Corso, Pascal; Tsolaki, Elena; Herrmann, Inge Katrin; Obrist, Dominik (September 2021). A fluid-structure interaction (FSI) framework for the identification of factors triggering calcification in native and bioprosthetic heart valves (Unpublished). In: 17th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering.
Background: Calcification of native or bioprosthetic aortic valves (BAV) represents a major concern since calcific aortic stenosis affects 12% of the population over age 75 and calcification limits BAV durability. Calcification consists of the irregular deposition of mineralised crystals that change both the micro- and macro-scale properties of the tissues. Understanding the mechanisms that lead to calcification in BAV leaflets remains challenging as the interplay of haemodynamic, host factors and implant factors is complex. Methods: In the present study, the approach considered to tackle the fluid-structure interaction (FSI) problem encompassing the simulation of flow around a heart valve and its leaflet dynamics is based on (i) a finite-element solver for the elastodynamics equation governing the valve mechanics, (ii) a high-order finite-difference solver for the incompressible Navier-Stokes equations governing the blood flow, (iii) a variational transfer for the strong coupling between fluid and structure. The mechanical constitutive law is a fibre-reinforced model for which different fixation pre-treatment resulting from different concentrations of gluteraldehyde are modelled by changing the coefficient of the isotropic term representing the stiffness of the extracellular matrix. The gradually increasing mineralisation of the BAV leaflet along collagen fibres is modelled by a larger coefficient of the anisotropic term of the constitutive law. Results: The simulation of the three-dimensional FSI problem allows to focus on the computation of flow-based time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) as well as the finite-time Lyapunov exponent based on the Cauchy-Green strain tensor. We show that these metrics correlate well with the location of calcium minerals observed from microtomography scans performed on bioprosthetic valves with different degrees of calcification. Conclusion: The macroscopic results obtained from the 3D FSI simulations provide extrapolated insight into the flow-dependent mechanisms whereby BAV leaflet calcific crystals nucleate and grow.
Item Type: |
Conference or Workshop Item (Speech) |
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Division/Institute: |
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Cardiovascular Engineering (CVE) |
UniBE Contributor: |
Corso, Pascal, Obrist, Dominik |
Subjects: |
600 Technology > 610 Medicine & health 600 Technology > 620 Engineering |
Language: |
English |
Submitter: |
Pascal Corso |
Date Deposited: |
31 Aug 2023 09:40 |
Last Modified: |
31 Aug 2023 12:27 |
Related URLs: |
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Additional Information: |
Talk designed and given by P. Corso. |
Uncontrolled Keywords: |
Aortic Valves, Calcification, Fluid-Structure Interaction Simulations, Mathematical Models |
URI: |
https://boris.unibe.ch/id/eprint/185906 |
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