Modeling the large-scale geometry of human coronary arteries

Changizi, Mark A.; Cherniak, Christopher

doi:10.1139/cjpp-78-8-603

Cited by 32 publications

(15 citation statements)

References 39 publications

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“…Motivated by Murray’s law, a mathematical relationship between vessel size and flow, an area-based approach was used to assign capacitance and resistance values at the outlets. Capacitance values were chosen to be proportional to outlet area, and resistances values were determined according to a modified Murray’s law using an exponent of 2.0 for the aortic branches and 2.6 for the coronary branches [27, 28]. The equations governing the LPN, and methods for their solution, follow our previous work [24].…”

Section: Methodsmentioning

confidence: 99%

Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts

Ramachandra

Kahn

Marsden

2016

J. of Cardiovasc. Trans. Res.

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Mechanical stimuli are key to understanding disease progression and clinically observed differences in failure rates between arterial and venous grafts following coronary artery bypass graft surgery. We quantify biologically relevant mechanical stimuli, not available from standard imaging, in patient-specific simulations incorporating non-invasive clinical data. We couple CFD with closed-loop circulatory physiology models to quantify biologically relevant indices, including wall shear, oscillatory shear, and wall strain. We account for vessel-specific material properties in simulating vessel wall deformation. Wall shear was significantly lower (p = 0.014*) and atheroprone area significantly higher (p = 0.040*) in venous compared to arterial grafts. Wall strain in venous grafts was significantly lower (p = 0.003*) than in arterial grafts while no significant difference was observed in oscillatory shear index. Simulations demonstrate significant differences in mechanical stimuli acting on venous vs. arterial grafts, in line with clinically observed graft failure rates, offering a promising avenue for stratifying patients at risk for graft failure.

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Section: Methodsmentioning

confidence: 99%

Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts

Ramachandra

Kahn

Marsden

2016

J. of Cardiovasc. Trans. Res.

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“…Recent studies reported morphometry exponents for the LCA ranging from 2.45 to 2.51 69 and m = 2.6 ± 0.64 for LCA in. 70 The total resistance of the downstream vasculature has been determined using various exponents m in coronary hemodynamics literature. Coronary models in Sankaran et al 55 assumed that the resistance is inversely proportional to the area of the distal branch with m = 2.…”

Section: Uncertainty In the Morphometry Exponentmentioning

confidence: 99%

The effects of clinically‐derived parametric data uncertainty in patient‐specific coronary simulations with deformable walls

Seo

Schiavazzi

Kahn

et al. 2020

Numer Methods Biomed Eng

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Cardiovascular simulations are increasingly used for noninvasive diagnosis of cardiovascular disease, to guide treatment decisions, and in the design of medical devices. Quantitative assessment of the variability of simulation outputs due to input uncertainty is a key step toward further integration of cardiovascular simulations in the clinical workflow. In this study, we present uncertainty quantification in computational models of the coronary circulation to investigate the effect of uncertain parameters, including coronary pressure waveform, intramyocardial pressure, morphometry exponent, and the vascular wall Young's modulus. We employ a left coronary artery model with deformable vessel walls, simulated via an Arbitrary‐Lagrangian‐Eulerian framework for fluid‐structure interaction, with a prescribed inlet pressure and open‐loop lumped parameter network outlet boundary conditions. Stochastic modeling of the uncertain inputs is determined from intra‐coronary catheterization data or gathered from the literature. Uncertainty propagation is performed using several approaches including Monte Carlo, Quasi Monte Carlo sampling, stochastic collocation, and multi‐wavelet stochastic expansion. Variabilities in the quantities of interest, including branch pressure, flow, wall shear stress, and wall deformation are assessed. We find that uncertainty in inlet pressures and intramyocardial pressures significantly affect all resulting QoIs, while uncertainty in elastic modulus only affects the mechanical response of the vascular wall. Variability in the morphometry exponent used to distribute the total downstream vascular resistance to the single outlets, has little effect on coronary hemodynamics or wall mechanics. Finally, we compare convergence behaviors of statistics of QoIs using several uncertainty propagation methods on three model benchmark problems and the left coronary simulations. From the simulation results, we conclude that the multi‐wavelet stochastic expansion shows superior accuracy and performance against Quasi Monte Carlo and stochastic collocation methods.

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“…29 Hypothetically, the optimal retinal vasculature will deliver the most efficient blood flow, whereby deviations or alterations from the optimal architecture are thought to result in impaired microcirculatory transport, increased shear stress, reduced efficiency, and hence a greater risk of vascular damage. [29][30][31] With state-of-the-art technology in retinal photography and computing image processing techniques, new computer-based programs were developed to perform objective and quantitative assessments of novel classes of retinal vascular parameters to reliably and rapidly quantify the geometric branching network, such as tortuosity, fractal dimension, and branching. These new retinal features capture the "optimality" of blood distribution in the retinal network that reflect the integrity of the cerebral microcirculation.…”

Section: Global Geometrical Patterns In Retinal Vasculaturementioning

confidence: 99%

Ocular Fundus Photography as a Tool to Study Stroke and Dementia

2015

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Although cerebral small vessel disease has been linked to stroke and dementia, due to limitations of current neuroimaging technology, direct in vivo visualization of changes in the cerebral small vessels (e.g., cerebral arteriolar narrowing, tortuous microvessels, blood-brain barrier damage, capillary microaneurysms) is difficult to achieve. As the retina and the brain share similar embryological origin, anatomical features, and physiologic properties with the cerebral small vessels, the retinal vessels offer a unique and easily accessible "window" to study the correlates and consequences of cerebral small vessel diseases in vivo. The retinal microvasculature can be visualized, quantified and monitored noninvasively using ocular fundus photography. Recent clinic- and population-based studies have demonstrated a close link between retinal vascular changes seen on fundus photography and stroke and dementia, suggesting that ocular fundus photography may provide insights to the contribution of microvascular disease to stroke and dementia. In this review, we summarize current knowledge on retinal vascular changes, such as retinopathy and changes in retinal vascular measures with stroke and dementia as well as subclinical makers of cerebral small vessel disease, and discuss the possible clinical implications of these findings in neurology. Studying pathologic changes of retinal blood vessels may be useful for understanding the etiology of various cerebrovascular conditions; hence, ocular fundus photography can be potentially translated into clinical practice.

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Modeling the large-scale geometry of human coronary arteries

Cited by 32 publications

References 39 publications

Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts

Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts

The effects of clinically‐derived parametric data uncertainty in patient‐specific coronary simulations with deformable walls

Ocular Fundus Photography as a Tool to Study Stroke and Dementia

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