Intraoperative Division of Left Renal Vein has No Impact on The Fate of Renal Function After the Open Surgery for Para- and Juxtarenal Abdominal Aortic Aneurysm

Abstract

Introduction - Left renal vein (LRV) division is occasionally imperative for better access to the suprarenal aorta during open surgery (OS) for pararenal and juxtarenal abdominal aortic aneurysm (P/JRAA). However, its impact on the postoperative renal function remains controversial. Prior studies referred to the impact on acute kidney injury (AKI), but they have rarely evaluated longer-term renal function. This study focused on a chronic renal decline (CRD) during follow-up. Methods - A retrospective review of our series of P/JRAA treated with OS from June 2007 to January 2017. Patients on hemodialysis at the time of surgery were excluded. Preoperative renal function was estimated using the chronic kidney disease (CKD) staging system. Postoperative AKI was defined by the RIFLE criteria (Risk, Injury, Failure, Loss of function, End-stage renal disease). CRD was defined as progression in CKD stage or estimated glomerular filtration rate (eGFR) decline of >20%. The impact of LRV division on the postoperative renal function was investigated by a time-to-event analysis. Results - Among 469 elective OS, 119 underwent repair for P/JRAA. Three patients with preoperative hemodialysis and 1 in-hospital deaths were excluded from the analysis. Consequently, 115 patients were enrolled. Preoperatively, 42 patients (36.5%) had CKD stage 3 (eGFR < 60 mL/min/1.73 m2). Eight patients (8.7%) were in stage 4 (eGFR < 30 mL/min/1.73 m2). Proximal clamping was supraceliac (5 patients), suprarenal (38 patients), and inter-renal (72 patients). The median renal ischemic time was 33 minutes. LRVs were divided in 27 patients (group D), and stayed intact in 88 patients (group I). There was no significant difference in patients’ backgrounds between the groups. Group D tended to require higher proximal clamping (P=0.087) and related to significantly longer operation time (P<0.001). However, the median renal ischemic time was not significantly different between the groups (P=0.916). AKI seemed more common in group D, but not significant (P=0.103). During a median renal function follow-up for 13.8 months (interquartile range, 1.9-36.4), CRD was observed in 5 patients of group D and 14 patients of group I (18.5% and 16.1%, respectively). One patient in group I required hemodialysis 5 years after surgery. Kaplan-Meier curves to compare the freedom from CRD showed no significant difference between the groups (P=0.805; log-rank test). Risk-adjusted comparison, matching preoperative CKD stage and proximal clamp sites, did not change these findings. Conclusion - LRV division had no significant impact on CRD for up to 2 years during follow-up. Our result supported the safety of LRV division in terms of the mid-term outcomes.