First off if you haven't talked to a specialist then I would strongly advise doing just that. I took my Zada to this one:
Veterinary Medical And Surgical Group (VMSG) | Veterinarian, Veterinary Emergency, Animal Hospital, Pet Surgery, Vet Surgeons, TPLO and saw Dr. Theresa M. Ortega
Doctors | Veterinary Medical And Surgical Group (VMSG) She explained how the shunt procedure works, then said if I wanted to have it done she would refer me to a different doctor because since it's a very dangerous operation that doesn't have good results, she won't do them. Then she let me know all the things to do to keep Zada as comfortable as possible. I managed to keep her healthy and happy for 9 years. She passed this past May.
So please, talk to a doctor that specializes in internal medicine.