Biomedical Engineering Reference
In-Depth Information
After cut-down of the aorta to the distal end of the prosthesis, verifi cation
that the left and right coronary artery ostia remained uncovered and were
perfectly free was carried out with the help of a 1 mm coronary guide, a search
for paravalvular leaks was performed with a 1 mm metal tip inserted between
the aortic wall and the external rim of the frame, further dissection of the
aorta to the annulus, and verifi cation of the adequate positioning of the pros-
thesis relative to the annulus and the subannular zone was also carried out.
The fi rst implantation was done in a 76-year-old male cadaver, four days
after death. The external iliac artery was measured at an external diameter
of 12 mm, compatible with access of the CoreValve delivery catheter. An
Amplatz 0.038 inch (0.97 mm) extra-stiff guidewire was advanced up to the
abdominal artery. No further progression was possible. A retroperitoneal
approach was then made in order to gain access to the external iliac artery.
Severe calcifi cations were noticed, which explained the diffi culty in advanc-
ing the guidewire. The guidewire was introduced through the abdominal
aorta and advanced up to the aortic valve. An opening was made in the
ascending aorta in order to see the progression of the catheter. The
CoreValve delivery catheter was advanced over the guide wire. Progression
was diffi cult. Possible causes were calcifi cations in the thoracic aorta, blood
clots, and a non-cylindrical shape. Nevertheless, the catheter took the
bending of the aortic arch following the guidewire. In this position, the
frame could be expanded in a controlled manner at the level of the valve
annulus but outside the anatomy because of the lack of precise visualiza-
tion.The heart was then explanted for a better view of the implantation site.
The second implantation was made on a 78-year-old male cadaver four
days postmortem. A retroperitoneal approach was made in order to gain
access to the external iliac artery. The guidewire was introduced through
the abdominal aorta and advanced up to the aortic valve. A visualization
opening was made in the ascending aorta in order to see the progression
of the catheter. The CoreValve delivery catheter was advanced over the
guidewire. Progression was easy and uneventful. The catheter slid over
the bending of the aortic arch, following the guidewire. In this position, the
frame could be expanded in a controlled manner at the level of the valve
annulus but outside the anatomy because of the lack of precise visualisa-
tion. Implantation with the CoreValve delivery catheter was possible
through a retroperitoneal access. Access through the external iliac artery
seems possible, but can be rendered diffi cult or impossible in the event of
a calcifi ed abdominal aorta. The fl exibility of the CoreValve delivery cath-
eter is compatible with access over the subclavian artery.
The observations were as follows: absence of interference with the mitral
valve was confi rmed; the coronary ostia were unchanged and the coronary
arteries were free from any obstruction (Fig. 5.8); the radial force of the
frame was suffi cient to maintain the expected opening even through a
Search WWH ::
Custom Search