Thoracic aortic parallel stent-graft behaviour when subjected to radial loading

Kwiecinski, Jakub; Cheng, Christopher P.; Uberoi, Raman; Hadi, Mohammed El; Hempel, Philipp; Degel, Christoph; Zhang, You

doi:10.1016/j.jmbbm.2021.104407

Cited by 5 publications

(2 citation statements)

References 35 publications

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“…Kwiecinski et al [ 26 ] documented an oversizing range of 26–35% for commercially available SGs used in chimney thoracic endovascular aortic repair (ch-TEVAR). In EVAR, SG iliac limb kinking has been identified as a common cause of limb occlusion complications, and excessive SG oversizing is a potential contributing risk factor [ 27 ].…”

Section: Discussionmentioning

confidence: 99%

Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells

Vellaparambil,

Han,

Di Giovanni

et al. 2023

Cardiovasc Eng Tech

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Purpose Inappropriate stent-graft (SG) flexibility has been frequently associated with endovascular aortic repair (EVAR) complications such as endoleaks, kinks, and SG migration, especially in tortuous arteries. Stents derived from auxetic unit cells have shown some potential to address these issues as they offer an optimum trade-off between radial stiffness and bending flexibility. Methods In this study, we utilized an established finite element (FE)-based approach to replicate the mechanical response of a SG iliac limb derived from auxetic unit cells in a virtual tortuous iliac aneurysm using a combination of a 180° U-bend and intraluminal pressurization. This study aimed to compare the mechanical performance (flexibility and durability) of SG limbs derived from auxetic unit cells and two commercial SG limbs (Z-stented SG and circular-stented SG models) in a virtual tortuous iliac aneurysm. Maximal graft strain and maximum stress in stents were employed as criteria to estimate the durability of SGs, whereas the maximal luminal reduction rate and the bending stiffness were used to assess the flexibility of the SGs. Results SG limbs derived from auxetic unit cells demonstrated low luminal reduction (range 4–12%) with no kink, in contrast to Z-stented SG, which had a kink in its central area alongside a high luminal reduction (44%). Conclusions SG limbs derived from auxetic unit cells show great promise for EVAR applications even at high angulations such as 180°, with acceptable levels of durability and flexibility.

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Section: Discussionmentioning

confidence: 99%

Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells

Vellaparambil,

Han,

Di Giovanni

et al. 2023

Cardiovasc Eng Tech

View full text Add to dashboard Cite

show abstract

“…Furthermore, even experimental data show that stent-graft behavior is highly nonlinear concerning the radial loads a graft exerts for a given degree of oversizing. 28 Future experimental work is needed to measure the interfacial strength and toughness of aorta-endograft interfaces at different degrees of oversizing to provided precise input parameters for our models. Moreover, future work will incorporate patient-specific migration loads through serial imaging similar to recent publication on increased risks in endoleak development.…”

Section: Discussionmentioning

confidence: 99%

Computational analysis of endovascular aortic repair proximal seal zone preservation with endoanchors: A case study in cylindrical neck anatomy

Dhara

Khabaz

Sankary

et al. 2021

JVS-Vascular Science

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Background Endovascular aortic repair is the common approach for abdominal aortic aneurysms, but endoleaks remain a significant problem with long-term success. Endoanchors have been found to reduce the incidence of type 1A endoleaks and can treat intraoperative type 1a endoleaks. However, little is known about the optimal number and position of endoanchors to achieve the best outcome. Methods Using image segmentation and a computational model derived from a reconstructed native patient abdominal aortic aneurysm geometry, the stability of the proximal seal zone was examined through finite element analysis in Abaqus (Dassault Systèmes, Providence, RI). The biomechanical parameter of contact area was compared for varying numbers (0, 2, 4, 8) and positions (proximal, medial, distal) of endoanchors under different adhesion strengths and physiologic pressure conditions. Results In every simulation, an increase in adhesion strength is associated with maintenance of proximal seal. For biologically plausible adhesion strengths, under conditions of normal blood pressure (120 mm Hg), the addition of any number of endoanchors increases the stability of the endograft-wall interface at the proximal seal zone by approximately 10% compared with no endoanchors. At hypertensive pressures (200 mm Hg), endoanchors increase the stability of the interface by 20% to 60% compared with no endoanchors. The positioning of endoanchors within the proximal seal zone has a greater effect at hypertensive pressures, with proximal positioning increasing stability by 15% compared with medial and distal positioning and 30% compared with no endoanchors. Conclusions Endoanchors improve fixation within the proximal seal zone particularly under conditions of high peak systolic pressure. Seal zone stabilization provides a mechanism through which endoanchor addition may translate into lower rates of type 1a endoleaks for patients.

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Do Balloon Catheters have a Different Radial Force Along Their Longitudinal Axis?

Choi,

Kim,

Won

2024

Cardiovasc Intervent Radiol

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Purpose This experimental study was designed to compare radial forces between the central portion and both ends of balloon catheters when dilating stenosis. Materials and Methods Three balloon catheters of 6 and 8 mm in diameter and of variable length were tested: Mustang, Conquest, and Genoss PTA. Cylindrical modules to position balloon catheters and install the measuring tip during radial force measurements were made using a 3D printer. The measuring tip created 20% stenosis at the inner lumen. Both ends and center of the balloon catheter were located at the measuring tip. The radial force was measured after inflating the balloon catheter to the rated burst pressure. Results For the different diameters and lengths of balloon catheters and cylinder sizes, the median inccenter, the radial rease in radial force at the distal end compared to the center was 16.5% (range: 9.8–35.2%) for Mustang, 12.4% (range: 10.3–25.5%) for Genoss, and 7.4% (range: −0.3–13.1%) for Conquest balloon catheters. Similarly, compared to that at the force at the proximal end was 10.8% greater (range: −2.9–18.3%) for Mustang, 9.9% greater (range: 3.9–22.3%) for Genoss, and 7.3% greater (range: −1.3–12.4%) for Conquest catheters. Conclusion The radial force is greater at both ends of the balloon than at the central portion, especially at the distal end. Dilation using the distal end of the balloon catheter is a practical method that can be applied in clinical practice without additional devices when encountering resistant stenosis, especially with semi-compliant balloons. Graphical Abstract

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Thoracic aortic parallel stent-graft behaviour when subjected to radial loading

Cited by 5 publications

References 35 publications

Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells

Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells

Computational analysis of endovascular aortic repair proximal seal zone preservation with endoanchors: A case study in cylindrical neck anatomy

Do Balloon Catheters have a Different Radial Force Along Their Longitudinal Axis?

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