Collapse of diseased arteries with eccentric cross section

Area of Science:

• Biomedical Engineering
• Cardiovascular Mechanics
• Computational Biology

Background:

• Atherosclerotic plaque rupture is a major cause of cardiovascular events, but the precise mechanisms remain unclear.
• Mechanical stress on the fibrous cap is a suspected factor in plaque instability.
• Severe arterial stenosis can lead to artery collapse and high stress concentrations.

Purpose of the Study:

• To quantitatively estimate stresses and deformations in collapsed thick-walled arteries.
• To identify locations and magnitudes of high stress concentrations.
• To assess the influence of plaque thickness and eccentricity on arterial collapse.

Main Methods:

• Large deformation finite element analysis of thick-walled artery models.
• Calculation of compressive and tensile stresses under varying transmural pressures.
• Comparison of thick-wall model results with thin-wall assumptions and elastic buckling theory.

Main Results:

• High stress concentrations were identified in locations not predicted by thin-wall models.
• Maximum compressive stress reached 80% of Young's modulus at low negative transmural pressures.
• Buckling pressure was significantly lower (nearly 30%) than predicted by thin-wall theory, especially with increased eccentricity.

Conclusions:

• Thick-walled artery models provide more accurate stress predictions than thin-wall assumptions for collapsed arteries.
• Compressive stresses in collapsed stenotic arteries are critical factors for plaque cap rupture.
• Eccentric and thick atherosclerotic plaques significantly increase the likelihood of arterial collapse.