Purpose
Evaluate uNGAL as a marker for AKI in patients undergoing PN to identify the preoperative clinical features and surgical factors during PN that are associated with renal injury as measured by increased uNGAL levels compared to controls.
Methods
Using RN and thoracic surgery patients as control groups, we prospectively collected and analyzed urine and serum of PN, RN, and thoracic surgery patients between April 2010 and April 2012. Urine was collected preoperatively and at multiple time points postoperatively. Differences in uNGAL levels between the 3 surgical groups were analyzed using a GEE model. The PN group was subdivided based on preoperative eGFR <60 or ≥60 ml/min/1.73m2.
Results
Of 162 patients included in the final analysis, >65% had CVD, and median eGFR was >60 ml/min/1.73m2 for all groups (RN=61, PN=78, thoracic surgery=84.5 ml/min/1.73m2). Preoperatively, a 10-unit increase in eGFR was associated with a 4- unit decrease in uNGAL in the PN group. Postoperatively, uNGAL levels in the PN group were not higher than thoracic surgery or RN control groups, and did not correlate with duration of ischemia. PN patients with preoperative eGFR <60 developed higher uNGAL levels postoperatively compared to those with a higher preoperative eGFR.
Conclusion
uNGAL does not appear to be a useful marker for detection of renal injury in healthy PN patients. However, patients with poorer preoperative renal function have higher baseline uNGAL levels and appear more susceptible to AKI as detected by uNGAL levels and AKIN criteria compared to those with normal eGFR.