Effects of Stenting Shapes on the Wall Shear Stress in the Angulated Coronary Stenosis

Abstract

The objective of the present study is to evaluate the effects of stenting shapes on flow velocity and wall shear stress in angulated coronary stenosis by computer simulation. Coronary angiograms and Doppler ultrasound measurements in patients with angulated coronary stenosis were obtained. Inlet wave velocity form was obtained from in vivo intracoronary Doppler data and used for the input data of the computer simulation. Spatial distributions of blood flow velocity and recirculation areas were drawn for the coronary models. Wall shear stresses in the intracoronary stent models were calculated by using three-dimensional computer simulations. A negative shear stress regions, where is recirculation area, is noted on the inner walls of post-stenotic regions of the pre-stenting models. The negative shear stress region disappeared after stenting. The peak wall shear stresses in the post-stenting models are markedly reduced up to about two orders of magnitude compared to those of the pre-stenting models. The present study demonstrated that angular difference between pre- and post-intracoronary stenting might induce optimal physiologic condition of wall shear stress for endothelial regeneration following intracoronary stenting and may suppress in vivo restenotic process. The present study suggests that hemodynamic forces exert by flowing blood may initiate the generation of atherosclerosis within the angulated vascular curvature. The local recirculation area, which low or negative shear stress prevails, may lead to progression of atherosclerosis.