Deformation of the Femoropopliteal Segment

Ghriallais, Ríona Ní; Heraty, Kevin B.; Smouse, Bob; Burke, Martin; Gilson, Paul R.; Bruzzi, Mark

doi:10.1177/1526602816669135

Cited by 20 publications

(8 citation statements)

References 14 publications

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“…No stent appears to accommodate all deformation modes without either exacerbating or restricting baseline deformations. Restriction of foreshortening within the stented segment observed in this study agrees with previous findings in patient 4,19 , cadaver 20 , and computational models 21 , and the amount of restriction for different devices correlates with device stiffness in compression determined with bench-top tests 8 . In these tests the Viabahn stent-graft restricted foreshortening the least, likely due to its helically wrapped wire around specially designed PTFE fabric, while most other devices contained multiple, rigid longitudinal connectors that restricted foreshortening.…”

Section: Discussionsupporting

confidence: 91%

“…Braided-wire and wrapped-wire stents on the other hand demonstrated more gentle curvatures in bench-top experiments (Figure 8), and produced less acute bending in situ. Effects of bending stiffness on curvature have been previously reported in cadaver models 20 and PAD patients 4 where kinks similar to those described in Figure 4C were observed at the distal end of some stents.…”

Section: Discussionsupporting

confidence: 78%

“…While foreshortening and bending can be quantified without the use of intra-arterial markers 19,20 , these markers are essential for accurate quantification of FPA twisting with limb flexion 6 . Our data demonstrate that stent design has significant effects on FPA twisting, and results are again in good agreement with bench-top data on torsional stiffness 8 .…”

Section: Discussionmentioning

confidence: 99%

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Stent Design Affects Femoropopliteal Artery Deformation

et al. 2019

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

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Stent Design Affects Femoropopliteal Artery Deformation

et al. 2019

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“…Finally, Ghriallais et al . 89 reported that axial compression and curvature of the FPA change in the presence of the stent, with the amount of change dependent on stent characteristics. No studies were found to investigate torsion of the stented FPA.…”

Section: Femoropopliteal Artery Obstructive Diseasementioning

confidence: 99%

Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material, Design, and Performance

et al. 2018

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Endovascular stenting has matured into a commonly used treatment for peripheral arterial disease (PAD) due to its minimally invasive nature and associated reductions in short-termmorbidity and mortality. The mechanical properties of the superelastic Nitinol alloy have played a major role in the explosion of peripheral artery stenting, with modern stents demonstrating reasonable resilience and durability. Yet in the superficial femoral and popliteal arteries, even the newest generation Nitinol stents continue to demonstrate clinical outcomes that leave significant room for improvement. Restenosis and progression of native arterial disease often lead to recurrence of symptoms and reinterventions that increase morbidity and health care expenditures. One of the main factors thought to be associated with stent failure in the femoropopliteal artery (FPA) is the unique and highly dynamic mechanical environment of the lower limb. Clinical and experimental data demonstrate that the FPA undergoes significant deformations with limb flexion. It is hypothesized that the inability of many existing stent designs to conform to these deformations likely plays a role in reconstruction failure, as repetitive movements of the leg and thigh combine with mechanical mismatch between the artery and the stent and result in mechanical damage to both the artery and the stent. In this review we will identify challenges and provide a mechanical perspective of FPA stenting, and then discuss current research directions with promise to provide a better understanding of Nitinol, specific features of stent design, and improved characterization of the biomechanical environment of the FPA to facilitate development of better stents for patients with PAD.

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“…As the SFA is a long, relatively straight vessel, it is exposed to low wall shear under resting conditions [ 9 ]—a circumstance that predisposes it to atherosclerotic disease while also serving as a factor that confounds the healing process after endovascular injury. Implantation into the SFA of a stent with a straight cylindrical configuration will act to further straighten the vessel, so that while the stent may restore vessel patency, it can alter effective arterial flexibility and reduce the capability of the vessel to shorten naturally (as in an unstented state), opening the way for kinking and buckling of the vessel at the ends of the stented segment as well as for possible stent fracture [ 5 ]. The introduction of a straight stent may jeopardize the antirestenotic swirling blood flow commonly imparted by the natural helical arterial geometry.…”

Section: The Biomimics 3d Helical Centerline Stentmentioning

confidence: 99%

Swirling Flow and Wall Shear: Evaluating the BioMimics 3D Helical Centerline Stent for the Femoropopliteal Segment

Sullivan

Zeller

Nakamura

et al. 2018

International Journal of Vascular Medicine

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The BioMimics 3D self-expanding nitinol stent represents a strategy for femoropopliteal intervention that is alternative or complementary to deployment of drug-coated stents or balloons. Whereas conventional straight stents reduce arterial curvature and disturb blood flow, creating areas of low wall shear, where neointimal hyperplasia predominantly develops, the helical centerline geometry of the BioMimics 3D maintains or imparts arterial curvature, promotes laminar swirling blood flow, and elevates wall shear to protect against atherosclerosis and restenosis. In the multicenter randomized MIMICS trial, treatment of femoropopliteal disease with the BioMimics 3D (n = 50) significantly improved 2-year primary patency (log-rank test p = 0.05) versus a control straight stent (n = 26), with no cases of clinically driven target lesion revascularization between 12 and 24 months (log-rank test p = 0.03 versus controls). In geometric X-ray analysis, the BioMimics stent was significantly more effective in imparting a helical shape even when the arterial segment was moderately to severely calcified. Computational fluid dynamics analysis showed that average wall shear was significantly higher with the helical centerline stent (1.13 ± 0.13 Pa versus 1.06 ± 0.12 Pa, p = 0.05). A 271-patient multicenter international MIMICS-2 trial and a 500-patient real-world MIMICS-3D registry are underway.

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Deformation of the Femoropopliteal Segment

Abstract: The deformation characteristics of the femoropopliteal segment change in the presence of a stent, with the change to the deformation behavior dependent on stent type, stent length, location, flexibility, and intrinsic centerline curvature.

Cited by 20 publications

References 14 publications

Stent Design Affects Femoropopliteal Artery Deformation

Stent Design Affects Femoropopliteal Artery Deformation

Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material, Design, and Performance

Swirling Flow and Wall Shear: Evaluating the BioMimics 3D Helical Centerline Stent for the Femoropopliteal Segment

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