(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.