Pulmonary valve stenosis causing right ventricle hypertension and eventually hypertrophy. Pulmonary valvoplasty is done when the peak systolic gradient is greater than 50 mm Hg. Nowadays it is performed in newborn also as small size hardware are available in the market. RV angiogram is done in AP and lateral projection using NIH marker catheter / Berman balloon angiographic catheter and the pulmonary valve annulus is measured. The NIH/BBA catheter removed. An end hole catheter is used to cross the valve and the gradient is measured.
Balloons: Weight, age and pulmonary valve annulus diameter determine the length and size. Usually, 2-3 cm length balloons are used. A longer balloon will overlap the tricuspid valve, sometimes damage it.
Femoral sheath/ s: The size will depend on the balloon used.
Guide wires: Exchange length and the diameter must match the balloon requirements. A SUPER STIFF wire will be used for large balloons. The 1- cm floppy tip should be chosen, as the 7- cm tip may not support the balloon at the valve level.
Prepare balloon by either aspiration or flushing air from a balloon. The balloon and vent lumens
contain air, which must be removed and replaced with a contrast and saline solution. Use
a dilution of 1:8 of omnipaque 350 and saline. The catheter body has 2 lumens, attach the 50
ml syringe with 5 ml,s of dilute contrast to the balloon port. This will be labeled BALLOON or
colored blue. Apply negative pressure for a few seconds; you will see the air bubbling into the
syringe. Relax the pressure keeping the syringe upright, the dead space in the balloon will fill
with dilute contrast. Repeat this 1 or 2 times until no further air is seen escaping in the syringe.
Flush the center lumen with a heparinized flush solution.
The catheter body has three lumens clearly labeled.
- Distal which is used for exchanging over the wire, flush this lumen with heparinized saline.
- A balloon is used for inflation of the balloon.
- VENT is used to vent the air from the balloon during preparation; it can also be used to increase the deflation time by attaching a 50- ml syringe and placing on negative pressure. The balloon and vent ports are connected together with a bridge. Ensure the bridge connections are tight when removed from the packaging.
- Attach a 20- ml syringe to the balloon port. Leave the balloon cover on the balloon to prevent inflation, position the bridge stopcock to the 3 o, clock position and flush the balloon holding the tip down, you will notice air escaping through the vent lumen.
- After all the air has been purged through the balloon turn the stopcock off to the 12- o, clock position and flush the bridge.
- Position the stopcock off to the 6- o, clock position and attach the inflation device to the balloon port. Remove the inflator cover. The inflator is now ready to be used. Inj Ketamin 1 mg/ m/ Kg should be drawn up and be ready for administration throughout the procedure, Children do not usually respond to verbal directions during invasive procedures and will struggle if not adequately sedated making it difficult to continue the procedure. Staff should be attentive to vital signs after the administration of Ketamin, especially repeated doses, Respiratory depression is common, but need not be critical with proper airway management.
Insert the exchange wire through the GL catheter and advance into the distal pulmonary
vessels. Remove the end hole catheter and sheath together, maintain pressure on the
femoral site to prevent hematoma formation and bleeding during an exchange. A large sheath
can be placed in the vein which allows the balloon to cross through it.
If using 2 balloons, both femoral veins and 2 exchange wires are needed. Position the wires,
one at a time into the distal pulmonary vessels.
Flush the catheter and sheath when time allows and keep the sheath on the catheter for reinsertion when the balloons are removed. The sheath size must be equal or greater size than the shaft of the balloon to maintain hemostasis.
Insert the prepped balloon over the wire, a slight twisting may be required to pass through
the femoral access site. Advance the balloon to the pulmonary valve. Coordination with
the wire is essential especially while the balloon is manipulated through the RA, and RV to
prevent arrhythmia,s, and damage to the distal pulmonary vessels. The balloon is inflated
quickly; High pressure is usually not required. Stop inflation when the waist on the balloon
disappears. Frequently the balloon will poop and jump forward as the valve is dilated; gentle
traction is usually needed to keep the ball-Cardiac Interventions, Hardware and Implants
loon in the annulus. If balloons are used, both are positioned across the valve. Inflation of
both balloons at the same time and rate is important to get uniform dilation of the valve.
The balloon is quickly deflated and withdrawn slightly to allow perfusion. Forward blood flow
is stopped while the balloon is inflated so it is important that the dilation is done quickly. The
dilation may be repeated 1 or 2 more times before the balloon is removed. While removing,
maintain the guide wire in the distal pulmonary vessels. Reinsert the catheter into the pulmonary
artery. Remove the guide wire. Reconnect to pressure. A pullback is done across the
valve to determine the peak systolic gradient. RV angiogram may be repeated using a side
hole catheter. The gradient will decrease further in time. There will be a degree of outflow
tract spasm and swelling post dilation.
Remove lines as required. If the patient is ventilated and returning to ICU the arterial line may be left in situ. Balloons commonly used for valvuloplasty and angioplasty ( keep packet for checking sheath size and rated nominal and burst pressure)