Factors influencing stent graft occlusion in endovascular repair of internal iliac artery aneurysms

Objective

This study aimed to evaluate technical factors influencing stent graft occlusion following endovascular repair of internal iliac artery aneurysms (IIAAs), with a specific focus on the longitudinal length of unsupported stent graft segments and connecting stent grafts.

Methods

A retrospective single-center analysis was performed on 61 IIAAs treated with endovascular techniques between 2010 and 2022. Anatomical and technical factors, including the unsupported stent graft length within the aneurysm sac (Distance A) and the length of the distal sealing zone (Distance B), were assessed. Statistical analyses were conducted to identify factors associated with stent graft occlusion, type Ib endoleaks, and clinical outcomes.

Results

The primary technical success rate was 90.2%, with a stent graft occlusion rate of 23% documented over a mean follow-up period of 25.7 months. A longer unsupported stent graft length (Distance A) was significantly associated with increased risk of occlusion (53.7 vs 37.0 mm in nonoccluded cases; P = .017). Occlusion rates were also higher in cases with a greater number of connecting stent grafts used to extend the iliac branched device to healthy vessel segments (P = .015). Type Ib endoleaks occurred in 6.6% of cases and were significantly associated with shorter distal sealing zones (≤15 mm; odds ratio, 18.0). Despite these technical challenges, clinical success was achieved in 83.3% over the follow-up period, with low rates of ischemic complications. Buttock claudication occurred in 12.9% of cases, and erectile dysfunction was reported in one patient.

Conclusions

Endovascular repair of IIAAs is effective and provides a viable option for patients unfit for open surgery. However, it carries risks of stent graft occlusion and endoleaks, particularly when the unsupported stent graft length is extended or when multiple connecting stents are used. Optimizing graft configurations and minimizing unsupported segments may reduce occlusion risks. Furthermore, ensuring an adequate distal sealing zone length is critical to minimizing the occurrence of type Ib endoleaks. These findings highlight the importance of careful procedural planning and technical considerations to improve long-term outcomes and enhance durability in endovascular management of IIAAs.