Prognostic Implications of the Degree of Shunt Narrowing and of the Portal Vein Diameter in Dogs with Congenital Portosystemic Shunts

Abstract

To determine prognostic evaluation and correlation of the degree of narrowing and the diameter of the portal vein in dogs with a congenital portosystemic shunt (CPS). Longitudinal prospective study. Ninety-seven dogs with CPS. Shunt diameter was recorded before and after silk ligation to calculate degree of closure. Portal vein diameter was measured in 74 dogs. Short-term (30 days) and long-term (>1 year) outcome were evaluated. Dogs with clinical signs after 1 year were re-examined to assess the degree of portosystemic shunting and compared with matched operated dogs without clinical signs. Correlations between clinical outcome, degree of closure, and portal vein diameter were statistically analyzed. Short-term and long-term mortality were 27% and 2.9% respectively. Clinical recurrence occurred in 10% of dogs. The degree of closure was significantly associated with mortality, but not with clinical recurrence. A significant correlation was found between degree of closure and the diameter of the cranial part of the portal vein. Portal vein diameter was only significantly associated with mortality in extrahepatic CPS. Subclinical portosystemic shunting was confirmed in 3 of 10 dogs. The degree of shunt closure depended on portal development. Long-term outcome did not depend on the degree of closure or portal development at the time of surgery. This suggested that factors such as hepatic and portal regeneration after surgery may be important. Determination of factors that predict the outcome after surgical treatment of CPS in dogs is important to gain insight in treatment selection or new therapeutic options.