(C) Device and Implantation Technique
The Perceval bio-prosthetic sutureless valve has two components. The
tissue valve which is made up of Bovine Pericardium, fixed with
Glutaraldehyde and neutralized with homocystic acid. It is a double
sheet design and has eyelets for guiding suture positioning. This tissue
valve is mounted on self-expanding nickel – titanium alloy stent with
anatomical strut design, double ring geometry and carbo film coating
(Figure-1).
After the excision of diseased valve, its aortic annulus is meticulous
decalcified. The appropriate size of the prosthesis is established when
the valve sizer end marked with “✓” passes easily through the aortic
annulus into the left ventricle, whereas the one marked with “✗”
remains stable. Guiding sutures help to position the device at the exact
level: 4-0 polypropylene suture (17mm needle) is placed 2 to 3 mm below
the annulus, across the annulus, and exiting the aortic wall 2 to 3 mm
above the annular line. This placement ensures that the bite is large
enough to hold the traction applied during implantation of the device
and the Perceval valve is not anchored too low in the left ventricular
outflow tract (LVOT).
After the lower needle of the guiding suture has been passed through the
eyelets of the device, the holder with the loaded valve is guided down
to the annular level. Gentle traction is applied to the guiding sutures
almost parallel to the holder, not tangled around the stent posts, while
commissural stay sutures are released. Deployment is started with the
screw on the tip of the implanting device, which unscrews the inflow
portion of the valve. After that, the safety clip is removed, and the
sheath is pulled back to deploy the outflow part of the stent. After
deployment is complete, the holder is removed gently, avoiding
entangling the device in the prosthesis. Accurate positioning of the
valve is then reconfirmed. Post-ballooning is carried out with the
size-dedicated balloon inserted into the prosthesis with the blue ring
at the level of the upper edge of the leaflets. The balloon was inflated
to 2-4 atm of pressure for the duration of 30 seconds depending upon
valve size and annular calcification. After release the balloon is
removed from the LVOT, as are the guiding and stay sutures.