Open AccessJournal Article
Pulsatile prosthetic valve flows.
TLDR
The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves, despite the volume and complexity of the data required.Abstract:
The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves. Significant differences among valve types and between models of one type have been documented. The complex variations of velocity profiles with time show that comparisons must be made for unsteady pulsatile rather than steady flow, despite the volume and complexity of the data required. Future studies will include methods of compacting the data presentation and improving the details of the experimental stimulation.read more
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Estimation of shear stress-related blood damage in heart valve prostheses--in vitro comparison of 25 aortic valves.
TL;DR: In the present study, the above data are incorporated into a mathematical correlation, which serves as a basic model for the estimation of blood damage and agreement was good, indicating that this model may be directly applied to the clinical situation.
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Bileaflet, tilting disc and porcine aortic valve substitutes: in vitro hydrodynamic characteristics.
Ajit P. Yoganathan,Aurelio Chaux,Richard Gray,Yi-Ren Woo,Michele DeRobertis,Frank P. Williams,Jack M. Matloff +6 more
TL;DR: Overall in vitro fluid dynamic performance of the St. Jude valve is superior to that of the two other commonly used prostheses, especially in the small sizes.
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Turbulent shear stress measurements in the vicinity of aortic heart valve prostheses
TL;DR: All the aortic valves studied (mechanical and tissue) create turbulent shear stress levels which are capable of causing sub-lethal and/or lethal damage to blood elements.
Journal ArticleDOI
Laser anemometry measurements of pulsatile flow past aortic valve prostheses
TL;DR: The results show that with increased angle of opening for the tilting disc valves, a large but locally confined vortex is observed along the wall in the minor flow region throughout most of the cardiac cycle.
Journal ArticleDOI
In vitro pulsatile flow velocity and shear stress measurements in the vicinity of mechanical mitral heart valve prostheses
Yi-Ren Woo,Ajit P. Yoganathan +1 more
TL;DR: The results indicate that all four prosthetic valve designs studied create very disturbed flow fields with elevated turbulent shear stresses and regions of flow separation and/or stagnation, which could lead to thrombus formation and/ or tissue overgrowth on the valve structure, as observed on clinically recovered prosthetic valves.