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Kim Y, Pyo WK, Kim WK, Suh GY, Kang K, Lee SH. A parametric study regarding structural design of a bioprosthetic aortic valve by 3D fluid-structure interaction simulations. Heliyon 2024; 10:e27310. [PMID: 38509976 PMCID: PMC10951528 DOI: 10.1016/j.heliyon.2024.e27310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/22/2024] Open
Abstract
Since the introduction of transcatheter aortic valve (AV) implantation as a viable option, surgical bioprosthetic AVs have recently started incorporating shorter struts considering future valve-in-valve procedures. However, the effect of leaflet coaptation geometry on the longevity of these valves remains unexplored. To address this gap, we performed a finite element analysis on bioprosthetic AVs with varying strut heights using a two-way fluid-structure interaction method. To establish a baseline, we used a standard height based on a rendered platform image of the CE PERIMOUNT Magna Ease valve from Edward Lifesciences in Irvine, CA. Bovine pericardium properties were assigned to the leaflets, while normal saline properties were used as the recirculating fluid in hemodynamic simulations. The physiological pressure profile of the cardiac cycle was applied between the aorta and left ventricle. We calculated blood flow velocity, effective orifice area (EOA), and mechanical stress on the leaflets. The results reveal that as the strut height increases, the stroke volume increases, leakage volume decreases, and EOA improves. Additionally, the maximum mechanical stress experienced by the leaflet decreases by 62% as the strut height increases to 1.2 times the standard height. This research highlights that a low-strut design in bioprosthetic AVs may negatively affect their durability, which can be useful in design of next-generation bioprosthetic AVs.
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Affiliation(s)
- Yongwoo Kim
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Won Kyung Pyo
- Department of Thoracic Cardiovascular Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Wan Kee Kim
- Department of Thoracic and Cariovascular Surgery, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Gyeonggi-do, Republic of Korea
| | - Ga-Young Suh
- Department of Biomedical Engineering, California State University, Long Beach, CA, USA
| | - Keonwook Kang
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Seung Hyun Lee
- Department of Thoracic Cardiovascular Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
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Monteleone A, Di Leonardo S, Napoli E, Burriesci G. A novel mono-physics particle-based approach for the simulation of cardiovascular fluid-structure interaction problems. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 245:108034. [PMID: 38244340 DOI: 10.1016/j.cmpb.2024.108034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
BACKGROUND AND OBJECTIVE Fluid-structure interaction (FSI) is required in the study of several cardiovascular engineering problems were the mutual interaction between the pulsatile blood flow and the tissue structures is essential to establish the biomechanics of the system. Traditional FSI methods are partitioned approaches where two independent solvers, one for the fluid and one for the structure, are asynchronously coupled. This process results into high computational costs. In this work, a new FSI scheme which avoids the coupling of different solvers is presented in the framework of the truly incompressible smoothed particle hydrodynamics (ISPH) method. METHODS In the proposed FSI method, ISPH particles contribute to define both the fluid and structural domains and are solved together in a unified system. Solid particles, geometrically defined at the beginning of the simulation, are linked through spring bounds with elastic constant providing the material Young's modulus. At each iteration, internal elastic forces are calculated to restore the springs resting length. These forces are added in the predictor step of the fractional-step procedure used to solve the momentum and continuity equations for incompressible flows of all particles. RESULTS The method was validated with a benchmark test case consisting of a flexible beam immersed in a channel. Results showed good agreement with the system coupling approach of a well-established commercial software, ANSYS®, both in terms of fluid-dynamics and beam deformation. The approach was then applied to model a complex cardiovascular problem, consisting in the aortic valve operating function. The valve dynamics during opening and closing phases were compared qualitatively with literature results, demonstrating good consistency. CONCLUSIONS The method is computationally more efficient than traditional FSI strategies, and overcomes some of their main drawbacks, such as the impossibility of simulating the correct valve coaptation during the closing phase. Thanks to the incompressibility scheme, the proposed FSI method is appropriate to model biological soft tissues. The simplicity and flexibility of the approach also makes it suitable to be expanded for the modelling of thromboembolic phenomena.
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Affiliation(s)
| | | | - Enrico Napoli
- Engineering Department, University of Palermo, Italy
| | - Gaetano Burriesci
- Ri.MED Foundation, Palermo, Italy; UCL Mechanical Engineering, University College London, UK.
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Bletsos G, Rung T, Radtke L. Hemodynamics in arterial bypass graft anastomoses with varying cuff sizes and proximal flow paths: a fluid-structure interaction study. Comput Methods Biomech Biomed Engin 2024:1-20. [PMID: 38323804 DOI: 10.1080/10255842.2024.2310747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/29/2023] [Indexed: 02/08/2024]
Abstract
This article investigates the effect of the cuff size of arterial bypass grafts and the flow conditions on the hemodynamics in the anastomosis (connection) to the artery, using numerical simulations. We consider a fluid-structure interaction problem which is solved based on a partitioned scheme. Additionally, we employ computational fluid dynamics to investigate the effect of a rigid wall assumption. The work focuses on clinically relevant hemodynamic quantities associated with the development of intimal hyperplasia. We also include a model for the prediction of hemolysis into the simulation. The results show that even minor changes of the cuff size can result into significant differences in the corresponding quantities of interest. The importance of the inflow path is shown to be lower than that of the cuff size. The usually employed rigid wall assumption is found to be adequate to address wall shear stress oscillations but falls short on predicting maximum and minimum wall shear stress-related quantities of interest.
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Affiliation(s)
- Georgios Bletsos
- Institute for Fluid Dynamics and Ship Theory (M-8), Hamburg University of Technology, Hamburg, Germany
| | - Thomas Rung
- Institute for Fluid Dynamics and Ship Theory (M-8), Hamburg University of Technology, Hamburg, Germany
| | - Lars Radtke
- Institute for Ship Structural Design and Analysis (M-10), Hamburg University of Technology, Hamburg, Germany
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Oliveira HL, Buscaglia GC, Paz RR, Del Pin F, Cuminato JA, Kerr M, McKee S, Stewart IW, Wheatley DJ. Three-dimensional fluid-structure interaction simulation of the Wheatley aortic valve. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3792. [PMID: 38010884 DOI: 10.1002/cnm.3792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/15/2023] [Accepted: 11/01/2023] [Indexed: 11/29/2023]
Abstract
Valvular heart diseases (such as stenosis and regurgitation) are recognized as a rapidly growing cause of global deaths and major contributors to disability. The most effective treatment for these pathologies is the replacement of the natural valve with a prosthetic one. Our work considers an innovative design for prosthetic aortic valves that combines the reliability and durability of artificial valves with the flexibility of tissue valves. It consists of a rigid support and three polymer leaflets which can be cut from an extruded flat sheet, and is referred to hereafter as the Wheatley aortic valve (WAV). As a first step towards the understanding of the mechanical behavior of the WAV, we report here on the implementation of a numerical model built with the ICFD multi-physics solver of the LS-DYNA software. The model is calibrated and validated using data from a basic pulsatile-flow experiment in a water-filled straight tube. Sensitivity to model parameters (contact parameters, mesh size, etc.) and to design parameters (height, material constants) is studied. The numerical data allow us to describe the leaflet motion and the liquid flow in great detail, and to investigate the possible failure modes in cases of unfavorable operational conditions (in particular, if the leaflet height is inadequate). In future work the numerical model developed here will be used to assess the thrombogenic properties of the valve under physiological conditions.
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Affiliation(s)
- Hugo L Oliveira
- Instituto de Ciências Matemáticas e de Computação-ICMC, Universidade de São Paulo-Campus de São Carlos, Avenida Trabalhador São-Carlense, São Carlos, Brazil
| | - Gustavo C Buscaglia
- Instituto de Ciências Matemáticas e de Computação-ICMC, Universidade de São Paulo-Campus de São Carlos, Avenida Trabalhador São-Carlense, São Carlos, Brazil
| | - Rodrigo R Paz
- ANSYS Inc., Livermore, California, USA
- IMIT, CONICET, National Council for Scientific and Technical Research, Resistencia, Argentina
| | | | - José A Cuminato
- Instituto de Ciências Matemáticas e de Computação-ICMC, Universidade de São Paulo-Campus de São Carlos, Avenida Trabalhador São-Carlense, São Carlos, Brazil
| | - Monica Kerr
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Sean McKee
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
| | - Iain W Stewart
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
| | - David J Wheatley
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
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Shah I, Samaee M, Razavi A, Esmailie F, Ballarin F, Dasi LP, Veneziani A. Reduced Order Modeling for Real-Time Stent Deformation Simulations of Transcatheter Aortic Valve Prostheses. Ann Biomed Eng 2024; 52:208-225. [PMID: 37962675 DOI: 10.1007/s10439-023-03360-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/01/2023] [Indexed: 11/15/2023]
Abstract
Computational modeling can be a critical tool to predict deployment behavior for transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis. However, due to the mechanical complexity of the aortic valve and the multiphysics nature of the problem, described by partial differential equations (PDEs), traditional finite element (FE) modeling of TAVR deployment is computationally expensive. In this preliminary study, a PDEs-based reduced order modeling (ROM) framework is introduced for rapidly simulating structural deformation of the Medtronic Evolut R valve stent frame. Using fifteen probing points from an Evolut model with parametrized loads enforced, 105 FE simulations were performed in the so-called offline phase, creating a snapshot library. The library was used in the online phase of the ROM for a new set of applied loads via the proper orthogonal decomposition-Galerkin (POD-Galerkin) approach. Simulations of small radial deformations of the Evolut stent frame were performed and compared to full order model (FOM) solutions. Linear elastic and hyperelastic constitutive models in steady and unsteady regimes were implemented within the ROM. Since the original POD-Galerkin method is formulated for linear problems, specific methods for the nonlinear terms in the hyperelastic case were employed, namely, the Discrete Empirical Interpolation Method. The ROM solutions were in strong agreement with the FOM in all numerical experiments, with a speed-up of at least 92% in CPU Time. This framework serves as a first step toward real-time predictive models for TAVR deployment simulations.
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Affiliation(s)
- Imran Shah
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Technology Circle, Atlanta, GA, 30313, USA
- Department of Mathematics, Emory University, 400 Dowman Drive, Atlanta, GA, 30322, USA
| | - Milad Samaee
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Technology Circle, Atlanta, GA, 30313, USA
| | - Atefeh Razavi
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Technology Circle, Atlanta, GA, 30313, USA
| | - Fateme Esmailie
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Technology Circle, Atlanta, GA, 30313, USA
| | - Francesco Ballarin
- Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, 48 Via Della Garzetta, 25133, Brescia, Italy
| | - Lakshmi P Dasi
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Technology Circle, Atlanta, GA, 30313, USA.
| | - Alessandro Veneziani
- Department of Mathematics, Emory University, 400 Dowman Drive, Atlanta, GA, 30322, USA.
- Department of Computer Science, Emory University, 400 Dowman Drive, Atlanta, GA, 30322, USA.
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6
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Zingaro A, Bucelli M, Fumagalli I, Dede' L, Quarteroni A. Modeling isovolumetric phases in cardiac flows by an Augmented Resistive Immersed Implicit Surface method. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3767. [PMID: 37615375 DOI: 10.1002/cnm.3767] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 06/05/2023] [Accepted: 07/30/2023] [Indexed: 08/25/2023]
Abstract
A major challenge in the computational fluid dynamics modeling of the heart function is the simulation of isovolumetric phases when the hemodynamics problem is driven by a prescribed boundary displacement. During such phases, both atrioventricular and semilunar valves are closed: consequently, the ventricular pressure may not be uniquely defined, and spurious oscillations may arise in numerical simulations. These oscillations can strongly affect valve dynamics models driven by the blood flow, making unlikely to recovering physiological dynamics. Hence, prescribed opening and closing times are usually employed, or the isovolumetric phases are neglected altogether. In this article, we propose a suitable modification of the Resistive Immersed Implicit Surface (RIIS) method (Fedele et al., Biomech Model Mechanobiol 2017, 16, 1779-1803) by introducing a reaction term to correctly capture the pressure transients during isovolumetric phases. The method, that we call Augmented RIIS (ARIIS) method, extends the previously proposed ARIS method (This et al., Int J Numer Methods Biomed Eng 2020, 36, e3223) to the case of a mesh which is not body-fitted to the valves. We test the proposed method on two different benchmark problems, including a new simplified problem that retains all the characteristics of a heart cycle. We apply the ARIIS method to a fluid dynamics simulation of a realistic left heart geometry, and we show that ARIIS allows to correctly simulate isovolumetric phases, differently from standard RIIS method. Finally, we demonstrate that by the new method the cardiac valves can open and close without prescribing any opening/closing times.
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Affiliation(s)
- Alberto Zingaro
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
- ELEM Biotech S.L., Barcelona, Spain
| | - Michele Bucelli
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | - Ivan Fumagalli
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | - Luca Dede'
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | - Alfio Quarteroni
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
- Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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7
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Torre M, Morganti S, Pasqualini FS, Reali A. Current progress toward isogeometric modeling of the heart biophysics. BIOPHYSICS REVIEWS 2023; 4:041301. [PMID: 38510845 PMCID: PMC10903424 DOI: 10.1063/5.0152690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 10/24/2023] [Indexed: 03/22/2024]
Abstract
In this paper, we review a powerful methodology to solve complex numerical simulations, known as isogeometric analysis, with a focus on applications to the biophysical modeling of the heart. We focus on the hemodynamics, modeling of the valves, cardiac tissue mechanics, and on the simulation of medical devices and treatments. For every topic, we provide an overview of the methods employed to solve the specific numerical issue entailed by the simulation. We try to cover the complete process, starting from the creation of the geometrical model up to the analysis and post-processing, highlighting the advantages and disadvantages of the methodology.
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Affiliation(s)
- Michele Torre
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Simone Morganti
- Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100 Pavia, Italy
| | - Francesco S. Pasqualini
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Alessandro Reali
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
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8
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Syed F, Khan S, Toma M. Modeling Dynamics of the Cardiovascular System Using Fluid-Structure Interaction Methods. BIOLOGY 2023; 12:1026. [PMID: 37508455 PMCID: PMC10376821 DOI: 10.3390/biology12071026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
Using fluid-structure interaction algorithms to simulate the human circulatory system is an innovative approach that can provide valuable insights into cardiovascular dynamics. Fluid-structure interaction algorithms enable us to couple simulations of blood flow and mechanical responses of the blood vessels while taking into account interactions between fluid dynamics and structural behaviors of vessel walls, heart walls, or valves. In the context of the human circulatory system, these algorithms offer a more comprehensive representation by considering the complex interplay between blood flow and the elasticity of blood vessels. Algorithms that simulate fluid flow dynamics and the resulting forces exerted on vessel walls can capture phenomena such as wall deformation, arterial compliance, and the propagation of pressure waves throughout the cardiovascular system. These models enhance the understanding of vasculature properties in human anatomy. The utilization of fluid-structure interaction methods in combination with medical imaging can generate patient-specific models for individual patients to facilitate the process of devising treatment plans. This review evaluates current applications and implications of fluid-structure interaction algorithms with respect to the vasculature, while considering their potential role as a guidance tool for intervention procedures.
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Affiliation(s)
- Faiz Syed
- College of Osteopathic Medicine, New York Institute of Technology, Northern Boulevard, Old Westbury, NY 11568, USA
| | - Sahar Khan
- College of Osteopathic Medicine, New York Institute of Technology, Northern Boulevard, Old Westbury, NY 11568, USA
| | - Milan Toma
- College of Osteopathic Medicine, New York Institute of Technology, Northern Boulevard, Old Westbury, NY 11568, USA
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Zhou J, Li Y, Li T, Tian X, Xiong Y, Chen Y. Analysis of the Effect of Thickness on the Performance of Polymeric Heart Valves. J Funct Biomater 2023; 14:309. [PMID: 37367273 DOI: 10.3390/jfb14060309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/17/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Polymeric heart valves (PHVs) are a promising and more affordable alternative to mechanical heart valves (MHVs) and bioprosthetic heart valves (BHVs). Materials with good durability and biocompatibility used for PHVs have always been the research focus in the field of prosthetic heart valves for many years, and leaflet thickness is a major design parameter for PHVs. The study aims to discuss the relationship between material properties and valve thickness, provided that the basic functions of PHVs are qualified. The fluid-structure interaction (FSI) approach was employed to obtain a more reliable solution of the effective orifice area (EOA), regurgitant fraction (RF), and stress and strain distribution of the valves with different thicknesses under three materials: Carbothane PC-3585A, xSIBS and SIBS-CNTs. This study demonstrates that the smaller elastic modulus of Carbothane PC-3585A allowed for a thicker valve (>0.3 mm) to be produced, while for materials with an elastic modulus higher than that of xSIBS (2.8 MPa), a thickness less than 0.2 mm would be a good attempt to meet the RF standard. What is more, when the elastic modulus is higher than 23.9 MPa, the thickness of the PHV is recommended to be 0.l-0.15 mm. Reducing the RF is one of the directions of PHV optimization in the future. Reducing the thickness and improving other design parameters are reliable means to reduce the RF for materials with high and low elastic modulus, respectively.
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Affiliation(s)
- Jingyuan Zhou
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yijing Li
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Tao Li
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Xiaobao Tian
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yan Xiong
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Yu Chen
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
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10
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Sacks MS, Motiwale S, Goodbrake C, Zhang W. Neural Network Approaches for Soft Biological Tissue and Organ Simulations. J Biomech Eng 2022; 144:121010. [PMID: 36193891 PMCID: PMC9632474 DOI: 10.1115/1.4055835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 09/27/2022] [Indexed: 11/08/2022]
Abstract
Given the functional complexities of soft tissues and organs, it is clear that computational simulations are critical in their understanding and for the rational basis for the development of therapies and replacements. A key aspect of such simulations is accounting for their complex, nonlinear, anisotropic mechanical behaviors. While soft tissue material models have developed to the point of high fidelity, in-silico implementation is typically done using the finite element (FE) method, which remains impractically slow for translational clinical time frames. As a potential path toward addressing the development of high fidelity simulations capable of performing in clinically relevant time frames, we review the use of neural networks (NN) for soft tissue and organ simulation using two approaches. In the first approach, we show how a NN can learn the responses for a detailed meso-structural soft tissue material model. The NN material model not only reproduced the full anisotropic mechanical responses but also demonstrated a considerable efficiency improvement, as it was trained over a range of realizable fibrous structures. In the second approach, we go a step further with the use of a physics-based surrogate model to directly learn the displacement field solution without the need for raw training data or FE simulation datasets. In this approach we utilize a finite element mesh to define the domain and perform the necessary integrations, but not the finite element method (FEM) itself. We demonstrate with this approach, termed neural network finite element (NNFE), results in a trained NNFE model with excellent agreement with the corresponding "ground truth" FE solutions over the entire physiological deformation range on a cuboidal myocardium specimen. More importantly, the NNFE approach provided a significantly decreased computational time for a range of finite element mesh sizes. Specifically, as the FE mesh size increased from 2744 to 175,615 elements, the NNFE computational time increased from 0.1108 s to 0.1393 s, while the "ground truth" FE model increased from 4.541 s to 719.9 s, with the same effective accuracy. These results suggest that NNFE run times are significantly reduced compared with the traditional large-deformation-based finite element solution methods. We then show how a nonuniform rational B-splines (NURBS)-based approach can be directly integrated into the NNFE approach as a means to handle real organ geometries. While these and related approaches are in their early stages, they offer a method to perform complex organ-level simulations in clinically relevant time frames without compromising accuracy.
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Affiliation(s)
- Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Shruti Motiwale
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Christian Goodbrake
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Wenbo Zhang
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
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11
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Efficient Local Refinement near Parametric Boundaries Using kd-Tree Data Structure and Algebraic Level Sets. ALGORITHMS 2022. [DOI: 10.3390/a15070245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
In analysis of problems with parametric spline boundaries that are immersed or inserted into an underlying domain, the discretization on the underlying domain usually does not conform to the inserted boundaries. While the fixed underlying discretization is of great convenience as the immersed boundaries evolve, the field approximations near the inserted boundaries require refinement in the underlying domain, as do the quadrature cells. In this paper, a kd-tree data structure together with a sign-based and/or distance-based refinement strategy is proposed for local refinement near the inserted boundaries as well as for adaptive quadrature near the boundaries. The developed algorithms construct and utilize implicit forms of parametric Non-Uniform Rational B-Spline (NURBS) surfaces to algebraically (and non-iteratively) estimate distance as well as sign relative to the inserted boundary. The kd-tree local refinement is demonstrated to produce fewer sub-cells for the same accuracy of solution as compared to the classical quad/oct tree-based subdivision. Consistent with the kd-tree data structure, we describe a new a priori refinement algorithm based on the signed and unsigned distance from the inserted boundary. We first demonstrate the local refinement strategy coupled with the the kd-tree data structure by constructing Truncated Hierarchical B-spline (THB-spline) “meshes”. We next demonstrate the accuracy and efficiency of the developed local refinement strategy through adaptive quadrature near NURBS boundaries inserted within volumetric three-dimensional NURBS discretizations.
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12
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Alharbi Y, Al Abed A, Bakir AA, Lovell NH, Muller DWM, Otton J, Dokos S. Fluid structure computational model of simulating mitral valve motion in a contracting left ventricle. Comput Biol Med 2022; 148:105834. [PMID: 35816854 DOI: 10.1016/j.compbiomed.2022.105834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 06/24/2022] [Accepted: 07/04/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Fluid structure interaction simulations h hold promise in studying normal and abnormal cardiac function, including the effect of fluid dynamics on mitral valve (MV) leaflet motion. The goal of this study was to develop a 3D fluid structure interaction computational model to simulate bileaflet MV when interacting with blood motion in left ventricle (LV). METHODS The model consists of ideal geometric-shaped MV leaflets and the LV, with MV dimensions based on human anatomical measurements. An experimentally-based hyperelastic isotropic material was used to model the mechanical behaviour of the MV leaflets, with chordae tendineae and papillary muscle tips also incorporated. LV myocardial tissue was prescribed using a transverse isotropic hyperelastic formulation. Incompressible Navier-Stokes fluid formulations were used to govern the blood motion, and the Arbitrary Lagrangian Eulerian (ALE) method was employed to determine the mesh deformation of the fluid and solid domains due to trans-valvular pressure on MV boundaries and the resulting leaflet movement. RESULTS The LV-MV generic model was able to reproduce physiological MV leaflet opening and closing profiles resulting from the time-varying atrial and ventricular pressures, as well as simulating normal and prolapsed MV states. Additionally, the model was able to simulate blood flow patterns after insertion of a prosthetic MV with and without left ventricular outflow tract flow obstruction. In the MV-LV normal model, the regurgitant blood flow fraction was 10.1 %, with no abnormality in cardiac function according to the mitral regurgitation severity grades reported by the American Society of Echocardiography. CONCLUSION Our simulation approach provides insights into intraventricular fluid dynamics in a contracting LV with normal and prolapsed MV function, as well as aiding in the understanding of possible complications after transcatheter MV implantation prior to clinical trials.
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Affiliation(s)
- Yousef Alharbi
- College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia; Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
| | - Amr Al Abed
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
| | - Azam Ahmad Bakir
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia; University of Southampton Malaysia Campus, Iskandar Puteri, Johor, Malaysia.
| | - Nigel H Lovell
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
| | - David W M Muller
- Victor Chang Cardiac Research Institute, Sydney, Australia; Department of Cardiology and Cardiothoracic Surgery, St Vincent's Hospital, Sydney, Australia.
| | - James Otton
- Victor Chang Cardiac Research Institute, Sydney, Australia; Department of Cardiology, Liverpool Hospital, Sydney, Australia.
| | - Socrates Dokos
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
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13
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Hagenah J, Scharfschwerdt M, Ernst F. Aortic Valve Leaflet Shape Synthesis With Geometric Prior From Surrounding Tissue. Front Cardiovasc Med 2022; 9:772222. [PMID: 35369295 PMCID: PMC8967325 DOI: 10.3389/fcvm.2022.772222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Even though the field of medical imaging advances, there are structures in the human body that are barely assessible with classical image acquisition modalities. One example are the three leaflets of the aortic valve due to their thin structure and high movement. However, with an increasing accuracy of biomechanical simulation, for example of the heart function, and extense computing capabilities available, concise knowledge of the individual morphology of these structures could have a high impact on personalized therapy and intervention planning as well as on clinical research. Thus, there is a high demand to estimate the individual shape of inassessible structures given only information on the geometry of the surrounding tissue. This leads to a domain adaptation problem, where the domain gap could be very large while typically only small datasets are available. Hence, classical approaches for domain adaptation are not capable of providing sufficient predictions. In this work, we present a new framework for bridging this domain gap in the scope of estimating anatomical shapes based on the surrounding tissue's morphology. Thus, we propose deep representation learning to not map from one image to another but to predict a latent shape representation. We formalize this framework and present two different approaches to solve the given problem. Furthermore, we perform a proof-of-concept study for estimating the individual shape of the aortic valve leaflets based on a volumetric ultrasound image of the aortic root. Therefore, we collect an ex-vivo porcine data set consisting of both, ultrasound volume images as well as high-resolution leaflet images, evaluate both approaches on it and perform an analysis of the model's hyperparameters. Our results show that using deep representation learning and domain mapping between the identified latent spaces, a robust prediction of the unknown leaflet shape only based on surrounding tissue information is possible, even in limited data scenarios. The concept can be applied to a wide range of modeling tasks, not only in the scope of heart modeling but also for all kinds of inassessible structures within the human body.
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Affiliation(s)
- Jannis Hagenah
- Institute for Robotics and Cognitive Systems, University of Lübeck, Lübeck, Germany
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | | | - Floris Ernst
- Institute for Robotics and Cognitive Systems, University of Lübeck, Lübeck, Germany
- *Correspondence: Floris Ernst
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14
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Computational Methods for Fluid-Structure Interaction Simulation of Heart Valves in Patient-Specific Left Heart Anatomies. FLUIDS 2022. [DOI: 10.3390/fluids7030094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Given the complexity of human left heart anatomy and valvular structures, the fluid–structure interaction (FSI) simulation of native and prosthetic valves poses a significant challenge for numerical methods. In this review, recent numerical advancements for both fluid and structural solvers for heart valves in patient-specific left hearts are systematically considered, emphasizing the numerical treatments of blood flow and valve surfaces, which are the most critical aspects for accurate simulations. Numerical methods for hemodynamics are considered under both the continuum and discrete (particle) approaches. The numerical treatments for the structural dynamics of aortic/mitral valves and FSI coupling methods between the solid Ωs and fluid domain Ωf are also reviewed. Future work toward more advanced patient-specific simulations is also discussed, including the fusion of high-fidelity simulation within vivo measurements and physics-based digital twining based on data analytics and machine learning techniques.
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15
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Zhu C, Seo JH, Mittal R. Computational Modeling of Aortic Stenosis With a Reduced Degree-of-Freedom Fluid-Structure Interaction Valve Model. J Biomech Eng 2022; 144:1120773. [PMID: 34590694 DOI: 10.1115/1.4052576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Indexed: 11/08/2022]
Abstract
In this study, a novel reduced degree-of-freedom (rDOF) aortic valve model is employed to investigate the fluid-structure interaction (FSI) and hemodynamics associated with aortic stenosis. The dynamics of the valve leaflets are determined by an ordinary differential equation with two parameters and this rDOF model is shown to reproduce key features of more complex valve models. The hemodynamics associated with aortic stenosis is studied for three cases: a healthy case and two stenosed cases. The focus of the study is to correlate the hemodynamic features with the source generation mechanism of systolic murmurs associated with aortic stenosis. In the healthy case, extremely weak flow fluctuations are observed. However, in the stenosed cases, simulations show significant turbulent fluctuations in the ascending aorta, which are responsible for the generation of strong wall pressure fluctuations after the aortic root mostly during the deceleration phase of the systole. The intensity of the murmur generation increases with the severity of the stenosis, and the source locations for the two diseased cases studied here lie around 1.0 inlet duct diameters (Do) downstream of the ascending aorta.
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Affiliation(s)
- Chi Zhu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Jung-Hee Seo
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Rajat Mittal
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
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16
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Johnson EL, Rajanna MR, Yang CH, Hsu MC. Effects of membrane and flexural stiffnesses on aortic valve dynamics: identifying the mechanics of leaflet flutter in thinner biological tissues. FORCES IN MECHANICS 2022; 6:100053. [PMID: 36278140 PMCID: PMC9583650 DOI: 10.1016/j.finmec.2021.100053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Valvular pathologies that induce deterioration in the aortic valve are a common cause of heart disease among aging populations. Although there are numerous available technologies to treat valvular conditions and replicate normal aortic function by replacing the diseased valve with a bioprosthetic implant, many of these devices face challenges in terms of long-term durability. One such phenomenon that may exacerbate valve deterioration and induce undesirable hemodynamic effects in the aorta is leaflet flutter, which is characterized by oscillatory motion in the biological tissues. While this behavior has been observed for thinner bioprosthetic valves, the specific underlying mechanics that lead to leaflet flutter have not previously been identified. This work proposes a computational approach to isolate the fundamental mechanics that induce leaflet flutter in thinner biological tissues during the cardiac cycle. The simulations in this work identify reduced flexural stiffness as the primary factor that contributes to increased leaflet flutter in thinner biological tissues, while decreased membrane stiffness and mass of the thinner tissues do not directly induce flutter in these valves. The results of this study provide an improved understanding of the mechanical tissue properties that contribute to flutter and offer significant insights into possible developments in the design of bioprosthetic tissues to account for and reduce the incidence of flutter.
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Affiliation(s)
- Emily L. Johnson
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Manoj R. Rajanna
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - Cheng-Hau Yang
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, USA
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17
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Dedè L, Menghini F, Quarteroni A. Computational fluid dynamics of blood flow in an idealized left human heart. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3287. [PMID: 31816195 DOI: 10.1002/cnm.3287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 09/17/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
We construct an idealized computational model of the left human heart for the study of the blood flow dynamics in the left atrium and ventricle. We solve the Navier-Stokes equations in the ALE formulation and we prescribe the left heart wall displacement based on physiological data; moreover, we consider the presence of both the mitral and aortic valves through the resistive method. We simulate the left heart hemodynamics by means of the finite element method and we consider the variational multiscale large eddy simulation (LES) formulation to account for the transitional and nearly turbulent regimes of the blood flow in physiological conditions. The main contribution of this paper is the characterization of the blood flow in an idealized configuration of the left heart aiming at reproducing function in normal conditions. Our assessment is based on the analysis of instantaneous and phase averaged velocity fields, blood pressure, and other clinically meaningful fluid dynamics indicators. Finally, we show that our idealized computational model can be suitably used to study and critically discuss pathological scenarios like that of a regurgitant mitral valve.
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Affiliation(s)
- Luca Dedè
- MOX-Mathematics Department, Politecnico di Milano, Milan, Italy
| | - Filippo Menghini
- Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Alfio Quarteroni
- MOX-Mathematics Department, Politecnico di Milano, Milan, Italy
- Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (Emeritus Professor)
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18
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Johnson EL, Laurence DW, Xu F, Crisp CE, Mir A, Burkhart HM, Lee CH, Hsu MC. Parameterization, geometric modeling, and isogeometric analysis of tricuspid valves. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2021; 384:113960. [PMID: 34262232 PMCID: PMC8274564 DOI: 10.1016/j.cma.2021.113960] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Approximately 1.6 million patients in the United States are affected by tricuspid valve regurgitation, which occurs when the tricuspid valve does not close properly to prevent backward blood flow into the right atrium. Despite its critical role in proper cardiac function, the tricuspid valve has received limited research attention compared to the mitral and aortic valves on the left side of the heart. As a result, proper valvular function and the pathologies that may cause dysfunction remain poorly understood. To promote further investigations of the biomechanical behavior and response of the tricuspid valve, this work establishes a parameter-based approach that provides a template for tricuspid valve modeling and simulation. The proposed tricuspid valve parameterization presents a comprehensive description of the leaflets and the complex chordae tendineae for capturing the typical three-cusp structural deformation observed from medical data. This simulation framework develops a practical procedure for modeling tricuspid valves and offers a robust, flexible approach to analyze the performance and effectiveness of various valve configurations using isogeometric analysis. The proposed methods also establish a baseline to examine the tricuspid valve's structural deformation, perform future investigations of native valve configurations under healthy and disease conditions, and optimize prosthetic valve designs.
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Affiliation(s)
- Emily L. Johnson
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
| | - Devin W. Laurence
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Fei Xu
- Ansys Inc., 807 Las Cimas Parkway, Austin, Texas 78746, USA
| | - Caroline E. Crisp
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
| | - Arshid Mir
- Division of Pediatric Cardiology, Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Harold M. Burkhart
- Division of Cardiothoracic Surgery, Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, Oklahoma 73019, USA
- Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
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19
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Coupling of IGA and peridynamics for air-blast fluid-structure interaction using an immersed approach. FORCES IN MECHANICS 2021. [DOI: 10.1016/j.finmec.2021.100045] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Hou Q, Liu G, Liu N, Zhang H, Qu Z, Zhang H, Li H, Pan Y, Qiao A. Effect of Valve Height on the Opening and Closing Performance of the Aortic Valve Under Aortic Root Dilatation. Front Physiol 2021; 12:697502. [PMID: 34526908 PMCID: PMC8435789 DOI: 10.3389/fphys.2021.697502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/04/2021] [Indexed: 12/13/2022] Open
Abstract
Patients with aortic valve disease can suffer from valve insufficiency after valve repair surgery due to aortic root dilatation. The paper investigates the effect of valve height (Hv) on the aortic valve opening and closing in order to select the appropriate range of Hv for smoother blood flow through the aortic valve and valve closure completely in the case of continuous aortic root dilatation. A total of 20 parameterized three-dimensional models of the aortic root were constructed following clinical surgical guidance. Aortic annulus diameter (DAA) was separately set to 26, 27, 28, 29, and 30 mm to simulate aortic root dilatation. HV value was separately set to 13.5, 14, 14.5, and 15 mm to simulate aortic valve alterations in surgery. Time-varying pressure loads were applied to the valve, vessel wall of the ascending aorta, and left ventricle. Then, finite element analysis software was employed to simulate the movement and mechanics of the aortic root. The feasible design range of the valve size was evaluated using maximum stress, geometric orifice area (GOA), and leaflet contact force. The results show that the valve was incompletely closed when HV was 13.5 mm and DAA was 29 or 30 mm. The GOA of the valve was small when HV was 15 mm and DAA was 26 or 27 mm. The corresponding values of the other models were within the normal range. Compared with the model with an HV of 14 mm, the model with an HV of 14.5 mm could effectively reduce maximum stress and had relatively larger GOA and less change in contact force. As a result, valve height affects the performance of aortic valve opening and closing. Smaller HV is adapted to smaller DAA and vice versa. When HV is 14.5 mm, the valve is well adapted to the dilatation of the aortic root to enhance repair durability. Therefore, more attention should be paid to HV in surgical planning.
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Affiliation(s)
- Qianwen Hou
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Guimei Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Ning Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Honghui Zhang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Zhuoran Qu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Hanbing Zhang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Hui Li
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Youlian Pan
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China.,Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
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21
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Computational Analysis of Wall Shear Stress Patterns on Calcified and Bicuspid Aortic Valves: Focus on Radial and Coaptation Patterns. FLUIDS 2021. [DOI: 10.3390/fluids6080287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Calcification and bicuspid valve formation are important aortic valve disorders that disturb the hemodynamics and the valve function. The detailed analysis of aortic valve hemodynamics would lead to a better understanding of the disease’s etiology. We computationally modeled the aortic valve using simplified three-dimensional geometry and inlet velocity conditions obtained via echocardiography. We examined various calcification severities and bicuspid valve formation. Fluid-structure interaction (FSI) analyses were adapted using ANSYS Workbench to incorporate both flow dynamics and leaflet deformation accurately. Simulation results were validated by comparing leaflet movements in B-mode echo recordings. Results indicate that the biomechanical environment is significantly changed for calcified and bicuspid valves. High flow jet velocities are observed in the calcified valves which results in high transvalvular pressure difference (TPG). Wall shear stresses (WSS) increased with the calcification on both fibrosa (aorta side) and ventricularis (left ventricle side) surfaces of the leaflet. The WSS distribution is regular on the ventricularis, as the WSS values proportionally increase from the base to the tip of the leaflet. However, WSS patterns are spatially complex on the fibrosa side. Low WSS levels and spatially complex WSS patterns on the fibrosa side are considered as promoting factors for further calcification and valvular diseases.
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22
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Nestola MGC, Zulian P, Gaedke-Merzhäuser L, Krause R. Fully coupled dynamic simulations of bioprosthetic aortic valves based on an embedded strategy for fluid-structure interaction with contact. Europace 2021; 23:i96-i104. [PMID: 33751086 DOI: 10.1093/europace/euaa398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
AIMS This work aims at presenting a fully coupled approach for the numerical solution of contact problems between multiple elastic structures immersed in a fluid flow. The key features of the computational model are (i) a fully coupled fluid-structure interaction with contact, (ii) the use of a fibre-reinforced material for the leaflets, (iii) a stent, and (iv) a compliant aortic root. METHODS AND RESULTS The computational model takes inspiration from the immersed boundary techniques and allows the numerical simulation of the blood-tissue interaction of bioprosthetic heart valves (BHVs) as well as the contact among the leaflets. First, we present pure mechanical simulations, where blood is neglected, to assess the performance of different material properties and valve designs. Secondly, fully coupled fluid-structure interaction simulations are employed to analyse the combination of haemodynamic and mechanical characteristics. The isotropic leaflet tissue experiences high-stress values compared to the fibre-reinforced material model. Moreover, elongated leaflets show a stress concentration close to the base of the stent. We observe a fully developed flow at the systolic stage of the heartbeat. On the other hand, flow recirculation appears along the aortic wall during diastole. CONCLUSION The presented FSI approach can be used for analysing the mechanical and haemodynamic performance of a BHV. Our study suggests that stresses concentrate in the regions where leaflets are attached to the stent and in the portion of the aortic root where the BHV is placed. The results from this study may inspire new BHV designs that can provide a better stress distribution.
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Affiliation(s)
- Maria G C Nestola
- Institute of Computational Science and Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Via Giuseppe Buffi 13, CH-6904 Lugano, Switzerland.,Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, 8092 Zürich, Switzerland
| | - Patrick Zulian
- Institute of Computational Science and Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Via Giuseppe Buffi 13, CH-6904 Lugano, Switzerland
| | - Lisa Gaedke-Merzhäuser
- Institute of Computational Science and Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Lugano, Switzerland
| | - Rolf Krause
- Institute of Computational Science and Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Via Giuseppe Buffi 13, CH-6904 Lugano, Switzerland
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23
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Zhang W, Rossini G, Kamensky D, Bui-Thanh T, Sacks MS. Isogeometric finite element-based simulation of the aortic heart valve: Integration of neural network structural material model and structural tensor fiber architecture representations. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3438. [PMID: 33463004 PMCID: PMC8223609 DOI: 10.1002/cnm.3438] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/08/2020] [Accepted: 01/08/2021] [Indexed: 05/27/2023]
Abstract
The functional complexity of native and replacement aortic heart valves (AVs) is well known, incorporating such physical phenomenons as time-varying non-linear anisotropic soft tissue mechanical behavior, geometric non-linearity, complex multi-surface time varying contact, and fluid-structure interactions to name a few. It is thus clear that computational simulations are critical in understanding AV function and for the rational basis for design of their replacements. However, such approaches continued to be limited by ad-hoc approaches for incorporating tissue fibrous structure, high-fidelity material models, and valve geometry. To this end, we developed an integrated tri-leaflet valve pipeline built upon an isogeometric analysis framework. A high-order structural tensor (HOST)-based method was developed for efficient storage and mapping the two-dimensional fiber structural data onto the valvular 3D geometry. We then developed a neural network (NN) material model that learned the responses of a detailed meso-structural model for exogenously cross-linked planar soft tissues. The NN material model not only reproduced the full anisotropic mechanical responses but also demonstrated a considerable efficiency improvement, as it was trained over a range of realizable fibrous structures. Results of parametric simulations were then performed, as well as population-based bicuspid AV fiber structure, that demonstrated the efficiency and robustness of the present approach. In summary, the present approach that integrates HOST and NN material model provides an efficient computational analysis framework with increased physical and functional realism for the simulation of native and replacement tri-leaflet heart valves.
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Affiliation(s)
- Wenbo Zhang
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas, USA
| | - Giovanni Rossini
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - David Kamensky
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California, USA
| | - Tan Bui-Thanh
- Department of Aerospace Engineering and Engineering Mechanics, Oden Institute for Computational Engineering and Science, The University of Texas at Austin, Austin, Texas, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas, USA
- Department of Aerospace Engineering and Engineering Mechanics, Oden Institute for Computational Engineering and Science, The University of Texas at Austin, Austin, Texas, USA
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA
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24
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Xu F, Johnson EL, Wang C, Jafari A, Yang CH, Sacks MS, Krishnamurthy A, Hsu MC. Computational investigation of left ventricular hemodynamics following bioprosthetic aortic and mitral valve replacement. MECHANICS RESEARCH COMMUNICATIONS 2021; 112:103604. [PMID: 34305195 PMCID: PMC8301225 DOI: 10.1016/j.mechrescom.2020.103604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The left ventricle of the heart is a fundamental structure in the human cardiac system that pumps oxygenated blood into the systemic circulation. Several valvular conditions can cause the aortic and mitral valves associated with the left ventricle to become severely diseased and require replacement. However, the clinical outcomes of such operations, specifically the postoperative ventricular hemodynamics of replacing both valves, are not well understood. This work uses computational fluid-structure interaction (FSI) to develop an improved understanding of this effect by modeling a left ventricle with the aortic and mitral valves replaced with bioprostheses. We use a hybrid Arbitrary Lagrangian-Eulerian/immersogeometric framework to accommodate the analysis of cardiac hemodynamics and heart valve structural mechanics in a moving fluid domain. The motion of the endocardium is obtained from a cardiac biomechanics simulation and provided as an input to the proposed numerical framework. The results from the simulations in this work indicate that the replacement of the native mitral valve with a tri-radially symmetric bioprosthesis dramatically changes the ventricular hemodynamics. Most significantly, the vortical motion in the left ventricle is found to reverse direction after mitral valve replacement. This study demonstrates that the proposed computational FSI framework is capable of simulating complex multiphysics problems and can provide an in-depth understanding of the cardiac mechanics.
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Affiliation(s)
- Fei Xu
- Ansys Inc., Austin, TX 78746, USA
| | - Emily L. Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | | | - Arian Jafari
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Cheng-Hau Yang
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Michael S. Sacks
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Adarsh Krishnamurthy
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
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25
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The effect of fundamental curves on geometric orifice and coaptation areas of polymeric heart valves. J Mech Behav Biomed Mater 2020; 112:104039. [DOI: 10.1016/j.jmbbm.2020.104039] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 08/04/2020] [Accepted: 08/12/2020] [Indexed: 12/29/2022]
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26
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Johnson EL, Wu MCH, Xu F, Wiese NM, Rajanna MR, Herrema AJ, Ganapathysubramanian B, Hughes TJR, Sacks MS, Hsu MC. Thinner biological tissues induce leaflet flutter in aortic heart valve replacements. Proc Natl Acad Sci U S A 2020; 117:19007-19016. [PMID: 32709744 PMCID: PMC7431095 DOI: 10.1073/pnas.2002821117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Valvular heart disease has recently become an increasing public health concern due to the high prevalence of valve degeneration in aging populations. For patients with severely impacted aortic valves that require replacement, catheter-based bioprosthetic valve deployment offers a minimally invasive treatment option that eliminates many of the risks associated with surgical valve replacement. Although recent percutaneous device advancements have incorporated thinner, more flexible biological tissues to streamline safer deployment through catheters, the impact of such tissues in the complex, mechanically demanding, and highly dynamic valvular system remains poorly understood. The present work utilized a validated computational fluid-structure interaction approach to isolate the behavior of thinner, more compliant aortic valve tissues in a physiologically realistic system. This computational study identified and quantified significant leaflet flutter induced by the use of thinner tissues that initiated blood flow disturbances and oscillatory leaflet strains. The aortic flow and valvular dynamics associated with these thinner valvular tissues have not been previously identified and provide essential information that can significantly advance fundamental knowledge about the cardiac system and support future medical device innovation. Considering the risks associated with such observed flutter phenomena, including blood damage and accelerated leaflet deterioration, this study demonstrates the potentially serious impact of introducing thinner, more flexible tissues into the cardiac system.
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Affiliation(s)
- Emily L Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Michael C H Wu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Fei Xu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Nelson M Wiese
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Manoj R Rajanna
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Austin J Herrema
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | | | - Thomas J R Hughes
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712;
| | - Michael S Sacks
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712;
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011;
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27
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An image-based computational hemodynamics study of the Systolic Anterior Motion of the mitral valve. Comput Biol Med 2020; 123:103922. [PMID: 32741752 DOI: 10.1016/j.compbiomed.2020.103922] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 01/23/2023]
Abstract
Systolic Anterior Motion (SAM) of the mitral valve - often associated with Hypertrophic Obstructive Cardiomyopathy (HOCM) - is a cardiac pathology in which a functional subaortic stenosis is induced during systole by the mitral leaflets partially obstructing the outflow tract of the left ventricle. Its assessment by diagnostic tests is often difficult, possibly underestimating its severity and thus increasing the risk of heart failure. In this paper, we propose a new computational pipeline, based on cardiac cine Magnetic Resonance Imaging (cine-MRI) data, for the assessment of SAM. The pipeline encompasses image processing of the left ventricle and the mitral valve, and numerical investigation of cardiac hemodynamics by means of Computational Fluid Dynamics (CFD) in a moving domain with image-based prescribed displacement. Patient-specific geometry and motion of the left ventricle are considered in view of an Arbitrary Lagrangian-Eulerian approach for CFD, while the reconstructed mitral valve is immersed in the computational domain by means of a resistive method. We assess clinically relevant flow and pressure indicators in a parametric study for different degrees of SAM severity, in order to provide a better quantitative evaluation of the pathological condition. Moreover, we provide specific indications for its possible surgical treatment, i.e. septal myectomy.
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28
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Balmus M, Massing A, Hoffman J, Razavi R, Nordsletten DA. A partition of unity approach to fluid mechanics and fluid-structure interaction. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2020; 362:112842. [PMID: 34093912 PMCID: PMC7610902 DOI: 10.1016/j.cma.2020.112842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
For problems involving large deformations of thin structures, simulating fluid-structure interaction (FSI) remains a computationally expensive endeavour which continues to drive interest in the development of novel approaches. Overlapping domain techniques have been introduced as a way to combine the fluid-solid mesh conformity, seen in moving-mesh methods, without the need for mesh smoothing or re-meshing, which is a core characteristic of fixed mesh approaches. In this work, we introduce a novel overlapping domain method based on a partition of unity approach. Unified function spaces are defined as a weighted sum of fields given on two overlapping meshes. The method is shown to achieve optimal convergence rates and to be stable for steady-state Stokes, Navier-Stokes, and ALE Navier-Stokes problems. Finally, we present results for FSI in the case of 2D flow past an elastic beam simulation. These initial results point to the potential applicability of the method to a wide range of FSI applications, enabling boundary layer refinement and large deformations without the need for re-meshing or user-defined stabilization.
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Affiliation(s)
- Maximilian Balmus
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, King’s College London, King’s Health Partners, London SE1 7EH, United Kingdom
| | - André Massing
- Department of Mathematics and Mathematical Statistics, Umeå University, SE-90187 Umeå, Sweden
- Department of Mathematical Sciences, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Johan Hoffman
- Division of Computational Science and Technology, KTH Royal Institute of Technology, Sweden
| | - Reza Razavi
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, King’s College London, King’s Health Partners, London SE1 7EH, United Kingdom
| | - David A. Nordsletten
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, King’s College London, King’s Health Partners, London SE1 7EH, United Kingdom
- Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, MI, USA
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29
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This A, Boilevin-Kayl L, Fernández MA, Gerbeau JF. Augmented resistive immersed surfaces valve model for the simulation of cardiac hemodynamics with isovolumetric phases. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3223. [PMID: 31206245 DOI: 10.1002/cnm.3223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/12/2019] [Accepted: 05/21/2019] [Indexed: 06/09/2023]
Abstract
In order to reduce the complexity of heart hemodynamics simulations, uncoupling approaches are often considered for the modeling of the immersed valves as an alternative to complex fluid-structure interaction (FSI) models. A possible shortcoming of these simplified approaches is the difficulty to correctly capture the pressure dynamics during the isovolumetric phases. In this work, we propose an enhanced resistive immersed surfaces (RIS) model of cardiac valves, which overcomes this issue. The benefits of the model are investigated and tested in blood flow simulations of the left heart where the physiological behavior of the intracavity pressure during the isovolumetric phases is recovered without using fully coupled fluid-structure models and without important alteration of the associated velocity field.
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Affiliation(s)
- Alexandre This
- Medisys, Philips Research, Suresnes, France
- COMMEDIA, Inria Paris, Paris, France
- Sorbonne Université, UMR 7598 LJLL, Paris, France
| | - Ludovic Boilevin-Kayl
- COMMEDIA, Inria Paris, Paris, France
- Sorbonne Université, UMR 7598 LJLL, Paris, France
| | - Miguel A Fernández
- COMMEDIA, Inria Paris, Paris, France
- Sorbonne Université, UMR 7598 LJLL, Paris, France
| | - Jean-Frédéric Gerbeau
- COMMEDIA, Inria Paris, Paris, France
- Sorbonne Université, UMR 7598 LJLL, Paris, France
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30
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Bettenhausen A, Hui DS. Commentary: Nature knows best. J Thorac Cardiovasc Surg 2020; 161:593-594. [PMID: 31926712 DOI: 10.1016/j.jtcvs.2019.10.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 10/25/2022]
Affiliation(s)
- Aaron Bettenhausen
- Department of Cardiothoracic Surgery, Long School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Tex
| | - Dawn S Hui
- Department of Cardiothoracic Surgery, Long School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
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31
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Balu A, Nallagonda S, Xu F, Krishnamurthy A, Hsu MC, Sarkar S. A Deep Learning Framework for Design and Analysis of Surgical Bioprosthetic Heart Valves. Sci Rep 2019; 9:18560. [PMID: 31811244 PMCID: PMC6898064 DOI: 10.1038/s41598-019-54707-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/15/2019] [Indexed: 12/17/2022] Open
Abstract
Bioprosthetic heart valves (BHVs) are commonly used as heart valve replacements but they are prone to fatigue failure; estimating their remaining life directly from medical images is difficult. Analyzing the valve performance can provide better guidance for personalized valve design. However, such analyses are often computationally intensive. In this work, we introduce the concept of deep learning (DL) based finite element analysis (DLFEA) to learn the deformation biomechanics of bioprosthetic aortic valves directly from simulations. The proposed DL framework can eliminate the time-consuming biomechanics simulations, while predicting valve deformations with the same fidelity. We present statistical results that demonstrate the high performance of the DLFEA framework and the applicability of the framework to predict bioprosthetic aortic valve deformations. With further development, such a tool can provide fast decision support for designing surgical bioprosthetic aortic valves. Ultimately, this framework could be extended to other BHVs and improve patient care.
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Affiliation(s)
- Aditya Balu
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA
| | - Sahiti Nallagonda
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA
| | - Fei Xu
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA
| | - Adarsh Krishnamurthy
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA.
| | - Ming-Chen Hsu
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA
| | - Soumik Sarkar
- Iowa State University, Department of Mechanical Engineering, Ames, Iowa, 50011, USA
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32
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Wu MCH, Muchowski HM, Johnson EL, Rajanna MR, Hsu MC. Immersogeometric fluid-structure interaction modeling and simulation of transcatheter aortic valve replacement. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2019; 357:112556. [PMID: 32831419 PMCID: PMC7442159 DOI: 10.1016/j.cma.2019.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The transcatheter aortic valve replacement (TAVR) has emerged as a minimally invasive alternative to surgical treatments of valvular heart disease. TAVR offers many advantages, however, the safe anchoring of the transcatheter heart valve (THV) in the patients anatomy is key to a successful procedure. In this paper, we develop and apply a novel immersogeometric fluid-structure interaction (FSI) framework for the modeling and simulation of the TAVR procedure to study the anchoring ability of the THV. To account for physiological realism, methods are proposed to model and couple the main components of the system, including the arterial wall, blood flow, valve leaflets, skirt, and frame. The THV is first crimped and deployed into an idealized ascending aorta. During the FSI simulation, the radial outward force and friction force between the aortic wall and the THV frame are examined over the entire cardiac cycle. The ratio between these two forces is computed and compared with the experimentally estimated coefficient of friction to study the likelihood of valve migration.
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Affiliation(s)
- Michael C. H. Wu
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
- School of Engineering, Brown University, 184 Hope Street, Providence, Rhode Island 02912, USA
| | - Heather M. Muchowski
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
- Department of Mathematics, Iowa State University, 396 Carver Hall, Ames, Iowa 50011, USA
| | - Emily L. Johnson
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
| | - Manoj R. Rajanna
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, Ames, Iowa 50011, USA
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33
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Gilmanov A, Stolarski H, Sotiropoulos F. Flow-Structure Interaction Simulations of the Aortic Heart Valve at Physiologic Conditions: The Role of Tissue Constitutive Model. J Biomech Eng 2019; 140:2668580. [PMID: 29305610 DOI: 10.1115/1.4038885] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 01/04/2023]
Abstract
The blood flow patterns in the region around the aortic valve depend on the geometry of the aorta and on the complex flow-structure interaction between the pulsatile flow and the valve leaflets. Consequently, the flow depends strongly on the constitutive properties of the tissue, which can be expected to vary between healthy and diseased heart valves or native and prosthetic valves. The main goal of this work is to qualitatively demonstrate that the choice of the constitutive model of the aortic valve is critical in analysis of heart hemodynamics. To accomplish that two different constitutive models were used in curvilinear immersed boundary-finite element-fluid-structure interaction (CURVIB-FE-FSI) method developed by Gilmanov et al. (2015, "A Numerical Approach for Simulating Fluid Structure Interaction of Flexible Thin Shells Undergoing Arbitrarily Large Deformations in Complex Domains," J. Comput. Phys., 300, pp. 814-843.) to simulate an aortic valve in an anatomic aorta at physiologic conditions. The two constitutive models are: (1) the Saint-Venant (StV) model and (2) the modified May-Newman&Yin (MNY) model. The MNY model is more general and includes nonlinear, anisotropic effects. It is appropriate to model the behavior of both prosthetic and biological tissue including native valves. Both models are employed to carry out FSI simulations of the same valve in the same aorta anatomy. The computed results reveal dramatic differences in both the vorticity dynamics in the aortic sinus and the wall shear-stress patterns on the aortic valve leaflets and underscore the importance of tissue constitutive models for clinically relevant simulations of aortic valves.
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Affiliation(s)
- Anvar Gilmanov
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414 e-mail:
| | - Henryk Stolarski
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN 55414 e-mail:
| | - Fotis Sotiropoulos
- College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY 11794-2200 e-mail:
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34
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Griffith BE, Patankar NA. Immersed Methods for Fluid-Structure Interaction. ANNUAL REVIEW OF FLUID MECHANICS 2019; 52:421-448. [PMID: 33012877 PMCID: PMC7531444 DOI: 10.1146/annurev-fluid-010719-060228] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fluid-structure interaction is ubiquitous in nature and occurs at all biological scales. Immersed methods provide mathematical and computational frameworks for modeling fluid-structure systems. These methods, which typically use an Eulerian description of the fluid and a Lagrangian description of the structure, can treat thin immersed boundaries and volumetric bodies, and they can model structures that are flexible or rigid or that move with prescribed deformational kinematics. Immersed formulations do not require body-fitted discretizations and thereby avoid the frequent grid regeneration that can otherwise be required for models involving large deformations and displacements. This article reviews immersed methods for both elastic structures and structures with prescribed kinematics. It considers formulations using integral operators to connect the Eulerian and Lagrangian frames and methods that directly apply jump conditions along fluid-structure interfaces. Benchmark problems demonstrate the effectiveness of these methods, and selected applications at Reynolds numbers up to approximately 20,000 highlight their impact in biological and biomedical modeling and simulation.
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Affiliation(s)
- Boyce E Griffith
- Departments of Mathematics, Applied Physical Sciences, and Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Neelesh A Patankar
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA
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35
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Lee CH, Laurence DW, Ross CJ, Kramer KE, Babu AR, Johnson EL, Hsu MC, Aggarwal A, Mir A, Burkhart HM, Towner RA, Baumwart R, Wu Y. Mechanics of the Tricuspid Valve-From Clinical Diagnosis/Treatment, In-Vivo and In-Vitro Investigations, to Patient-Specific Biomechanical Modeling. Bioengineering (Basel) 2019; 6:E47. [PMID: 31121881 PMCID: PMC6630695 DOI: 10.3390/bioengineering6020047] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 12/29/2022] Open
Abstract
Proper tricuspid valve (TV) function is essential to unidirectional blood flow through the right side of the heart. Alterations to the tricuspid valvular components, such as the TV annulus, may lead to functional tricuspid regurgitation (FTR), where the valve is unable to prevent undesired backflow of blood from the right ventricle into the right atrium during systole. Various treatment options are currently available for FTR; however, research for the tricuspid heart valve, functional tricuspid regurgitation, and the relevant treatment methodologies are limited due to the pervasive expectation among cardiac surgeons and cardiologists that FTR will naturally regress after repair of left-sided heart valve lesions. Recent studies have focused on (i) understanding the function of the TV and the initiation or progression of FTR using both in-vivo and in-vitro methods, (ii) quantifying the biomechanical properties of the tricuspid valve apparatus as well as its surrounding heart tissue, and (iii) performing computational modeling of the TV to provide new insight into its biomechanical and physiological function. This review paper focuses on these advances and summarizes recent research relevant to the TV within the scope of FTR. Moreover, this review also provides future perspectives and extensions critical to enhancing the current understanding of the functioning and remodeling tricuspid valve in both the healthy and pathophysiological states.
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Affiliation(s)
- Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK 73019, USA.
| | - Devin W Laurence
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Colton J Ross
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Katherine E Kramer
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Anju R Babu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India.
| | - Emily L Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ankush Aggarwal
- Glasgow Computational Engineering Centre, School of Engineering, University of Glasgow, Scotland G12 8LT, UK.
| | - Arshid Mir
- Division of Pediatric Cardiology, Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Harold M Burkhart
- Division of Cardiothoracic Surgery, Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Rheal A Towner
- Advance Magnetic Resonance Center, MS 60, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
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36
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Extended Finite Elements Method for Fluid-Structure Interaction with an Immersed Thick Non-linear Structure. ACTA ACUST UNITED AC 2018. [DOI: 10.1007/978-3-319-96649-6_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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37
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Study on the Accuracy of Structural and FSI Heart Valves Simulations. Cardiovasc Eng Technol 2018; 9:723-738. [DOI: 10.1007/s13239-018-00373-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/11/2018] [Indexed: 12/29/2022]
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38
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Formato GM, Lo Rito M, Auricchio F, Frigiola A, Conti M. Aortic expansion induces lumen narrrowing in anomalous coronary arteries: a parametric structural finite element analysis. J Biomech Eng 2018; 140:2694849. [PMID: 30098160 DOI: 10.1115/1.4040941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Indexed: 01/05/2023]
Abstract
Anomalous aortic origin of coronary arteries (AAOCA) is a congenital disease that can lead to cardiac ischemia during intense physical activity. Although AAOCA is responsible for sudden cardiac death (SCD) among young athletes and soldiers, the mechanisms underlying the coronary occlusion during physical effort still have to be clarified. The present study investigates the correlation between geometric features of the anomaly and coronary lumen narrowing under aortic root dilatations. Idealized parametric computer-aided designed (CAD) models of the aortic root with anomalous and normal coronary are created and static finite element (FE) simulations of increasing aortic root expansions are carried out. Different coronary take-off angles and intramural penetrations are investigated to assess their role on coronary lumen narrowing. Results show that increasing aortic and coronary pressures lead to lumen expansions in normal coronaries, particularly in the proximal tract, while the expansion of anomalous coronary is impaired especially at the ostium. Concerning the geometric features of the anomaly, acute take-off angles cause elongated coronary ostia, with an eccentricity increasing with aortic expansion; the impact of intramural penetration of coronary on its luminal narrowing is limited. The present study provides a proof of concept of the biomechanical reasons underlying the lumen narrowing in AAOCA during aortic expansion, promoting the role of computational simulations as a tool to assess the mechanisms of this pathology.
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Affiliation(s)
- Giovanni Maria Formato
- University of Pavia, Dept. of Civil Engineering and Architecture (DICAr), Pavia, Italy, 27100
| | - Mauro Lo Rito
- IRCCS Policlinico San Donato, Dept. of Congenital Cardiac Surgery, San Donato Milanese, Italy, 20097
| | - Ferdinando Auricchio
- University of Pavia, Dept. of Civil Engineering and Architecture (DICAr), Pavia, Italy, 27100
| | - Alessandro Frigiola
- IRCCS Policlinico San Donato, Dept. of Congenital Cardiac Surgery, San Donato Milanese, Italy, 20097
| | - Michele Conti
- University of Pavia, Dept. of Civil Engineering and Architecture (DICAr), Pavia, Italy, 27100
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39
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Sodhani D, Reese S, Aksenov A, Soğanci S, Jockenhövel S, Mela P, Stapleton SE. Fluid-structure interaction simulation of artificial textile reinforced aortic heart valve: Validation with an in-vitro test. J Biomech 2018; 78:52-69. [PMID: 30086860 DOI: 10.1016/j.jbiomech.2018.07.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 06/05/2018] [Accepted: 07/09/2018] [Indexed: 01/11/2023]
Abstract
Prosthetic heart valves deployed in the left heart (aortic and mitral) are subjected to harsh hemodynamical conditions. Most of the tissue engineered heart valves have been developed for the low pressure pulmonary position because of the difficulties in fabricating a mechanically strong valve, able to withstand the systemic circulation. This necessitates the use of reinforcing scaffolds, resulting in a tissue-engineered textile reinforced tubular aortic heart valve. Therefore, to better design these implants, material behaviour of the composite, valve kinematics and its hemodynamical response need to be evaluated. Experimental assessment can be immensely time consuming and expensive, paving way for numerical studies. In this work, the material properties obtained using the previously proposed multi-scale numerical method for textile composites was evaluated for its accuracy. An in silico immersed boundary (IB) fluid structure interaction (FSI) simulation emulating the in vitro experiment was set-up to evaluate and compare the geometric orifice area and flow rate for one beat cycle. Results from the in silico FSI simulation were found to be in good coherence with the in vitro test during the systolic phase, while mean deviation of approximately 9% was observed during the diastolic phase of a beat cycle. Merits and demerits of the in silico IB-FSI method for the presented case study has been discussed with the advantages outweighing the drawbacks, indicating the potential towards an effective use of this framework in the development and analysis of heart valves.
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Affiliation(s)
- Deepanshu Sodhani
- Institute of Applied Mechanics, RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany.
| | - Stefanie Reese
- Institute of Applied Mechanics, RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany
| | - Andrey Aksenov
- Capvidia NV, Research Park Haasrode, Technologielaan 3, B-3001 Leuven, Belgium
| | - Sinan Soğanci
- Capvidia NV, Research Park Haasrode, Technologielaan 3, B-3001 Leuven, Belgium
| | - Stefan Jockenhövel
- Institute of Applied Medical Engineering, Helmholtz Institute & ITA-Institut for Textiltechnik, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Petra Mela
- Institute of Applied Medical Engineering, Helmholtz Institute & ITA-Institut for Textiltechnik, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Scott E Stapleton
- Dept. of Mechanical Engineering, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
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40
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Kandail HS, Trivedi SD, Shaikh AC, Bajwa TK, O'Hair DP, Jahangir A, LaDisa JF. Impact of annular and supra-annular CoreValve deployment locations on aortic and coronary artery hemodynamics. J Mech Behav Biomed Mater 2018; 86:131-142. [PMID: 29986288 DOI: 10.1016/j.jmbbm.2018.06.032] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 06/04/2018] [Accepted: 06/21/2018] [Indexed: 01/12/2023]
Abstract
CoreValve is widely used in transcatheter aortic valve replacement, but the impact of its deployment location on hemodynamics is unexplored despite a potential role in subsequent aortic and coronary artery pathologies. The objectives of this investigation were to perform fluid-structure interaction (FSI) simulations for a 29 mm CoreValve deployed in annular vs supra-annular locations, and characterize resulting hemodynamics including velocity and wall shear stress (WSS). Patient-specific geometry was reconstructed from computed tomography scans and CoreValve was deployed using a finite element approach. FSI simulations were then performed using a boundary conforming method and realistic boundary conditions. Results showed that CoreValve deployment location impacts hemodynamics in the ascending aorta and flow patterns in the coronary arteries. During peak-systole, annularly deployed CoreValve produced a jet-like flow structure impinging on the outer-curvature of the ascending aorta. Supra-annularly deployed CoreValve having a lateral tilt of 10° led to a more centered jet impinging further downstream. At mid-systole, valve leaflets of the annularly deployed CoreValve closed asymmetrically leading to disorganized flow patterns in the ascending aorta vs those from the supra-annular position. Supra-annularly deployed CoreValve also led to high-velocity para-valvular flow supplying the coronary arteries. CoreValve in the supra-annular position significantly (P < 0.05) elevated WSS within the first few diameters of both coronary arteries as compared to the annular position for many time points quantified. These results afforded by the advanced simulation methods may have important clinical implications given the role of aortic hemodynamics in dilation and the pro-atherogenic nature of WSS alterations in the coronary arteries.
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Affiliation(s)
- Harkamaljot S Kandail
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Setu D Trivedi
- Aurora Cardiovascular Services, Aurora St. Luke's Medical Center, Milwaukee, WI, USA
| | - Armaan C Shaikh
- Aurora Cardiovascular Services, Aurora St. Luke's Medical Center, Milwaukee, WI, USA
| | - Tanvir K Bajwa
- Aurora Cardiovascular Services, Aurora St. Luke's Medical Center, Milwaukee, WI, USA
| | - Daniel P O'Hair
- Aurora Cardiovascular Services, Aurora St. Luke's Medical Center, Milwaukee, WI, USA
| | - Arshad Jahangir
- Aurora Cardiovascular Services, Aurora St. Luke's Medical Center, Milwaukee, WI, USA
| | - John F LaDisa
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA; Department of Medicine, Division of Cardiovascular Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
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41
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Govindarajan V, Mousel J, Udaykumar HS, Vigmostad SC, McPherson DD, Kim H, Chandran KB. Synergy between Diastolic Mitral Valve Function and Left Ventricular Flow Aids in Valve Closure and Blood Transport during Systole. Sci Rep 2018; 8:6187. [PMID: 29670148 PMCID: PMC5906696 DOI: 10.1038/s41598-018-24469-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/27/2018] [Indexed: 11/30/2022] Open
Abstract
Highly resolved three-dimensional (3D) fluid structure interaction (FSI) simulation using patient-specific echocardiographic data can be a powerful tool for accurately and thoroughly elucidating the biomechanics of mitral valve (MV) function and left ventricular (LV) fluid dynamics. We developed and validated a strongly coupled FSI algorithm to fully characterize the LV flow field during diastolic MV opening under physiologic conditions. Our model revealed that distinct MV deformation and LV flow patterns developed during different diastolic stages. A vortex ring that strongly depended on MV deformation formed during early diastole. At peak E wave, the MV fully opened, with a local Reynolds number of ~5500, indicating that the flow was in the laminar-turbulent transitional regime. Our results showed that during diastasis, the vortex structures caused the MV leaflets to converge, thus increasing mitral jet’s velocity. The vortex ring became asymmetrical, with the vortex structures on the anterior side being larger than on the posterior side. During the late diastolic stages, the flow structures advected toward the LV outflow tract, enhancing fluid transport to the aorta. This 3D-FSI study demonstrated the importance of leaflet dynamics, their effect on the vortex ring, and their influence on MV function and fluid transport within the LV during diastole.
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Affiliation(s)
- Vijay Govindarajan
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Texas McGovern Medical School, Houston, TX, USA
| | - John Mousel
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA
| | - H S Udaykumar
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA
| | - Sarah C Vigmostad
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA
| | - David D McPherson
- Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Texas McGovern Medical School, Houston, TX, USA
| | - Hyunggun Kim
- Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Texas McGovern Medical School, Houston, TX, USA. .,Department of Biomechatronic Engineering, Sungkyunkwan University, Suwon, Gyeonggi, Korea.
| | - Krishnan B Chandran
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA.
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Wu MCH, Zakerzadeh R, Kamensky D, Kiendl J, Sacks MS, Hsu MC. An anisotropic constitutive model for immersogeometric fluid-structure interaction analysis of bioprosthetic heart valves. J Biomech 2018; 74:23-31. [PMID: 29735263 DOI: 10.1016/j.jbiomech.2018.04.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/25/2018] [Accepted: 04/04/2018] [Indexed: 12/01/2022]
Abstract
This paper considers an anisotropic hyperelastic soft tissue model, originally proposed for native valve tissue and referred to herein as the Lee-Sacks model, in an isogeometric thin shell analysis framework that can be readily combined with immersogeometric fluid-structure interaction (FSI) analysis for high-fidelity simulations of bioprosthetic heart valves (BHVs) interacting with blood flow. We find that the Lee-Sacks model is well-suited to reproduce the anisotropic stress-strain behavior of the cross-linked bovine pericardial tissues that are commonly used in BHVs. An automated procedure for parameter selection leads to an instance of the Lee-Sacks model that matches biaxial stress-strain data from the literature more closely, over a wider range of strains, than other soft tissue models. The relative simplicity of the Lee-Sacks model is attractive for computationally-demanding applications such as FSI analysis and we use the model to demonstrate how the presence and direction of material anisotropy affect the FSI dynamics of BHV leaflets.
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Affiliation(s)
- Michael C H Wu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
| | - Rana Zakerzadeh
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - David Kamensky
- Department of Structural Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0085, La Jolla, CA 92093, USA
| | - Josef Kiendl
- Department of Marine Technology, Norwegian University of Science and Technology, O. Nielsens veg 10, 7052 Trondheim, Norway
| | - Michael S Sacks
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA.
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43
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Sigüenza J, Pott D, Mendez S, Sonntag SJ, Kaufmann TAS, Steinseifer U, Nicoud F. Fluid-structure interaction of a pulsatile flow with an aortic valve model: A combined experimental and numerical study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2945. [PMID: 29181891 DOI: 10.1002/cnm.2945] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 10/03/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
The complex fluid-structure interaction problem associated with the flow of blood through a heart valve with flexible leaflets is investigated both experimentally and numerically. In the experimental test rig, a pulse duplicator generates a pulsatile flow through a biomimetic rigid aortic root where a model of aortic valve with polymer flexible leaflets is implanted. High-speed recordings of the leaflets motion and particle image velocimetry measurements were performed together to investigate the valve kinematics and the dynamics of the flow. Large eddy simulations of the same configuration, based on a variant of the immersed boundary method, are also presented. A massively parallel unstructured finite-volume flow solver is coupled with a finite-element solid mechanics solver to predict the fluid-structure interaction between the unsteady flow and the valve. Detailed analysis of the dynamics of opening and closure of the valve are conducted, showing a good quantitative agreement between the experiment and the simulation regarding the global behavior, in spite of some differences regarding the individual dynamics of the valve leaflets. A multicycle analysis (over more than 20 cycles) enables to characterize the generation of turbulence downstream of the valve, showing similar flow features between the experiment and the simulation. The flow transitions to turbulence after peak systole, when the flow starts to decelerate. Fluctuations are observed in the wake of the valve, with maximum amplitude observed at the commissure side of the aorta. Overall, a very promising experiment-vs-simulation comparison is shown, demonstrating the potential of the numerical method.
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Affiliation(s)
- Julien Sigüenza
- IMAG, Univ Montpellier, CNRS, Montpellier, France
- Sim&Cure, Cap Gamma, 1682 rue de la Valsière, 34790, Grabels, France
| | - Desiree Pott
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Simon Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
| | - Simon J Sonntag
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Tim A S Kaufmann
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
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Kamensky D, Xu F, Lee CH, Yan J, Bazilevs Y, Hsu MC. A contact formulation based on a volumetric potential: Application to isogeometric simulations of atrioventricular valves. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2018; 330:522-546. [PMID: 29736092 PMCID: PMC5935269 DOI: 10.1016/j.cma.2017.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This work formulates frictionless contact between solid bodies in terms of a repulsive potential energy term and illustrates how numerical integration of the resulting forces is computationally similar to the "pinball algorithm" proposed and studied by Belytschko and collaborators in the 1990s. We thereby arrive at a numerical approach that has both the theoretical advantages of a potential-based formulation and the algorithmic simplicity, computational efficiency, and geometrical versatility of pinball contact. The singular nature of the contact potential requires a specialized nonlinear solver and an adaptive time stepping scheme to ensure reliable convergence of implicit dynamic calculations. We illustrate the effectiveness of this numerical method by simulating several benchmark problems and the structural mechanics of the right atrioventricular (tricuspid) heart valve. Atrioventricular valve closure involves contact between every combination of shell surfaces, edges of shells, and cables, but our formulation handles all contact scenarios in a unified manner. We take advantage of this versatility to demonstrate the effects of chordal rupture on tricuspid valve coaptation behavior.
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Affiliation(s)
- David Kamensky
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, USA
- Corresponding author: (David Kamensky)
| | - Fei Xu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Jinhui Yan
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yuri Bazilevs
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
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Estimation of Element-Based Zero-Stress State in Arterial FSI Computations with Isogeometric Wall Discretization. BIOMEDICAL TECHNOLOGY 2018. [DOI: 10.1007/978-3-319-59548-1_7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Wojciechowska D, Liberski AR, Wilczek P, Butcher J, Scharfschwerdt M, Hijazi Z, Kasprzak J, Pibarot P, Bianco R. The optimal shape of an aortic heart valve replacement – on the road to the consensus. QSCIENCE CONNECT 2017. [DOI: 10.5339/connect.2017.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The steady increase in the number of patients with diseased aortic valves demands the development of effective aortic valve replacement procedures. Engineering and technology offer various manufactured alternatives, but none can exactly match the natural human valve. In addition to the experts of heart valve tissue engineering, many researchers focus on specific aspects of the manufacturing of artificial valves. The aim of this study was to benefit such manufacturing processes. From the contributor's perspective, it is vital to gain comprehensive knowledge before embarking on this project. The perfect/optimal shape of the valve is the fundamental aspect that needs to be considered by all participants. It is noteworthy that the geometry not only limits the functionality of the structure but also determines the choice of material and engineering methods. In this study, we attempt to determine if current knowledge is sufficient to reach consensus on the issue of the optimum shape of the valve. Here, we not only provide a brief overview of traditional literature but also include the opinions of experts. This innovative way of scientific communication is unprecedented in scientific literature, and we hope that both professionals and contributors will find this study useful.
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Affiliation(s)
- Dorota Wojciechowska
- 1Lodz University of Technology, Faculty of Material Technologies and Textile Design, Department of Material and Commodity Sciences and Textile Metrology, ul. Zeromskiego 116, 90-924 Lodz, Poland
| | - Albert Ryszard Liberski
- 2Sustainability Division, College of Science & Engineering (CSE), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Piotr Wilczek
- 3Heart Prosthesis Institute, Bioengineering Laboratory, Professor Zbigniew Religa Foundation of Cardiac Surgery Development, Wolnosci 345A, 41-800 Zabrze, Poland
| | - Jonathan Butcher
- 4Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA
| | - Michael Scharfschwerdt
- 5Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany
| | - Ziyad Hijazi
- 6Sidra Cardiac Program, Sidra Medical & Research Center, Doha-Qatar and Weill Cornell Medicine, New York, New York, United States
| | | | - Philippe Pibarot
- 8Department of Medicine, Laval University, Quebec City, Quebec, Canada
| | - Richard Bianco
- 9Experimental Surgical Services, University of Minnesota, United States
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47
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Kamensky D, Evans JA, Hsu MC, Bazilevs Y. Projection-based stabilization of interface Lagrange multipliers in immersogeometric fluid-thin structure interaction analysis, with application to heart valve modeling. COMPUTERS & MATHEMATICS WITH APPLICATIONS (OXFORD, ENGLAND : 1987) 2017; 74:2068-2088. [PMID: 29225420 PMCID: PMC5720179 DOI: 10.1016/j.camwa.2017.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This paper discusses a method of stabilizing Lagrange multiplier fields used to couple thin immersed shell structures and surrounding fluids. The method retains essential conservation properties by stabilizing only the portion of the constraint orthogonal to a coarse multiplier space. This stabilization can easily be applied within iterative methods or semi-implicit time integrators that avoid directly solving a saddle point problem for the Lagrange multiplier field. Heart valve simulations demonstrate applicability of the proposed method to 3D unsteady simulations. An appendix sketches the relation between the proposed method and a high-order-accurate approach for simpler model problems.
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Affiliation(s)
- David Kamensky
- Department of Structural Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0085, La Jolla, CA 92093, USA
| | - John A. Evans
- Department of Aerospace Engineering Sciences, University of Colorado at Boulder, 429 UCB, Boulder, CO 80309, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
| | - Yuri Bazilevs
- Department of Structural Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0085, La Jolla, CA 92093, USA
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48
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Zakerzadeh R, Hsu MC, Sacks MS. Computational methods for the aortic heart valve and its replacements. Expert Rev Med Devices 2017; 14:849-866. [PMID: 28980492 PMCID: PMC6542368 DOI: 10.1080/17434440.2017.1389274] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/04/2017] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Replacement with a prosthetic device remains a major treatment option for the patients suffering from heart valve disease, with prevalence growing resulting from an ageing population. While the most popular replacement heart valve continues to be the bioprosthetic heart valve (BHV), its durability remains limited. There is thus a continued need to develop a general understanding of the underlying mechanisms limiting BHV durability to facilitate development of a more durable prosthesis. In this regard, computational models can play a pivotal role as they can evaluate our understanding of the underlying mechanisms and be used to optimize designs that may not always be intuitive. Areas covered: This review covers recent progress in computational models for the simulation of BHV, with a focus on aortic valve (AV) replacement. Recent contributions in valve geometry, leaflet material models, novel methods for numerical simulation, and applications to BHV optimization are discussed. This information should serve not only to infer reliable and dependable BHV function, but also to establish guidelines and insight for the design of future prosthetic valves by analyzing the influence of design, hemodynamics and tissue mechanics. Expert commentary: The paradigm of predictive modeling of heart valve prosthesis are becoming a reality which can simultaneously improve clinical outcomes and reduce costs. It can also lead to patient-specific valve design.
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Affiliation(s)
- Rana Zakerzadeh
- Center for Cardiovascular Simulation Institute for Computational Engineering & Sciences Department of Biomedical Engineering The University of Texas at Austin, Austin, TX
| | - Ming-Chen Hsu
- Department of Mechanical Engineering Iowa State University, Ames, IA
| | - Michael S. Sacks
- Center for Cardiovascular Simulation Institute for Computational Engineering & Sciences Department of Biomedical Engineering The University of Texas at Austin, Austin, TX
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AVANZINI ANDREA. INFLUENCE OF LEAFLET’S MATRIX STIFFNESS AND FIBER ORIENTATION ON THE OPENING DYNAMICS OF A PROSTHETIC TRILEAFLET HEART VALVE. J MECH MED BIOL 2017. [DOI: 10.1142/s0219519417500968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
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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Affiliation(s)
- ANDREA AVANZINI
- Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze, 38, I-25123, Brescia, Italy
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50
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Tagliabue A, Dedè L, Quarteroni A. Complex blood flow patterns in an idealized left ventricle: A numerical study. CHAOS (WOODBURY, N.Y.) 2017; 27:093939. [PMID: 28964151 DOI: 10.1063/1.5002120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper, we study the blood flow dynamics in a three-dimensional (3D) idealized left ventricle of the human heart whose deformation is driven by muscle contraction and relaxation in coordination with the action of the mitral and aortic valves. We propose a simplified but realistic mathematical treatment of the valves function based on mixed time-varying boundary conditions (BCs) for the Navier-Stokes equations modeling the flow. These switchings in time BCs, from natural to essential and vice versa, model either the open or the closed configurations of the valves. At the numerical level, these BCs are enforced by means of the extended Nitsche's method (Tagliabue et al., Int. J. Numer. Methods Fluids, 2017). Numerical results for the 3D idealized left ventricle obtained by means of Isogeometric Analysis are presented, discussed in terms of both instantaneous and phase-averaged quantities of interest and validated against those available in the literature, both experimental and computational. The complex blood flow patterns are analysed to describe the characteristic fluid properties, to show the transitional nature of the flow, and to highlight its main features inside the left ventricle. The sensitivity of the intraventricular flow patterns to the mitral valve properties is also investigated.
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Affiliation(s)
- Anna Tagliabue
- CMCS-Chair of Modeling and Scientific Computing MATHICSE-Mathematics Institute of Computational Science and Engineering EPFL-École Polytechnique Fédérale de Lausanne Station 8, Lausanne CH 1015, Switzerland
| | - Luca Dedè
- CMCS-Chair of Modeling and Scientific Computing MATHICSE-Mathematics Institute of Computational Science and Engineering EPFL-École Polytechnique Fédérale de Lausanne Station 8, Lausanne CH 1015, Switzerland
| | - Alfio Quarteroni
- CMCS-Chair of Modeling and Scientific Computing MATHICSE-Mathematics Institute of Computational Science and Engineering EPFL-École Polytechnique Fédérale de Lausanne Station 8, Lausanne CH 1015, Switzerland
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