The microcalcification influence on the ateroma plaque vulnerability

Resumen

Rupture of atherosclerotic plaque, which is related to maximal stress conditions in the plaque, is
a major cause of mortality worldwide. More careful examination of stress distributions in
plaques reveals that it may be caused by the local stress behaviors caused by cap thinning,
inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications, at
critical sites. However, the role of microcalcifications is not yet fully understood and most finite
element models of blood vessels with atheroma plaque do not consider the heterogeneity of the
plaque constituents at the micro-scale. The goal of the present work is to investigate the effects
of microcalcifications on the stress field of an atheroma plaque vessel section. This is achieved
by performing a parametric finite element study, assuming a plane strain hypothesis, of an
idealized coronary artery cross-section with eccentric atheroma plaque and one
microcalcification incorporated. The model was extruded at a small length in order to introduce
some purely 3D parameters such as the fiber orientation. Healthy (adventitia) and diseased
(fibrotic, lipidic and calcification) tissues were considered. The parametric analysis includes the
most influential geometric parameter on atheroma vulnerability and the position and dimensions
of the microcalcification: the fibrous cap thickness, the microcalcification ratio, angle and
eccentricity. In total, a large set of 108 different geometries were studied. We could conclude
that microcalcifications should be considered in the modeling of this kind of problems since
they cause a significant alteration of the vulnerable risk by increasing the maximum maximal
principal stress up to 40%.