Cardiovascular diseases are the leading cause of death worldwide. In conditions such as atherosclerosis, arterial microstructure undergoes significant changes, including fatty tissue deposition that occludes the artery and collagen accumulation combined with elastin degradation that stiffens the wall. Treatments like balloon angioplasty, with or without stenting, aim to reopen the artery by pushing to the side fatty deposits. However, these interventions often trigger strong inflammatory responses, leading to further microstructural remodeling and eventual re-occlusion. Two essential proteins, elastin and collagen, are crucial to the passive mechanical behavior of arteries, and their remodeling is a hallmark of disease progression and treatment failure. Understanding how these microstructural alterations affect mechanical behavior is therefore critical for improving therapeutic strategies. Computational modeling offers a powerful way to explore these relationships and predict their impact.

Existing models are largely phenomenological, relying on a few parameters and containing little information on the microstructure. To address this gap, this thesis introduces a microstructure-inspired microscale model that integrates imaging and mechanical data. First, robust imaging protocols were developed using contrast-enhanced microcomputed tomography (CECT) to quantify features such as fiber thickness, orientation, and tortuosity, revealing directional differences in alignment and tortuosity. Next, mechanical characterization was performed to calibrate and validate the model.

Finally, a computational framework based on representative volume elements (RVEs) was implemented. This approach discretely incorporates arterial components and surpasses traditional constitutive models by capturing the contributions of elastin, collagen, and smooth muscle cells. Sensitivity analysis showed that small variations in microstructural parameters can lead to large differences in mechanical response, emphasizing the need for detailed microstructural and mechanical characterization.

In summary, this work bridges imaging, mechanics, and modeling to advance understanding of arterial biomechanics and lays the foundation for improved treatment strategies and future research on diseased tissues.

Membres du jury :

• Prof. Greet Kerckhofs  (UCLouvain)(Promotrice)
• Prof. Nele Famaey (KU Leuven) (Promotrice)
• Prof. Nicolas Moës  (UCLouvain) (Président) 
• Prof. Thomas Pardoen  (UCLouvain) 
• Prof. Inge Fourneau (UZ Leuven)
• Prof. Stéphane Avril (Ecole des Mines de Saint-Etienne, France)
• Dr. Grzgorz Pyka (UCLouvain)
• Dr. Heleen Fehervary (KU Leuven) (Secrétaire)
• Dr. Seyed Ali Elahi (KU Leuven)

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