The effects of changes in flow velocity waveform and arterial geometry before and after percutaneous coronary intervention (PCI) in the right coronary artery (RCA) were investigated using computational fluid dynamics. An RCA from a patient with a stenosis was reconstructed based on multislice computerized tomography images. A nonstenosed model, simulating the same RCA after PCI, was also constr...

BACKGROUND Atherosclerotic lesions are predominantly observed in curved arteries and near side branches, where low or oscillatory shear stress patterns occur, suggesting a causal connection. However, the effect of shear stress on plaque vulnerability is unknown because the lack of an appropriate in vivo model precludes cause-effect studies. METHODS AND RESULTS We developed a perivascular shea...

Build-up of cement-based suspensions is a complex phenomenon affected by the mixture concentration and testing parameters as well as the shear history. Accurate measurements of build-up rely on the efficiency of the applied pre-shear regime to achieve an initial defined and dispersed structure to eliminate the shear history. This can therefore enable understanding mechanisms of build-up and qua...

Background—Atherosclerotic lesions are predominantly observed in curved arteries and near side branches, where low or oscillatory shear stress patterns occur, suggesting a causal connection. However, the effect of shear stress on plaque vulnerability is unknown because the lack of an appropriate in vivo model precludes cause-effect studies. Methods and Results—We developed a perivascular shear ...

Many studies of the human vascular tree have shown that atherosclerosis develops at an early age, with areas of the posterior aorta and branch sites showing the earliest fatty streaks. Closer analysis of the branch points showed that the flow dividers, regions of high shear stress with laminar flow, were relatively protected from fatty streak formation. In contrast, there was a predilection for...

Sommerfeld paradox roughly says that mathematically Couette shear flow is linearly stable for all Reynolds number, but experimentally it is unstable to any size perturbation when the Reynolds number is large enough. Our study here focuses upon a sequence of 2D oscillatory shears which are the Couette linear shear plus small amplitude and high frequency sinusoidal shear perturbations. The sequen...

PURPOSE Abnormalities in blood vessels by virtue of complex blood flow dynamics is being supported by non-Newtonian behavior of blood. Thus it becomes a focus of research to most of the researchers. Additionally, consideration of real life patient specific model of vessel as well as patient specific inlet flow boundary condition implementation was limited in literature. Thus a thorough implemen...

Wall shear stress (WSS) on anchored cells affects their responses, including cell proliferation and morphology. In this study, the effects of the directionality of pulsatile WSS on endothelial cell proliferation and morphology were investigated for cells grown in a Petri dish orbiting on a shaker platform. Time and location dependent WSS was determined by computational fluid dynamics (CFD). At ...

Oscillatory shear stress occurs at sites of the circulation that are vulnerable to atherosclerosis. Because oxidative stress contributes to atherosclerosis, we sought to determine whether oscillatory shear stress increases endothelial production of reactive oxygen species and to define the enzymes responsible for this phenomenon. Bovine aortic endothelial cells were exposed to static, laminar (...

Hemodynamic forces play an active role in vascular pathologies, particularly in relation to the localization of atherosclerotic lesions. It has been established that low shear stress combined with cyclic reversal of flow direction (oscillatory shear stress) affects the endothelial cells and may lead to an initiation of plaque development. The aim of the study was to analyze the effect of hemody...