Impact of coronary tortuosity on the artery hemodynamics (original) (raw)
Related papers
Fluid-structure analysis of an atherosclerotic coronary artery
2018
A theoretical fluid-structure interaction (FSI) model for the stress field of atherosclerotic coronary arteries are obtained and the influence of various characteristics on the stress distribution in diseased coronary arteries is highlighted. A reliable model is developed (and hence accurate heart attack prediction), the following factors are incorporated: (1) non-Newtonian blood flow; (2) artery’s tapered shape; (3) the micro-calcification of the plaque; (4) blood pulsation. Incorporating these factors in the model makes it possible to accurately predict plaque ruptures. The system is modelled based on a 3D fluid-structure interaction analysis via the finite element method (FEM). Experimental data from previous studies are used to generate a realistic material model. The generated model is utilised as a predictive model for plaque rupture and to determine high risk situations in the coronary arteries. It is shown that incorporating the physiological flow rate in the model, the wall...
Impact of local flow haemodynamics on atherosclerosis in coronary artery bifurcations
EuroIntervention, 2015
Coronary artery bifurcations are susceptible to atherosclerosis as a result of the unique local flow patterns and the subsequent endothelial shear stress (ESS) environment that are conducive to the development of plaques. Along the lateral walls of the main vessel and side branches, a distinct flow pattern is observed with local low and oscillatory ESS, while high ESS develops at the flow divider (carina). Histopathologic studies have shown that the distribution of plaque at bifurcation regions is related to the local ESS patterns. The local ESS profile also influences the outcome of percutaneous coronary interventions in bifurcation lesions. A variety of invasive and non-invasive imaging modalities have enabled 3D reconstruction of coronary bifurcations and thereby detailed local ESS assessment by computational fluid dynamics. Highly effective strategies for treatment and ultimately prevention of atherosclerosis in coronary bifurcations are anticipated with the use of advanced imaging and computational fluid dynamic techniques.
International Journal of Numerical Methods for Heat & Fluid Flow, 2010
Purpose-This paper aims to perform numerical simulations through different shaped double stenoses in a vascular tube for a better understanding of arterial blood flow patterns, and their possible role during the progression of atherosclerosis. The dynamics of flow features have been studied by wall pressure, streamline contour and wall shear stress distributions for all models. Design/methodology/approach-A finite volume method has been employed to solve the governing equations for the two-dimensional, steady, laminar flow of an incompressible and Newtonian fluid. Findings-The paper finds that impact of pressure drop, reattachment length and peak wall shear stress at each restriction primarily depends upon percentage of restriction, if restriction spacing is sufficient. The quantum of impact of pressure drop, reattachment length and peak wall shear stress is much effected for smaller restriction spacing. If recirculating bubble of first restriction merges with the recirculating bubble formed behind the second restriction in this smaller restriction spacing. The similar effect of smaller restriction spacing is observed, if Reynolds number increases also. Originality/value-The effect of different shaped stenoses, restriction spacing and Reynolds number on the flow characteristics has been investigated and the role of all the flow characteristics on the progression of the disease, atherosclerosis, is discussed.
This paper presents the circumferential and longitudinal variation of lesion deposition on the wall of the artery. A mathematical model that approximates the typical atherosclerotic artery is developed. Axial and radial shape parameters are designed to adjust the geometry of the vessel and construct realistic models of the diseased artery. The degree and configuration of atherosclerosis is varied to understand the relationship between the arterial geometry and blood flow resistance. Useful deductions on the geometrical variation and its effect on the hemodynamics of blood are presented. The study examines, in particular, how the axial and radial variability of arterial wall geometry can be combined to affect the blood flow resistance in a single isolated vessel. The model is able to predict the degree of aggravation in occluded arteries vis-à-vis development of atherosclerotic spiraling lesion. Furthermore, the theoretical framework can be utilized for real-time diagnosis of atherosclerosis.
This paper presents the circumferential and longitudinal variation of lesion deposition on the wall of the artery. A mathematical model that approximates the typical atherosclerotic artery is developed. Axial and radial shape parameters are designed to adjust the geometry of the vessel and construct realistic models of the diseased artery. The degree and configuration of atherosclerosis is varied to understand the relationship between the arterial geometry and blood flow resistance. Useful deductions on the geometrical variation and its effect on the hemodynamics of blood are presented. The study examines, in particular, how the axial and radial variability of arterial wall geometry can be combined to affect the blood flow resistance in a single isolated vessel. The model is able to predict the degree of aggravation in occluded arteries vis-à-vis development of atherosclerotic spiraling lesion. Furthermore, the theoretical framework can be utilized for real-time diagnosis of atherosclerosis.
Flow and atherosclerosis in coronary bifurcations
EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, 2010
Coronary bifurcations are among the most frequent sites affected by atherosclerosis. In these regions, complex haemodynamic conditions prevail and local flow disturbances dictate the localisation and progression of atheroma. Endothelial shear stress (ESS) is the main flow-related factor affecting the distribution of atherosclerosis in a bifurcation. Plaques are more prevalent in low ESS areas, such as the lateral walls of the main vessel and side branches, while they are less common in the flow divider or carina, which is characterised by high ESS. However, the carina is not free of atheroma and is affected in up to one third of cases, but never in isolation. Lesions in the carina are likely to develop at a later stage of atherosclerosis, as result of circumferential expansion of plaques from the lateral wall. Pulsatile flow augments the local atherogenic environment by inducing low and oscillatory ESS. The geometrical configuration is also important as increased curvature and wide ...
Applied Bionics and Biomechanics, 2022
Atherosclerosis is a vascular disease in which some parts of the artery undergo stenosis due to the aggregation of fat. The causes and location of stenosis can be determined using fluid mechanics and parameters such as pressure, effective wall shear stress, and oscillatory shear index (OSI). The present study, for the first time, numerically investigates the pulsatile blood flow inside arteries with elastic and rigid walls in simple and double stenosis (80% stenosis) by using k-ω model and physiological pulse. The reason for applying the k-ω model in the present study was to provide more consistent results with clinical results to improve the accuracy in estimating atherosclerosis disease. The investigation of the time-mean wall shear stress indicated that for double stenosis, the difference between the results of the rigid and elastic artery assumptions is greater than the case of simple stenosis, so that this difference percent can be up to 2.5 times. In addition, the results show...
Circulation Research, 1983
The distribution of nonstenosing, asymptomatic intimal plaques in 12 adult human carotid bifurcations obtained at autopsy was compared with the distribution of flow streamline patterns, flow velocity profiles, and shear stresses in corresponding scale models. The postmortem specimens were fixed while distended to restore normal in vivo length, diameter, and configuration. Angiograms were used to measure branch angles and diameters, and transverse histological sections were studied at five standard sampling levels. Intimal thickness was determined at 15 degrees intervals around the circumference of the vessel sections from contour tracings of images projected onto a digitizing plate. In the models, laser-Doppler anemometry was used to determine flow velocity profiles and shear stresses at levels corresponding to the standard specimen sampling sites under conditions of steady flow at Reynolds numbers of 400, 800, and 1200, and flow patterns were visualized by hydrogen bubble and dye-w...
Computational and structural biotechnology journal, 2014
Atherosclerotic plaques develop at particular sites in the arterial tree, and this regional localisation depends largely on haemodynamic parameters (such as wall shear stress; WSS) as described in the literature. Plaque rupture can result in heart attack or stroke and hence understanding the development and vulnerability of atherosclerotic plaques is critically important. The purpose of this study is to characterise the haemodynamics of blood flow in the mouse aortic arch using numerical modelling. The geometries are digitalised from synchrotron imaging and realistic pulsatile blood flow is considered under rigid wall assumptions. Two cases are considered; arteries with and without plaque. Mice that are fed under fat diet present plaques in the aortic arch whose size is dependent on the number of weeks under the diet. The plaque distribution in the region is however relatively constant through the different samples. This result underlines the influence of the geometry and consequent...