Long-term outcome after surgical ameroid ring constrictor placement for treatment of single extrahepatic portosystemic shunts in dogs

Objective: To report long-term clinical outcome in dogs treated for single congenital extrahepatic portosystemic shunt (CEHPSS) with a ameroid ring constrictor (ARC) and to identify perioperative variables associated with outcome. Study Design: Retrospective, multi-institutional study. Animals: Dogs (n=206) with CEHPSS. Methods: Medical records of dogs with CEHPSS treated by ARC were reviewed for perioperative and short-term (<1 month) data. Long-term follow-up information was obtained by telephone interview with referring veterinarians and/or owners. Kaplan-Meier analysis was used to estimate median survival time. Factors associated with short-term survival, outcome grade, and total survival time were identified. Results: Fifteen dogs died <1 month after ARC placement. Follow-up data were obtained for 112 of 191 dogs that survived >1 month; median follow was 54 months (range, 1-175 months) and 103 (92%) dogs had no clinical signs. Estimated median survival time was 152 months. Variables significantly associated with short-term survival included being intact and a low total white blood cell (WBC) count. Variables significantly associated with a successful outcome included having surgery later in the study period and negative postoperative nuclear scintigraphy. In the long-term survival analyses, intact dogs and those with higher WBC counts and occlusion pressures and lower bile acid concentrations were more likely to survive. Conclusions: Dogs with CEHPSS treated by ARC generally have a good prognosis and prolonged postoperative survival.