Biomedical Engineering Reference
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Of the two cases in which there was apparent obstruction to blood fl ow,
one was due to leafl et level offset, and the second was due to occlusion of
the coronary arteries with the angioplasty balloon. Both cases were consid-
ered to be extraordinary in nature, and the device was considered to be
largely safe in terms of both function and deployment mechanics.
A further series of studies were reported using the second generation of
the CoreValve technology. In these experiments 21 animals underwent the
same experimental procedure as described for the fi rst generation. Of these
17 were euthanized early and their study showed no impairment of
coronary fl ow, no prosthesis migration, good adhesion and no valvular or
paravalvular leaks. Two 10-day and two 6-week follow-ups confi rmed the
intimate adhesion of the frame to the local tissue and persistent good val-
vular function, with absence of valve tear, calcifi cation and impairment.
5.5.2 Conclusions from animal studies
The animal studies carried out using this percutaneous heart valve have
confi rmed that the device can be loaded into a delivery system and deliv-
ered to the animal's valvular site through an endovascular approach on a
beating heart.
The prosthesis can be precisely implanted on the animal's valve annulus.
The added features of the frame's ultimate design gives the device in this
animal model controlled delivery, precise implantation, satisfactory attach-
ment to the adjacent tissues and absence of migration. Overall, these studies,
together with those carried out on the bench, suggest that this revolutionary
valve technology is suitable as a minimally invasive valve replacement
modality. Subsequent clinical assessment has been carried out over the past
few years.
5.6
Clinical studies with the CoreValve system
After successful cadaver and animal studies, a human feasibility and safety
study was planned.
23
The objectives of this investigation were to demon-
strate the safety and feasibility of percutaneous implantation of the Core-
Valve prosthetic valve in patients requiring replacement of their native or
bioprosthetic aortic valve. This study was carried out as a prospective, single
arm feasibility study, conducted in accordance with the Standard EN-ISO
14155:2003 on clinical investigations with medical devices on compassionate-
use patients and in accordance with recommendations guiding physicians
in biomedical research involving human subjects adopted by the 18th
World Medical Assembly, Helsinki, Finland, 1964, and later revisions. This
approach refl ects the fact that the conventional open-heart valve replace-
ment procedure remains the gold standard in this fi eld, in the absence
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