No abstract

No abstract

No abstract

Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Alterations of the phase shift between pressure and flow waveform created by a different stents were studied to compare the hemodynamic effects of stent design properties on restenosis in stented human coronary artery. Blood pressure waveforms were computed in three different sites, pre-stent, middle of stented arterial segment, and post-stent regions using computational fluid dynamics. Blood flow was assumed as pulsatile, incompressible, and Newtonian flow. Rigid boundary conditions were assumed for all models. The governing Navier-Stokes equations were solved using commercial software package (Fluent V6.0.12). Stents were assumed with real structure and modeled using the commercial software package (Gambit, V2.0). The alterations of the phase shift between pressure and flow waveform created by a different stents were investigated in three major regions using commercial software package (Matlab, V7.0). It is concluded that stent geometry changes the phase shift between pressure and flow waveforms in stented human coronary artery, and wall shear stress between stent struts was sensitive to these variations. The results show that variation in the phase shift is sensitive to stent geometry

Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Local flow alterations created by a different stents without and with flow divider were studied to compare the hemodynamic effects of Stent design properties on restenosis in stented human coronary artery. Blood pressure and shear stress values were computed in three different sites, including stented arterial segment, pre-stent and post-stent regions using computational fluid dynamics. Blood flow was assumed as pulsatile, incompressible and Newtonian flow. Rigid boundary conditions were assumed for all models. The governing Navier-Stokes equations were solved using commercial software package (Fluent V6.0.12). Stents are assumed with real structure and modeled using the commercial software package (Gambit, V2.0). The arterial wall shear stress distribution was investigated in three major regions and critical sites were located. It is concluded that the wall shear stress between stent struts was sensitive to strut spacing, profile of strut, number of struts and curvature. Our 3D computational fluid dynamics modeling demonstrate that with increasing the angle between two sides of the stent strut the percentage of intrastrut area that exposed to critical value of WSS decreases. By application of a flow divider, the wall shear stress in stented segment increases markedly and so is the pressure gradient in stented segment. Flow divider influences the blood flow pattern in proximal of stented segment. In this section, the WSS increases with application of the flow divider. The results for different diameters of flow divider show that optimum diameter for flow divider is D/3