PhD defence A. (Aikaterini) Tziotziou

Below is a brief summary of the dissertation: 

This thesis investigates the development of atherosclerosis disease, a chronic inflammatory condition primarily affecting the coronary and carotid arteries. It emphasizes the importance of atherosclerotic plaque morphology and biomechanics, particularly the wall shear stress (WSS) and mechanical wall stress (MWS), in disease initiation and progression. While WSS, a flow-driven force, has long been recognized for its role in endothelial regulation and early plaque formation, MWS, a pressure-driven stress, has been less studied but may significantly contribute to the advancement of established plaques.

Part I of the thesis analyzes porcine and human coronary arteries using longitudinal intravascular ultrasound (IVUS) and optical coherence tomography (OCT). It shows that low WSS is linked to early plaque growth, while high MWS is associated with progression, especially in sectors with lipid-rich necrotic cores (LRNC). In human studies, statin therapy may reduce wall thickness, particularly where WSS and MWS are increased.

Part II examines human carotid arteries from the PARISK study using computed tomography angiography (CTA) imaging and computational modeling. It explores how calcification morphology varies with sex and cardiovascular risk factors, and how plaque geometry differs in symptomatic versus asymptomatic arteries. Notably, high MWS and low oscillatory shear index are linked to increased calcification thickness and plaque development.

Overall, the thesis demonstrates that both WSS and MWS influence atherosclerosis but at different stages and vascular regions. These insights underline the clinical relevance of integrating biomechanical assessments for more accurate risk prediction and personalized intervention strategies in atherosclerotic disease management.