Analysis of Effects of Fixation Type on Renal Function After Endovascular Aneurysm Repair

PURPOSE: To report a prospective nonrandomized study comparing the effects of suprarenal (SR) vs. infrarenal (IR) stent-graft fixation on renal function in patients undergoing endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). METHODS: Patients with AAA undergoing elective EVAR between June 2008 and June 2010 were eligible for the comparative study of fixation method on renal function. Patients with impaired renal function [estimated creatinine clearance (eCrCl) <30 mL/min] or a history of renal impairment were not eligible. Renal function was assessed by measuring serum creatinine (SCr) and total proteins and microalbumin in the urine preoperatively, on postoperative day 1, and at 1, 6, and 12 months. The eCrCl was calculated using the Cockcroft-Gault formula. A standard preoperative hydration protocol was followed in all patients, and stent-graft choice was at the operator's discretion. Of 116 patients undergoing elective EVAR in the study period, 16 were ineligible, leaving 100 patients (95 men; median age 74 years) enrolled in the study (49 SR and 51 IR). RESULTS: There was no statistically significant difference between the groups in the prevalence of any risk factor, the baseline SCr and eCrCl values, contrast usage, or procedure duration. At the postoperative measurement, there was no significant deterioration of renal function in either group, although total urinary proteins increased significantly in both groups (IR p=0.01, SR p<0.001). At the 12-month follow-up, patients in the IR group had no significant alteration in any marker vs. baseline, while patients in the SR group had significant alterations in SCr (p=0.001), eCrCl (p<0.001), and microalbumin (p=0.04) in urine. The number of patients with a >20% decrease in eCrCl was not significantly different between the groups. No patient had an adverse renal event. CONCLUSION: Deterioration in renal function was observed 12 months after EVAR in patients receiving a stent-graft with suprarenal fixation, even though this did not seem to increase the likelihood of postoperative renal impairment. Furthermore, suprarenal fixation may be responsible for progressively significant proteinuria. Further studies are needed to determine the long-term impact of suprarenal fixation on renal function and investigate the potential risk of progressive renal disease in relation to type of fixation.