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.

Two Decades of Abdominal Aortic Endovascular Repair With the Anatomical FiXation at the Aortic Bifurcation in a Large Single-Center Experience

OBJECTIVE

The introduction of new endograft models improved long-term results of abdominal aortic aneurysm (AAA) endovascular repair (EVAR), but most of them maintained an old and unchanged design: a short body and long legs shifting up the flow divider. This study assessed the long-term results of EVAR with unimodular endoprosthesis fixed at the aorto-iliac bifurcation (Anatomical FiXation), in a large, unselected cohort.

MATERIALS AND METHODS

In a single-center, retrospective cohort study, 623 patients selectively treated between 1999 and 2016, were analyzed. Follow-up protocol included at least a computed tomography angiography within 3 months and a duplex ultrasound and clinical exam yearly. All enrolled patients were analyzed by 2020. The primary outcomes were technical success, clinical success, and survival. Secondary outcomes included survival-free from late-open-conversion (LOC), reintervention, and endoleaks.

RESULTS

Median age was 74±11 years and the follow-up 93±54 months. The technical success was achieved in 99.4% and the 30-day clinical success was 98.4%. A 5-year clinical success of 97.7% was registered and at 10 years success was 96.7%. The overall survival at 1, 5, 10, and 15 years was 92.4%, 79.5%, 64.9%, and 45.5%, respectively. Six (0.98%) AAA-related death were registered, 3 caused by infection of the endograft and 3 for secondary rupture. LOCs were 9 (1.47%) and reintervention-free survival at 1, 5, 10, and 15 years were 88.4%, 78.0%, 76.2%, and 74.6%, respectively. Freedom from endoleaks was 88.8% at 1 year and 72.7% at 15 years. A total of 63 high-flow endoleaks were registered (43 type I, 7 type IIIa, 12 type IIIb, and 1 type Ib+IIIb). No migrations were recorded, and the graft limb thrombosis rate was 1.14%. From a multivariate analysis resulted that long-term clinical success appeared to be reduced in patients affected by diabetes [odds ratio (OR) 0.24; p=0.04] and in presence of calcified and thrombotic iliac accesses (OR 0.16; p=0.006).

CONCLUSION

EVAR with the Anatomical FiXation was confirmed to be safe, feasible, and effective to prevent AAA rupture in the long term as well. However, the overall survival remains afflicted by cardiovascular accident. The original concept of unibody bifurcated design allowed a very low rate of graft thrombosis and zeroed the risk of migration and related reintervention.