OBJECTIVES The atherosclerotic process in arteries is correlated with the local wall shear stress (WSS). Plaque development particularly occurs in regions with recirculation (ie, where the WSS oscillates). We investigated the effects of non-Newtonian blood viscosity, variations in flow rate, and vessel diameter on wall phenomena in a carotid bifurcation model. MATERIALS AND METHODS The flow t...

The purpose of this study is to elucidate the role, which Wall Shear Stress (WSS) differentiation between diastole and systole plays in coronary atherosclerosis. A finite-element analysis of the 3D, pulsatile, nonNewtonian, heamodynamics of the normal human left main coronary artery bifurcation, based on published data, is performed. The time averaged mean WSS in the entire left coronary artery...

Chronic high flow can induce arterial remodeling, and this effect is mediated by endothelial cells (ECs) responding to wall shear stress (WSS). To assess how WSS above physiological normal levels affects ECs, we used DNA microarrays to profile EC gene expression under various flow conditions. Cultured bovine aortic ECs were exposed to no-flow (0 Pa), normal WSS (2 Pa), and very high WSS (10 Pa)...

A model for characterizing the spectral response of the passband of Wavelength Selective Switches (WSS) is presented. We demonstrate that, in contrast to the commonly used supergaussian model, the presented model offers a more complete match to measured results, as it is based on the physical operation of the optical system. We also demonstrate that this model is better suited for calculation o...

Background Aortic blood flow in healthy people is characterised by helical flow in the ascending and descending aorta, with corresponding patterns of wall shear stress (WSS) imposed upon the wall of the aorta by moving blood. Flow and WSS patterns in the aortic root and sinuses of Valsalva, and the flow patterns in diseased aortas are incompletely defined. We describe the use of a validated, ti...

Atherosclerosis development is strongly believed to be influenced by hemodynamic forces such as wall shear stress (WSS). To estimate such an entity in-vivo in humans, image-based computational fluid dynamics (CFD) is a useful tool. In this study, we use a combination of magnetic resonance imaging (MRI) and CFD to estimate WSS. In such method, a number of steps are included. One important step i...

OBJECTIVE The hemodynamic environment is a determinant of susceptibility to atherosclerosis in the vasculature. Although mouse models are commonly used in atherosclerosis studies, little is known about local variations in wall shear stress (WSS) in the mouse and whether the levels of WSS are comparable to those in humans. The objective of this study was to determine WSS values in the mouse aort...

Restenosis resulting from neointimal hyperplasia (NH) limits the effectiveness of intravascular stents. Rates of restenosis vary with stent geometry, but whether stents affect spatial and temporal distributions of wall shear stress (WSS) in vivo is unknown. We tested the hypothesis that alterations in spatial WSS after stent implantation predict sites of NH in rabbit iliac arteries. Antegrade i...

Despite the fact that the role of wall shear stress (WSS) as a local mechanical factor in atherogenesis is well established, its distribution over the entire normal human left coronary artery (LCA) tree has not yet been studied. A three-dimensional computer generated model of the epicardial LCA tree, based on averaged human data set extracted from angiographies, was adopted for finite-element a...

The patho-physiologic process of restenosis and tissue growth may not be completely eliminated and is the primary concern of clinicians performing angioplasty and stent implantation procedures. Recent evidence suggests that the restenosis process is influenced by several factors: (1) geometry and size of vessel; (2) stent design; and (3) it's location that alter hemodynamic parameters, includin...