Splenophrenic portosystemic shunt in dogs with and without portal hypertension: can acquired and congenital porto-caval connections coexist?

The possible existence of the same pattern of porto-caval connection in dogs having a single congenital portosystemic shunt (CPSS) and in dogs having multiple acquired portosystemic shunt (MAPSS) secondary to portal hypertension (PH) was evaluated. Retrospective evaluation of all CT examinations of patients having portosystemic shunt (PSS) was performed in a 4-year time period. All anomalous porto-caval connections were assessed for anatomical pattern and compared with published veterinary literature. Records of 25 dogs were reviewed. 16 dogs had a single CPSS (CPSS group), and 9 dogs had multiple acquired PSS secondary to PH (APSS group). The splenophrenic shunt pattern was found in 3 dogs of the CPSS group as a single congenital anomaly without PH and in 2 dogs of the APSS group associated with MAPSS and ascites due to different hepatic diseases causing PH. These findings corroborate two hypotheses: 1) Splenophrenic PSS should be considered as a classical CPSS but if this is not sufficient to alleviate a PH developed after birth because of eventual hepatic or portal diseases, in this case ascites and acquired portal collaterals may develop. In this case, MAPSS and CPSS may coexist. 2) The pattern of splenophrenic PSS, classically described among CPSS, may develop as acquired portal collateral in dogs with PH and it should also be included in the category of APSS. These preliminary findings may be helpful in reconsidering the classical haemodynamics of porto-caval diseases, enrich the classification of APSS in dogs and refine the imaging evaluation of patients with PH. Keywords: Computed tomography, Dog, Portal hypertension, Portosystemic shunt