Renal tubular injury after infrarenal aortic aneurysm repair

OBJECTIVE: To investigate markers of tubular injury (glutathione-S-transferase GST] isoforms) as early markers for renal damage in patients undergoing abdominal aortic aneurysm repair. DESIGN: Prospective study. SETTING: Regional teaching hospital. PARTICIPANTS: Eight consecutive patients undergoing elective infrarenal abdominal aortic aneurysm repair. INTERVENTIONS: All patients received a standard anesthetic technique including a dopamine infusion (3 microg/kg/min) but without supplemental renoprotective agents. Urine and blood samples were taken at induction, at 1 hour and 3 hours after limb reperfusion, and on days 1 and 2 postoperatively. Urine microalbumin and creatinine concentrations were measured using standard assays, and urine pi-GST and alpha-GST enzyme measurements were performed by a commercial immunoassay (Biotrin, Biotrin International Ltd., Co., Dublin, Ireland). MEASUREMENTS AND MAIN RESULTS: Five patients (63%) showed a postoperative elevation of serum creatinine (median increase from baseline, 35.4%; range, 8.3% to 50.6%) that was associated with significant elevations of urinary microalbumin-to-creatinine, alpha-GST-to-creatinine, and pi-GST-to-creatinine ratios soon after clamp removal. The remaining 3 patients showed no increase in serum creatinine or urine proteins. Peak alpha-GST-to-creatinine levels were different between the 2 groups. The peak levels of GST enzymes were significantly (r(2) > 80%) associated with the percent increase in serum creatinine from baseline. CONCLUSION: Urinary GST-to-creatinine ratios are a sensitive early biomarker for renal injury after infrarenal abdominal aortic aneurysm repair.