Impact of simple renal cysts on sac shrinkage after endovascular aortic repair

<h2>Abstract</h2><h3>Objective</h3> Related to a shared pathophysiological mechanism between abdominal aortic aneurysm (AAA) and simple renal cyst (SRC) formation, patients with or without combined SRCs and AAA might have a different pattern of sac shrinkage after endovascular aortic repair (EVAR). Patients with sac shrinkage have a significantly lower risk of early or late complications after EVAR. In this study, we investigated whether SRCs independently predict aneurysm sac shrinkage after EVAR. Finally, potential differences in overall survival after EVAR between patients with and without SRC were analyzed. <h3>Methods</h3> We analyzed a retrospective study of a cohort of patients, treated with four different types of endografts at the authors' institution between January 2005 and January 2017. Maximum aneurysm sac diameter was compared between patients with and without SRC at baseline and ≤5 years postoperatively. The presence of SRCs and the potential influence on sac shrinkage were assessed after adjusting for endoleak and endograft type. Estimated overall survival rates after EVAR in patients with and without SRC were analyzed using Kaplan-Meier survival analysis. <h3>Results</h3> In total, 270 patients were included for analysis. At 1 and 2 years of follow-up, patients with SRC showed greater sac shrinkage compared with patients without SRC (−4.3 mm [95% confidence interval (CI), −5.1 to 3.5 mm] vs −1.8 mm [95% CI, −3.1 to 0.5 mm; <i>P</i> = .001] at 1 year and −5.5 ± 2.3 mm vs −3.2 ± 3.6 mm [<i>P</i> = .03] at 2 years of follow-up). Patients with bilateral SRCs had greater sac shrinkage than those with unilateral SRCs (−5.2 ± 2.1 mm vs −2.8 ± 2.5 mm [<i>P</i> = .005] at 1 year and −3.9 ± 3.7 mm vs −6.5 ± 3.1 mm [<i>P</i> = .04] at 2 years follow-up.) However, no difference in sac shrinkage was observed at 3 to 5 years of follow-up between patients with and without SRC (<i>P</i> > .005) or between patients with unilateral vs bilateral SRCs (<i>P</i> > .05). Overall survival after EVAR was 100% and 95.2% at 2 years and 78.7% and 72.4% at 5 years of follow-up in patients without and with combined SRCs, respectively (<i>P</i> = .730). <h3>Conclusions</h3> This study demonstrates greater sac shrinkage after EVAR at 1 and 2 years of follow-up in patients with SRCs compared with patients without SRCs. However, at longer follow-up, no difference in sac shrinkage after EVAR was observed in patients with and without concomitant SRC. No difference in overall survival after EVAR was found in patients with and without combined SRCs.