Less Aortic Neck Dilatation of the ALTO Stent Graft compared to the Self-Expanding Stent Grafts after Endovascular Aortic Repair for Abdominal Aortic Aneurysms

Purpose: Proximal neck dilatation (PND) is a common issue after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs), being a potential cause of stent graft migration or type Ia endoleak. The ALTO stent graft, featuring a unique polymer sealing mechanism, has been reported to exhibit less PND. This study aims to compare PND and clinical outcomes between the ALTO stent graft and alternative self-expanding stent grafts. Methods: The CustomSEAL study is a multi-center retrospective observational study involving 18 institutions in Japan. It compares EVAR outcomes using the ALTO stent graft and alternative self-expanding stent grafts for fusiform AAAs. The primary outcome measure was the difference in PND at 12 months post-EVAR. Secondary outcome measures included aneurysm sac diameter changes, reintervention rates, and mortality outcomes during the follow-up. Results: After propensity score matching, 111 patient pairs were extracted. Baseline characteristics, including proximal neck length/diameter and stent graft oversizing, were comparable between groups. The ALTO stent graft was associated with significantly less PND at 12 months (2.3% vs. 26.7%, P < 0.001). There were no significant differences in perioperative outcomes, aneurysm sac diameter changes, reintervention rates, or overall survival between the groups. Conclusions: The ALTO stent graft demonstrated significantly less PND at 12 months post-EVAR compared to alternative self-expanding stent grafts, highlighting its potential advantage in exerting less chronic expanding force on the proximal aortic neck. Long-term follow-up is needed to validate the clinical benefits of the ALTO stent graft over the alternative self-expanding stent grafts. Level of Evidence: Non-randomized controlled cohort/follow-up study. Visual Abstract: (Figure presented.)