Journal ArticleDOI
Velocity and pressure distributions in the aortic valve
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In this article, the distribution of pressure in normal and stenosed aortic valves is investigated experimentally with a rigid-walled model placed in a pulsatile water-tunnel, and the experiments are complemented by a one-dimensional solution of the unsteady inviscid-flow equations.Abstract:
The distribution of pressure in normal and stenosed aortic valves is investigated experimentally with a rigid-walled model placed in a pulsatile water-tunnel, and the experiments are complemented by a one-dimensional solution of the unsteady inviscid-flow equations. In the normal valve, convectively fed vortices are formed in the aortic sinuses; the vortices aid cusp positioning and the prevention of jet formation during valve closure. Aortic valve stenosis is shown to prevent the generation of vortices, causing the formation of a turbulent jet, with reduction of the pressure difference between the inlets (ostia) of the coronary arteries and the ventricle. This pressure difference is calculated for man resting and exercising, and for various degrees of stenosis.read more
Citations
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Fluid Mechanics of Heart Valves
TL;DR: The state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use and the fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed.
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Aortic root and valve relationships: Impact on surgical repair
TL;DR: This work morphologically examined normal human aortic roots and valve leaflets and applied mathematic analyses to the results, showing that the root has a consistent shape with varying size and that there is a definable mathematic relationship between root diameter and clinically measurable leaflet dimensions.
Journal ArticleDOI
Stress variations in the human aortic root and valve: the role of anatomic asymmetry.
TL;DR: An anatomically representative model was created from magnetic-resonance images of nine human valve–root specimens, carefully preserving their asymmetry, and stresses vary across the valve and root, likely due to their inherent morphologic asymmetry and stress sharing.
Journal ArticleDOI
Vorticity dynamics of a bileaflet mechanical heart valve in an axisymmetric aorta
TL;DR: Instantaneous and ensemble-averaged velocity measurements as well as the associated statistics of leaflet kinematics are reported and analyzed in tandem to elucidate the structure of the velocity and vorticity fields of the ensuing flow-structure interaction.
Journal ArticleDOI
A simple, versatile valve model for use in lumped parameter and one-dimensional cardiovascular models.
TL;DR: A simple valve model is presented that predicts valve motion on the basis of the instantaneous difference between upstream and downstream pressures, and can be used to investigate not only valve pathology, but a wide range of cardiac and vascular factors that are likely to influence valve motion.
References
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Journal ArticleDOI
The fluid mechanics of the aortic valve
Brian John Bellhouse,L. Talbot +1 more
TL;DR: In this article, the human aortic valve is investigated experimentally with a rigid-walled model placed in a pulsatile water-tunnel and it is shown that the valve is controlled by a fluid feed-back system incorporating a stagnation point at the downstream end of each sinus and a trapped vortex within it, and threequarters of the valve's closure is accomplished during forward flow, requiring only very little reversed flow to seal it.
Journal ArticleDOI
Mechanism of Closure of the Aortic Valve
TL;DR: This action suggests a fluid dynamic control mechanism which positions the cusps away from the wall of the aorta, so that the slightest reversed flow will close the valve.
Journal ArticleDOI
Fluid mechanics of the aortic root with application to coronary flow
TL;DR: Analytical studies have demonstrated the lateral extent of the sinus of Valsalva which has a well defined ridge forming its upper margin, and have indicated that the geometry of the aortic root remains constant between different species.
Journal ArticleDOI
The George E. Brown Memorial Lecture Physiology of the Coronary Circulation
TL;DR: Evidence has been presented to show that much of this systolic flow represents intramural flow and will cause some recasting of present views concerning the regulation of the coronary circulation.