Numerical Simulation and Clinical Implications of Stenosis in Coronary Blood Flow

Zhang, Junmei; Zhong, Liang; Luo, Tong; Huo, Yunlong; Tan, Swee Yaw; Wong, Aaron; Su, Boyang; Wan, Min; Zhao, Xiaodan; Kassab, Ghassan S.; Lee, Heow Pueh; Khoo, Boo Cheong; Kang, Chang Wei; Ba, Te; Tan, Ru San

doi:10.1155/2014/514729

Cited by 24 publications

(26 citation statements)

References 35 publications

(48 reference statements)

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“…Because higher flow rate led to lower FFR and the stenosis located at proximal portion normally had higher flow rate than that at distal, the stenosis located at proximal portion may have lower FFR than that at distal, holding other variable constant. These findings are consistent with clinical observations and in our previous CFD study .…”

Section: Resultssupporting

confidence: 94%

“…Therefore, the mean reference Reynolds number at the inlet was 338, and the maximal Reynolds number during the cycle was 646. Resistance boundary conditions were assigned to every coronary outlet to enforce a relationship between pressure and flow , so as to closely resemble physiological condition.…”

Section: Image Processing and Numerical Simulationmentioning

confidence: 99%

“…The determination of the resistance values of downstream vasculatures was based on the steady simulations for the virtually healthy model under two sets of boundary conditions. One set of boundary conditions represented the peak phase of systole, and the other simulation represented the peak diastole phase . For both simulations, the distributions of flow rate among the coronary outlets were assigned according to the generalized scaling law .…”

Section: Image Processing and Numerical Simulationmentioning

confidence: 99%

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Hemodynamic analysis of patient‐specific coronary artery tree

Zhang

Luo

Tan

et al. 2015

Numer Methods Biomed Eng

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Local hemodynamic parameters, such as wall shear stress (WSS), oscillatory shear index and relative resident time (RRT), have been linked to coronary plaque initiation and progression. In this study, a left coronary artery tree model was reconstructed from computed tomography angiography images of a patient with multiple stenoses. The geometry of the coronary artery tree model was virtually restored by eliminating the lesions, essentially re-creating the virtually healthy artery anatomy. Using numerical simulations, flow characteristics and hemodynamic parameter distributions in the stenosed and virtually healthy models were investigated. In the virtually healthy artery model, disturbed flows were found at four locations, prone to initialization of plaque formation. Low WSS and high RRT were exhibited in three of the four locations, and high WSS and low RRT were exhibited in the fourth. These findings suggest that coronary plaque is more likely to form in locations with disturbed flow conditions characterized by low WSS and high RRT or high WSS and low RRT. In addition, clinical index of fractional flow reserve was found to significantly correlate with blood flow rate, rather than anatomic parameters, such as diameter stenosis, which implied the importance of hemodynamic environment in stenosis formation.

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Section: Resultssupporting

confidence: 94%

Section: Image Processing and Numerical Simulationmentioning

confidence: 99%

Section: Image Processing and Numerical Simulationmentioning

confidence: 99%

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Hemodynamic analysis of patient‐specific coronary artery tree

Zhang

Luo

Tan

et al. 2015

Numer Methods Biomed Eng

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“…Numerical simulation of coronary blood flow in patient‐specific geometry has been focus of several papers. The procedure was reviewed by Zhong et al and Zhang et al Usually, the geometry is obtained from computed tomography (CT) images of patients with or without lesions in their arteries …”

Section: Introductionmentioning

confidence: 99%

Geometrical effects in the hemodynamics of stenotic and non‐stenotic left coronary arteries—numerical and in vitro approaches

Doutel

Viriato

Carneiro

et al. 2019

Numer Methods Biomed Eng

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Atherosclerosis is a common cardiovascular disease found in the left coronary artery (LCA), closely linked to local hemodynamic, which, in turn, is highly influenced by the artery geometry. The hemodynamics in the LCA was studied in a patient‐specific geometry without any sign of disease using both numerical and in vitro approaches. The influence of non‐planarity was evaluated through two models of the patient‐specific LCA that deviate from its original geometry in their planarity. Afterwards, in all models, irregular stenoses were created by a procedure in which the stenosis emerges by diffusion from low wall shear stress (WSS) areas. The WSS distribution and flow patterns were evaluated in all the models. The experimental results validate the numerical code developed to study the blood flow assuming a steady state Newtonian behavior. Comparison between the planar and non‐planar idealized LCA revealed no significant differences in low WSS regions forming stenotic regions with identical shape. In the patient‐specific LCA, the low WSS regions are not consistent with the idealized models leading to a different stenosis shape. The results revealed that the non‐planarity has an unquestionable effect in helicity. It was also demonstrated that eccentricity of the vessels cross section and the position of the apex in relation to the axis of the parent branch contribute to the flow patterns observed. Numerical results of pulsatile blood flow assuming a non‐Newtonian behavior, in the patient‐specific LCA, reinforce the non‐planarity effect in local hemodynamics.

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“…the investigation of specific disease conditions in the heart (Zhang et al, 2014). In this study, we endeavoured to exploit organ level vasculature modelling to 179 investigate potential causes for our clinical myocardial BF heterogeneity 180 observations.…”

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confidence: 99%

Computational assessment of blood flow heterogeneity in dialysis patients’ cardiac ventricles

Kharche

Salerno

Lee

et al. 2018

Preprint

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52Dialysis prolongs life but augments cardiovascular mortality. Imaging data suggests 53 that dialysis increases myocardial blood flow (BF) heterogeneity, but its causes 54 remain poorly understood. A biophysical model of human coronary vasculature was 55 used to explain the imaging observations, and highlight causes of coronary BF 56 heterogeneity. 57Post-dialysis CT images from patients under control, pharmacological stress 58 (adenosine), therapy (cooled dialysate), and adenosine and cooled dialysate 59 conditions were obtained. The data presented disparate phenotypes. To dissect 60 vascular mechanisms, a 3D human coronary vasculature model was implemented. 61Simulations were performed to investigate the effects of altered aortic pressure and 62 blood vessel diameters on myocardial BF heterogeneity which was quantified using 63 relative dispersion, fractal dimension, and transmural BF distribution. 64Imaging showed that stress and therapy potentially increased mean and total BF, 65 while reducing heterogeneity. BF histograms of one patient showed multi-modality. 66Using the model, it was found that total coronary BF increased as coronary perfusion 67 pressure (CPP) was increased. BF heterogeneity was differentially affected by large 68 or small vessel blocking. BF heterogeneity was found to be inversely related to small 69 blood vessel diameters. Simulation of large artery stenosis indicates that BF became 70 heterogeneous (increase relative dispersion) and gave multi-modal histograms. The 71 total transmural BF as well as transmural BF heterogeneity reduced due to large 72 artery stenosis, generating large patches of very low BF regions downstream. 73Blocking of arteries at various orders showed that blocking larger arteries results in 74 multi-modal BF histograms and large patches of low BF, whereas smaller artery 75 blocking results in augmented relative dispersion and fractal dimension. Transmural 76 heterogeneity was also affected. Finally, the effects of augmented aortic pressure in 77 the presence of blood vessel blocking shows differential effects on BF heterogeneity 78 as well as transmural BF. 79Improved aortic blood pressure may lead to improved BF. Stress and therapy may 80 be effective if they dilate small vessels. A potential cause for the observed complex 81 BF distributions (multi-modal BF histograms) may indicate existing large vessel 82 stenosis. 83The intuitive BF heterogeneity methods used can be readily used in clinical studies. 84Further development of the model and methods will permit personalised assessment 85 of patient BF status. 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 106 107

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Numerical Simulation and Clinical Implications of Stenosis in Coronary Blood Flow

Cited by 24 publications

References 35 publications

Hemodynamic analysis of patient‐specific coronary artery tree

Hemodynamic analysis of patient‐specific coronary artery tree

Geometrical effects in the hemodynamics of stenotic and non‐stenotic left coronary arteries—numerical and in vitro approaches

Computational assessment of blood flow heterogeneity in dialysis patients’ cardiac ventricles

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