title: Computational Modeling to Predict Fatigue Behavior of NiTi Stents: What Do We Need?
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.
authors.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.
authors.forename: Elena
authors.initials: E
authors.lastname: Dordoni
authors.affiliation: Department of Civil and Environmental Engineering, Politecnico di Milano, Milan 20133, Italy. lorenza.petrini@polimi.it.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Petrini
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. wei.wu@polimi.it.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. francesco.migliavacca@polimi.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Migliavacca
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. gabriele.dubini@polimi.it.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Dubini
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan 20133, Italy. giancarlo.pennati@polimi.it.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pennati
keywords: cardiovascular devices; fatigue failure; finite element analyses; peripheral arterial diseases; shape memory alloys