Page 18 - Journal of Structural Heart Disease Volume 3, Issue 3

71
Review Article
valve is trying to reach the RVOT and it can be replaced with a less sti valve so long as the dis- tal tip of the delivery system is already in one of the pulmonary arteries.
Consider doing any of the above one at a time. A constant but gentle push on the delivery system with controlled counter traction on the wire are much more likely to be successful in reaching the RVOT than aggressive pushing and struggling.
Complications
The procedure is generally safe but the following complications may occur:
a) Vascular injury that may require surgery b) Stent or valve displacement
c) Conduit rupture
d) Tricuspid valve damage
e) Arrhythmias which include heart block or ven- tricular tachycardia/ brillation
f ) Valve malfunction – may require a valve-in-valve device
g) Coronary occlusion h) Infection
i) Death
Current Limitations
This design works well for the aortic implanta- tions and for the majority of pulmonary ones too. There are, however, 2 theoretical concerns when the Sapien is pushed over the balloon when orientated for placement in the RVOT
c) The valve is pushed over the balloon against the valve lea ets whereas for aortic implantation the lea ets are in-line and less likely to be dam- aged by the balloon. This is more theoretical although there are anecdotal reports of valve lea et damage but the precise cause was not established.
d) The uncovered distal valve frame is pushed against the balloon and the sharp tips of the cells may potentially create pinhole punctures in the balloon which may impede full balloon in ation. It is always wise to have a Luer lock syringe with dilate contrast available in case balloon perforation has occurred and rapid in- jection is required to in ate the balloon and de- ploy the valve avoiding displacement from the target zone.
If operators are concerned about the above po- tential problems, an option is to mount the Sapien directly on the balloon outside the patient ( instead of placing the valve on the catheter shaft ) but this will mandate using a larger sheath; however, this is not usually an issue for pulmonary valves as the veins are large and stretchable and do not have the stenot- ic calci ed lesions seen in the iliac arteries when the Sapien is used for TAVR.
Conclusion
The Edwards XT and Edwards 3 valves are very suitable for implantation in the pulmonary position. Their size range from 20 to 29 mm and this allows for broader indications; the XT valves are all delivered through a NovaFlex delivery system whereas the Sapien 3 uses the Commander delivery system [3- 7]. The technique is well established. Pre-stenting is often performed except for some types of valve-in- valve implantation. Longevity is expected to be simi- lar to surgical bioprosthetic valves and is likely to take over most cases for pulmonary valve replacement, although a few may still require surgery. The Compas-
a) Anatomical features. As many as 70% of patients with Fallot’s Tetralogy will require a trans-an- nular patch and this can become large and aneurysmal over the years. Although a 29 mm valve in the pulmonary position is adequate for haemodynamic purposes, some RVOTs can be much larger. For this reason, several options are being considered by manufacturers includ- ing the concept of a reducer designed to nar- row the RVOT to allow placement of a 29 mm Sapien or to have a combined reducer with an integral valve to accommodate within the very dilated RVOT. There are several designs being evaluated at the moment, most of which using self expanding Nitinol technology.
b)Technical issues. The current loading design with the valve mounted on the shaft and even- tually placed on the balloon within the patient has allowed for smaller introducer sheaths.
DeGiovanni, J.
Pulmonary Valve Replacement