Circulation, Vol 60, 62-70, Copyright © 1979 by American Heart Association
S Gabbay, DM McQueen, EL Yellin and RW Frater
With the use of the pulse duplicator built in our laboratory, the
hydrodynamic characteristics of three sizes of the four commercially
available mitral bioprostheses, Hancock, Carpentier-Edwards, Angell-
Shiley, and Ionescu-Shiley, were studied and compared. A wide range of
performance was found: for example, during pulsatile testing, at peak flow
of 15 1/min (corresonding to a normal resting cardiac output) transvalvular
gradients varied from as high as 20 mm Hg (Angell-Shiley) to 5 mm
Hg(Ionescu-Shiley) in the 25 mm mounting diameter size. Effective orifice
areas (EOA) are significantly different in valves of the same mounting
size, e.g., at peak flows of 20 1/min, the Ionescu- Shiley 25 provides an
EOA of 1.7 cm2 while the Angell-Shiley provides only 1.17 cm2. The EOAs of
all bioprostheses have been found to increase with increasing flow (e.g.,
from 10--30 1/min peak flow, the Hancock 25 changed from 1.25 cm2 to 1.50
cm2). The Gorlin formula, as constituted for calculating the area of
stenotic mitral valves, is inappropriate for prosthetic valves. But the
discharge coefficients of the bioprostheses have been found to be around 1
when the planimetered area of the open valve orifice is determined at a
given flow. By using this discharge coefficient, the Gorlin formula will
give an excellent estimate of the true orifice area of mitral
bioprostheses.
ARTICLES
In vitro hydrodynamic comparison of mitral valve bioprostheses
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