Abdominal aortic aneurysm (AAA) is a life-threatening abnormal dilation of the abdominal aorta to >3 cm, which is 1.5 times its normal diameter and can lead to serious complications such as rupture (1, 2). Importantly, ruptured AAA can have a mortality of up to 80% if untreated (3). Management of AAA includes repair, which can be performed either endovascularly or via open surgical repair (OSR). OSR was considered the mainstay treatment for AAA for many years; however, since the introduction of endovascular aortic repair (EVAR) almost three decades ago, it has seen major utilization in the treatment of AAA, replacing OSR for most elective cases (4–6). Considering lower mortality and improved morbidity, EVAR now accounts for 60% of elective infrarenal AAA repairs, 61.3% of complex AAA repairs, and 41.3% of ruptured AAA repairs in the United Kingdom since 2020 (7).

Several EVAR stent-grafts exist commercially on the global market, these having undergone significant upgrades over the years to widen their armamentarium in tackling increasingly complex AAA pathology and improve clinical outcomes (8). EVAR devices can be predominantly split into three main categories, namely, off-the-shelf endografts, physician-modified devices, or custom-made devices (CMDs), with their main variants being standard, fenestrated, and branched EVAR (9). The Anaconda™ AAA stent-graft system is a leading custom-made fenestrated EVAR (FEVAR) device developed by Terumo Aortic and has been associated with excellent clinical outcomes. The Anaconda™ device can be considered the superior commercial EVAR device on the market due to its unique design and high versatility with multiple device categories.

Furthermore, there are different configurations with a global market for its use. These are in addition to its global use, outstanding custom-made approach, and superior results (10–12).

In this study, we sought to provide an international perspective using multicenter-multinational data on the Anaconda™ device delivery, including its categories, configurations, geographical distribution, indications, delivery time frame, prototype requirement, and custom-made approach for fenestrations. Essentially, can the Anaconda™ CMD deliver?

The current third-generation Anaconda™ device used globally evolved from two earlier versions, first of which was introduced in 1998 to address some of the failures observed with other EVAR stent-grafts in the 1990’s (8, 10, 12). The first-generation Anaconda™ device did not feature any hooks and completely relied on friction sealing for proximal fixation and prevention of endograft migration. The second-generation device had independent nitinol rings, zero columnar support, and straight limbs (10). This device underwent modifications based on many years of experience to develop its current version. The third-generation Anaconda™ features the ONE-LOK™ platform (8). This readjustable self-expanding bimodular device comprised of a nitinol skeleton that supports a woven polyester fabric (13). The flexible skeleton is formed by independent nitinol stent rings in a circular design, with zero body support of the graft with the possibility of adding an augmented valley (8, 10, 12). This design has proven to have greater flexibility, as well as lower stress values than Z-stents such as Zenith, and thus better durability (14). The proximal seal is achieved with the two saddle-shaped proximal nitinol ring stents in addition to hooks connected to them, which is a new feature of the third-generation Anaconda™ added to absolutely minimize incidence of endograft migration. Three to four nitinol hooks support the proximal seal to the aortic wall (8, 10, 12). The device also features a magnetic guidewire/docking system for navigating the bifurcated distal portion of the graft and can be used for cannulation of the contralateral gate (15).

As for the limbs, these are supported with independent nitinol rings to prevent kinking and come in three configurations according to iliac artery diameter, namely, tapered, straight, and flared, each measuring either 60, 100, or 120 mm in length (10, 15, 16). One unique feature of the Anaconda™ is its high versatility, offering a wide range of body-limb size combinations, as the docking zone limb diameter was standardized in its third iteration (16). The main body of the graft is commercially available in eight different diameters ranging from 19.5 to 34 mm while the iliac leg branches are also available with diameters ranging from 9 to 18 mm (15). Once inserted, it can be fully repositioned by use of the control collar of the delivery system handle (12, 17). This feature is vital in FEVAR to ensure perfect alignment between fenestrations and target vessels ostia. In addition, the fenestrations can be cannulated from either end of the graft (17).

The Anaconda™ custom-made approach allows the device to be tailored to individual patient anatomy and expands its use for treating hostile aortic anatomy such as angulated or stenosed necks and diseased iliac artery branches (12, 13). However, this is only feasible for elective cases. Although Anaconda™ construction time is between 3 and 6 weeks, this is less than half the time required for other competitor devices to be customized (10–12 weeks) (12, 18). In addition, device prototypes are provided by Terumo Aortic. Preoperatively, a 3D model of the patient’s exact aorta can be printed, and the procedure can be rehearsed using the non-sterile device prototype (12). In turn, any modifications to the device or plan can be done at that point to allow for a safer smoother procedure and optimized results. Finally, the Anaconda™ instruction for use (IFU) recommends oversizing the stent-graft by 10–20% and indicates the possibility for treating highly angulated necks with indication for up to 90°, ensuring that clinicians are using the device on label (12, 17).

As indicated in the “Materials and methods” and “Results” section, out of the 5,030 Anaconda™ devices implanted globally, 3,891 (77.4%) were utilized due to the competitors’ inabilities/incompatibilities to treat the unsuitable/complex aortic anatomy presented. The third-generation Anaconda™ innovative design features, along with its unique custom-made approach, allow it to thrive in hostile aortic anatomy. In addition, the Anaconda™ IFU allows a wider range of indications compared to competitors, which enables it to be used in tortuous clinical circumstances where other devices fail. The Anaconda™ is also a highly versatile endograft offering a wide range of device categories and configurations (15–17). The availability of the device prototype has been proven to be a highly valuable tool in the era of custom-made endografts. This is evident in Taher et al. (19), who reported that 21.7% of their 60 Anaconda™ devices were modified after prototype testing. As demonstrated in our results, 95% of the 5,058 Anaconda™ devices implanted were delivered along with a prototype. Similarly, Pini et al. (20) were provided with Anaconda™ prototypes for all their 127 cases.

The Anaconda™’s superiority in rough terrain as mentioned earlier is evident in a multicenter 6-year prospective cohort study by Rodel el al. (21). The study population consisted of 36 patients (83.3% men) with infrarenal AAAs with severely angulated necks (> 60°) treated with the second-generation Anaconda™. The mean neck angulation was 82°, which is outside the IFU of many devices, including Zenith. Successful deployment was achieved in 34/36 (94.4%) patients while the primary technical success rate was 83.3%. After 30 days, all-cause mortality, primary clinical success, primary assisted and secondary clinical success rates were 0, 88.9, and 94.4%, respectively. This demonstrates the excellent performance of the Anaconda™ even in higher-risk clinical circumstances. During the full study period, no aneurysm-related deaths occurred. Freedom from reintervention was 89, 83, and 80% at 1, 2, and 3 years of follow-up. Similarly, freedom from endograft migration was 100 and 97% after 2 and 4 years, respectively (21). These rates are superior to freedom from reintervention and endograft migration achieved with Zenith (22–25). Interestingly, incidence of iliac limb occlusion was 14%, which is still comparable to values reported in studies using other devices in normal circumstances (21). For example, in their Zenith group, Bogdanovic et al. reported a 12.4% rate of limb occlusion (26).

The French multicenter prospective observational study (EPI-ANA-01) by Midy et al. (27) used the Anaconda™ endograft in 176 patients with a suitable infrarenal AAA. However, 33.9% had hostile neck anatomy (with neck angulation >90° in 5.1%) and 10.7% were treated outside the already widespan IFU. Hostile neck anatomy was defined as any or all of length < 10 mm, angle > 60°, diameter > 28 mm, ≥ 50% circumferential thrombus, ≥ 50% calcified neck, and reverse taper. Successful deployment was achieved in 99.4% of patients with 98.3 and 94.9% technical and clinical success rates, respectively. The repositionable deployment system was used in 36.4% of the cases (31.7% in hostile necks vs. 33.3% in favorable necks; p = 0.87) and the magnet wire cannulation system in 93.8%. All Anaconda™ grafts were bifurcated, and all three limb configurations were utilized (32.4% straight, 2.8% tapered, 64.8% flared). Importantly, outstanding clinical outcomes were achieved, including 1.7% 30-day mortality, 4.3% limb occlusion, and 19.9% secondary intervention and significant aneurysm sac regression (27). These results, despite the technical and clinical challenges, are superior to those achieved with Zenith. Oderich et al. (23) and Vaaramaki et al. (24) reported a 29.9 and 22% reintervention rate, respectively, at 12 months post-EVAR using Zenith. The latter study also observed a 5% incidence of iliac limb occlusion (24).

Demanget and colleagues (14) modeled eight commercial EVAR devices using finite element analysis. The grafts’ flexibility was assessed, and a numerical benchmark combining bending up to 180° and pressurization at 150 mmHg was performed. Owing to its circular-stented design, the Anaconda™ demonstrated the lowest luminal reduction rate as well as the lowest maximal stress both at 180°, hence greater flexibility and durability compared to the other grafts, particularly the Z-stented grafts, including Zenith (14). Furthermore, using a custom-developed testing apparatus, Crawford investigated the structural impact of misaligned fenestrations in Anaconda™ and Zenith regarding luminal patency and proximal aortic neck apposition (28). The Anaconda™ demonstrated a linear decrease in luminal patency as the angulation degree was increased without any losses in wall apposition, while in contrast Zenith was associated with a decrease in cross-sectional area along with a significant loss in wall apposition (28). Therefore, it can be suggested that the mechanical properties of the Anaconda™ make it a more effective device for extremes of the vascular anatomy.

Finally, de Niet et al. (29) also compared Anaconda™ against Zenith. This 14-year study of 145 patients sought to evaluate the conformability of both the Anaconda™ (n = 35) and Zenith (n = 110) endografts. The influence of different graft designs on aortic anatomy after implantation was assessed. The procedural details of both devices can be seen in Figure 8 [reproduced from de Niet et al. (29)]. The slight difference in procedural time was insignificant, but, on the other hand, both contrast volume and estimated blood loss were significantly less with the Anaconda™ graft. In addition, the majority of devices used were bifurcated and with two fenestrations in both groups. Interestingly, 36 adjunctive procedures were required in 33 Zenith patients compared with 11 in 10 Anaconda™ patients, shedding light on the Anaconda™ more advanced delivery system (29).

There is enough evidence to suggest that the Anaconda™ is associated with superior performance and optimal delivery thanks to its distinctively novel design. This, in addition to its custom-made approach and high versatility, makes it the prime endograft choice to navigate tortious aortic anatomy where competitors will not dare to or simply cannot.

The original contributions presented in this study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.

MJ, AS, and ST were involved in the drafting of the manuscript. DB, IW, and MB were involved in reviewing and providing feedback on the manuscript. All authors contributed to the article and approved the submitted version.

On behalf of the Southeast Wales Vascular Network (DB and IW) and National Cardiovascular Research Network (DB). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.