Part of the Fontan operation involves making a tunnel to bring oxygen-poor blood directly from the body into the lungs. The tunnel connects the inferior vena cava to the pulmonary artery, bypassing the heart. It can be made in one of two ways:

  • outside the heart (extracardiac conduit)
  • inside the heart (lateral tunnel)

This new circulation can put extra pressure on the lungs while your child’s body is getting used to it. To relieve this pressure, the surgeon makes a fenestration (hole) between the tunnel and the heart.

The fenestration allows some blood to flow from the tunnel into the heart. It acts as a temporary pressure release valve while your child’s body is adjusting to the new circulation. It is usually closed several months after the Fontan operation, so that oxygen-poor and oxygen-rich blood no longer mix.

What does the closure device look like and how does it stay in place?

The closure device is made of metal and mesh material. It looks like a short tube with different-sized discs (circles) on either end. Before it is put in, the discs are folded so the device will fit in the catheter. When it is in the right place, one disc opens up as the device is moved out of the catheter. The tube portion plugs the hole and the other disc opens up on the opposite side of the hole.

What happens during the fenestration closure?

The procedure is performed while your child is under a general anaesthetic and usually takes 2-4 hours.

During the procedure, the doctor inserts a catheter with a balloon on the tip into a blood vessel in the groin at the top of your child’s leg. The catheter is moved up the blood vessel into the heart and into the fenestration. An X-ray picture is taken of the fenestration.

The balloon is then inflated so that it fills the hole and closes it for a short time. This lets the doctor see if your child’s heart is ready to have the closure device in place. If the pressure is good, the closure device is threaded through the catheter and placed into the fenestration.

Once the device is in place, the doctor takes out the catheter and covers the cut on your child’s leg with a bandage.

The doctor will explain the risks of heart catheterization to you in more detail before you give your consent for the procedure. The most common risks with fenestration closure are as follows:

  • There is a very small risk that the catheter may break through a blood vessel or the heart wall. To reduce this risk, a type of X-ray called fluoroscopy is used so one can see where the catheter is at all times.
  • While the device is being put in position, there is a risk that it may be put in the wrong place, move, or fall out of the fenestration. If this happens, the cardiologist will try to put it back in place. If this is not possible, surgery will be arranged to take out the device and close the fenestration.

After the procedure

The cardiologist will let you know when your child can go home. Your child will stay in the hospital for at least 4 to 6 hours after the procedure, or possibly overnight.

Source: AboutKidsHealth.com