I hope that your baby gets better. It sounds like you are having a scintigraphy done. Did you ever share your bile acid test results? If so, I missed them.
I REALLY do not recommend to "hold off" on surgery if she indeed does have a liver shunt. Like Debbie (dwerten) said, it could cause multiple shunts which would mean that she could not be operated on at all.
I know its all expensive (I'm going through all of this right now as well) but its a part of being a pet owner. Trust me, it will be worth it in the long run.
Please join this group
Liver_Shunt_And_MVD_Support : Liver Shunt & MVD/HMD Support There are several others who are going through this or have gone through this in this group. They are VERY knowledgable and will be able to give you several tips and you will have information coming out of your rear on the folders they have saved with info.