Endovascular aneurysm repair (EVAR) is currently the preferred choice to treat the
abdominal aortic aneurysms (AAA) with a feasible anatomy. However, approximately 40-60%
of AAA patients presented unfavorable characteristics for EVAR, mainly due to a "hostile
neck anatomy". In ''real-world'' clinical practice, up to 44% of EVAR cases are performed
outside Instruction For Use (IFU) for an adverse neck anatomy6. Short (<15-mm), angulated
(>60°), and wide (>28-mm) aortic necks are the main features concurring to the proximal
HNA.
The recourse to standard EVAR is currently routine for patients who are not eligible for
OR, with acceptable short- and mid-term outcomes, but the long-term durability of EVAR
depends on maintaining proper sealing between the endograft and the aortic neck as well
as the iliac arteries. HNAs demonstrated worse results when compared to "favorable" ones
in terms of technical success (94% vs. 98%) and type-Ia endoleak rate (10% vs. 2%). The
issue linked to an unfavorable anatomy can be addressed with more complex techniques, but
these are limited by high production costs and considerable complexity .
TREO (Terumo Aortic, Inchinnan, Renfrewshire, UK; formerly Treovance, Bolton Medical,
Sunrise, Fla) is a standard bifurcated, modular stent-graft that has shown compelling
early- and mid-term results. It seems clear that several physicians are still looking for
a feasible solution for HNA patients to keep the complexity of the procedure comparable
to standard EVAR while yielding improved results.
Moreover, there is a lack of publications addressing the issue of mismatched take-off of
the renal arteries (RAs). This morphology seems to influence the sealing length and could
justify the introduction of dedicated devices. A recent study from our group currently
under review for publication demonstrated that 25% of patients eligible for EVAR
presented with mismatched RAs and that a dedicated device could improve sealing
significantly. The study group sealing zone's length increased by about 25% when applying
a hypothetical prototype with a single 10x10mm (wide x high) renal scallop. The same
approach could be applied to the sealing surface with similar results. In the light of
obtained results in selected patients, the use of a "single renal-scallop" custom-made
device has been our standard of care.
The results will demonstrate whether the supra mentioned graft can the treatment of AAA
with mismatched RAs in the real world. The effectiveness will be evaluated in terms of
technical and clinical success.
The benefits could be relevant for the patients in terms of reduction of
procedure-related adverse events such as endoleaks and related re-interventions.
Furthermore, the use of custom-made standardized devices could significantly reduce costs
for health care providers and in the future, it could be the base for an "off-the-shelf"
endograft. Procedure-related complications were expected to be similar to standard EVAR
and reduced in comparison with literature reporting adverse events in more complex
techniques.
The present study aims to evaluate the clinical effectiveness of the custom-made
standardized single renal scalloped stent-graft (Treo, Terumo Aortic) to treat infrarenal
AAA. The final objective will be to employ the data obtained in this cohort for a future
eventual development of an "off-the-shelf" device dedicated to patients with mismatched
renal arteries. Such an endograft could keep the complexity of the procedure as similar
as possible to standard EVAR while improving sealing.
