Cardiovascular Biomechanics
Saeed Bahrami; Faramarz Firouzi
Volume 9, Issue 3 , December 2015, , Pages 293-303
Abstract
It is accepted that wall shear stress (WSS) and Oscillatory Shear index (OSI) are strong hemodynamic factors to development of atherosclerotic (AS) plaque. Sometimes, OSI has an important effect on AS plaque formation, because WSSdoesn't make it happenalone. Most computational fluid dynamic (CFD) simulations ...
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It is accepted that wall shear stress (WSS) and Oscillatory Shear index (OSI) are strong hemodynamic factors to development of atherosclerotic (AS) plaque. Sometimes, OSI has an important effect on AS plaque formation, because WSSdoesn't make it happenalone. Most computational fluid dynamic (CFD) simulations were performed on left main coronary bifurcation geometry, and whole left coronary artery tree has not been investigated by now. In this paper, a thorough three-dimensional model of left coronary artery tree was considered, including left main coronary, left anterior descending and its branches, left circumflex artery and its branches. Effects of cardiac motions on vessel wall of left coronary were considered. The governingNavier–Stokes equations for pulsatile flow and incompressible non-Newtonian blood was analyzed with finite element method. The study concentrates on shear stress distribution and OSI distribution on the vessel wall. Comparing the results of this study with previous clinical investigations shows that the regions with low wall shear stress (equal to and less than 1.5[Pa]) along with high OSI value (equal to and more than 0.3) have potential to development of AS plaque.So it can be predicted that the LAD region after D3 and the bifurcation of LCxA-OM have high potential to development of AS, in addition to the bifurcation of LCxA-LMCA which had been specified before.
Cardiovascular Biomechanics
Faramarz Firouzi; Nasser Fatouraee; Siamak Najarian
Volume -1, Issue 2 , June 2005, , Pages 129-142
Abstract
Nowadays in the industrial world, because of increase of heart transplantation demand, long-term ventricular assist devices (VAD) are more needed. Implantable sac-type is one of the newest of them producing pulsatile flow. In this research, three different models of sac-type VAD are numerically simulated. ...
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Nowadays in the industrial world, because of increase of heart transplantation demand, long-term ventricular assist devices (VAD) are more needed. Implantable sac-type is one of the newest of them producing pulsatile flow. In this research, three different models of sac-type VAD are numerically simulated. Simple motion is supposed for moving wall in model 1. In model 2, the motion of moving wall is assumed wavy form to study the effect of moving wall form on blood flow. In model 3, the pressure boundary condition is added to model 2. In this model, the effect of actual blood pressure on flow pattern is considered. Results of each model demonstrate the viscose term of blood flow stresses applied to the membrane is negligible, and only pressure term is effective. However, the motional pattern of membrane and also applied pressure on boundary are approximately ineffective on blood flow pattern.
