Use of transcolonic portal scintigraphy to monitor blood flow and progressive postoperative attenuation of partially ligated single extrahepatic portosystemic shunts in dogs

Abstract

Summary Transcolonic portal scintigraphy was used to evaluate immediate and long-term changes in shunt blood flow after partial ligation of single extrahepatic portosystemic shunts in 8 dogs. Scintigraphy was performed before surgery, within the first 7 days after surgery, and 3 to 9 months after surgery. Shunt fraction values for this group of dogs before surgery ranged from 67 to 87% (normal reference range, ≤ 15%). On the basis of postoperative scintigraphy, 4 dogs had immediate and lasting occlusion of shunt blood flow (shunt fraction, ≤ 15%). One dog had a shunt fraction value within the reference range immediately after surgery, had evidence of recurrent shunt blood flow (shunt fraction, 23%) at 3 months after surgery, and again had a shunt fraction value within the reference range 9 months after surgery. Persistent, though reduced, shunt blood flow (shunt fractions, 23 and 2 7%) was evident immediately after surgery in 2 dogs. One of these dogs had a shunt fraction within the reference range 3 months after surgery, whereas shunt blood flow in the other dog had increased to 41%. One dog had no appreciable change in shunt blood flow immediately after surgery (shunt fraction, 70%), but the shunt fraction value had decreased to 41% at the time of the final scintigraphic examination. As assessed by transcolonic portal scintigraphy, partial single extrahepatic portosystemic ligation caused a significant decrease in mean shunt blood flow in this group of 8 dogs and resulted in eventual shunt occlusion in a majority of the dogs (6 of 8 dogs). Partial ligation with progressive attenuation of shunt blood flow may obviate the need to perform additional surgery.