CFD Comparative Study of a Flat Versus a Cylindrical Stent Configuration for PIV Investigations of the Prosthetic Influence on Local Hemodynamics.

Abstract

Mechanical stresses and flow dynamics alteration in a stented artery region are known to stimulate intimal thickening and increase the risk of restenosis, the closure of a revascularized artery. Particle imaging velocimetry flow visualization technique (PIV) can be useful in characterizing the local flow dynamics around stents. However, usual cylindrical stent models present some visualization and optical difficulties when studying fluid dynamics using PIV. A flat stent model has two main advantages over the usual cylindrical models. First, planar stent models are cheaper to manufacture than cylindrical ones. Secondly, it is easier with a flat model to get data acquisition planes cutting through the model without inducing diffraction errors due to the cylindrical model’s curvature. The wall shear stress distribution, which is believed to be of primary importance in stented artery restenosis, should be comparable in both the flat and cylindrical stent models for the regions of interest. In order to study the feasibility of using a flat version of the stent model for PIV flow investigation the shear stress distribution computed in the CFD analysis will be compared between the flat and the cylindrical stent configurations. It will be shown that for a physiological pulsatile flow the flat model yields results in the shear strain rate that are comparable to the cylindrical model. A cheaper and less diffraction error prone validated flat model would be advantageous when several stent design have to be studied and optimized.