U of Tenn has some good info on LS here:
Portosystemic Shunts FAQ
The menu on the left side of the above link's page has all info on Liver Shunt
Here's a link to their contact page... has a link to directions and lodgings at the bottom (some hotels give a discount for people with pets getting treatment at the University)
Contact
There's also a link to a referral form you could print and have your vet fill it out and fax it or take with you...