Fatigue behaviour of Nitinol peripheral stents: The role of plaque shape studied with computational structural analyses

Dordoni, Elena; Meoli, Alessio; Wu, Wei; Dubini, Gabriele; Migliavacca, Francesco; Pennati, Giancarlo; Petrini, Lorenza

doi:10.1016/j.medengphy.2014.03.006

Cited by 62 publications

(48 citation statements)

References 39 publications

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“…At this stage, only the vessel with heavily calcified plaque satisfied the requirement to continue with stent implantation, as it was the only arterial model that reached a diseased lumen diameter corresponding to 70% of the healthy lumen diameter. 15 This can be explained by the low stress-strain threshold (0.16 MPa at a nominal strain of 0.55) required to start the plastic deformation process in the heavily calcified plaque. As a result, the heavily calcified plaque underwent greater plastic deformation than both the moderately and lightly calcified plaques, which reached their constant stress thresholds at considerably higher strain values of 0.75 and 1.15, respectively (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Although not exactly a failure model, perfect plasticity is commonly used to model plaque failure during endovacular therapy. 6,8,9,15,35 The majority of these studies have set the stress threshold at 400 kPa 6,8,9 , which corresponded to an average value of plaque failure under uniaxial tensile tests. 28 The remaining studies have used 270 kPa, which represented the rupture stress of a single atheresclerotic plaque.…”

Section: Discussionmentioning

confidence: 99%

“…6,8,9,15,35 This method allows the plaque to undergo plastic deformation, while preventing an increase in its stresses. Once the plastic limit is reached, the loads exerted onto the artery are transferred to the healthy layers.…”

Section: Constitutive Modelsmentioning

confidence: 99%

“…1c). If the lumen diameter was below 70% of the healthy lumen diameter, 15 then an additional angioplasty was performed using a larger balloon diameter. Following the adequate expansion of the lumen, the contact interaction between the inner surface of the crimp tool and the outer surface of the stent was activated and the stent was crimped to its insertion diameter of 1.2 mm by radially displacing each node of the crimp tool (Fig.…”

Section: Simulations Of the Endovascular Therapymentioning

confidence: 99%

“…15,29,30,34 They are also frequently used to understand the mechanical and hemodynamic behaviors of both healthy and diseased arteries due to stent implantation. 3,8,17,24 In this instance, the numerical approach is a suitable substitute to performing clinical investigations that would be ethically questionable due to a high risk of damage to both the plaque and healthy arterial tissues.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque Type on the Outcomes of Endovascular Therapy

2017

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Oversizing of the Nitinol stents in the femoro-popliteal arterial tract is commonly performed by clinicians and further encouraged by stent manufacturers. However, in spite of the procedure's supposed benefits of strong wall apposition and increased luminal gain, its effects on the mechanical behavior of arteries with peripheral arterial disease are not fully clear. In this study, finite element analyses of endovascular revascularization of an idealized artery with 70% stenosis and three different plaque types have been performed to examine the influence of Nitinol stent oversizing on the arterial stresses and acute lumen gain. The analyses included the simulation of balloon angioplasty to model plaque failure, followed by stent implantation, in which four different oversizing ratios were investigated. Results showed that balloon angioplasty was crucial in determining the stress levels of the artery prior to stent implantation and heavily affected the outcome of endovascular therapy. For all plaque types, Nitinol stent oversizing was found to produce a marginal lumen gain in contrast to a significant increase in arterial stresses. For the arteries with lightly and moderately calcified plaques, oversizing was found to be non-critical; whereas for the arteries with heavily calcified plaques, the procedure should be avoided due to a risk of tissue failure.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Constitutive Modelsmentioning

confidence: 99%

Section: Simulations Of the Endovascular Therapymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque Type on the Outcomes of Endovascular Therapy

2017

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Comparison of treatment strategies for femoro‐popliteal disease: A network meta‐analysis

Koifman

Lipinski

Buchanan

et al. 2018

Cathet Cardio Intervent

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The impact of modeling choices on the assessment of Ni‐Ti fatigue properties through surrogate specimens

Berti

Petrini

2023

Numer Methods Biomed Eng

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The implant of self‐expandable Ni‐Ti stents for the treatment of peripheral diseases has become an established medical practice. However, the reported failure in clinics highlights the open issue of the fatigue characterization of these devices. One of the most common approaches for calculating the Ni‐Ti fatigue limit (commonly defined in terms of mean and alternate strain for a fixed number of cycles) consists of using surrogate specimens which replicate the strain distributions of the final device but in simplified geometries. The main drawback lies in the need for computational models to determine the local distribution and, hence, interpret the experimental results. This study aims at investigating the role of different choices in the model preparation, such as the mesh refinement and the element formulation, on the output of the fatigue analysis. The analyses show a strong dependency of the numerical results on modeling choices. The use of linear reduced elements enriched by a layer of membrane elements is successful to increase the accuracy of the results, especially when coarser meshes are used. Due to material nonlinearity and stent complex geometries, for the same loading conditions and element type, (i) different meshes result in different couples of mean and amplitude strains and (ii) for the same mesh, the position of the maximum mean strain is not coincident with the maximum amplitude, making difficult the selection of the limit values.

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Fatigue behaviour of Nitinol peripheral stents: The role of plaque shape studied with computational structural analyses

Cited by 62 publications

References 39 publications

Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque Type on the Outcomes of Endovascular Therapy

Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque Type on the Outcomes of Endovascular Therapy

Comparison of treatment strategies for femoro‐popliteal disease: A network meta‐analysis

The impact of modeling choices on the assessment of Ni‐Ti fatigue properties through surrogate specimens

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