A Newly Developed Tri-Leaflet Polymeric Heart Valve Prosthesis

Gaetano, Francesco De; Bagnoli, Paola; Zaffora, Adriano; Pandolfi, Anna; Serrani, Marta; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D.; Costantino, Maria Laura

doi:10.1142/s0219519415400096

Cited by 17 publications

(14 citation statements)

References 8 publications

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“…A custom-made pulse duplicator was used to test the prototypes at different flow rate and frequency conditions; pressure and flow signals were recorded and pressure drops, effective orifice area (EOA), and regurgitant volume were computed. All the tested PHVs met the requirements defined by the ISO 5840 Standard (EOA > 1 cm 2 and regurgitant volume < 10% of the stroke volume), indicating good device hydrodynamics under the prescribed conditions [34,35]. However, these valves were not optimized in terms of material microstructure and determining the optimum cylinders' orientation of the PHV is one of the main challenges to solve in the development of a new anisotropic valve.…”

Section: Introductionmentioning

confidence: 99%

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

Serrani

Brubert

Stasiak

et al. 2016

Journal of Biomechanical Engineering

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Styrene-based block copolymers are promising materials for the development of a polymeric heart valve prosthesis (PHV), and the mechanical properties of these polymers can be tuned via the manufacturing process, orienting the cylindrical domains to achieve material anisotropy. The aim of this work is the development of a computational tool for the optimization of the material microstructure in a new PHV intended for aortic valve replacement to enhance the mechanical performance of the device. An iterative procedure was implemented to orient the cylinders along the maximum principal stress direction of the leaflet. A numerical model of the leaflet was developed, and the polymer mechanical behavior was described by a hyperelastic anisotropic constitutive law. A custom routine was implemented to align the cylinders with the maximum Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts principal stress direction in the leaflet for each iteration. The study was focused on valve closure, since during this phase the fibrous structure of the leaflets must bear the greatest load. The optimal microstructure obtained by our procedure is characterized by mainly circumferential orientation of the cylinders within the valve leaflet. An increase in the radial strain and a decrease in the circumferential strain due to the microstructure optimization were observed. Also, a decrease in the maximum value of the strain energy density was found in the case of optimized orientation; since the strain energy density is a widely used criterion to predict elastomer's lifetime, this result suggests a possible increase of the device durability if the polymer microstructure is optimized. The present method represents a valuable tool for the design of a new anisotropic PHV, allowing the investigation of different designs, materials, and loading conditions. Keywordspolymeric heart valve; heart valve prosthesis; computational modeling

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Section: Introductionmentioning

confidence: 99%

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

Serrani

Brubert

Stasiak

et al. 2016

Journal of Biomechanical Engineering

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“…In polymer sciences, researchers emulate biological structures with feature sizes down to 10 nm and with self‐cleaning, adhesive, antireflective, and sensing properties. In the biomedical field, nanostructures and microstructures are fabricated as antibacterial and antiadhesive coatings for implantable prostheses and as scaffolds for enhanced tissue regeneration . Nanofabrication and microfabrication methods are also used to make nanoelectrochemical and microelectromechanical systems (NEMS and MEMS), for example, for trapping biomolecules or biostructures, for facilitating diagnostic purposes, and for carrying out chemical reactions in a configurable and scalable fashion .…”

Section: Introductionmentioning

confidence: 99%

Nanostructure and Microstructure Fabrication: From Desired Properties to Suitable Processes

Assenbergh

Meinders²,

Geraedts

et al. 2018

Small

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When designing a new nanostructure or microstructure, one can follow a processing-based manufacturing pathway, in which the structure properties are defined based on the processing capabilities of the fabrication method at hand. Alternatively, a performance-based pathway can be followed, where the envisioned performance is first defined, and then suitable fabrication methods are sought. To support the latter pathway, fabrication methods are here reviewed based on the geometric and material complexity, resolution, total size, geometric and material diversity, and throughput they can achieve, independently from processing capabilities. Ten groups of fabrication methods are identified and compared in terms of these seven moderators. The highest resolution is obtained with electron beam lithography, with feature sizes below 5 nm. The highest geometric complexity is attained with vat photopolymerization. For high throughput, parallel methods, such as photolithography (≈10 m h ), are needed. This review offers a decision-making tool for identifying which method to use for fabricating a structure with predefined properties.

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“…Interestingly a similar approach, but with a slightly different definition of the strain energy contributions, has been adopted also to model a newly developed polymeric valve. 9 This anisotropic strain energy formulation well suited the purpose of the present work, since by varying fiber angle  in eq. (1) different degree of anisotropy can be obtained, whereas by changing the value of coefficient c 10 the influence of matrix can be investigated.…”

Section: Leaflet Constitutive Lawmentioning

confidence: 99%

“…Similar types of constitutive law have been used also to represent valve candidate tissues other than BP. 9 The results of the present study are thus intended as not necessarily restricted to pericardial valves but rather as applicable to materials of different nature. The complex influence of anisotropic leaflet properties on valve performances was studied considering leaflet opening dynamics in the context of Fluid-Structure Interaction (FSI) approach.…”

Section: Introductionmentioning

confidence: 99%

Influence of Leaflet’s Matrix Stiffness and Fiber Orientation on the Opening Dynamics of a Prosthetic Trileaflet Heart Valve

Avanzini

2017

J. Mech. Med. Biol.

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Biological valves are employed for aortic valve substitution since a long time but there is a growing effort toward the development of new engineered tissues, in which the complex mechanical response of native leaflets is replicated using composite materials consisting of a soft matrix with embedded reinforcing fibers. The main goal of the present study is to investigate the influence that variations on fiber orientation and matrix stiffness may have on valve dynamics. To this aim, a fluid–structure interaction (FSI) model of a trileaflet valve was implemented in which the opening phase was simulated and leaflet matrix stiffness and fiber orientation were varied in the framework of an anisotropic hyperelastic strain energy function. Results show that both parameters may affect significantly transvalvular pressure gradient and effective orifice area (EOA). For the opening phase of the valve examined, less favorable flow conditions were found when preferred fiber orientation is circumferential, due to lower maximum EOA achievable. Such configuration in combination with stiffer matrix may result in significant degradation of valve performances. Overall fiber orientation can potentially be taylored to optimize valve dynamics, provided also structural aspects that may be prominent in the closure phase, are considered.

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A Newly Developed Tri-Leaflet Polymeric Heart Valve Prosthesis

Cited by 17 publications

References 8 publications

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

Nanostructure and Microstructure Fabrication: From Desired Properties to Suitable Processes

Influence of Leaflet’s Matrix Stiffness and Fiber Orientation on the Opening Dynamics of a Prosthetic Trileaflet Heart Valve

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