Biomedical Engineering Reference
In-Depth Information
Inflow
cone
Inflow
tube
Outflow
cap
Outflow
cone
Outflow
tube
5.7
Disposable CoreValve loading system (model CLS-3000, 18 Fr).
Control of prosthesis expansion using the thumbwheel is very precise. It
is possible to pass from one mode of expansion to the other as frequently
as required.
5.2.6 The CoreValve loading tool
The loading system is used to collapse the framed valve into the catheter
just before introducing it into the patient. The framed tissue valve is stored
in its naturally expanded position to prevent any damage to the tissue of
the valve. A few minutes before implantation, the framed valve is rinsed
per standard bioprosthesis protocol and cooled so as to render the nitinol
frame deformable and collapsible.
The prosthesis is fi rstly pushed through a precompression cone. The
catheter is then introduced in a way that does not damage the valve. The
attached prosthesis is pulled into the catheter sheath using another com-
pression cone and the catheter thumbwheel (Fig. 5.7).
5.3
In vitro
studies
The implantation procedure and the effi ciency of the delivery technology
have been investigated under
in vitro
conditions, using explanted human
hearts with calcifi ed aortic stenosis. In these studies, human hearts were
explanted, including the ascending aorta up to the root of the brachio-
cephalic arterial trunk. After immobilizing the hearts, the distance between
the arteriotomy and the aortic annulus was measured. The left atrium was
opened, the mitral valve visualized, and its effective orifi ce area (EOA)
measured. The prosthesis was loaded into the delivery catheter previously
used during the animal study and the prosthesis was implanted. To investi-
gate the impact of the implanted arotic valve technology upon the mechan-
ics and structures of the mitral valve, seating of the apparatus in the aortic
annulus, paravalvular leakage and potential for aortic insult, the following
analyses were carried out:
Through the left atrium, verifi cation of the mitral valve, determination
of the mobility of the two mitral leafl ets, and measurement of the mitral
EOA (effective orifi ce area).
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