Design considerations and quantitative assessment for the development of percutaneous mitral valve stent

Kumar, Gideon Praveen; Cui, Fangsen; Phang, Hui Qun; Su, Boyang; Leo, Hwa Liang; Hon, Jimmy Kim Fatt

doi:10.1016/j.medengphy.2014.03.010

Cited by 17 publications

(12 citation statements)

References 23 publications

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“…This assembly is shown in Figure a. Axial and circumferential boundary conditions are used to constrain the translational ( U z ) and rotational ( U θ ) degrees of freedom of the balloon, stent, and artery models to prevent rigid body translation and allow deformation only in the radial direction. We used a surface‐to‐surface algorithm to model the interactions between the different parts and used a frictionless contact between the balloon outer surface and the stent inner surface and a friction of 0.05 between the stent outer surface and the inner surface of the coronary artery .…”

Section: Methodsmentioning

confidence: 99%

Nanoglass‐based balloon expandable stents

et al. 2019

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Here, a prototypical metallic nanoglass is proposed as a new alloy for balloon expandable stents. Traditionally, the stainless steel SS 316L alloy has been used as a preferred material for this application due to its proper combination of mechanical properties, corrosion resistance, and biocompatibility. Recently, metallic glasses (MGs) have been considered as promising materials for biodevice applications. MGs often display outstanding mechanical properties superior to those of conventional metallic alloys and overcome some of the weaknesses of SS 316L, such as radiopacity, stainless steel allergy, and thrombosis‐induced restenosis. However, commonly used monolithic MGs, which have an amorphous homogeneous microstructure, suffer from lack of ductility that is necessary for deployment of balloon expandable stents. In contrast, nanoglasses, that is, amorphous alloys with heterogeneous microstructure, exhibit enhanced ductility which makes them promising materials for balloon expandable stents. We evaluate the feasibility of a prototypical Zr64Cu36 nanoglass with a grain size of 5 nm for balloon expandable stents by performing finite element method modeling of the stent deployment process in a coronary artery. We consider the BX‐Velocity stent design and the nanoglass mechanical properties calculated from atomistic simulations. The results suggest that nanoglasses are suitable materials for balloon expandable stent applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:73–79, 2020.

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Section: Methodsmentioning

confidence: 99%

Nanoglass‐based balloon expandable stents

et al. 2019

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“…Stents are tube-like structures that are increasingly employed in interventional cardiology revascularization, with proven symptomatic and prognostic effectiveness [ 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 ]. They are typically used to treat occlusions, blockages, and aneurysms in endovascular lumen, both in central and peripheral vessels, and also used as bio-prosthetic heart valve frames [ 154 , 207 , 208 , 209 , 210 , 211 ]. Stents are classified depending on their deployment mechanism either balloon-expanding (BX) or self-expanding (SX) [ 212 ].…”

Section: Cardiovascular Stents and Their Required Mechanical Propementioning

confidence: 99%

“…Contrary to other conventional engineering materials, fracture in a nitinol based SX stent is not stress-based but strain-based [ 235 ]. In general, one of the most important mechanical properties required of an SX stent material would be the high recoverable strain limit during stent crimping (often referred to as crimping strain) [ 207 , 229 ]. Nitinol offers a high recoverable strain ( Figure 6 b) of about 8–10% [ 236 , 237 , 238 ] due to austenite-martensite-austenite phase transformation.…”

Section: Cardiovascular Stents and Their Required Mechanical Propementioning

confidence: 99%

A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications

Jafary-Zadeh

Kumar

Branı́cio

et al. 2018

JFB

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Functional and mechanical properties of novel biomaterials must be carefully evaluated to guarantee long-term biocompatibility and structural integrity of implantable medical devices. Owing to the combination of metallic bonding and amorphous structure, metallic glasses (MGs) exhibit extraordinary properties superior to conventional crystalline metallic alloys, placing them at the frontier of biomaterials research. MGs have potential to improve corrosion resistance, biocompatibility, strength, and longevity of biomedical implants, and hence are promising materials for cardiovascular stent applications. Nevertheless, while functional properties and biocompatibility of MGs have been widely investigated and validated, a solid understanding of their mechanical performance during different stages in stent applications is still scarce. In this review, we provide a brief, yet comprehensive account on the general aspects of MGs regarding their formation, processing, structure, mechanical, and chemical properties. More specifically, we focus on the additive manufacturing (AM) of MGs, their outstanding high strength and resilience, and their fatigue properties. The interconnection between processing, structure and mechanical behaviour of MGs is highlighted. We further review the main categories of cardiovascular stents, the required mechanical properties of each category, and the conventional materials have been using to address these requirements. Then, we bridge between the mechanical requirements of stents, structural properties of MGs, and the corresponding stent design caveats. In particular, we discuss our recent findings on the feasibility of using MGs in self-expandable stents where our results show that a metallic glass based aortic stent can be crimped without mechanical failure. We further justify the safe deployment of this stent in human descending aorta. It is our intent with this review to inspire biodevice developers toward the realization of MG-based stents.

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“…This is critical since the stents are expected to undergo large deformations during the crimping stage. More specifically, the crimping strain while the stents are progressively crimped to a small diameter is a major concern in self‐expandable stent design which has been studied extensively in nitinol‐based stents . However, to the best of our knowledge, the mechanical behavior of BMG‐based self‐expandable stents during crimping has not been explored yet.…”

Section: Introductionmentioning

confidence: 99%

“…More specifically, the crimping strain while the stents are progressively crimped to a small diameter is a major concern in self-expandable stent design which has been studied extensively in nitinol-based stents. [41][42][43] However, to the best of our knowledge, the mechanical behavior of BMG-based self-expandable stents during crimping has not been explored yet. In this work, we aim at studying the mechanics of a prototypical Zr-based BMG as a stent material during the crimping of four selfexpandable stents designed for percutaneous applications including percutaneous carotid artery stenting (CAS), transcatheter aortic valve implantation (TAVI), percutaneous cava valve implantation, and transcatheter mitral valve replacement (TMR).…”

Section: Introductionmentioning

confidence: 99%

Feasibility of using bulk metallic glass for self-expandable stent applications

Kumar

Jafary-Zadeh

Tavakoli

et al. 2016

J. Biomed. Mater. Res.

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Self-expandable stents are widely used to restore blood flow in a diseased artery segment by keeping the artery open after angioplasty. Despite the prevalent use of conventional crystalline metallic alloys, for example, nitinol, to construct self-expandable stents, new biomaterials such as bulk metallic glasses (BMGs) are being actively pursued to improve stent performance. Here, we conducted a series of analyses including finite element analysis and molecular dynamics simulations to investigate the feasibility of using a prototypical Zr-based BMG for self-expandable stent applications. We model stent crimping of several designs for different percutaneous applications. Our results indicate that BMG-based stents with diamond-shaped crowns suffer from severe localization of plastic deformation and abrupt failure during crimping. As a possible solution, we further illustrate that such abrupt failure could be avoided in BMG-based stents without diamond shape crowns. This work would open a new horizon for a quest toward exploiting superior mechanical and functional properties of metallic glasses to design future stents. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1874-1882, 2017.

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Design considerations and quantitative assessment for the development of percutaneous mitral valve stent

Cited by 17 publications

References 23 publications

Nanoglass‐based balloon expandable stents

Nanoglass‐based balloon expandable stents

A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications

Feasibility of using bulk metallic glass for self-expandable stent applications

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