Long-term decline in renal function is more significant after endovascular repair of infrarenal abdominal aortic aneurysms.

Objective: It is not clear whether endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs) results in an increase in renal insufficiency during the long term compared with open repair (OR). We reviewed our experience with AAA repair to determine whether there was a significant difference in postoperative and long-term renal outcomes between OR and EVAR.

Methods: A retrospective cohort study was conducted of all patients who underwent AAA repair between January 1993 and July 2013 at a tertiary referral hospital. Demographics, comorbidities, preoperative and postoperative laboratory values, morbidity, and mortality were collected. Patients with ruptured AAAs, preoperative hemodialysis, juxtarenal or suprarenal aneurysm origin, and no follow-up laboratory values were excluded. Preoperative, postoperative, 6-month, and yearly serum creatinine values were collected. Glomerular filtration rate (GFR) was calculated on the basis of the Chronic Kidney Disease Epidemiology Collaboration equation. Acute kidney injury (AKI) was classified using the Kidney Disease: Improving Global Outcomes guidelines. Change in GFR was defined as preoperative GFR minus the GFR at each follow-up interval. Comparison was made between EVAR and OR groups using multivariate logistics for categorical data and linear regression for continuous variables.

Results: During the study period, 763 infrarenal AAA repairs were performed at our institution; 675 repairs fit the inclusion criteria (317 ORs and 358 EVARs). Mean age was 73.9 years. Seventy-nine percent were male, 78% were hypertensive, 18% were diabetic, and 31% had preoperative renal dysfunction defined as GFR below 60 mL/min. Using a multivariate logistic model to control for all variables, OR was found to have a 1.6 times greater chance for development of immediate postoperative AKI compared with EVAR (P = .038). Hypertension and aneurysm size were independent risk factors for development of AKI (P = .012 and .022, respectively). Using a linear regression model to look at GFR decline during several years, there was a greater decline in GFR in the EVAR group. This became significant starting at postoperative year 4. AKI and preoperative renal dysfunction were independent risk factors for long-term decline in renal function.

Conclusions: Although AKI is less likely to occur after EVAR, patients undergoing EVAR experience a significant but delayed decline in GFR over time compared with OR. This became apparent after postoperative year 4. Studies comparing EVAR and OR may need longer follow-up to detect clinically significant differences in renal function.