Effects of geometric variations on buckling of arteries

The mechanical stability of arteries is important to the maintenance of normal arterial function. Mechanical buckling of cylindrical arteries under internal pressure has recently reported, however effects of geometric variations in arteries, for example elliptic or eccentric cross sections, stenosis, or tapering along the longitudinal axis, on the mechanical stability of arterial wall have not been investigated. The objective of this study was to determine the buckling behavior of arteries with elliptic, eccentric, stenotic, and tapered cross sections. The arterial wall was modeled as a homogenous anisotropic nonlinear material. Finite element analysis was used to simulate the buckling process of arteries under lumen pressure and axial stretch. Our results demonstrated that arteries with an oval cross section buckled in the short axis direction at lower critical pressures compared to circular arteries. Eccentric cross-sections, stenosis, or tapering also decreased the critical pressure. Stenosis led to dramatic pressure variations along the vessel and stenotic arteries buckled at very low entrance pressures. Tapering shifted the buckling deformation profile of the artery towards the distal end. We concluded that geometric variations reduced the critical pressure of arteries and thus made arteries more vulnerable to instability. These results improve our understanding of the stability of arteries.