Among the many factors influencing the effectiveness of cardiovascular
stents, tissue
prolapse indicates the potential of a
stent to cause restenosis. The deflection of the arterial wall between the struts of the
stent and the tissue is known as a
prolapse or draping. The
prolapse is associated with injury and damage to the vessel wall due to the high stresses generated around the
stent when it expands. The current study investigates the impact of
stenosis severity and plaque morphology on
prolapse in stented coronary arteries. A finite
element method is applied for the
stent, plaque, and artery set to quantify the tissue
prolapse and the corresponding stresses in stenosed coronary arteries. The variable size of
atherosclerotic plaques is considered. A plaque is modelled as a multi-layered medium with different thicknesses attached to the single layer of an arterial wall. The results reveal that the tissue
prolapse is influenced by the degree of
stenosis severity and the thickness of the plaque layers. Stresses are observed to be significantly different between the plaque layers and the arterial wall tissue. Higher stresses are concentrated in
fibrosis layer of the plaque (the harder core), while lower stresses are observed in necrotic core (the softer core) and the arterial wall layer. Moreover, the morphology of the plaque regulates the magnitude and distribution of the stress. The fibrous cap between the necrotic core and the endothelium constitutes the most influential layer to alter the stresses. In addition, the thickness of the necrotic core and the
stenosis severity affect the stresses. This study reveals that the morphology of
atherosclerotic plaques needs to be considered a key parameter in designing coronary
stents.