Fenestration failure?

We knew going into this surgery that Riley's Fontan pressures were low (around 11). Which is good. We thought, anyway. Well, now that the fenestration is not visible on the echo, we are hearing different things. Basically there are two scenarios:

1) The fenestration has clotted. They are giving Riley tPA (anti-clotting medicine) to free up the clot. Still, if the fenestration clotted because there isn't enough flow going through there, it will just clot again once tPA is stopped. Also, tPA is a little risky for someone recovering from surgery. Clotting is a very important part of healing from surgery. If other things start to unclot that should be clotted, then that could open a whole new can of worms.

2) The fenestration has closed or narrowed to the point of being useless. In Ken's previous post, he said that they could try to balloon the fenestration open. However, one of the cardiologists told us that would not try to balloon it open. If the fenestration is closing or narrowing and essentially not functioning, it is not going to work even if it is made larger.

Blood flows due to different pressures forcing blood in different directions. If there is no pressure difference to help the blood go through the fenestration, then it doesn't matter how big the hole is.

We always knew that the fenestration may or may not fix his protein-losing enteropathy. We have heard that we'd know within a couple of months if it was working. I don't ever remember hearing, though, that the fenestration might just not work and we'd be exactly where we were a month ago, only our kid has had to endure yet another open-heart operation.

We obviously need to talk with Riley's cardiologist--the doctor who knows his anatomy best. Only then will we feel more confident about where we are heading and what is coming next. Riley was slated to go to the cath lab tonight, but they decided to hold off until tomorrow. We're not sure when, but hopefully we'll have an opportunity to talk with Dr. Tarnoff in the morning to get his perspective.

We don't want to get ahead of ourselves, but when I asked the cardiologist where this new development leaves us, he lowered his eyes for a second and said he's not sure. Still, we pretty much know the answer. We'll be facing two equally-awful options: a Fontan take-down or a heart transplant.

UPDATE FROM KEN: I'm here in the ICU and I've talked with the surgeon and the cardiologist. They are going to start tPA any moment. It is an 8 hour course. They will wait three hours and if his oxygen levels have not dropped, they'll double the dosage. They need to watch him like a hawk for any signs of bleeding or "neurological" issues. That worries me since he'll be sleeping so how can we detect slurred speech and the like? The cardiologists agree the timing is "not ideal" but it's important that we try. In the best case, the tPA will free the clot, lower his sats and we'll do an echo in the morning to verify. If there is no change in saturation, we'll head to the cath lab around noon (they need to wait at least four hours for the tPA to leave Riley's system). If they can see clotting in the cath lab, they may try intervention to free it. But as Suzanne mentioned above, if the problem is due to pressure gradients, there's nothing they can do to "salvage" the fenestration.