Page 17 - Journal of Structural Heart Disease Volume 3, Issue 3

Review Article
70
the valve may not be totally stable so it is important to de ate the balloon slowly and observe the valve care- fully. It is common for the blood pressure and heart rate to fall during valve deployment but these recover quickly. Once the balloon is fully de ated, the delivery system is withdrawn under uoroscopy making sure that there is no resistance against the Edwards valve. It may be necessary to adjust the wire to keep the balloon in the center of the valve during withdraw- al. The gradient can be measured using a multi-track catheter over the wire and a pulmonary angiogram is performed to make sure the valve is competent. Mild regurgitation is acceptable especially when there is still a catheter across the valve, but if the leak is more than mild, it is important to establish if this is due to a paravalvular leak or lea et dysfunction. A paravalvular leak, if signi cant, may be addressed by in ating the balloon to a larger diameter adding between 1–3 cc to the nominal volume. If the leak is due to valve dys- function, ICE may be required to establish the reason. If this is due to a stuck lea et, this may be mobilized using a pigtail catheter, but if the valve lea et is dam- aged, a valve-in-valve device should be considered. With the NovaFlex/Commander system, the valve is pushed over the balloon against the lea ets and the- oretically, damage can occur but in vitro testing has shown that this is not a problem.
If the hemodynamics are satisfactory and the valve is stable, the wire can be withdrawn and the procedure terminated. It is advisable for the dilator to be placed within the eSheath during withdraw- al in order to avoid inadvertent pinching of the IVC wall as this may cause vessel tear with uncontrolla- ble internal bleeding. It is customary to prescribe an antiplatelet agent for 6 months; many administer an- tibiotic prophylaxis for invasive procedures for the rst 6 to 12 months, although this depends on local and national practice (Figures 4, 5 and 6).
If there is an existing failing bioprosthetic valve in the pulmonary position, an Edwards TM valve can be placed within the surgical valve; in this situation, pre-stenting is not usually required and coronary compression is not an issue. Pre-stenting may be needed if the obstruction extends beyond the bio- prosthetic valve. What is essential is to nd out exact- ly what type and size of bioprosthetic valve had been implanted and to know the exact characteristics of
the valve, including the height, internal diameter and the lea et design as this will determine the precise position of the Edwards valve within the bioprosthe- sis. In general, only one row or part of this of the Sa- pien is deployed proximal to the surgical valve ring and the majority of the implanted valve is distal to the surgical ring in order to open up the degenerated lea ets of the surgical valve.
Tips to reach RVOT
The delivery system is sti and unwieldy and the course to reach the RVOT can be tortuous and in dif- ferent planes, this making it di cult to deliver the mounted valve to the RVOT. A very sti wire helps to rail road the valve but this can sometimes also proved a handicap particularly when the RVOT has been presented and the wire abuts against the stent preventing free movement of the valve in the RVOT. When di culties are experienced delivering the Sapi- en from the IVC to the RVOT, there are several tips that can be considered:
a) Make the delivery system less sti by withdraw- ing the catheter on the delivery system proxi- mally. A variable degree of withdrawal can be checked to get the best of sti ness and softness for smooth movement of the valve. If the valve is in the right ventricle but cannot reach it’s tar- get in the RVOT, the catheter may only need to be withdrawn to the level of the tricuspid valve.
b) Balloon assisted wire anchoring. This is achieved by inserting a separate wire in the pulmonary artery where the sti wire has been parked and a balloon is in ated in the pulmonary ar- tery adjacent to the deployment wire in order to anchor this and achieve counter traction to help deliver the Sapien in the RVOT. The wire and balloon must be withdrawn before valve deployment.
c) Partial in ation of the balloon on the delivery system. This only requires 1 -2 cc of dilute con- trast delivered through the Atrion and observed on uoroscopy in order to create a smoother tip particularly if the RVOT is heavily calci ed or if it has been presented.
d) Replace wire with a less sti alternative. A very sti wire may be more of an obstacle when the
Journal of Structural Heart Disease, [Month Year]
Volume 3, Issue 3:62-72