Anatomical Feasibility of an Off-the-shelf Single-Renal Scalloped Stent-Graft for Hostile Neck Abdominal Aortic Aneurysm: A Preclinical Study

Objectives: To evaluate the feasibility of a standardized single-renal scallop stent-graft. Design: Preclinical, single-center, real-world, all-comers, retrospective cohort study. Methods: A total of 1347 abdominal aortic aneurysm (AAA) repairs (endovascular and open) performed between 2010 and 2020 were screened for elective treatment and retrievable preoperative high-quality computed tomography angiography (CTA) performed <6 months of the surgical procedure. Six hundred of the included CTAs involved prespecified measurements and a morphological assessment protocol (NCT05150873). The proximal sealing zones suitable for standard stent-graft implantations were further analyzed (N=547). The primary outcome assessed the feasibility of 2 single-renal scallop designs (10×10 mm and 15×10 mm, height × width). The feasibility was the inter-renal length ≥10 mm and ≥15 mm for prototypes #10 and #15, respectively. The secondary outcome quantified hypothetical length and surface improvements comparing those suitable for investigational devices implantation (study group) versus those not (control group). Results: Of the total, 24.7% (n=135) was feasible with prototype #10. The study versus control group sealing zones were shorter (p=0.008), with a smaller surface (p=0.009) and a higher alpha angle (p=0.039). The length and surface area increased by about 25% and 23%, respectively, (both p<0.001) within the study group and became significantly better versus the control group (standard stent-graft; both p<0.001). Of the total, 7.1% (n=39) was suitable for prototype #15. The study versus control group sealing zones were shorter (p=0.148), with a smaller surface (p=0.077) and a higher alpha angle (p=0.027). The length and surface area increased by about 34% and 31%, respectively, (both p<0.001) within the study group and became significantly higher versus the control group (standard stent-graft; both p<0.001). Conclusions: The use of single-renal scalloped stent-graft might be feasible in a considerable number of AAA patients. The breakthrough stands in treating hostile AAAs presenting in mismatched renal arteries, keeping the complexity of the repair as similar as possible to standard endovascular repair with a remarkable improvement in sealing. Clinical Impact: The anatomic feasibility of a single renal stent graft for the treatment of “hostile” abdominal aortic aneurysm (AAA) with mismatched renal arteries was evaluated. The experimental device could be feasible in a considerable number of patients with AAA, approaching 25%, and demonstrate significant improvements in sealing. As far as we know, this is the first paper to report the prevalence of mismatched renal arteries in a large cohort of AAA patients in the real world, while proposing a dedicated device. The breakthrough is to keep the complexity of the repair as close as possible to standard endovascular repair.