I know that this is a little old, but I was wondering how Trike is doing. We're going through this with my other half's dog right now, and his shunt was detected with an ultrasound. That cost much less than a biopsy would have. Roscoe has an appointment for the surgery in a couple of weeks.
We've got him on tripsy and milk thistle. They are supposed to help rid the body of toxins that the liver can't handle. Also, a very low protein diet is suggested for dogs with liver issues, which I'm sure you're already aware of.
Good luck to you and Trike!