Renal Response to Open and Endovascular Repair of Abdominal Aortic Aneurysm: A Prospective Study

Abstract

Because of incompatible reports about the renal impairment to abdominal aortic aneurysm (AAA) repair, we conducted a prospective study to determine the differences in renal response between open (OR) and endovascular (EVAR) aneurysm repair. In a prospective, nonrandomized, single-center study, we evaluated 485 patients with AAAs undergoing OR or EVAR between January 2000 and December 2005. Only electively performed procedures were analyzed in detail. The OR group included 229 patients (males/females 203/26, median age 69.8 [range 43-90] years, aneurysm diameter in median 57 [26-95] mm), and the EVAR group integrated 144 patients (males/females 129/15, 73.1 [49-90] years [p=.001], 55 [33-100] mm). Renal function was assessed by determinating the preoperative serum creatinine (SCr) level and SCr clearance according to Cockcroft-Gault. Postoperatively, SCr level and SCr clearance were determined at defined intervals, reported as highest postoperative SCr level, SCr level at time of discharge, lowest postoperative SCr clearance, and SCr clearance at time of discharge. The parameters of height, weight, diabetes, smoking habit, serum cholesterol level, and hemoglobin were not different between the groups. Significantly different were the American Society of Anesthesiologists classification, the Society for Vascular Surgery Comorbidity Score, and the exposure to contrast dye. Moreover, significantly different were intraoperatively measured median blood loss (1,200 vs. 400 mL) and the median time of operation (164 vs. 135 min). Although, the preoperative SCr levels between the groups were not statistically different (OR group 1.0 [0.87-1.23] mg/dL [median, interquartile range], EVAR group 1.0 [0.9-1.3]; p > 0.05), the SCr clearance was (OR group 72.8 [58.2-98.8] mL/min, EVAR group 67.6 [51.3-85.1] mL/min; p = 0.007). In the postoperative period, SCr level did not change significantly in the OR group but did in the EVAR group to a level of 1.08 (0.9-1.36) mg/dL (p = 0.007). Similarly, SCr clearance decreased significantly in the EVAR group to a level of 66.7 (49.9-81.4) mL/min. These results were influenced by the stent graft design (deployment under the renal arteries vs. covering the renals with bared stents). Mortality was 3/229 in the OR group and 4/144 in the EVAR group. Acute renal impairment occurred in a subset of patients with AAAs with regard to the type of repair. EVAR showed a slight deterioration of renal function, but the evaluated tests are insensitive and without prognostic value concerning mortality or hospitalization. More sensitive markers of the differentiated renal functions (cystatin C for renal glomerular function, N-acetyl-ss-d-glucosamidase for proximal tubular function) should be evaluated in future studies.