Analysis of the mechanical performance of a cardiovascular stent design based on micromechanical modelling

McGarry, J. Patrick; O’Donnell, Brendan; McHugh, Peter E.

doi:10.1016/j.commatsci.2004.05.001

Cited by 75 publications

(52 citation statements)

References 25 publications

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“…The constitutive behaviour of a stent material depends on a number of pre-treatments such as hot rolling, annealing, cold finishing, electropolishing. McGarry et al 2004). In the past, a number of different material properties have been used for finite element analysis of 316L stainless steel stent expansion.…”

Section: Stentmentioning

confidence: 93%

Geometry parameterization and multidisciplinary constrained optimization of coronary stents

Pant

Bressloff

Limbert

2011

Biomech Model Mechanobiol

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Coronary stents are tubular type scaffolds that are deployed, using an inflatable balloon on a catheter, most commonly to recover the lumen size of narrowed (diseased) arterial segments. A common differentiating factor between the numerous stents used in clinical practice today is their geometric design. An ideal stent should have high radial strength to provide good arterial support post-expansion, have high flexibility for easy manoeuvrability during deployment, cause minimal injury to the artery when being expanded and, for drug eluting stents, should provide adequate drug in the arterial tissue. Often, with any stent design, these objectives are in competition such that improvement in one objective is a result of trade-off in others. This study proposes a technique to parameterize stent geometry, by varying the shape of circumferential rings and the links, and assess performance by modelling the processes of balloon expansion and drug diffusion. Finite element analysis is used to expand each stent (through balloon inflation) into contact with a representative diseased coronary artery model, followed by a drug release simulation. Also, a separate model is constructed to measure stent flexibility. Since the computational simulation time for each design is very high (approximately 24 h), a Gaussian process modelling approach is used to analyse the design space corresponding to the proposed parameterization. Four objectives to assess recoil, stress distribution, drug distribution and flexibility are set up to perform optimization studies. In particular, single objective constrained optimization problems are set up to improve the design relative to the baseline geometry-i.e. to improve one objective without compromising the others. Improvements of 8, 6 and 15% are obtained individually for stress, drug and flexibility metrics, respectively. The relative influence of the design features on each objective is quantified in terms of main effects, thereby suggesting the design features which could be altered to improve stent performance. In particular, it is shown that large values of strut width combined with smaller axial lengths of circumferential rings are optimal in terms of minimizing average stresses and maximizing drug delivery. Furthermore, it is shown that a larger amplitude of the links with minimum curved regions is desirable for improved flexibility, average stresses and drug delivery.

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Section: Stentmentioning

confidence: 93%

Geometry parameterization and multidisciplinary constrained optimization of coronary stents

Pant

Bressloff

Limbert

2011

Biomech Model Mechanobiol

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“…The stent model was fixed at one end to prevent rigid body motion and the radial expansion boundary condition allowed for expansion, uncoiling and a corresponding reduction in length. In FE modeling of wire mesh stent expansion, it is common to apply a prescribed radial displacement or pressure to the inner surface of the stent [Bedoya, 2006;Rogers, 1999;Dumoulin, 2002;McGarry, 2004;Mori, 2005;Martin, 2002]. However, radial expansion of helical stents is the result of uncoiling and a decrease in the pitch value of the stent.…”

Section: Displacement Driven Expansionmentioning

confidence: 99%

“…Several approaches have been applied to model the effect of the balloon on stent expansion, such as creating idealized models that ignore the balloon's complex geometry during expansion and instead consider a fixed internal pressure load [Bedoya, 2006;Rogers, 1999;Dumoulin, 2002;McGarry, 2004;Mori, 2005;Martin, 2002] or an expanding high stiffness cylinder Takashim, 2007;Wu, 2007;Hall, 2006], which depict uniform expansion. Models have also been built to capture the behaviour of an actual folded balloon [Oberhofer, 2006;Gervaso, 2008;De Beulea, 2008;Wu, 2010;Zahedmanesh, 2010]; however, while highly accurate, this approach is computationally expensive.…”

Section: Motivationmentioning

confidence: 99%

Finite element methods to analyze helical stent expansion

Paryab

Cronin

Lee‐Sullivan

2013

Numer Methods Biomed Eng

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SUMMARYHelical polymeric stents have been proposed as a suitable geometry for biodegradable drug‐eluting polymer‐based stents. However, helical stents often experience nonuniform local expansion (dog boning), which can prohibit full stent expansion using conventional methods. The development of stents and deployment methods is challenging and can be supported by numerical analysis; however, this complex problem is often approached with simplified boundary conditions that may not be appropriate for helical stents. The finite element method (explicit and implicit) was used to investigate three common stent expansion approaches with a focus on helical stent geometry, which differs from traditional wire mesh stent expansion. Although each of the three methods considered provided some insight into the expansion characteristics, common displacement controlled, and uniform expansion methods were not able to demonstrate the characteristic local deformations observed in expansion. A coupled stent‐balloon model, although computationally expensive, was able to demonstrate the expected nonuniform deformation. To address nonuniform expansion, a progressive expansion approach has been investigated and verified numerically. This method may also provide a suitable solution for nonuniform expansion in other stent designs by minimizing loading and potential damage to the artery that can occur during stent deployment. Copyright © 2013 John Wiley & Sons, Ltd.

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“…To date, several studies have been carried out to investigate how geometrical properties, material properties and deployment methods affect the expansion characteristics of various stent designs (Whitcher 1997;Brauer et al 1999;Dumoulin and Cochelin 2000;Etave et al 2001;Tan et al 2001;Chua et al 2002Chua et al , 2003Chua et al , 2004aMigliavacca et al 2002Migliavacca et al , 2005Stolpmann et al 2003;McGarry et al 2004;Petrini et al 2004;Savage et al 2004;Gu et al 2005;Hall and Kasper 2006;Wang et al 2006;De Beule, Mortier, Belis et al 2007;De Beule et al 2008;Donnelly et al 2007;Wu et al 2007a;Xia et al 2007;Ju et al 2008;Lim et al 2008;Mortier et al 2008;Li et al 2009). A number of these studies which represent significant contributions to research in this field are discussed and summarised in this section (Table 1).…”

Section: Fe Analysis Of the Free Expansion Of Coronary Stentsmentioning

confidence: 99%

Computational structural modelling of coronary stent deployment: a review

Martín¹,

Boyle²

2011

Computer Methods in Biomechanics and Biomedical Engineering

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The finite element (FE) method is a powerful investigative tool in the field of biomedical engineering, particularly in the analysis of medical devices such as coronary stents whose performance is extremely difficult to evaluate in vivo. In recent years, a number of FE studies have been carried out to simulate the deployment of coronary stents, and the results of these studies have been utilised to assess and optimise the performance of these devices. The aim of this paper is to provide a thorough review of the state-of-the-art research in this area, discussing the aims, methods and conclusions drawn from a number of significant studies. It is intended that this paper will provide a valuable reference for future research in this area.

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Analysis of the mechanical performance of a cardiovascular stent design based on micromechanical modelling

Cited by 75 publications

References 25 publications

Geometry parameterization and multidisciplinary constrained optimization of coronary stents

Geometry parameterization and multidisciplinary constrained optimization of coronary stents

Finite element methods to analyze helical stent expansion

Computational structural modelling of coronary stent deployment: a review

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