Currently, tissue-engineered heart valves (TEHV) have shown a great prospective to replace the conventional prosthetics heart valves for their ability to grow and remodel. It is well established that in order for the seeded cells to behave in an appropriate manner and infiltrate, populate and remodel during in vitro culture, they need to be exposed to appropriate levels of mechanical stimulation that favour the regeneration of the valve-equivalent tissue with appropriate valvular-tissue- specific functionality. Mathematical modelling is an important tool that can be used alongside TEHV bioreactors with a view to optimising their function by relating the stress-strain distributions in the valve leaflets to the flow and pressure conditions generated by the bioreactor. For that, physiologically accurate 3D fluid structure interaction (FSI) models of fresh and decellularised aortic valves were developed. At first two FSI methods were used to study FSI of a 20 aortic valve, the Arbitrary Lagrangian Eulerian (ALE) method and the Multi-Material Arbitrary Lagrangian Eulerian (MM- ALE) method. The ALE method uses a dynamic mesh in the fluid domain to account for the valve deformations, while in the MM-ALE method, the fluid mesh remains fixed during the computation. Good agreement was found between the results of the two FSI methods. Furthermore, the MM-ALE method was employed to perform FSI of a bileaflet mechanical valve and the results were validated by comparison with pulsatile flow experim~nts. 3D FSI models of the natural aortic valve were developed using three material models for the leaflet (nonlinear isotropic, fiber-reinforced and Fung-type nonlinear orthotropic) and comparisons were conducted to in vivo and in vitro data. Finally, FSI models of decellularised aortic valve scaffolds cultured in vitro under different operation conditions were performed using the nonlinear orthotropic model for optimising a TEHV bioreactor.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:550815 |
| Date | January 2011 |
| Creators | Joda, Akram Abdelazim Osman |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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