Outcome Analysis of Pre-Emptive Embolization of the Collateral Branches of the Abdominal Aorta During Standard Infrarenal Endovascular Aortic Repair

<b>Objectives:</b> To report the results of pre-emptive embolization of collateral branches of the abdominal aorta in patients undergoing standard bifurcated EVAR versus those undergoing standard EVAR without embolization. <b>Methods:</b> This study is a single-center, retrospective, observational cohort analysis of consecutive patients who underwent elective standard endovascular aneurysm repair (EVAR) between 1 October 2013, and 31 December 2022, with a minimum follow-up period of 2 years. The patients were divided into two groups: group A, which did not receive embolization, and group B, which underwent pre-emptive embolization of aortic collateral branches. The primary outcomes for this study include overall survival, freedom from aorta-related mortality (ARM), and freedom from reinterventions related to type 2 endoleak (T2E). In cases of multiple reinterventions, only the first one was considered for this analysis. The secondary outcome focused on assessing freedom from aneurysm sac enlargement. <b>Results:</b> We analyzed a total of 265 endovascular aneurysm repairs (EVARs): 183 (69.1%) were classified into group A, and 82 (30.9%) into group B. The median follow-up duration was 48 months [interquartile range (IQR), 28-65.5], which was not significantly different between the two groups [45 months (26-63) in group A vs. 52.5 months (29.5-72.5) in group B, <i>p</i> = 0.098]. The estimated cumulative survival rates were 87% (0.2) at 2 years (95% confidence interval [CI]: 82.6-92.9) and 67% (0.3) at 5 years (95% CI: 60.3-73.1), with no significant difference between the groups (<i>p</i> = 0.263). The aorta-related mortality rate was 1.1% (<i>n</i> = 3); all instances occurred following open conversion due to graft infection (<i>n</i> = 2) and in one case of secondary aortic rupture (<i>n</i> = 1). In total, 34 cases (12.8%) indicated a secondary intervention related to type 2 endoleak (T2E). The freedom from T2E-related reintervention rate was 99% (0.01) at 2 years (95% CI: 99.4-99.8) and 88% (0.3) at 5 years (95% CI: 81.4-92.5), with no differences between the groups (<i>p</i> = 0.282). Cox regression analysis revealed that age over 80 years is an independent negative predictor of survival, with a hazard ratio (HR) of 3.5 (95% confidence interval [CI]: 2.27-5.50; <i>p</i> < 0.001). Additionally, T2E-related reintervention was identified as a negative predictor, with an HR of 2.4 (95% CI: 1.05-5.54; <i>p</i> = 0.037). In this study, conversion to open repair was necessary for 14 patients (5.3%), with three conversions occurring due to rupture; however, T2E was not a determining factor in any of these conversions. At the last available follow-up computed tomography angiography (CT-A), the median aneurysm diameter was significantly lower in group B, measuring 44 mm (range 37.7-50), compared to group A, measuring 48 mm (range 39-57.5) (<i>p</i> < 0.001). Both groups showed a significant change from baseline measurements (<i>p</i> = 0.001). <b>Conclusions:</b> Pre-emptive embolization of the aortic collateral branches does not lead to improved aorta-related outcomes after EVAR.