The cath Dr. just came back to talk to us, and the results were mixed. The good news is that blood flow to his right lung, which was nonexistent in August, has normalized, and also that they didn't need to do any interventions, which means that we should be able to go home from the hospital tonight. The bad news is that his pressures are actually a little bit higher than they were in August, and the culprit seems to be that his heart ventricle is not relaxing as much as it should, which is making the pressure higher in his Fontan circuit. There are some options for managing this with medication. The cath doc said that they would most likely consider a higher diuretic dose, an ACE inhibitor (which he's been on before), and the dreaded Remodulin (this is the medication that must be administered via a subcutaneous pump). We haven't actually talked to our cardiology team yet, though, so it remains to be seen what will actually be recommended to us.
So, not as good as we'd hoped, but not as bad as it could have been.