I can understand your concern but as MauiGirl said "Don't Panic". We had DJ for only a couple of months, he was an adoption at 6 years old, before we found out that he had a liver shunt. It was taken care while he was having other tests/biopsies done, but it was his kidneys that were his downfall with the gloumerii (sp)/filters in his kidneys/allowing protein to go through. Basically he was on a slow kidney failure and died late 1/08 at around 7 1/2. 
 
You are Not alone and there are many VT members that will help you through these tough times. 
Here is a Yahoo group that is all about liver shunts.   
Liver_Shunt_And_MVD_Support : Liver Shunt & MVD/HMD Support 
Dr. Karen M. Tobias, DVM, University of Tennessee College of Veterinary Medicine, is doing a lot of research on liver shunts. The group is free. 
I have many other links from my web searching for DJ. If you would like some please PM me and I will send them to you.