Modeling lipid transport through the transverse clip stenosis

A finite-element model is used to determine the internal wall stresses in a rat aorta compressed with a U-shaped clip. These results are correlated with the location of various cell shapes found in vivo. Previous studies with this stenosis found polygonal cells and increased lipid deposition in small regions adjacent to each edge of the clip. The finite-element calculations suggest that the internal wall longitudinal shear stress changes sign rapidly over these small sections. By assuming that the permeability of the polygonal cells is much higher than in normal endothelial cells, the rate of lipoprotein uptake through the endothelium is calculated. As expected, the blood itself provides little resistance to the lipid uptake and significant transfer takes place only in the regions with the elevated permeability