Simulation of NiTi Stent Deployment in a Realistic Patient Carotid Artery Using Isogeometric Analysis

Chavalla, Sharath; Hoffmann, Thomas; Juhre, Daniel

doi:10.1016/j.prostr.2019.07.003

by Sharath Chavalla, Thomas Hoffmann, Daniel Juhre

Abstract:

Cardiovascular diseases are one of the main reasons of death in western countries. In such diseases, arteries develop a plaque resulting in narrowing (stenosis) and reduction of blood flow. Stenosis leads to stroke which often occur without any warning. To treat stenosis, high-tech implants called stents are deployed along an endoluminal path into the pathological area. Stents are uniquely characterized by their complex geometries and material properties. Treatment procedures optimized for individual patients (predictive medicine) is gaining importance and cost-effective, robust simulation tools are inevitable for such procedures. Self-expandable stents made of Nickel Titanium (NiTi) alloy are also known as shape memory alloys (SMA). In addition to the shape memory effect, these alloys exhibit pseudoelasticity and excellent biocompatibility which makes their choice highly favourable. The complexity of stent implant is a result of its material property, geometry and loading conditions which makes it difficult to effectively characterize its mechanical behaviour. Also, proper stent deployment plays an important role in successful intervention procedure. Finite element analysis (FEA) is a popular tool to perform such evaluations in order to test different configurations before prototype testing. However, the complex stent geometry demands a finer finite element mesh for qualitatively good results which in turn results in high computation times. Over the recent years a numerical method called isogeometric analysis (IGA) is developed with a primary motivation to minimise the gap between the computer aided design (CAD) and FEA. IGA is based on the representation and calculation of geometric structures through non-uniform rational B-splines (NURBS) which are standard representations for complex geometries in CAD packages. The implementation of stenting procedure involves modelling interaction between the stent geometry and patient artery which, till date is a challenge. Major challenges arise in the form of large deformations during crimping and subsequent expansion and contact interaction between the soft vascular vessel and a rigid stent geometry. In the present work, the virtual stenting procedure involving stent crimping, expansion and stent placement is simulated for NiTi stents inside a real carotid artery geometry of the patient using IGA.

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Reference:

Simulation of NiTi Stent Deployment in a Realistic Patient Carotid Artery Using Isogeometric Analysis (Sharath Chavalla, Thomas Hoffmann, Daniel Juhre), In International Conference on Stents: Materials, Mechanics and Manufacturing ICS3M 2019, volume 15, 2019.

Bibtex Entry:

@article{chavalla_simulation_2019,
	title = {Simulation of {NiTi} {Stent} {Deployment} in a {Realistic} {Patient} {Carotid} {Artery} {Using} {Isogeometric} {Analysis}},
	volume = {15},
	issn = {2452-3216},
	url = {http://www.sciencedirect.com/science/article/pii/S245232161930109X},
	doi = {10.1016/j.prostr.2019.07.003},
	abstract = {Cardiovascular diseases are one of the main reasons of death in western countries. In such diseases, arteries develop a plaque resulting in narrowing (stenosis) and reduction of blood flow. Stenosis leads to stroke which often occur without any warning. To treat stenosis, high-tech implants called stents are deployed along an endoluminal path into the pathological area. Stents are uniquely characterized by their complex geometries and material properties. Treatment procedures optimized for individual patients (predictive medicine) is gaining importance and cost-effective, robust simulation tools are inevitable for such procedures. Self-expandable stents made of Nickel Titanium (NiTi) alloy are also known as shape memory alloys (SMA). In addition to the shape memory effect, these alloys exhibit pseudoelasticity and excellent biocompatibility which makes their choice highly favourable. The complexity of stent implant is a result of its material property, geometry and loading conditions which makes it difficult to effectively characterize its mechanical behaviour. Also, proper stent deployment plays an important role in successful intervention procedure. Finite element analysis (FEA) is a popular tool to perform such evaluations in order to test different configurations before prototype testing. However, the complex stent geometry demands a finer finite element mesh for qualitatively good results which in turn results in high computation times. Over the recent years a numerical method called isogeometric analysis (IGA) is developed with a primary motivation to minimise the gap between the computer aided design (CAD) and FEA. IGA is based on the representation and calculation of geometric structures through non-uniform rational B-splines (NURBS) which are standard representations for complex geometries in CAD packages. The implementation of stenting procedure involves modelling interaction between the stent geometry and patient artery which, till date is a challenge. Major challenges arise in the form of large deformations during crimping and subsequent expansion and contact interaction between the soft vascular vessel and a rigid stent geometry. In the present work, the virtual stenting procedure involving stent crimping, expansion and stent placement is simulated for NiTi stents inside a real carotid artery geometry of the patient using IGA.},
	journal = {International Conference on Stents: Materials, Mechanics and Manufacturing ICS3M 2019},
	author = {Chavalla, Sharath and Hoffmann, Thomas and Juhre, Daniel},
	month = jan,
	year = {2019},
	keywords = {IGA, NiTi, NURBS, stent deployment},
	pages = {8--15}
}