3D MRI-Based Anisotropic FSI Models With Cyclic Bending for Human Coronary Atherosclerotic Plaque Mechanical Analysis

Abstract

Background-Heart attack and stroke are often caused by atherosclerotic plaque rupture which happens without warning most of the time. MRI-based atherosclerotic plaque models with fluidstructure interactions (FSI) have been introduced to perform flow and stress/strain analysis and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. For coronary arteries, cyclic bending associated with heart motion and anisotropy of the vessel walls may have significant influence on flow and stress/strain distributions in the plaque. FSI models with cyclic bending and anisotropic vessel properties for coronary plaques are lacking in the current literature.Method of Approach-In this paper, cyclic bending and anisotropic vessel properties were added to 3D FSI coronary plaque models so that the models would be more realistic for more accurate computational flow and stress/strain predictions. Six computational models using one ex vivo MRI human coronary plaque specimen data were constructed to assess the effects of cyclic bending, anisotropic vessel properties, pulsating pressure, plaque structure, and axial stretch on plaque stress/ strain distributions.Results-Our results indicate that cyclic bending and anisotropic properties may cause 50%-800% increase in maximum principal stress (Stress-P 1 ) values at selected locations. The stress increase varies with location and is higher when bending is coupled with axial stretch, non-smooth plaque structure, and resonant pressure conditions (zero phase angle shift). Effects of cyclic bending on flow behaviors are more modest (9.8% decrease in maximum velocity, 2.5% decrease in flow rate, 15% increase in maximum flow shear stress).Conclusions-Inclusion of cyclic bending, anisotropic vessel material properties, accurate plaque structure, and axial stretch in computational FSI models should lead to considerable improvement of accuracy of computational stress/strain predictions for coronary plaque vulnerability assessment. Further studies incorporating additional mechanical property data and in vivo MRI data are needed to obtain more complete and accurate knowledge about flow and stress/strain behaviors in coronary plaques and to identify critical indicators for better plaque assessment and possible rupture predictions.

Microcalcifications Increase Coronary Vulnerable Plaque Rupture Potential: A Patient-Based Micro-CT Fluid–Structure Interaction Study

“…This isotropic hyperelastic model was used for all the vessel components such as wall, fibrous cap, calcifications and lipid core. These parameters were taken from previous experiments performed by Tang and coworkers 31,46 The material properties used in the FSI simulations for the fibrous cap, vessel wall, lipid core and calcifications are listed in Table 1. A three-dimensional plot illustrating the response of Cauchy stress vs. the stretch is shown in Fig.…”

“…The limited data concerning biomechanical properties of human coronary arteries and underlying plaques 11,13,25,46 is likely due to smaller dimensions compared to other vessels. 3D modified Mooney-Rivlin anisotropic models have appeared in the literature 31,46 and shown usefulness in considering anisotropy of the soft tissues.…”

Influence of arterial wall-stenosis compliance on the coronary diagnostic parameters

“…Time varying pressure p(t) (Tang et al, 2009) was applied at the inlet and a transient parabolic velocity, u(t), (Cho et al, 1983) was applied at the outlet of the artery (Fig. 1B).…”

Stability of Carotid Artery Under Steady-State and Pulsatile Blood Flow: A Fluid–Structure Interaction Study

“…Tang et al modeled the coronary artery atherosclerosis plaque with cyclic bending using three-dimensional (3D) FSI modeling [27]. They focused on the stresses in the region of bending to investigate the effect of stresses on coronary plaques.…”