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Computational Modeling to Predict Fatigue Behavior of NiTi Stents: What Do We Need?

Dordoni E, Petrini L, Wu W, Migliavacca F, Dubini G, Pennati G - J Funct Biomater (2015)

Bottom Line: However, their effectiveness is still debated in the clinical field.However, confidence in numerical methods is only possible after verification and validation of the models used.For the case of NiTi stents, mechanical properties are strongly dependent on the device dimensions and the whole treatments undergone during manufacturing process.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. elena.dordoni@hotmail.it.

ABSTRACT
NiTi (nickel-titanium) stents are nowadays commonly used for the percutaneous treatment of peripheral arterial disease. However, their effectiveness is still debated in the clinical field. In fact a peculiar cyclic biomechanical environment is created before and after stent implantation, with the risk of device fatigue failure. An accurate study of the device fatigue behavior is of primary importance to ensure a successful stenting procedure. Regulatory authorities recognize the possibility of performing computational analyses instead of experimental tests for the assessment of medical devices. However, confidence in numerical methods is only possible after verification and validation of the models used. For the case of NiTi stents, mechanical properties are strongly dependent on the device dimensions and the whole treatments undergone during manufacturing process. Hence, special attention should be paid to the accuracy of the description of the device geometry and the material properties implementation into the numerical code, as well as to the definition of the fatigue limit. In this paper, a path for setting up an effective numerical model for NiTi stent fatigue assessment is proposed and the results of its application in a specific case study are illustrated.

No MeSH data available.


Related in: MedlinePlus

Constant-life diagram from fatigue tests on NiTi dog bone specimens and cyclic axial tests on peripheral stents for different conditions of mean and amplitude strain.
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jfb-06-00299-f016: Constant-life diagram from fatigue tests on NiTi dog bone specimens and cyclic axial tests on peripheral stents for different conditions of mean and amplitude strain.

Mentions: The comparison between computational and experimental results showed the good ability of the finite element model to predict the fatigue behavior of all the tested devices, also locating fracture position when fractures occurred (Figure 15). Moreover, a perfect overlay was obtained for the experimental stent axial fatigue-life data on the dog bone fatigue-life data (Figure 16). These findings allow the validation of the fatigue resistance criterion adopted for Maris Plus™ stent, at least in the case of simple loading conditions.


Computational Modeling to Predict Fatigue Behavior of NiTi Stents: What Do We Need?

Dordoni E, Petrini L, Wu W, Migliavacca F, Dubini G, Pennati G - J Funct Biomater (2015)

Constant-life diagram from fatigue tests on NiTi dog bone specimens and cyclic axial tests on peripheral stents for different conditions of mean and amplitude strain.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493513&req=5

jfb-06-00299-f016: Constant-life diagram from fatigue tests on NiTi dog bone specimens and cyclic axial tests on peripheral stents for different conditions of mean and amplitude strain.
Mentions: The comparison between computational and experimental results showed the good ability of the finite element model to predict the fatigue behavior of all the tested devices, also locating fracture position when fractures occurred (Figure 15). Moreover, a perfect overlay was obtained for the experimental stent axial fatigue-life data on the dog bone fatigue-life data (Figure 16). These findings allow the validation of the fatigue resistance criterion adopted for Maris Plus™ stent, at least in the case of simple loading conditions.

Bottom Line: However, their effectiveness is still debated in the clinical field.However, confidence in numerical methods is only possible after verification and validation of the models used.For the case of NiTi stents, mechanical properties are strongly dependent on the device dimensions and the whole treatments undergone during manufacturing process.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. elena.dordoni@hotmail.it.

ABSTRACT
NiTi (nickel-titanium) stents are nowadays commonly used for the percutaneous treatment of peripheral arterial disease. However, their effectiveness is still debated in the clinical field. In fact a peculiar cyclic biomechanical environment is created before and after stent implantation, with the risk of device fatigue failure. An accurate study of the device fatigue behavior is of primary importance to ensure a successful stenting procedure. Regulatory authorities recognize the possibility of performing computational analyses instead of experimental tests for the assessment of medical devices. However, confidence in numerical methods is only possible after verification and validation of the models used. For the case of NiTi stents, mechanical properties are strongly dependent on the device dimensions and the whole treatments undergone during manufacturing process. Hence, special attention should be paid to the accuracy of the description of the device geometry and the material properties implementation into the numerical code, as well as to the definition of the fatigue limit. In this paper, a path for setting up an effective numerical model for NiTi stent fatigue assessment is proposed and the results of its application in a specific case study are illustrated.

No MeSH data available.


Related in: MedlinePlus