Page 10 - Journal of Structural Heart Disease Volume 3, Issue 3

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Review Article
Figure 1: Edwards equipment.
valve tissue is treated with a patented Carpentier Ed- wards ThermaFix process that is designed to remove major calcium-binding sites in order to optimize valve longevity. The ThermaFix process uses (i) a heat process to remove glutaraldehyde molecules and (ii) a patented chemical process that removes 98% of phospholipids, as these are known calcium-binding sites; moreover, calci cation of the valve is known to be the main reason for valve tissue degeneration but the long-term bene t of the ThermaFix still needs to be established. The pericardium is shaped into a three-lea et valve, originally mounted on a stainless steel frame using polyethylene terephthalate fabric but the frame is now made from a Chromium-Cobalt alloy. In vitro durability testing simulating 5 years of implantation was successfully carried out for the valve components.
The pericardial lea ets are mounted on a laser-cut, biomedical grade Chromium-Cobalt frame consist- ing of 4 rows and 4 columns providing a high radial strength; this results in better hemodynamics by ex- panding into a round circle and is resistant to stress fractures. The latter was con rmed by a simulation process equivalent to 15 years of implantation. Due to the strength of the frame and for more uniform placement of the delivery system, Edwards developed a crimper to mount the valve on the delivery system. Originally, the Sapien valve came in 23- and 26-mm
diameters. Edwards expanded the range, adding 20- and a 29-mm diameter options. The frame height, after implantation is 13.5 mm for the 20 mm valve, is 14.3 mm for the 23-mm valve, 17.2 mm for the 26-mm valve, and 19.1 mm for the 29-mm valve.
The original Sapien valve was mounted on a balloon that was part of the delivery system. Initially, this was known as the Retro ex and was upgraded to the Ret- roFlex 3 System, until recently. All the current models, except for the Edwards 3, can be delivered through the NovaFlex system; the Edwards 3 is delivered through a Commander delivery system. The change in design to the NovaFlex delivery system has made it possible to go through a smaller sheath by mounting the Edwards valve on the shaft proximal to the balloon for easy of entry into the patient and it is then placed across the balloon with- in the inferior vena cava. The NovaFlex ranges from 18 to 21 Fr in size and consists of a long catheter with a short, soft tapered tip for easy transition and to protect the Ed- wards valve during delivery. Proximal to the tapered tip is the balloon, over which the valve is placed for deploy- ment. The balloon is volume and not pressure driven; the recommended volume of dilute contrast is placed in the Atrion QL in ation device to achieve the desired diame- ter for the size of valve being deployed..
The Edwards valve is crimped on to the shaft of the NovaFlex at the time of the procedure proximal to the balloon and using the Edwards crimper of the appro-
DeGiovanni, J.
Pulmonary Valve Replacement