Oh, and as for dogs living for years with liver shunts....that is actually quite common. My Teddy Bear was diagnosed last year and he was an adult pup. I adopted him in 2007 and he never had symptoms...he suddenly got bladder stones and ended up being diagnosed with a shunt. He had the surgery, and is doing very well now on a regular diet.
Link to Teddy's thread about his surgery:
http://www.yorkietalk.com/forums/sic...ver-shunt.html