Navigating Challenges in the Endovascular Treatment of Asymptomatic Aortoiliac Aneurysms: A 10-Year Comparative Analysis

Background: Treating an abdominal aortoiliac aneurysm (AAIA) with endovascular methods can be challenging when the internal iliac artery (IIA) is involved. Embolizing the IIA and extending the limb to the external iliac artery (IIAE + EE) to prevent a type 2 endoleak may lead to pelvic ischemic complications. To avoid these complications, strategies that preserve the IIA, such as the bell-bottom technique (BBT) and the iliac branch device (IBD), have been proposed. This study aims to compare the outcomes of these three endovascular approaches for AAIA. Methods: Between January 2010 and December 2019, 174 patients with asymptomatic AAIA were enrolled in this retrospective analysis. They were divided into two groups: 81 patients underwent non-IIAE procedures, and 93 patients underwent IIAE procedures. The iliac limb study group consisted of 106 limbs treated with the BBT, 113 limbs treated with the IIAE + EE, and 32 limbs treated with the IBD. The primary outcomes included the 30-day mortality rate and intraoperative limb complications. The secondary outcomes included postoperative pelvic ischemia, freedom from reintervention, and the overall 10-year survival rate. Results: There was no significant difference in the perioperative mortality rate between the non-IIAE group (0%) and the IIAE group (2.1%), p = 0.500. The intraoperative limb complications did not differ significantly between the BBT limbs (7.5%), the IIAE + EE limbs (3.5%), and the IBD limbs (3.1%) groups, p = 0.349. The incidence of buttock claudication was significantly greater in the bilateral IIAE + EE group compared to the unilateral IIAE + EE and non-IIAE groups (25%, 11%, and 2.5%, p-value < 0.004), and was similar to the incidence of buttock rest pain with skin necrosis (15%, 0%, and 0%, p < 0.001). During the 10-year follow-up, the BBT limbs group had a significantly lower rate of iliac limb reintervention free time than the IIAE + EE limbs and the IBD limbs groups (88.7%, 98.2%, and 93.8%, p = 0.016). There was no significant difference in the overall 10-year survival rate between the non-IIAE and IIAE groups (51.4% vs. 55.9%, p = 0.703). Conclusions: The early and late mortality rates were similar between the non-IIAE and IIAE groups. Preserving the IIA is recommended to avoid pelvic ischemic complications. Considering the higher rate of reintervention in the BBT group, the IBD strategy may be preferred for AAIA.