OBJECTIVE: To assess outcomes of dogs with side-to-side portocaval extrahepatic portosystemic shunts (PC-EHPSS) and poor portal perfusion to the liver treated with medical management alone (MM) or surgical attenuation (SA). STUDY DESIGN: Multi-institutional retrospective study. ANIMALS: A total of 21 dogs with PC-EHPSS (14/21 MM and 7/21 SA). METHODS: Medical records were reviewed, and data was collected on dogs <
12 kg with PC-EHPSS treated with MM or SA between June 2008 to June 2021. Signalment, clinical signs, postoperative complications, bloodwork values, long-term clinical outcome, survival, and owner reported quality of life were recorded. RESULTS: Of 21 dogs included, 10 were mixed breeds and 14 were females. Median age at time of presenting clinical signs was 163 days. At final follow-up examination (median 1119 days), all SA and 6/14 MM dogs were alive, with a median survival time of 2138 days following treatment onset. In surviving MM dogs, outcome was fair in 3/6 and poor in 3/6. In SA dogs with long-term follow-up, outcome was fair in 5/6, and poor in 1/6. A greater proportion of SA dogs had improved bloodwork parameter values at final follow-up examination, and the mean relative change in final bloodwork values was higher when compared to MM dogs. CONCLUSION: These findings demonstrate that SA has improved clinical outcomes to MM for PC-EHPSS
however, SA clinical outcomes appear worse than those previously reported for other EHPSS. CLINICAL SIGNIFICANCE: This information may have implications for expected outcomes in other EHPSS subtypes associated with severely diminished portal perfusion.