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Whelan A, Williams E, Nolan DR, Murphy B, Gunning PS, O'Reilly D, Lally C. Bovine Pericardium of High Fibre Dispersion Has High Fatigue Life and Increased Collagen Content; Potentially an Untapped Source of Heart Valve Leaflet Tissue. Ann Biomed Eng 2020; 49:1022-1032. [PMID: 33063231 DOI: 10.1007/s10439-020-02644-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 09/30/2020] [Indexed: 02/07/2023]
Abstract
Bioprosthetic heart valves (BHVs) are implanted in aortic valve stenosis patients to replace the native, dysfunctional valve. Yet, the long-term performance of the glutaraldehyde-fixed bovine pericardium (GLBP) leaflets is known to reduce device durability. The aim of this study was to investigate a type of commercial-grade GLBP which has been over-looked in the literature to date; that of high collagen fibre dispersion (HD). Under uniaxial cyclic loading conditions, it was observed that the fatigue behaviour of HD GLBP was substantially equivalent to GLBP in which the fibres are highly aligned along the loading direction. It was also found that HD GLBP had a statistically significant 9.5% higher collagen content when compared to GLBP with highly aligned collagen fibres. The variability in diseased BHV delivery sites results in unpredictable and complex loading patterns across leaflets in vivo. This study presents the possibility of a shift from the traditional choice of circumferentially aligned GLBP leaflets, to that of high fibre dispersion arrangements. Characterised by its high fatigue life and increased collagen content, in addition to multiple fibre orientations, GLBP of high fibre dispersion may provide better patient outcomes under the multi-directional loading to which BHV leaflets are subjected in vivo.
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Affiliation(s)
- Alix Whelan
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical, Manufacturing & Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.,Structural Heart Division, Boston Scientific Corporation, Galway, Ireland
| | - Elizabeth Williams
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical, Manufacturing & Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - David R Nolan
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical, Manufacturing & Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Bruce Murphy
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical, Manufacturing & Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER), Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - Paul S Gunning
- Structural Heart Division, Boston Scientific Corporation, Los Gatos, CA, 95032, USA
| | - David O'Reilly
- Structural Heart Division, Boston Scientific Corporation, Galway, Ireland
| | - Caitríona Lally
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland. .,Department of Mechanical, Manufacturing & Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland. .,Advanced Materials and Bioengineering Research Centre (AMBER), Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland.
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Joyce K, Rochev Y, Rahmani S. Assessment of the uniaxial experimental parameters utilised for the mechanical testing of bovine pericardium. J Mech Behav Biomed Mater 2019; 96:27-37. [DOI: 10.1016/j.jmbbm.2019.04.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/09/2019] [Accepted: 04/13/2019] [Indexed: 11/26/2022]
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Collagen fibre orientation and dispersion govern ultimate tensile strength, stiffness and the fatigue performance of bovine pericardium. J Mech Behav Biomed Mater 2018; 90:54-60. [PMID: 30343171 DOI: 10.1016/j.jmbbm.2018.09.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/29/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
Abstract
The durability of bovine pericardium leaflets employed in bioprosthetic heart valves (BHVs) can significantly limit the longevity of heart valve prostheses. Collagen fibres are the dominant load bearing component of bovine pericardium, however fibre architecture within leaflet geometries is not explicitly controlled in the manufacture of commercial devices. Thus, the purpose of this study was to ascertain the influence of pre-determined collagen fibre orientation and dispersion on the mechanical performance of bovine pericardium. Three tissue groups were tested in uniaxial tension: cross-fibre tissue (XD); highly dispersed fibre-orientations (HD); or preferred-fibre tissue (PD). Both the XD and PD tissue were tested under cyclic loading at 1.5 Hz and a stress range of 2.7 MPa. The results of the static tensile experiments illustrated that collagen fibre orientation and degree of alignment significantly influenced the material's response, whereby, there was a statistically significant decrease in material properties between the XD groups and both the PD and HD groups for ultimate tensile strength and stiffness (p < 0.01). Furthermore, HD tissue had a stiffness of approximately 58% of the PD group, and XD tissue had a stiffness of approximately 18% of the PD group. The dynamic behaviour of the XD and PD groups was extremely distinct; for example a Weibull analysis indicated that the 50% probability of failure in specimens with fibres orientated perpendicular (XD) to the loading direction occurred at 375 cycles. Due to this failure, XD specimens survived on average less than 20% of the cycles completed by those in which fibres were aligned along the loading direction (PD). The results from this study indicate that fibre architecture is a significant factor in determining static strength and fatigue life in bovine pericardium, and thus must be incorporated in the design process to improve future device durability.
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Caballero A, Sulejmani F, Martin C, Pham T, Sun W. Evaluation of transcatheter heart valve biomaterials: Biomechanical characterization of bovine and porcine pericardium. J Mech Behav Biomed Mater 2017; 75:486-494. [PMID: 28826102 PMCID: PMC5614867 DOI: 10.1016/j.jmbbm.2017.08.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Bovine pericardium (BP) has been identified as a choice biomaterial for the development of surgical bioprosthetic heart valves (BHV) and transcatheter aortic valves (TAV). Porcine pericardium (PP) and younger BP have been suggested as candidates TAV leaflet biomaterials for smaller-profile devices due to their reduced thickness; however, their mechanical and structural properties remain to be fully characterized. This study characterized the material properties of chemically treated thick (PPK) and thin (PPN) PP, as well as fetal (FBP), calf (CBP) and adult (ABP) BP tissues in order to better understand their mechanical behavior. METHODS Planar biaxial testing and uniaxial failure testing methods were employed to quantify tissue mechanical responses and failure properties. Fiber characteristics were examined using histological analysis. RESULTS ABP and CBP tissues were significantly stiffer and stronger than the younger FBP tissues. Histological analysis revealed a significantly larger concentration of thin immature collagen fibers in the FBP tissues than in the ABP and CBP tissues. While PP tissues were thinnest, they were stiffer and less extensible than the BP tissues. CONCLUSIONS Due to comparable mechanical properties but significantly reduced thickness, CBP tissue may be a more suitable material for TAV manufacturing than ABP tissue. FBP tissue, despite its reduced thickness and higher flexibility, was weaker and should be studied in more detail. Although PP tissues are the thinnest, they were least extensible and failed at earlier strain than BP tissues. The differences between PP and BP tissues should be further investigated and suggest that they should not be used interchangeably in the manufacturing of TAV.
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Affiliation(s)
- Andrés Caballero
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - Fatiesa Sulejmani
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - Caitlin Martin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - Thuy Pham
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States.
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Aguiari P, Fiorese M, Iop L, Gerosa G, Bagno A. Mechanical testing of pericardium for manufacturing prosthetic heart valves. Interact Cardiovasc Thorac Surg 2015; 22:72-84. [DOI: 10.1093/icvts/ivv282] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/03/2015] [Indexed: 01/15/2023] Open
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Age dependent differences in collagen alignment of glutaraldehyde fixed bovine pericardium. BIOMED RESEARCH INTERNATIONAL 2014. [PMID: 25295250 DOI: 10.1155/2014/189197(2014)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bovine pericardium is used for heart valve leaflet replacement where the strength and thinness are critical properties. Pericardium from neonatal animals (4-7 days old) is advantageously thinner and is considered as an alternative to that from adult animals. Here, the structures of adult and neonatal bovine pericardium tissues fixed with glutaraldehyde are characterized by synchrotron-based small angle X-ray scattering (SAXS) and compared with the mechanical properties of these materials. Significant differences are observed between adult and neonatal tissue. The glutaraldehyde fixed neonatal tissue has a higher modulus of elasticity (83.7 MPa) than adult pericardium (33.5 MPa) and a higher normalised ultimate tensile strength (32.9 MPa) than adult pericardium (19.1 MPa). Measured edge on to the tissue, the collagen in neonatal pericardium is significantly more aligned (orientation index (OI) 0.78) than that in adult pericardium (OI 0.62). There is no difference in the fibril diameter between neonatal and adult pericardium. It is shown that high alignment in the plane of the tissue provides the mechanism for the increased strength of the neonatal material. The superior strength of neonatal compared with adult tissue supports the use of neonatal bovine pericardium in heterografts.
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Age dependent differences in collagen alignment of glutaraldehyde fixed bovine pericardium. BIOMED RESEARCH INTERNATIONAL 2014; 2014:189197. [PMID: 25295250 PMCID: PMC4180201 DOI: 10.1155/2014/189197] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/02/2014] [Indexed: 11/18/2022]
Abstract
Bovine pericardium is used for heart valve leaflet replacement where the strength and thinness are critical properties. Pericardium from neonatal animals (4–7 days old) is advantageously thinner and is considered as an alternative to that from adult animals. Here, the structures of adult and neonatal bovine pericardium tissues fixed with glutaraldehyde are characterized by synchrotron-based small angle X-ray scattering (SAXS) and compared with the mechanical properties of these materials. Significant differences are observed between adult and neonatal tissue. The glutaraldehyde fixed neonatal tissue has a higher modulus of elasticity (83.7 MPa) than adult pericardium (33.5 MPa) and a higher normalised ultimate tensile strength (32.9 MPa) than adult pericardium (19.1 MPa). Measured edge on to the tissue, the collagen in neonatal pericardium is significantly more aligned (orientation index (OI) 0.78) than that in adult pericardium (OI 0.62). There is no difference in the fibril diameter between neonatal and adult pericardium. It is shown that high alignment in the plane of the tissue provides the mechanism for the increased strength of the neonatal material. The superior strength of neonatal compared with adult tissue supports the use of neonatal bovine pericardium in heterografts.
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Rojo FJ, Páez JMG, Jorge-Herrero E, Atienza JM, Millán I, Rocha A, de Córdova AHF, Guinea GV. Optimal selection of biological tissue using the energy dissipated in the first loading cycle. J Biomed Mater Res B Appl Biomater 2010; 95:414-20. [DOI: 10.1002/jbm.b.31732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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