A Methodology to Quantify the Geometrical Complexity of the Abdominal Aortic Aneurysm

Abstract

The abdominal aortic aneurysm (AAA) anatomy influences the technical success of the endovascular aneurysm repair (EVAR), yet very few data regarding the aortic tree angles exist in the literature. This poses great limitations in the numerical analyses of endografts, constraining their design improvement as well as the identification of their operational limitations. In this study, a matrix Φ of 10 angles was constructed for the description of the pathological region and was implemented on a large dataset of anatomies. More specifically, computed tomography angiographies from 258 patients were analysed and 10 aortic angles were calculated per case, able to adequately describe the overall AAA shape. 9 dimensional variables (i.e. diameters and lengths) were also recorded. The median and extreme values of these variables were computed providing a detailed quantification of the geometrical landscape of the AAA. Moreover, statistical analysis showed that the identified angles presented no strong correlation with each other while no lateral or anterior/posterior symmetry of the AAA was identified. These findings suggest that endograft designers are free to construct any extreme case-studies with the values provided in a mix-and-match manner. This strategy can have a powerful effect in EVAR stent graft designing, as well as EVAR planning.

Iliofemoral Tortuosity Increases the Risk of Access-Site-Related Complications After Aortic Valve Implantation and Plug-Based Access-Site Closure

“…These findings connect well to the findings of Mach et al, who published similar findings (a tortuosity score of 21.2) in a population treated with suture-based closure devices and clinical experience with endovascular aneurysm repair. 13 , 15 , 16 A possible explanation could be the distortion of tortuous vessels, caused by the guidewire and temporary placement of the intravascular parts of the closure devices. This possibility may explain our findings of local bleeding complications and the need for additional manipulations to achieve complete hemostasis (30% of our patients).…”

“…To acquire a tortuosity index, the true arterial length (centreline of flow) and the direct distance between the aortic bifurcation and the femoral bifurcation were measured, and their relation was determined: ([centreline of flow / direct distance] - 1) ∗ 100). 15 , 16 Maximal angulation was measured over the centreline with an arm length of 15 mm. ( Fig.…”

Prediction of guidewire-induced aortic deformations during EVAR: a finite element and in vitro study

“…The obtained segmented 3D geometry was used to manufacture the physical models. The considered geometry has the following characteristic measures: the tortuosity of the iliac arteries, measured following ( Piccinelli et al, 2009 ), are equal to 0.14 and 0.05, respectively, for the left and right iliac artery; the neck angle, defined as in ( Kyriakou et al, 2019 ), is equal to 158°; the volume of calcifications is equal to 1.14 cm 3 . Thus, the relative calcification presence is equal to 3.2%, classified as moderate ( McLennan et al, 2021 ); the ILT percentage volume is equal to 21.4% ( Crawford et al, 2016 ).…”

Initial experience of endovascular aneurysm repair at the Dr. Eduardo Liceaga General Hospital of Mexico

“…13,27 In clinical practice, several methods have been proposed to define, grade and evaluate the aneurysm site, with small variations, all of them take into account the following anatomical characteristics: proximal neck evaluation: includes determining morphology (straight, conical, inverted conical, bulging), length, diameter, angle, amount of thrombus, and calcification; aneurysm: the maximum diameter of the AAA is mainly evaluated, whether there are tortuosities, the most acute aortic angle, the amount of thrombus and calcifications; evaluation of the distal neck: diameter and length are mainly measured; and evaluation of common, internal and external iliac arteries. 28 Apart from the analysis of the aneurysm and the aortic necks themselves, which obviously need to be examined, the evaluation of the iliac arteries is of utmost importance and is included in all reports, because when they are poorly formed they can be an exclusion criterion for EVAR. In the presurgical planning protocol it is important to measure the diameter, length, evaluation of the presence of areas of stenosis/occlusion, length of the sealing zone, presence of tortuosities, more acute angles, amount of thrombus and calcification.…”