High-Resolution Measurements of Leakage Flow Inside the Hinge of a Large-scale Bileaflet Mechanical Heart Valve Hinge Model

2019 ◽  
Vol 10 (3) ◽  
pp. 469-481
Author(s):  
Ewa Klusak ◽  
Nathan J. Quinlan
Keyword(s):  
High Resolution ◽  
Heart Valve ◽  
Large Scale ◽  
Mechanical Heart Valve ◽  
Leakage Flow ◽  
Bileaflet Mechanical Heart Valve ◽  
Hinge Model

Passive flow control of bileaflet mechanical heart valve leakage flow

2008 ◽  
Vol 41 (6) ◽  
pp. 1166-1173 ◽  
Author(s):  
Lakshmi P. Dasi ◽  
David W. Murphy ◽  
Ari Glezer ◽  
Ajit P. Yoganathan
Keyword(s):  
Flow Control ◽  
Heart Valve ◽  
Mechanical Heart Valve ◽  
Leakage Flow ◽  
Passive Flow Control ◽  
Bileaflet Mechanical Heart Valve ◽  
Passive Flow ◽  
Valve Leakage

High-Resolution Measurements of Velocity and Shear Stress in Leakage Jets From Bileaflet Mechanical Heart Valve Hinge Models

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Ewa Klusak ◽  
Alessandro Bellofiore ◽  
Sarah Loughnane ◽  
Nathan J. Quinlan
Keyword(s):  
Shear Stress ◽  
High Resolution ◽  
Flow Field ◽  
Heart Valve ◽  
Temporal Resolution ◽  
Mechanical Heart Valve ◽  
Small Scale ◽  
Bileaflet Mechanical Heart Valve ◽  
Viscous Shear Stress ◽  
Viscous Shear

In flow through cardiovascular implants, hemolysis, and thrombosis may be initiated by nonphysiological shear stress on blood elements. To enhance understanding of the small-scale flow structures that stimulate cellular responses, and ultimately to design devices for reduced blood damage, it is necessary to study the flow-field at high spatial and temporal resolution. In this work, we investigate flow in the reverse leakage jet from the hinge of a bileaflet mechanical heart valve (BMHV). Scaled-up model hinges are employed, enabling measurement of the flow-field at effective spatial resolution of 167 μm and temporal resolution of 594 μs using two-component particle image velocimetry (PIV). High-velocity jets were observed at the hinge outflow, with time-average velocity up to 5.7 m/s, higher than reported in previous literature. Mean viscous shear stress is up to 60 Pa. For the first time, strongly unsteady flow has been observed in the leakage jet. Peak instantaneous shear stress is up to 120 Pa, twice as high as the average value. These high-resolution measurements identify the hinge leakage jet as a region of very high fluctuating shear stress which is likely to be thrombogenic and should be an important target for future design improvement.

scholarly journals Transient Study of Flow and Cavitation Inside a Bileaflet Mechanical Heart Valve

2020 ◽  
Vol 10 (7) ◽  
pp. 2548 ◽  
Author(s):  
Wen-qing Li ◽  
Zhi-xin Gao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Heart Valve ◽  
High Speed ◽  
Heart Valves ◽  
High Reliability ◽  
Mechanical Heart Valve ◽  
Water Hammer ◽  
Leakage Flow ◽  
Total Period ◽  
Flow Effect ◽  
Bileaflet Mechanical Heart Valve

A mechanical heart valve (MHV) is an effective device to cure heart disease, which has the advantage of long life and high reliability. Due to the hemodynamic characteristics of blood, mechanical heart valves can lead to potential complications such as hemolysis, which have damage to the blood elements and thrombosis. In this paper, flowing features of the blood in the valve are analyzed and the cavitation mechanism in bileaflet mechanical heart valve (BMHV) is studied. Results show that the water hammer effect and the high-speed leakage flow effect are the primary causes of the cavitation in the valve. Compared with the high-speed leakage flow effect, the water hammer has a greater effect on the cavitation strength. The valve goes through four kinds of working condition within one heart beating period, including, fully opening stage, closing stage and fully closing stage. These four stages, respectively, make up 8.5%, 16.1%, 4.7% and 70.7% of the total period. The cavitation occurs on the fully closing stage. When the valve is in closing stage, the high pressure downstream of the valve lasts for about 20 ms and the high-speed leakage flow lasts for about 200 ms. This study systematically analyzes the causes of cavitation emerged in the process of periodic motion, which proposes the method for characterizing the intensity of the cavitation, and can be referred to for the cavitation suppression of the BHMV and similar valves.

Thrombogenic Performance of a St. Jude Bileaflet Mechanical Heart Valve in a Sheep Model

ASAIO Journal ◽  
2006 ◽  
Vol 52 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Wei Yin ◽  
Irvin B. Krukenkamp ◽  
Adam E. Saltman ◽  
Glenn Gaudette ◽  
Krishnamurthy Suresh ◽  
...  
Keyword(s):  
Heart Valve ◽  
Mechanical Heart Valve ◽  
Sheep Model ◽  
Bileaflet Mechanical Heart Valve

Static and Dynamic Stresses during Valve Closure of a Bileaflet Mechanical Heart Valve Prosthesis

1991 ◽  
Vol 14 (12) ◽  
pp. 781-788 ◽  
Author(s):  
T.H. Chiang ◽  
H. Lam ◽  
R. Quijano ◽  
R. Donham ◽  
P. Gilliam ◽  
...  
Keyword(s):  
Heart Valve ◽  
Mechanical Heart Valve ◽  
Heart Valve Prosthesis ◽  
Valve Prosthesis ◽  
Valve Closure ◽  
Element Analysis ◽  
Dynamic Stresses ◽  
Magnitude Distribution ◽  
Bileaflet Mechanical Heart Valve ◽  
The Impact

The effect of contact geometry and component compliance on the magnitude, distribution, and state of various types of stresses on a bileaflet mechanical heart valve prosthesis during valve closure was analyzed using an Edwards-Duromedics™ mitral valve as example. Static and dynamic stresses developing on both the leaflet and pivot ball during valve closure were modeled using finite element analysis (FEA). Uniform contact between the leaflet and housing as well as between the pivot ball and pivot slot can significantly reduce both static and dynamic stresses around the contact area. The level of the dynamic flexural stresses can be an order of magnitude higher than that of the static stresses. When both the radial and axial compliance of the housing are taken into consideration, peak dynamic stress was more than 40% less than that generated through the impact between a moving leaflet and a non-compliant rigid housing.

Flow Patterns Downstream of a Mechanical Heart Valve During Systole

2007 ◽  
Author(s):  
P. Oshkai ◽  
F. Haji-Esmaeili
Keyword(s):  
Turbulent Flow ◽  
Heart Valve ◽  
Large Scale ◽  
Cardiac Cycle ◽  
Mechanical Heart Valve ◽  
Opening Angle ◽  
Image Velocimetry ◽  
Imaging Approach ◽  
Systolic Phase ◽  
Flow Through

Digital particle image velocimetry is employed to study turbulent flow through a bileaflet mechanical heart valve during systolic phase of a cardiac cycle. Unsteady vortex shedding from the valve’s leaflets displays distinct characteristic frequencies, depending on the opening angle of each leaflet. Small- and large-scale transverse oscillations of the separated shear layers are studied using global quantitative flow imaging approach. Turbulent flow structures including jet-like regions and shed vortices are characterized in terms of patterns of instantaneous and time-averaged velocity, vorticity, and turbulence statistics.

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