Simulated Bioprosthetic Heart Valve Deformation under Quasi-Static Loading

Wei Sun; Ajay Abad; Michael S. Sacks

doi:10.1115/1.2049337

Simulated Bioprosthetic Heart Valve Deformation under Quasi-Static Loading

Journal of Biomechanical Engineering ◽

10.1115/1.2049337 ◽

2005 ◽

Vol 127 (6) ◽

pp. 905-914 ◽

Cited By ~ 111

Author(s):

Wei Sun ◽

Ajay Abad ◽

Michael S. Sacks

Keyword(s):

Heart Valves ◽

Constitutive Models ◽

Material Model ◽

Structural Failure ◽

Bioprosthetic Heart Valves ◽

Prosthetic Devices ◽

Biomechanical Behavior ◽

Biaxial Tests ◽

Parametric Studies ◽

Good Agreement

For more than 40years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. In this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120mmHg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design.

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Nonlinear Analysis of Bioprosthetic Heart Valves under Dynamic Loading

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.152-154.732 ◽

2012 ◽

Vol 152-154 ◽

pp. 732-736

Author(s):

Quan Yuan ◽

Xin Ye ◽

Hai Bo Ma ◽

Hua Cong ◽

Xu Huang

Keyword(s):

Heart Valve ◽

Heart Valves ◽

Material Model ◽

Von Mises Stress ◽

Stress Distributions ◽

Bioprosthetic Heart Valve ◽

Element Analysis ◽

Bioprosthetic Heart Valves ◽

Diastolic Phase ◽

Von Mises

In order to investigate the effect of material nonlinearity on the dynamic behavior of bioprosthetic heart valve, we establish the spherical, cylindrical and ellipsoidal leaflets models with the material model of Mooney-Rivlin. The mechanical behavior of bioprosthetic valve leaflet during diastolic phase is analyzed. The finite element analysis results show that the stress distributions of the ellipsoidal and spherical valve leaflets are comparatively reasonable. The ellipsoidal and spherical valve leaflets have the following advantages over the cylindrical leaflet valve, lower peak von-Mises stress, smaller stress concentration area, and relatively uniform stress distribution. This work is very helpful to manufacture reasonable shaped valvular leaflets，thus to prolong the lifetime of the bioprosthetic heart valve.

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Application of Computational Biomechanics in Bioprosthetic Heart Valve Design

Journal of Medical Devices ◽

10.1115/1.2936218 ◽

2008 ◽

Vol 2 (2) ◽

Author(s):

Wei Sun ◽

Milton DeHerrera

Keyword(s):

Heart Valve ◽

Heart Valves ◽

Anticoagulation Therapy ◽

Design Parameters ◽

Effective Orifice Area ◽

Valve Design ◽

Prosthetic Devices ◽

Computational Biomechanics ◽

Biomechanical Behavior ◽

Hemodynamic Performance

For more than 40years, the replacement of diseased natural heart valves with prosthetic devices has dramatically improved the quality and length of the lives of millions of patients. Bioprosthetic heart valves (BHV), which are composed of biologically derived tissues, have good hemodynamic performance and do not require the anticoagulation therapy necessary when mechanical heart valves are implanted. However, these bioprostheses continue to fail due to structural failure resulting from poor tissue durability and faulty design. AHA∕ACC guideline recommends use of BHV for patients 65years or older, primarily due to its current 10–15years of limited durability. Clearly, an in-depth understanding of the biomechanical behavior of BHV is essential to improving BHV design to reduce rates of failure and increase its durability. Objective: develop a robust computational model to simulate BHV deformations and optimize its design. Methods: Experimentally driven, nonlinear, anisotropic material models are used for modeling the mechanical properties of valve leaflets; A novel method of constructing parametric finite element models is used to rapidly generate 3D free-from geometries of BHV for valve design optimization; Valve design parameters, such as peak stresses and effective orifice area (EOA) are evaluated. Results: multiple applications of the approach demonstrate the feasibility of utilizing computational biomechanics in BHV design. The computational approach provides us with an efficient new platform to develop and optimize the next generation heart valve design such as transcatheter valve and valve repair device design.

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Thrombosis of Surgical Bioprosthetic Heart Valves-Insights from Reports to International Medical Device Vigilance Systems

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-0037-1598875 ◽

2017 ◽

Vol 65 (S 01) ◽

pp. S1-S110

Author(s):

C. Gestrich ◽

J.E. Klein ◽

B. Toctam ◽

G.D. Dürr ◽

J.M. Sinning ◽

...

Keyword(s):

Medical Device ◽

Heart Valves ◽

International Medical ◽

Bioprosthetic Heart Valves

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Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

Tire Science and Technology ◽

10.2346/1.2965832 ◽

2008 ◽

Vol 36 (3) ◽

pp. 211-226 ◽

Cited By ~ 9

Author(s):

F. Liu ◽

M. P. F. Sutcliffe ◽

W. R. Graham

Keyword(s):

High Speed ◽

Slip Rate ◽

Material Model ◽

Contact Forces ◽

Block Modeling ◽

Rate Dependent ◽

Linear Viscoelastic Material ◽

Linear Viscoelastic ◽

The Impact ◽

Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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In Situ “Humanization” of Porcine Bioprostheses: Demonstration of Tendon Bioprostheses Conversion into Human ACL and Possible Implications for Heart Valve Bioprostheses

Bioengineering ◽

10.3390/bioengineering8010010 ◽

2021 ◽

Vol 8 (1) ◽

pp. 10

Author(s):

Uri Galili ◽

Kevin R. Stone

Keyword(s):

Extracellular Matrix ◽

Heart Valves ◽

Cruciate Ligament ◽

Anticoagulation Therapy ◽

Young Patients ◽

Collagen Fibers ◽

Reconstruction Process ◽

Bioprosthetic Heart Valves ◽

Porcine Tissue ◽

Anterior Cruciate

This review describes the first studies on successful conversion of porcine soft-tissue bioprostheses into viable permanently functional tissue in humans. This process includes gradual degradation of the porcine tissue, with concomitant neo-vascularization and reconstruction of the implanted bioprosthesis with human cells and extracellular matrix. Such a reconstruction process is referred to in this review as “humanization”. Humanization was achieved with porcine bone-patellar-tendon-bone (BTB), replacing torn anterior-cruciate-ligament (ACL) in patients. In addition to its possible use in orthopedic surgery, it is suggested that this humanization method should be studied as a possible mechanism for converting implanted porcine bioprosthetic heart-valves (BHV) into viable tissue valves in young patients. Presently, these patients are only implanted with mechanical heart-valves, which require constant anticoagulation therapy. The processing of porcine bioprostheses, which enables humanization, includes elimination of α-gal epitopes and partial (incomplete) crosslinking with glutaraldehyde. Studies on implantation of porcine BTB bioprostheses indicated that enzymatic elimination of α-gal epitopes prevents subsequent accelerated destruction of implanted tissues by the natural anti-Gal antibody, whereas the partial crosslinking by glutaraldehyde molecules results in their function as “speed bumps” that slow the infiltration of macrophages. Anti-non gal antibodies produced against porcine antigens in implanted bioprostheses recruit macrophages, which infiltrate at a pace that enables slow degradation of the porcine tissue, neo-vascularization, and infiltration of fibroblasts. These fibroblasts align with the porcine collagen-fibers scaffold, secrete their collagen-fibers and other extracellular-matrix (ECM) components, and gradually replace porcine tissues degraded by macrophages with autologous functional viable tissue. Porcine BTB implanted in patients completes humanization into autologous ACL within ~2 years. The similarities in cells and ECM comprising heart-valves and tendons, raises the possibility that porcine BHV undergoing a similar processing, may also undergo humanization, resulting in formation of an autologous, viable, permanently functional, non-calcifying heart-valves.

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Determination of a Rubber-Like Material Model as an Inverse Problem

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.70.225 ◽

2011 ◽

Vol 70 ◽

pp. 225-230 ◽

Cited By ~ 1

Author(s):

Agnieszka Derewonko ◽

Andrzej Kiczko

Keyword(s):

Selection Process ◽

Axial Stress ◽

Constitutive Models ◽

Material Model ◽

Polyester Fabric ◽

Point Of View ◽

Air Cushion ◽

Ill Conditioning ◽

Stress States

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.

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Thermo-Mechanical Modeling and Analysis of Equal Channel Angular Pressing

Journal of Metastable and Nanocrystalline Materials ◽

10.4028/www.scientific.net/jmnm.23.263 ◽

2005 ◽

Vol 23 ◽

pp. 263-266 ◽

Cited By ~ 1

Author(s):

Qing Xiang Pei ◽

B.H. Hu ◽

C. Lu

Keyword(s):

Equal Channel Angular Pressing ◽

Temperature Rise ◽

Flow Behavior ◽

Material Model ◽

Workpiece Material ◽

Element Analysis ◽

Modeling And Analysis ◽

Die Geometry ◽

Angular Pressing ◽

Good Agreement

Thermo-mechanical finite element analysis was carried out to study the deformation behavior and temperature distribution during equal channel angular pressing (ECAP). The material model used is the Johnson-Cook constitution model that can consider the multiplication effect of strain, strain rate, and temperature on the flow stress. The effects of pressing speed, pressing temperature, workpiece material and die geometry on the temperature rise and flow behavior during ECAP process were investigated. The simulated temperature rise due to deformation heating was compared with published experimental results and a good agreement was obtained. Among the various die geometries studied, the two-turn die with 0° round corner generates the highest and most uniform plastic strain in the workpiece.

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Establishment of an ANSYS-Based Constitutive Modeling for Age Forming of Aluminum Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.1497 ◽

2012 ◽

Vol 217-219 ◽

pp. 1497-1500 ◽

Cited By ~ 2

Author(s):

Xiao Jun Zuo ◽

Jun Chu Li ◽

Da Hai Liu ◽

Long Fei Zeng

Keyword(s):

Aluminum Alloy ◽

Constitutive Equation ◽

Material Model ◽

Tensile Tests ◽

Material Constants ◽

Tensile Process ◽

Simulation Based ◽

Optimal Material ◽

Two Stages ◽

Good Agreement

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.

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