In vitro pulsatile flow velocity and shear stress measurements in the vicinity of mechanical mitral heart valve prostheses

1986 ◽  
Vol 19 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Yi-Ren Woo ◽  
Ajit P. Yoganathan
Keyword(s):  
Shear Stress ◽  
Flow Velocity ◽  
Heart Valve ◽  
Pulsatile Flow ◽  
Stress Measurements ◽  
Heart Valve Prostheses ◽  
Valve Prostheses

In Vitro Hemolysis by Mechanical Heart Valve Prostheses with Tilting Disc

1992 ◽  
Vol 15 (11) ◽  
pp. 681-685 ◽  
Author(s):  
M.O. Wendt ◽  
M. Pohl ◽  
S. Pratsch ◽  
D. Lerche
Keyword(s):  
Heart Valve ◽  
Test Chamber ◽  
Mechanical Heart Valve ◽  
Hemoglobin Concentration ◽  
Clinical Results ◽  
Artificial Heart Valve ◽  
Valve Prosthesis ◽  
Heart Valve Prostheses ◽  
Valve Prostheses

Hemolytic and subhemolytic blood damage by mechanical heart valve prostheses have been observed in both clinical and in vitro investigations. A direct comparison between these studies is not possible. Nevertheless the transfer of some in vitro results to the behaviour of the valve in situ may be performed considering the similarity principle. This requires the use of dimensionless similarity numbers such as the plasma's hemoglobin concentration (PHb) or others, instead of dimensioned parameters. To evaluate the in vitro hemolysis of valve prosthesis a test chamber filled with human banked blood was used. An artificial ventricle ensuring an oscillatory flow through the valve was also used. The rise of PHb was evaluated in terms of a similarity number, called the lysis number. This number describes the probability of destroying a single red blood cell participating once in the hemolytic process under consideration. The lysis number, a Björk-Shiley valve (TAD 29), was found to be in the order of 2 × 10−4. From this, the survival time of erythrocytes in patients with an artificial heart valve was estimated. It was found to be in the order of 20 d of T50 Cr in agreement with clinical results

Systolic sequential flow velocity profiles in four currently used bileaflet heart valve prostheses

1993 ◽  
Vol 7 (2) ◽  
pp. 107-108
Author(s):  
J VANSON ◽  
H REUL ◽  
U STEINSEIFER ◽  
B SCHMITZ ◽  
A SCHMID ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Heart Valve ◽  
Velocity Profiles ◽  
Heart Valve Prostheses ◽  
Valve Prostheses

scholarly journals In vitro comparison of aortic heart valve prostheses

1988 ◽  
Vol 96 (6) ◽  
pp. 952-961 ◽  
Author(s):  
Erwin Knott ◽  
Helmut Reul ◽  
Martin Knoch ◽  
Ulrich Steinseifer ◽  
Günter Rau
Keyword(s):  
Heart Valve ◽  
Heart Valve Prostheses ◽  
Aortic Heart Valve ◽  
Valve Prostheses ◽  
In Vitro Comparison

In vitro assessment of the lenz effect on heart valve prostheses at 1.5 T

2014 ◽  
Vol 41 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Maria-Benedicta Edwards ◽  
John Mclean ◽  
Stephanos Solomonidis ◽  
Barrie Condon ◽  
Terence Gourlay
Keyword(s):  
Heart Valve ◽  
Heart Valve Prostheses ◽  
In Vitro Assessment ◽  
Valve Prostheses
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