Hostile Neck Solutions: How to deal with hostile necks using off-the-shelf solutions

September 2019 | Educational Supplement

Hostile Neck Solutions How to deal with hostile necks using off-the-shelf solutions

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This educational supplement has been sponsored by Medtronic

Comment & Analysis

Defining the boundaries of the hostile neck

In this article, Jean-Paul de Vries and Richte Schuurmann discuss the challenges of defining the hostile neck anatomy in abdominal aortic aneurysms, and outline the implications of this anatomy for planning and technique of endovascular repair. ACROSS ALL AVAILABLE LITERATURE describing how to measure and define the aneurysmal neck, only a few groups have a standardised method for performing this measurement. These are mainly based on centreline reconstruction and workstations, but there is still some degree of subjectivity involved as “eyeballing” is required at some stages. For example, even a centreline reconstruction provides a type of twodimensional image of what is in reality a three-dimensional area. This also depends, for instance, on the amount of oversizing, which some physicians might do in certain neck anatomies in order to provide an optimal sealing zone. Therefore, the process of defining the hostile neck anatomy becomes challenging, due to a combination of obstacles. From standardisation of measurements, to the amount of experience and expertise of the individual vascular surgeon Jean-Paul de Vries or interventional radiologist, to the particular devices used, there are many factors that will vary from case to case, making it difficult to give a simple definition of a hostile neck anatomy. Nevertheless, the importance of implementing a dedicated route for obtaining quality measurements is significant, as hostile neck anatomy is a predictor for complications and later failures, and careful planning is needed to achieve successful and durable outcomes. Workstation reconstructions are essential for case planning, as a normal CT scan will not be able to provide adequate information on the neck length. Anyone can learn to do a reconstruction, and it is worthwhile having someone on each team, or the whole team, trained to do so, but in some cases CT scans can also be sent to manufacturers to aid in this process. Some degree of subjectivity and reliance on experience remains, as physicians learn the limitations of specific devices and techniques. Currently, the SWAC (short, wide, angulated, conical) classification exists

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to help define the hostile neck in a more thorough set of parameters. In literature several definitions of the length of the neck do exist, and this has to be taken into account when interpreting data and results. For example in Medtronic’s ANCHOR registry the core lab defined neck length over which the neck diameter remains within 10% of the infrarenal diameter. Some physicians consider the neck ending when the diameter increase is >4 mm compared to baseline. At the post-operative CT-scan the infrarenal neck ends where circumferential apposition of the endograft is lost. Wide neck (>28mm), angulated (>60° infrarenal) and conical (>20% diameter increase) are the other important challenging neck characteristics. Although a hostile neck has typically been defined in many publications by a certain degree of neck angulation, the presence of Richte Schuurmann high curvature may be a more useful indication of a hostile neck than simply assessing the angulation. For example, if you bend an endograft, you will see that the device can only bend to a certain degree of curvature. An angle of 60° can nevertheless be a very long angle, with the lower curvature allowing an endograft to sit perfectly. However, with very sharp angle and high curvature neck anatomy, there may be more difficulty in placing an endograft successfully. We have demonstrated this idea in several publications, and challenged the notion that a hostile neck may only be defined by suprarenal or infrarenal angulation. Our addition of curvature, we argue, may be a better predictor for type 1a endoleak or migration. As this factor really defines bending of the neck of the aneurysm, it provides a more useful definition of what a hostile neck looks like. Additionally, thrombus in the neck and amount of calcium need to be considered as well. Again, the amount of thrombus and calcium present is a difficult measurement to standardise, as occlusion can be local and

the region of occlusion can vary greatly. It is still unclear in literature whether thrombus is an accurate predictor of failure or even if it helps to prevent failure in the short-term. This lack of clarity may be due in part to measurements not being standardised across studies. Finally, international guidelines point to a range of classification systems, from Rutherford to TASC, but we do not yet have a scoring system dedicated to defining a range of hostile aneurysm necks. This is something that may be worth development in the future. Currently, another important unmet needs for this patient population is the need for virtual stenting: a tool on the workstation which enables the physician to place the stent in the individual patient’s anatomy virtually, first, before performing the procedure in reality. This will enable the physician to ensure they have the correct measurements for the stent, the correct anatomy, and that a circumferential seal will be achieved. The amount of oversizing of the endograft will influence the length of the circumferential apposition between the endograft and the infrarenal neck. In general, the more oversizing of the endograft the longer will be the length of the infrarenal aortic neck that is sealed. Currently useful adjuncts are available to improve fixation and seal in challenging aortic necks. The use of EndoAnchor implants have been proven to prevent migration during follow-up in challenging aortic neck anatomies and to reinforce fixation. Moreover, EndoAnchor implants are of great help to treat acute and late type Ia endoleaks. In case of very short necks, when a suitable sealing zone cannot be achieved infrarenally, other endovascular techniques must be used for a sustainable seal. Chimney stent grafts for the renal arteries in combination with an Endurant II/IIs endograft is a useful technique. If the seal must be extended to the superior mesenteric artery and celiac trunk a fenestrated endograft should be preferred. If you decide to treat a patient with a challenging or hostile neck, one of the most important things to do is to follow up after the procedure, to see if the procedure was successful and sufficient immediately after, and to make sure the treatment remains effective over time. There is a small category of patients who benefit from some CT follow-up, but all patients who have potentially challenging anatomy should be followed up rigorously. Jean-Paul de Vries is a Professor of Surgery and Richte Schuurmann is a Postdoctoral Researcher at the University Medical Centre Groningen, the Netherlands. September 2019

Case reports

How to deal with hostile necks using off-the-shelf solutions

Limitations of custom-made solutions and the added value of off-the-shelf treatment options Custom-made solutions for complex aortic aneurysm seem promising, writes Antoine Millon. However, there are still situations whether off-the-shelf solutions are preferable. Millon describes limitations and advantages of current endovascular options for hostile necks treatment, including endosuture aneurysm repair (ESAR). FENESTRATED STENT GRAFTS require large femoral and iliac access due to manufacture constraints with 20F, 22F or 24F delivery systems compared to standard EVAR stent graft. Besides diameter, iliac tortuosity and calcifications can also make trackability, orientation and positioning of the fenestrated stent graft challenging as well as manipulation of the catheters for visceral vessels cannulation. Angulation of the visceral aorta makes positioning of the fenestrated stent graft at the level of the renal arteries hazardous and affect stent graft manipulation. Shaggy thrombus in the aorta increases the risk of thromboembolic event during deployment, positioning of the fenestrated stent graft as well as during target vessels catheterisation. Small diameter (<5mm), short trunk or early bifurcation (<15mm) of the renal arteries increase the risk of occlusion or endoleak. Anterior take off, angulation and stenosis can also make cannulation and stenting very challenging. Both FEVAR and ChEVAR procedures can be associated with renal function degradation, peri- and post-operatively, according to previous literature. Thereby, patients with severe chronic renal failure treated with FEVAR or ChEVAR are at high risk of renal insufficiency and dialysis in the midterm. Patients with large aneurysms but with short life expectancy probably do not require the same treatment as patients with longer life

CASE REPORT

expectancy. Large or symptomatic aneurysm requires treatment in short delay. Patients with additional pathology like cancer who require immediate treatment should take advantage from off-the-shelf solutions. The manufacturing time makes some situations very complex both from a clinical and an emotional perspective. Besides the cost of the custom-made devices, FEVAR procedures require a large number of sheaths, catheters and stents, increasing the cost of the treatment. FEVAR procedures are also technically demanding with a long learning curve compared to standard EVAR procedure. Positioning the custom-made device, cannulating and stenting all fenestrations and the target vessels requires time and experience. ChEVAR could answer some of these limitations by offering an off-the-shelf solution and technically easier procedure than FEVAR, leveraging on a similar approach in extending the neck, creating a sealing zone above the renals. However, this technique still requires renal arteries cannulation and stenting (with the anatomical limitation and the renal risk mentioned above). Moreover, a very careful evaluation of the superior mesenteric artery patency is paramount at completion angiography. ESAR is a promising solution for hostile neck abdominal aortic aneurysms, addressing all these limitations with an offthe-shelf device. This is a simple procedure without renal manipulations.

A 69-year-old man with no relevant comorbidities who presented with chest pain. X-ray showed pleural effusion and CT scan confirmed hemothorax related to bronchopulmonary neoplasia. CT scan also showed a 90mm abdominal aortic aneurysm. Anatomical analysis (Figure 1) revealed a short (length 9mm) and angulated neck (α 42° and β 48°), an upper polar right renal artery (diameter 3.5mm) and an early bifurcation of the left renal artery (length <15mm). Aneurysm size and the need of not delaying cancer treatment make a custom-made device not appropriate because of the manufacturing delay. Moreover, renal arteries disposition (upper polar, short trunk) makes FEVAR at high risk of endoleak and renal impairment. An off-the-shelf solution was considered. ChEVAR was not the best choice due to the same FEVAR anatomical challenges related to the renal arteries. An ESAR procedure was the only on-label option without renal arteries manipulation (Figure 2). At one year, significant sac regression has been observed (maximum transverse diameter went from 86.4mm at one month to 78.8mm at one year), with no evidence of endoleaks or graft related complications.

September 2019

Left: Antoine Millon

A

B

C

D

Figure 1: Anatomical situation. Short and angulated proximal neck (A, B); right renal artery associated with an upper polar (C); short trunk of the left renal artery (D).

A

B Figure 2: Juxta renal deployment of the Endurant II stent graft followed by eight EndoAnchor implants placement with final angiography showing no proximal endoleak (A); MPR reconstruction of postoperative CT scan allowing visualisation of EndoAnchor implants (B).

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Interview

Securing the hostile neck: Benefits of ESAR In this article, three experts on hostile aneurysm neck antomy discuss the benefits of endosuture aneurysm repair (ESAR) with Endurant II/IIs and Heli-FX EndoAnchor System, and outline the current available evidence.

What advantages do wide and conical necks present for treatment?

LATE COMPLICATIONS AND subsequent reinterventions after EVAR remain to be a significant burden. The incidence of these complications is a result of patient-, device- and physician-related factors. There is considerable evidence that the proximal neck anatomy is predictive for the risk of both early and late complications. In a recent study, Mc Farland et al showed in a group of 500 EVAR treated patients that standard EVAR in patients with an infrarenal neck diameter of â&#x2030;Ľ29mm is independently associated with an increased rate of proximal failures. Besides those with a large infrarenal neck diameter, also those with short and/or conical neck are also at risk for failure. With the increased

What is the impact of EndoAnchor implants on aneurysmal sac regression?

knowledge on long-term outcome after EVAR it became apparent that infrarenal neck enlargement is a problem that is not to be underestimated. In a review of literature, Michel Reijnen including 9,721 patients, Kouvelos et al described an incidence of neck enlargement after EVAR of 24.6%. In these patients with neck enlargement there was a more than tenfold increased incidence of type Ia endoleak, migration and/or reinterventions. The pathophysiology of neck enlargement is not fully elucidated but is likely to be a combination of progression of disease and

THE ANEURYSMAL SAC REGRESSION has long been considered as a surrogate of durable EVAR treatment. Moreover, it represents also for the patient a very important feature of EVAR success. Jetty et al recently published in the JVS a large cohort of patients treated by EVAR for an abdominal aortic Francois Saucy aneurysm (AAA) with 60% of >5mm sac regression at two years. Age <75 years, sex female and large original AAA diameter and specific endograft design influenced the variability in sac regression. Unfortunately, many of these characteristics cannot be modified to improve the rate of sac regression. Endoleak type Ia and migration are also independent risk factors for aneurysmal sac expansion and occurred more frequently in hostile neck. These factors can be addressed by fixing the fabric to the aortic wall just below the lowest renal artery. The Heli-FX EndoAnchor system (Medtronic) evolves standard EVAR to improve aorta- graft apposition by creating an endovascular suture line. Muhs et al recently published in the JVS a propensitymatched comparison between subjects who received prophylactic EndoAnchor implants during EVAR (ANCHOR) and a retrospective cohort who underwent standard EVAR. The rate of sac regression at two years was observed in 81.1% in ANCHOR subjects compared to 48.7% of control subjects. The potential negative effect of wide neck and presence of thrombus in the neck might be mitigated by EndoAnchor implants, as stated by authors. A hypothesis of unnoticed microendoleaks with usual CTA-scan imaging should evaluate the impact of Heli-FX EndoAnchor system on adjusting perfectly the fabric to the aortic wall and thus limiting potential microendoleaks. In conclusion, ESAR promotes sac regression through two years and is indicated in wide and thin thrombotic neck to mitigate their adverse effects on sac regression.

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the continuous outward force on the vessel wall induced by oversized endografts. The observation that neck enlargement occurs after both open and endovascular repair points towards the first mechanism. However, in a study performed on 257 patients treated with ESAR, Tassiopoulos et al found endograft oversizing to be an independent risk factor for early neck enlargement. Interestingly, the use of EndoAnchor implants had a protective effect on early neck enlargement in this study. This indicates that, particularly in those patients with wide and conical necks, there may be a benefit of protective stapling, enhancing stability and potentially reducing neck enlargement. A confirmatory prospective trial on this topic in patients with a large and conical necks is therefore indicated.

Latest evidence available in prophylactic treatment of the hostile neck.

ANEURYSMS SPORTING A challenging short, wide, angulated and conical necks present a hostile target for sealing and fixation over the long term. The plain fact of the matter is that the hostile neck is almost always a diseased neck. There is inevitably degeneration, dilatation and graft failure. An attractive proposition is the principle of Colin Bicknell anchoring a standard stent graft system to the aorta with EndoAnchor implants, providing fixation and maintaining the sealing zone even in difficult anatomical neck configurations. There is now retrospective propensity matched cohort evidence that this system is effective in preventing migration, neck dilatation (at least in the first few years) and seems to lead to a significantly greater rate of sac regression. The ANCHOR registry, a prospective, observational, international, multicentre, dual-arm registry, has now reported three-year results. The cohort of patients where EndoAnchor implants have been placed as a prophylactic measure, have a median neck length of 11.2mm and over 85.8% are classified as having a hostile (short, wide, angled or conical) neck. Despite this, there is a 1.7% rate of type Ia endoleak, no migration and there is also a significant incidence of sac regression in this series. These data are encouraging signs, as the complication rate is so low in this difficult group. This technology allows for the safe and effective (at least to three years) treatment of more complex AAA anatomies with greater confidence. The longer-term results are needed before this technology will become widely adopted one expects. There is a great deal of work to be done in understanding which technology fits which patient in which situation. Algorithms of treatment that utilise the strengths of each technology are fiendishly difficult to design, but as further evidence emerges the options available to treat the hostile neck increase, to the benefit of those who are unable to tolerate an open repair. September 2019

Comment & Analysis

How to deal with hostile necks using off-the-shelf solutions

New in vitro study confirms that the degree of aortic stent graft oversizing plays a decisive role in the rapid disappearance of gutter-related endoleaks with ChEVAR In this article, Konstantinos Donas and Gergana Taneva outline the in vitro data, to investigate the impact of oversizing aortic stent grafts for chimney endovascular aneurysm repair (ChEVAR), specifically with regards to flow in the gutters. IN DECEMBER 2016, the Endurant II/IIs stent graft system received a European CE mark approval for use in conjuction with BECS as chimney grafts having indication for use in renal arteries. In order to evaluate the impact of oversizing of the aortic stent graft on the area of the gutters, we conducted an in vitro study. The silicon model was manufactured by the Medizinische Modellbau Manufaktur GmbH (MMM). The anatomical characteristics and design were based on the findings of a preoperative computed tomography angiography (CTA) of a patient with a 7cm

could be adjusted individually. A 128-slice multidetector-row CT scanner was used to generate CTA images. The model was placed in the CT scanner (Figure 1). CTA data were analysed using the OsiriX MD v.8.5.2 (Pixmeo, Bernex) evaluating the area of the gutters. The area of the gutters was defined as that luminal area inside the silicon aortic model (in mm2) that was not covered by endograft or parallel stent. It was measured 1mm caudally to the endograft markers indicating the upper fabric edge of the endograft. Measurements were made using a plane perpendicular to the blood flow centerline.

Konstantinos Donas

these and more in vitro findings of our group (Gergana T Taneva, Konstantinos P Donas, Giovanni B Torsello, Francisco Azevedo and Giovanni F Torsello) will be published soon in the Journal of Endovascular Therapy. The use of the Advanta V12 was associated with promising in vivo results based on the PROTAGORAS Study. The patency of 95% and freedom from reintervention of 93% demonstrate the superiority as chimney graft. Therefore, we used in our in vitro testing this successful combination of devices changing only the degree of oversizing and having all other conditions similar. Our results showed that even if we use the combination with the best results (Endurant II/IIs and Advanta V12) the outcomes regarding the area of the gutters and consequently the risk of persistent type IA endoleaks can be worsen if we select the device with 32mm diameter vs the one with the 36mm diameter. This small difference in selection of the devices is associated with

Figure 2: Endurant II/IIs (32mm) with 7mm Advanta

Figure 1: The yellow circle on the CT angiography highlights the position of the angiographic catheter to inject contrast medium

degenerative juxtarenal aneurysm treated with single chimney EVAR (ChEVAR) by placement of Endurant II/IIs stent graft and a 7x38mm Advanta/i-Cast V12 chimney graft for the right renal artery. The model was connected to a pulsatile pumping system (60 beats per minute) with a systolic/diastolic “blood” pressure of 140/60mmHg and a fluid temperature of 37°C. All these parameters September 2019

Figures 2 and 3 demonstrate the impact of 15% vs 30% oversizing of the Endurant II/IIs stent graft on the area of the gutters. Figure 3 which shows the case with the 30% oversizing illustrates clearly an excellent conformability with no remarkable evidence of gutters having enough fabric material to wrap up the chimney graft compared to Figure 2 with the 15% oversized device. A detailed presentation of

Gergana Taneva

Figure 3: Endurant II/IIs (36mm) with 7mm Advanta

completely different outcomes regarding the area of the gutters and consequently the persistence of gutter-related endoleaks. The conclusion of our work is that the degree of oversizing of the abdominal stent graft plays a crucial role for the fast disappearance of gutter-related endoleaks postoperatively and should be well considered during sizing and planning of ChEVAR. Konstantinos P Donas is professor of Vascular Surgery. vascular surgeon, phlebologist and endovascular specialist at St Franziskus Hospital in Münster, Germany. Gergana T Taneva is a research fellow at St Franziskus Hospital in Münster, Germany.

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Case reports

Off-the-shelf options for short necks

Endosuture aneurysm repair (ESAR) with the Heli-FX EndoAnchor system and chimney EVAR (ChEVAR) are off-the-shelf solutions that, combined with the Endurant II-IIs stent graft, add treatment options for patients with short-neck aneurysms. In this article, epxerts in the field outline the latest data and the possibilities for improved durability of endovascular aneurysm repair, towards a treatment choice algorithm.

Clear wins of ESAR in short necks THE ESAR THERAPY PROVIDES A clear improvement of the fixation and sealing mechanism during EVAR (when properly deployed to provide with adequate aortic wall penetration in selected patients), especially in short <10mm and conical necks, where durability may be compromised if treated with standard EVAR. Although other Andres Reyes techniques have demonstrated to be safe and durable (fenestrated and chimney EVAR) certain anatomical constraints may lead to procedural complications or failure, such as (upwards) orientation of renal arteries, iliac/arm access tortuosity or calcifications or arch thrombus load (increasing the risk of stroke). Hence, EndoAnchor implants become an extremely useful tool and a “clear win” for the endovascular approach of hostile abdominal aortic aneurysm in such conditions.

CASE REPORT

A 90-year-old self-sufficient male, with a symptomatic 72mm abdominal aortic aneurysm came to the emergency department. No pain killers relieved the abdominal symptoms. CT-scan revealed a 7.5mm neck length with a reverse conical configuration, 22–20mm diameter and 60 degrees infrarenal angulation. No calcium or thrombus were encountered. He was urgently treated with a bifurcated Endurant IIs 25mm endograft (12–22% oversizing) and a small type Ia endoleak appeared after balloon remodeling. We circumferentially deployed five EndoAnchor implants and the type Ia endoleak disappeared on final angiography (A). Control CT-scan at six months showed adequate aortic wall EndoAnchor implant penetration (B) and absence of proximal endoleak (C), with 5mm sac regression.

Latest data from the ANCHOR short neck cohort ENDOVASCULAR SUTURE ANEURYSM repair (ESAR) using Heli-FX EndoAnchor system in combination with standard endograft has been proposed as an off-theshelf endovascular solution in patients with challenging neck, including short, angulated and wide infrarenal aortic neck. Results from Giovanni Pratesi the primary arm of the ANCHOR registry with prophylactic use of EndoAnchor implants, proved ESAR to be effective in preventing neck dilatation and increase aneurysm sac regression.1,2 Additional data from a subgroup analysis of the ANCHOR registry demonstrated the safety and effectiveness of ESAR in treating AAA with short aortic neck.3 The ANCHOR short neck cohort includes 70 patients with an infrarenal neck length of <10mm (with an average neck length of 6.9±1.6mm) treated using the Endurant II/IIs endograft in conjunction with Heli-FX EndoAnchor implants. Neck length is defined by Core Lab as the length over which neck diameter remains within 10% of infrarenal diameter. Primary outcomes of the analysis included technical and procedural success, rate of type Ia endoleak at one and 12 months and rate of secondary procedures at 12 months. Overall procedural success rate, defined as technical success without a type Ia endoleak at completion angiography, was 97.1%. An average of 5.5±2.1 EndoAnchor implants were implanted per patient and total procedure time was 148±80 minutes. At 30-day followup, four type Ia endoleaks were detected, of which three resolved spontaneously by the 12-month follow-up. There was an additional type Ia endoleak through the 12-month follow-up not associated with AAA enlargement or secondary procedure. There were four (5.7%) deaths within 30 days of the index procedure; three were cardiac related deaths and one was due to acute hepatitis, renal failure and pancreatitis. The Kaplan-Meier estimate for freedom from secondary endovascular procedures and all-cause mortality was 95.5% and 92.8% through 365 days, respectively. No patient in the short-neck cohort experienced main body stent migration, increase in maximum aneurysm diameter, or aneurysm rupture or required conversion to open repair through 12 months. Whereas long-term follow-up is still needed to assess the durability of this treatment strategy, the ANCHOR short neck cohort results showed that ESAR with Endurant II/IIs endograft and complementary Heli-FX EndoAnchor implants is a safe and effective off-the-shelf therapy in treating short aortic neck, providing high technical success rate and low incidence of type Ia endoleak at 12-month follow-up. References 1. Tassiopoulos AK, Monastiriotis S, Jordan WD, et al. Predictors of early aortic neck dilatation after endovascular aneurysm repair with EndoAnchors. J Vasc Surg. 2017;66(1):45-52. 2. Muhs BE, Jordan W, Ouriel K, et al. Matched cohort comparison of endovascular abdominal aortic aneurysm repair with and without EndoAnchors. J Vasc Surg. 2018;67(6):1699-1707. 3. Arko FR 3rd, Stanley GA, Pearce BJ, et al. Endosuture aneurysm repair in patients treated with Endurant II/IIs in conjunction with Heli-FX EndoAnchor implants for short-neck abdominal aortic aneurysm. J Vasc Surg. 2019; 5.

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September 2019

How to deal with hostile necks using off-the-shelf solutions

ChEVAR

CHIMNEY ENDOVASCULAR aneurysm repair (ChEVAR) has grown steadily over the years, despite resistance to the technique due to some misleading Konstantinos Donas conclusions regarding gutters and endoleaks. The PERICLES group observed that the majority of ChEVAR gutter endoleaks detected on completion angiography have resolved spontaneously by the time the first postoperative CTA is performed, when the two important parameters of 30% oversizing and new sealing zone of 20mm are taken into account. This demonstrated in the most exemplary way that the phenomenon of the gutters represents a benign condition in the majority of the treated cases. However, these important scientific findings were not screened as they should during presentations and discussions at various meetings, resulting that ChEVAR gutter endoleaks tend to be lumped together as the sum-total of those detected on completion angiography, first CTA, and even late-onset endoleaks. Consequently, the incidence of the overall observed endoleaks —independent of disappearance or not gutterrelated—was significantly higher compared to the real persistent gutters needing a reintervention. Despite this, ChEVAR is currently on the rise, with inclusion in the 2019 AAA Treatment Guidelines from the European Society for Vascular Surgery where it is recommended in urgent cases and when fenestrated repair is unfeasible or contraindicated. In this context, the use of chimneys should be restricted to a maximum of two in order to have the best results. Worth noting is that the published ESVS Guidelines assign the same level of evidence (C) both to ChEVAR and fenestrated EVAR. In 2016, Medtronic received CE mark for the Endurant II/IIs stent graft system to treat AAA using ChEVAR. Previous studies including the PROTAGORAS trial and the PERICLES study have built a growing basis of knowledge, with the ongoing ENCHANT multicentre prospective trial set to add robust evidence for future guidelines. These developments will serve to improve perception in the vascular community regarding its utility and efficacy. Meanwhile, however, the chimney technique remains an effective complementary alternative modality of complex abdominal pathologies.

September 2019

Conical and short necks: what to do in the grey area IN CASE OF complex short and/ or conical necks, a personalized approach, based on operator’s experience is crucial. We define a neck “short”, when it is shorter than the IFUs recommendation for Vincent Riambau standard endograft. For example, when we use the Endurant II stent graft we consider short neck when the distance between the lowest renal artery and the beginning of the sac is less than 10mm. We consider it as a “conical” when the difference between the proximal and distal diameter of the neck is more than 4mm. For conical necks we prefer to use

EndoAnchor implants (ESAR) even when the neck is not short, especially when the life expectancy for the patient is longer than 10 years, since we expect this adjunct therapy to increase the durability of EVAR repair. A pure short neck or a combination of short and conical neck is not a favorable condition for regular EVAR. We prefer to think about open surgery if the patient is fit for that intervention. If the patient is considered as a high risk for open repair, we consider fenestrated EVAR (FEVAR). If the FEVAR is not a good choice for any unfavorable anatomical reason or the procedure should be applied within a short period of time, then we consider parallel graft technique (ChEVAR) with or without ESAR, depending on the new suprarenal sealing area status. If it is optimal we can avoid adding EndoAnchor implants. If for any reason the new neck is not optimal (wider more than 28mm, some conical shape, irregular contour), we would perform ESAR on top of ChEVAR.

CASE REPORT 1: CHEVAR

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1B

74-year-old male with a past history of coronary disease, with coronary artery bypass surgery, severe chronic obstructive pulmonary disease, colon ADK (colon resection) and a symptomatic abdominal aortic aneurysm of 56mm in diameter. Some peculiar anatomical features were observed in the angio-CT scan: 6mm infrarenal neck length, without calcium; both renal arteries were downward oriented; the potential new neck up to the superior mesenteric artery was longer than 2cm. Both iliofemoral axes were quite narrow with 5.5mm in some segments. Due to the medical and anatomical conditions, we decided to fix the case with a ChEVAR procedure, performed without complications 24 hours after patient admission (see Figures 1A and B).

2A

2B

CASE REPORT 2: ESAR

62-year-old male with a past history of coronary disease (myocardial infarction 13 years ago), ex-smoker, severe chronic obstructive pulmonary disease, type II diabetes mellitus. Patient had an abdominal aortic aneurysm of 55mm in diameter. Peculiar anatomical findings were observed in this case: neck was 10.6mm in length and moderately conical (20.77mm juxtarenal diameter and 23.33mm at the distal aspect of the neck). 2C No calcium and no relevant thrombus formation was observed at the neck level. Due to the medical and anatomical conditions, we decided to treat the case with an endosuture aneurysm repair (ESAR) procedure, performed without complications 15 days after the patient's diagnosis (see Figures 2A and 2B).

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