. Multivariate analyses failed to reveal any correctable clinical features associated with postoperative uNGAL changes, whereas preoperative serum creatinine levels and the onset of AKI correlated with eGFR at 6 months postoperatively. CONCLUSIONS uNGAL levels may increase following PN. However, it does not appear to be a useful marker for quantifying the degree of AKI or predicting postoperative renal function in patients with normal contralateral kidney and relatively good preoperative renal function. Further analysis is necessary to assess the usefulness of uNGAL in patients with poor preoperative renal function.