Medical Term of the Day: The Fontan

It's been a long time since I've done one of these, but the time (unfortunately) has come again.

The repair of Ayden's congenital heart defect - hypoplastic left heart syndrome - has three stages. The first was the Norwood. The second was the bi-lateral, bi-directional Glenn. The third, which is on deck for today, is the Fontan. (Check the links if you need refreshers on the first two.)

The Fontan is basically the mirror image of the Glenn, at least as to purpose. The end result of the procedure is the oxygen-depleted blood returning from the lower half of Ayden's body, via the inferior vena cava (IVC), will proceed directly to his lungs and no longer pass through his heart. Thus, after the surgery is done, Ayden's cardiovascular system will have been completely rewired to best fit his single ventricle existence. I have often explained it to people this way:

For those of us with fully developed hearts, our blood travels through our bodies like its on a figure-8 race track, with the heart sitting where the track crosses itself. Blood gets oxygen from the lungs, moves through one heart ventricle, goes out to the body, moves through the other heart ventricle, then returns to the lungs to pick up more oxygen. As you can see, there's two trips through the heart in one complete cycle. After today, none of Ayden's blood will follow that pattern (approximately half of it hasn't been since the Glenn). Instead, his blood will flow like its on a circle track. It will get oxygen from the lungs, move through his single ventricle, go out to the body, then return to the lungs - only one trip through the heart.

Specifically, the surgeon will be disconnecting the IVC from Ayden's heart and attaching it to his pulmonary arteries (under normal circumstances, these carry oxygen depleted blood from the heart to the lungs). Because the pulmonary arteries are nearer to the top of the heart (away from the IVC connection), the surgeon will need to build a bridge between the two (this was not necessary for the Glenn). There are a few ways to do this. Ayden's surgeon's preferred method is to use the outside of the heart wall and some very fancy cloth-like material to create the connection (some surgeons prefer to use the inside of the heart wall). While there will be artificial material, there won't be any plastic, meaning Ayden won't outgrow the procedure.

As I have with every other surgical procedure, I'll be posting status updates throughout the process today.