Page 11 - Journal of Structural Heart Disease Volume 3, Issue 3

Review Article
64
Figure 2: NovaFlex detail.
priate size for the valve that is being used. Proximal to where the valve is mounted on the shaft, there is a ared sheath which is part of the delivery system and designed to place the valve over the balloon when the system is inside the patient. Precise and ne placement of the valve on to the centere of the balloon is achieved by a rotating knob on the deliv- ery handle. To in ate the balloon to a predetermined diameter, the Edwards Atrion in ation device is used with nominal volumes for the various size valves.
Edwards LifeSciences also manufacture a set of precisely tapered hydrophilic dilators as well as 35-cm hydrophilic introducer sheaths with a tri-seal valve in various diameters to accommodate the NovaFlex de- livery system; however, nowadays, the expandable 16 Fr eSheath is preferred and uniformly suitable.
Edwards also provide the short Ascendra/Certi- tude sheath and delivery system designed for mini- mally invasive surgical implantation using a hybrid approach.
Additional Equipment
Diagnostic Catheters
A selection of catheters may be required to obtain angiography of the right ventricle, the right ventricu- lar out ow tract (RVOT), and the pulmonary arteries, and to assess the degree of pulmonary and tricuspid regurgitation. Common types of catheters include the pigtail, multipurpose A2, the Gensini/MPB3, multi- track, balloon wedge/ oatation, and pre-shaped cor- onary catheters for angiography during balloon inter- rogation of the RVOT.
Wires
Apart from the standard guide wires, it is import- ant to have a hydrophilic wire and a selection of sti exchange length wires, such as, the Amplatz sti wires (Extra Sti , Super Sti , and Ultra Sti by William Cook), the Lunderquist wire (William Cook) and the Back-up Meier wire (Boston Scienti c).
Balloons
These are required for interrogating the RVOT, not only to assess the anatomy of the out ow tract but also to look at the impact on coronary artery paten- cy, compression, and ow. Although compliant siz- ing balloons, such as the ones from St Jude Medical or NuMed, can be used, semi-compliant ones may be more appropriate; examples of these balloons include the Cristal (Balt) and BiB (NuMed) balloons. These balloons are also used for pre-stenting the RVOT when required. High pressure noncompliant balloons, such as the Z-Med and Mullins (NuMed) and the Atlas (Bard) are required to abolish resistant stenosis of the RVOT and these are usually used after stent placement and before valve implantation.
Stents
In many instances, pre-stenting is usual in order to cover areas of stenosis longer than the Edwards valve frame both in the context of a previous tissue homograft/xenograft conduit but also when there has been a trans-annular patch placed at the time of surgical repair. Pre-stenting not only helps to scaf- fold the RVOT, but it prepares the landing zone for the valve. Although pre-stenting is essential for the
Journal of Structural Heart Disease, [Month Year]
Volume 3, Issue 3:62-72