Mechanical properties of the ascending thoracic aorta of man

Gozna, E. R.; Marble, A. E.; Shaw, Aidan; Winter, David

doi:10.1093/cvr/7.2.261

Cited by 38 publications

(17 citation statements)

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“…The cardiac output, which was obtained by multiplying the stroke volume with a heart rate of 72 bpm, was 5,256 mL/min. The computed value of the PWV in the aorta was within the range 4.4 to 8.5 m/sec, which is consistent with an experimental study in humans (22). …”

Section: Resultssupporting

confidence: 89%

An Integrative Model of the Cardiovascular System Coupling Heart Cellular Mechanics with Arterial Network Hemodynamics

et al. 2013

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The current study proposes a model of the cardiovascular system that couples heart cell mechanics with arterial hemodynamics to examine the physiological role of arterial blood pressure (BP) in left ventricular hypertrophy (LVH). We developed a comprehensive multiphysics and multiscale cardiovascular model of the cardiovascular system that simulates physiological events, from membrane excitation and the contraction of a cardiac cell to heart mechanics and arterial blood hemodynamics. Using this model, we delineated the relationship between arterial BP or pulse wave velocity and LVH. Computed results were compared with existing clinical and experimental observations. To investigate the relationship between arterial hemodynamics and LVH, we performed a parametric study based on arterial wall stiffness, which was obtained in the model. Peak cellular stress of the left ventricle and systolic blood pressure (SBP) in the brachial and central arteries also increased; however, further increases were limited for higher arterial stiffness values. Interestingly, when we doubled the value of arterial stiffness from the baseline value, the percentage increase of SBP in the central artery was about 6.7% whereas that of the brachial artery was about 3.4%. It is suggested that SBP in the central artery is more critical for predicting LVH as compared with other blood pressure measurements.

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Section: Resultssupporting

confidence: 89%

An Integrative Model of the Cardiovascular System Coupling Heart Cellular Mechanics with Arterial Network Hemodynamics

et al. 2013

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“…E¢ values of 2.2-15 MPa, at p eqi 5-40 kPa of arterial prostheses were higher than E¢ values of 0.17-2.68 MPa of native human arteries estimated by others. 8,16,17 It might be suggested that same pressure load could evoke greater strain in vital arterial wall than in the implanted prosthesis, which might result in the unequal stress distribution. The higher VEC values of human arterial prostheses suggest that prostheses have a lower circumferential distensibility.…”

Section: Discussionmentioning

confidence: 99%

Viscoelastic Characteristics of In Vitro Vital and Devitalized Rat Aorta and Human Arterial Prostheses

et al. 2008

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The arterial wall viscoelasticity plays an essential role in the vascular responsiveness to vasoactive drugs or pathologies. The aim of this investigation was to derive and compare resonance curve (RC), natural frequency (f(0)), dynamic modulus of elasticity (E'), and coefficient of viscosity (beta) of (i) vital and devitalized preparations of rat thoracic and abdominal aorta, (ii) human arterial prostheses, and to study the histomorphology of vital and devitalized rat aorta. The method of low frequency forced oscillations was employed. RC of vital preparations showed a hardening type of elasticity whereas in devitalized preparations it was of softening type. E' increased nonlinearly, f(0) decreased and beta increased linearly with equivalent intraluminal pressure (p(eqi)). Distensibility of abdominal aorta was lower than thoracic aorta. Distensibility decreased with increasing p(eqi). E', f(0), and beta increased significantly after devitalization. It was suggested that postmortem viscoelastic characteristics should not be used directly to specify the vital arteries viscoelasticity. RC of human prostheses showed a softening type of elasticity. Arterial prostheses have low circumferential distensibility with E'-values higher than reported in the literature for human arteries. The method of forced oscillations could be employed for studying the arterial wall biomechanics and viscoelasticity of arterial prostheses.

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“…When it is exchanged in site with the stiffer abdominal aorta in hypercholesterolemic dogs, the aorta in the pulmonary circulation develops plaques but the pulmonary artery segment placed below the renal arteries remains plaque-free. 7 The ascending aorta expands about 11% in circumference with each heartbeat, 6 responding appropriately to the abrupt delivery of 70 ml. of blood.…”

Section: Blood Pressure Gradient and Arterial Wallmentioning

confidence: 99%

Blood flow and the localization of atherosclerotic plaques.

McMillan¹

1985

Stroke

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SUMMARY Saphenous veins used in aortocoronary bypass procedures slowly narrow. The narrowing and atherosclerosis appear to develop in reaction to the new flow conditions present in the saphenous veins. Localization of atherosclerosis in the arterial system also suggests that local flow conditions play a role in atherogenesis; plaques are characterically found in regions of separated flow. The pattern of separated flow in arteries is influenced by the pulsatility of arterial flow. Stagnation points delimiting flow separations migrate with each systole. An additional motion of blood, angular momentum, produces a corkscrew component to the flow. This added rotary component generates a stress that combines with the stress generated by to and fro motion of stagnation points to produce an area of multidirectional shear stress in the stagnation region. The rapidly reorienting shear stress places a special burden on the region's endothelial cells, producing an area of non-elongated cells, compromising cell internal fluidity, and modifying adhesion to neighboring cells to increase local permeability. The amount of multi-directional force generated in regions of multi-directional shear stress is increased by the flow properties of blood. Studies of blood, particularly in diabetes, will be able to characterize the factors that control the magnitude of permeabilityenhancing multi-directional stress and suggest new ways to slow atherogenesis and ultimately prevent atherosclerosis.A RECENT STEP FORWARD in the surgical treatment of ischemic heart disease has been the introduction of the coronary bypass operation. This procedure follows a number of less successful predecessors by directly enhancing impaired coronary artery blood flow. It utilizes saphenous vein segments to connect the ascending aorta to sites distal to atheromatous blockage' in one or more coronary arteries. Commonly, three or four segments of saphenous vein are used to anastomose as many coronary sites. This procedure is more than a decade old and it has now been established that the transplanted saphenous veins develop a progressive diminution in lumen size. The progressive occlusion is due to a combination of intimal thickening, intimomedial sclerosis, and late development of local atherosclerotic plaques.2 For that reason, it has become more and more common practice in surgical management of ischemic heart disease to use an internal mammary artery rather than a saphenous vein to bypass the coronary site most sensitive to progressive ischemia. The internal mammary artery bypass initially delivers less blood flow than a saphenous vein but it is not subject to progressive narrowing and so gives a better long term result.3 This lesson from coronary bypass surgery and previous observations about atherogenesis suggest that local arterial conditions of blood flow and pressure gradient determine the site and rate development of atherosclerotic plaques. We will review here current information about the role From the Hal B. Wallis Research Facility. Eisenhower Medica...

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Mechanical properties of the ascending thoracic aorta of man

Cited by 38 publications

References 0 publications

An Integrative Model of the Cardiovascular System Coupling Heart Cellular Mechanics with Arterial Network Hemodynamics

An Integrative Model of the Cardiovascular System Coupling Heart Cellular Mechanics with Arterial Network Hemodynamics

Viscoelastic Characteristics of In Vitro Vital and Devitalized Rat Aorta and Human Arterial Prostheses

Blood flow and the localization of atherosclerotic plaques.

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