Elliptic delamination as an early stage in atherosclerotic plaque evolution: fluid mechanical aspects

Relatively little attention has been given to vessel wall mechanics in interaction with the pulsatile fluid motion of blood in the epicardial coronary arteries which are prone to atherosclerotic plaque development. Theories for lipid transport by convective effects, while appealing in many ways, do not serve to explain the predominantly bounded, elliptic profiles of atherosclerotic plaques when examined en face at gross autopsy. This paper outlines how structural-mechanical concepts relating to plaque shapes (starting from the shapes available even with isometric shell peeling to create the cavities typical of early plaques) can be combined with understanding of the blood pressure distribution which develops in the vicinity of a predominantly T-junction in a blood vessel to modulate and interact in shape formation by cyclic, local flexure. This provides a foundation for a rational hypothesis to be tested in vivo with bi-plane angiography and vessel wall imaging, e.g., intravascular ultrasound, to better assess the roles of solid and fluid mechanics in the localization of plaques.