Introduction
The market of aortic endografts is in continuous development. Several endografts that have gained the CE mark are under investigation by the FDA before launching in the U.S. market. This chapter describes their peculiarities and the evidence acquired with the use of these endografts. Since the majority of the devices described in this chapter have been recently introduced, the evidence on the feasibility of their use in the treatment of aortic aneurysm is limited. The available data report of short-term results in terms of patency, freedom from Types I and III endoleak (EL), and freedom from aneurysm sac enlargement is comparable to those of devices that have been longer in use ( Table 12.1 ).
| Freedom from endoleak Type I/III | Endograft patency | Freedom from sac enlargement | |
|---|---|---|---|
| Infrarenal devices | |||
| Anaconda (33±23 months) | 96.7% | 94.4% | 96% |
| Incraft (48 months) | 97.4% | 97.6% | 89.7% |
| E-vita/E-tegra (10 months) | 100% | 94.7% | 100% |
| 98.9% | 99% | 91% |
| 95.2% | 99.6% | 87.9% |
| 100% | 98.8% | 94% |
| Fenestrated devices | |||
| Anaconda fenestrated (11 months) | 100% | Not reported | 100% a |
| 100% | 100% | 95.5% |
Descriptions of the Devices
Altura
Lombard Medical (Irvine, California) launched the Altura endograft system in 2016. The Altura endograft is designed to treat infrarenal abdominal aortic aneurysms (AAAs) with an aortic neck of 18–28 mm and distal iliac of 8–18 mm (only straight iliac legs available). The endograft consists of two parallel aortic grafts that can be placed at different heights. The ability to position and offset the aortic endografts independently with their bilateral D-stent design is thought to maximize sealing in infrarenal neck. The two aortic grafts are then extended into the iliac vessels.
Because of its 14-French low-profile design, the Altura endograft has the advantage of a minimally invasive approach. The use of two parallel aortic endografts eliminates contralateral limb cannulation, theoretically shortening procedures. The removal of the delivery system does not require any redocking. Furthermore, a built-in injection port simplifies the procedure, allowing precise endograft placement.
The presence of six different sealing zones (aortic neck, between the aortic endografts, two overlap zones between the aortic and the iliac endografts, and the two distal iliac landing zones) theoretically increases the risk of the occurrence of Type III EL.
There is in 2018, a published report on the efficacy of the system in treatment of AAA at 10 clinical sites in two prospective, controlled clinical studies. Krievins et al. report 90 patients treated with a technical success rate of 99%. The procedure-related mortality and reintervention rates were 1% and 4%.
During a median follow-up of 12.5 months (range 11.5–50.9), there were no aneurysm ruptures, surgical conversions, or AAA-related deaths. Clinical success was 94% (84/89) at 30 days, 98% (85/87) at 6 months, and 99% (82/83) at 1 year.
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Treatment range: 18–28 mm aortic neck; 8–18 mm distal iliac landing zone
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Neck length: ≥15 mm
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Neck angulation: ≤60 degrees
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Iliac arteries length: ≥15 mm
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14-French low-profile design
Anaconda
The Anaconda AAA Stent Graft System (Vascutek, Terumo, Inchinnan, Scotland) gained the CE mark in 2014. It is indicated for angulated infrarenal necks up to 90 degrees. A peculiarity of this three-piece system is the fully repositionable deployment, enabling relocation of the proximal ring stents for optimal positioning at the aortic neck. The bifurcated component and the aortic cuffs have a treatment range of 17.5–31 mm (20–23 French). Iliac legs sizes range from 8.5 to 21 mm (all 18 French) for straight, tapered, and flared configurations. The multiple independent leg ring stent design is intended to minimize potential for kinking and allowing treatment of isolated iliac artery aneurysms. Cannulation of the contralateral limb is accelerated by using magnetic forces.
The Anaconda endograft is also available as a fenestrated custom-made device. In comparison with other fenestrated endografts, the presence of two sealing rings and of the unsupported body at the proximal sealing zone allows a more flexible positioning of fenestrations. Furthermore, the Fenestrated Anaconda Custom AAA Stent Graft System is the only fully repositionable fenestrated endograft available on the market. The absence of a top cap allows access to fenestrations proximally and distally.
The widest single-center experience published to date reports 177 patients who underwent implantation of an Anaconda endograft to treat unruptured AAA. Technical success was achieved in 98.9% of the cases. After a mean follow-up time of 33±23.3 months, the late assisted clinical success was 97.7%. The overall survival at 12, 24, and 36 months was 96.4%, 89%, and 86.2%, respectively. Freedom from reintervention was 94%, 92%, and 85% at 12, 24, and 36 months, respectively. Three (1.7%) conversions to open surgery occurred during follow-up. There were 14.1% ELs at the completion angiography (EL Ia, 1.1%; EL II, 13%). Late ELs were 20.2% (EL Ia, 1.1%; EL Ib, 2.2%; EL II, 16.9%). Iliac leg complications occurred in 5.6% of the cases. An AAA shrinkage >5 mm was observed in 130 (73.4%) patients. In 7 (4%) cases there was an AAA enlargement >5 mm.
The widest experience with the fenestrated Anaconda endograft is the result of a prospective study in eight Dutch institutions, where 25 patients were treated for juxtarenal (n=23) and short-neck infrarenal AAA (n=2). A total of 56 fenestrations were incorporated, and 53 (94.6%) were successfully cannulated and stented. On completion of angiography, three Type I ELs and seven Type II ELs were observed. One patient died of bowel ischemia caused by occlusion of the superior mesenteric artery in the immediate postoperative period. At 1 month of follow-up, all ELs had spontaneously resolved, while the primary patency of cannulated and stented target vessels was 96%. After a median follow-up time of 11 months (range 1–29 months) no aneurysm ruptures or aneurysm-related deaths and no reinterventions had occurred.
One of the claimed advantages of the Anaconda graft is the ability to treat AAA with severe angulated necks. The same Dutch research group previously cited conducted a prospective study on 36 patients treated because of infrarenal AAA with an aortic neck of >60 degrees (mean angulation: 82 degrees). In this study cohort, the primary technical success was achieved in 30 of 36 patients (83%). There was no aneurysm-related death. Four-year primary clinical success was 69%. In the first year, eight clinical failures were reported including four leg occlusions that could be solved using standard procedures. After the first year, three patients with additional failures occurred; two of them were leg occlusions. Four patients needed conversion to open AAA exclusion. In six of 36 patients, one or more reinterventions were necessary. Three of them were performed for occlusion of one Anaconda leg and two were for occlusion of the body. The authors concluded that the use of the Anaconda endovascular graft in AAA with a severe angulated infrarenal neck can lead to clinical failures, mostly in the first year postimplantation, but midterm results have been considered acceptable.
