My Mia has just been dignosed with MVD. We went through all of the blood test and bile acid test which showed abnormal liver functions. The vet actually thought it was a liver shunt. He said we needed to take her to Texas A & M and have an ultrasound done. We did that, but it showed nothing. They decided at A & M that we needed to do a liver biopsy to check for MVD and while they were in there doing the biopsy they could look around for a shunt that the ultrasound may have missed. She did great through the surgery and we were able to bring her home a couple of days later. Took about a week to get the pathology report back on the biopsy, but it did come back with a dignosis of MVD. They put her on the Hill's L/D food and it has made such a differnce in her. If your baby has MVD she can not tolerate protein. In the beginning I was giving the Nutracal too, but that was the worse thing I could do because it is full of protein. Little did I know at the time that the protein was the problem.
You stated that they have your baby on Valume. Just double check with your vet about that, because they told me that most pain medicine was a no-no for dogs with MVD because it was to hard on the liver.
I know what you are going threw, I was in your shoes a month ago. MVD is not as scary as it sounds. Mia seems totaly normal now just from simply changing her diet. As my vet put it to me, the only thing Mia needs to put in her mouth is L/D and water. That means no treats and no people food.
Here is a very informative site about liver shunt, MVD and other liver problems that affect Yorkies.
http://livershunt.com/