Anatomical Feasibility of an Off-the-shelf Scalloped Stent-graft for Infrarenal Abdominal Aneurysm With a Hostile Neck

Study Overview
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Brief Summary
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In clinical practice a lot of EVAR cases are performed IFU for adverse neck anatomy(6) with acceptable short- and mid-term outcomes, but the long-term durability is currently an issue (7). Neck length shorter than 15 mm and angulation are two of. neck charteristics. that contribute more to define an hostile neck (8). The issue linked to the anatomical not feasibility of standard EVAR in patients not eligible for OR can be solved with custom made devices (CMD), but they were limited by high production costs and long time for creations (10-12 weeks)1. Nowadays no one off-the-shelf device aimed to overcome neck hostility in AAA is available on the market. The present study aims at evaluating the anatomical applicability of an off-the-shelf scalloped stent-graft to treat infrarenal AAA with a short and/or angulated neck.

Detailed Description
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Endovascular aneurysm repair (EVAR) is currently accepted as the preferred choice to treat abdominal aortic aneurysms (AAA) with feasible anatomy. Although approximately 40-60% of AAA patients are not considered anatomically feasible for EVAR, mainly in reason of a hostile neck anatomy. In ''real-world'' clinical practice, up to 44% of EVAR cases are performed outside Instruction For Use (IFU) for adverse neck anatomy. The off-label use of standard EVAR is currently used for patients who are not eligible for OR, with acceptable short- and mid-term outcomes, Endovascular aneurysm repair (EVAR) is currently accepted as the preferred choice to treat the abdominal aortic aneurysms (AAA) with feasible anatomy. Although approximately 40-60% of AAA patients are not considered anatomically feasible for EVAR, mainly in reason of a hostile neck anatomy3-5. In ''real-world'' clinical practice, up to 44% of EVAR cases are performed outside Instruction For Use (IFU) for adverse neck anatomy. The off-label use of standard EVAR is currently used for patients who are not eligible for OR, with acceptable short- and mid-term outcomes, but the long-term durability of EVAR depends on the maintenance of the seal between the endograft and the aortic neck as well as the iliac arteries. Some aortic neck characteristics contribute to the definition of ''hostile neck,'' particularly length shorter than 15 mm and angulation among others. From a recent Consensus Conference, the influence of each characteristic on early or late EVAR failure is not clear, but hostile neck morphology is generally associated with higher rates of aneurysm-related adverse events and mortality. A recent independent Expert Panel, applying the Delphi methodology Indeed, agreed to define 10 mm as the threshold value below which standard EVAR should not be considered feasible. Moreover, the same experts agreed on the fact that an angulation above 60° is considered a hostile criterion for EVAR procedure. Finally should be considered that some hostility factors can be present at the same time and create the ideal condition for EVAR failure. The issue linked to the anatomical not the feasibility of standard EVAR in patients not eligible for OR can be solved with custom made devices (CMD), but they were limited by high production costs and long time for creations (10-12 weeks)1. Nowadays no one off-the-shelf device aimed to overcome neck hostility in AAA is available on the market. The present study aims at evaluating the anatomical applicability of an off-the-shelf scalloped stent graft to treat infrarenal AAA with a short and/or angulated neck. From an informal review of some CTA of patients treated with EVAR or OR in mentioned unit, the authors found that more the 20% presented a distance between the two renal arteries more than 5mm. The idea of an off-the-shelf graft with a single scallop theoretically had to permit to gain some length along the aortic neck. Furthermore also in the case of angulation, a single scallop theoretically reduced the risk of bird beck and gutter. The aim of the study is to evaluate if a single scalloped off-the-shelf stent graft could be appliable and feasible in an adequate number of patients.

Official Title
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Anatomical Feasibility of an Off-the-shelf Scalloped Stent-graft for Infrarenal Abdominal Aneurysm With a Hostile Neck (ReSTHoNe Study)

Conditions
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Aortic Aneurysm

Intervention / Treatment
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* Other: CTA evaluation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients Electively treated with EVAR or AAA at the coordinator center Age >18 Both sex Preoperative 2.5mm CTA available Written informed consent. Exclusion Criteria: All. patients not fulfilling the inclusion criteria

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients ttreatted for AAA<br>Patients affected by AAA and treated att our institution with EVAR and/or Open Repair between 2010 and 2020 | Other: CTA evaluation<br>* Any pre-operattive CTA of the patients of the cohort will be carefully evaluated to determine the theoric anatomical feasibility of an off the shelf Endograft, particularly in patients with an angulated and short aortic neck<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anatomica feasibility and applicability of an off-the-shelf scallopped stent-graft measured mesured fitting three device model with data recorded from CTA of patients with AAA treted in our unit | observational study on the anatomical applicability in the coordinator center of an off-the-shelf scalloped device to treat infrarenal AAA with short and/or angulated neck. 3 different endograft designs were constructed. The preoperative measurements were made according to a previously described methodology. The models were matched with each preoperative CTA measure in order to evaluate if they fit or not in the index patients. | 6-months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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EVAR, AAA, Off-the-shelf