Morphology of splenocaval congenital portosystemic shunts in dogs and cats

OBJECTIVE: To describe the anatomy of congenital portosystemic shunts involving the splenic vein communicating with the caudal vena cava at the level of the epiploic foramen. MATERIALS AND METHODS: A retrospective review of a consecutive series of dogs and cats managed for congenital portosystemic shunts. RESULTS: Ninety‐eight dogs and eight cats met the inclusion criteria of a congenital portosystemic shunt involving the splenic vein communicating with the prehepatic caudal vena cava plus recorded intra‐operative mesenteric portovenography or computed tomography angiography and gross observations at surgery. All cases (both dogs and cats) had a highly consistent shunt that involved a distended gastrosplenic vein that communicated with the caudal vena cava at the level of the epiploic foramen via an anomalous left gastric vein. CLINICAL SIGNIFICANCE: The morphology of the shunt type described appeared to be a result of an abnormal communication between the left gastric vein and the caudal vena cava and the subsequent development of preferential blood flow through an essentially normal portal venous system. The abnormal communication (shunt) was through the left gastric vein and not the splenic vein, as might have been expected. This information may help with surgical planning in cases undergoing shunt closure surgery.