Long-term Outcome After Surgical Ligation for Treatment of Congenital Portosystemic Shunts in Dogs

Abstract

Objectives: To report long-term clinical outcome in dogs treated for congenital portosystemic shunting (CPSS) with complete or partial ligation and to develop a scoring system to determine persistent shunting. Also to report the predictive value of pre-operative albumin, white blood cell count, fasting plasma ammonia concentration and fasting plasma bile acid concentration for the long-term outcome, and to determine the percentage of persistent and recurrent shunting in a group of patients that came back for a long-term follow up. Study Design: Retrospective study. Animals: 167 dogs with surgical attenuation of an intra- or extrahepatic CPSS. Procedure: Medical records of dogs with CPSS treated by ligation were reviewed pre- and postoperative short and long-term. Long-term information was obtained by telephone interviews with veterinarians and questionnaires sent to the owners. With use of the questionnaires a CPSS scoring system was developed. A randomized group of 21 dogs came back for a control visit for persistent or recurrent shunting. Logistic regression analysis was used to determine the predictive value of pre-operative albumin, white blood cell count, fasting plasma ammonia concentration and fasting plasma bile acid concentration for persistent shunting after surgery. Results: Preoperatively the majority of the dogs suffered from decreased activity, decreased appetite, gastrointestinal signs and signs of hepatic encephalopathy. Dogs which had the ammonia metabolism tested (fasting plasma ammonia concentration, ammonia tolerance test), all had an abnormal ammonia metabolism. The fasting plasma bile acid concentration was above reference for the majority of dogs that were tested. During surgery the majority of the shunts were partially ligated. The postoperative mortality rate (< 1 month) was 11%. During the routine control visits after surgery all dogs of the study population were clinically improved. With the use of the questionnaires a basic scoring system for CPSS was developed. Preoperative a mean CPSS score of 43 (SD 27) was calculated, postoperative the mean CPSS score was 11 (SD 13). This improvement in CPSS score was significant (P < 0.001). During the extra control visit of the randomized group of dogs, 58% of the dogs had no shunting, 16% had asymptomatic shunting and 26% had symptomatic shunting. The CPSS score was also calculated for these dogs, which corresponded with the shunting classification. Conclusions: Complete or partial surgical ligation is an effective technique to improve the quality of life of dogs with CPSS. Owners are very satisfied with the result of the surgery. A basic clinical scoring system is developed to help diagnose portosystemic shunting, which is promising for the future.