Influence of Supporting Tissue on the Deformation and Compliance of Healthy and Diseased Arteries

Abstract

Hemodynamics and the interaction between the components of the cardiovascular system are complex and involve a structural/fluid flow interaction. During the cardiac cycle, changes to vascular pressure induce a compliant response in the vessels as they cyclically stretch and relax. The compliance influences the fluid flow throughout the system. The interaction is influenced by the disease state of the artery, and in particular, a plaque layer can reduce the compliance. In order to properly quantify the fluid-structural response, it is essential to consider whether the tissue surrounding the artery provides a support to the vessel wall. Here, a series of calculations are provided to determine what role the supporting tissue plays in the vessel wall and how much tissue must be included to properly carry out future fluid-structure calculations. Additionally, we calculate the sensitivity of the compliance to material properties such as the Young's modulus or to the transmural pressure difference.

Numerical Analysis of Arterial Plaque Thickness and its Impact on Artery Wall Compliance

“…Linear elastic properties have been shown to suitably calculate artery deformation [50]. In [59], it was shown that the results are not sensitive to the value of the Poisson ratio. There, it was also shown that the required thickness of the surrounding sheet was 6.5 mm and that value is used through this study.…”

“…The figure shows a three-part solution domain that includes calcified plaque, artery wall tissue, and surrounding tissue. The thicknesses of the artery wall and the surrounding tissue and the material properties are from [59]. They are listed here in Table 1.…”

“…With respect to the radial extent, it was previously shown that a 6.5 mm thick surrounding tissue zone was sufficient to ensure accuracy [59]. The axial extent (annotated in Figure 1) was determined by systematically enlarging the domain and repeating compliance calculations until further enlargements did not influence results.…”

“…In [58], the surrounding tissue was modeled with a viscoelastic support along the artery. Most recently [59], a systematic study was completed to vary the thickness of the surrounding artery wall until further changes to its thickness no longer impacted the results. It was found that the presence of plaque significantly reduces the compliance of the artery and that for a healthy artery, a 6.5 mm sheath is required.…”

A New Catheter Technology to Deliver Vascular Stem-Cells

“…Among the most common surgical interventions are balloon angioplasty, stenting, medicated stenting [1][2][3][4][5][6][7], atherectomy [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], or a combination treatment. One positive outcome of these treatments is that they often increase the compliance of the artery wall which is a measure of cardiovascular health [26][27][28][29][30][31][32][33][34][35].…”