Use of portocaval venografts with ameroid constrictor placement and hepatic lobectomy for treatment of intralobular intrahepatic portocaval shunts in four dogs

Retriever (dog 1) weighing 20.6 kg (45.3 lb) was evaluated because of lethargy, polydipsia, polyuria, head pressing, ptyalism, disorientation, ataxia, and failure to grow of 5 months’ duration. Blood and serum biochemical abnormalities included high bile acids concentrations (preprandial, 143 mmol/L; postprandial, 119 mmol/L; reference range, 0.0 to 12.0 mmol/L), low BUN (6 mg/dL; reference range, 8 to 25 mg/dL), low total protein concentration (4.5 g/dL; reference range, 5.4 to 7.6 g/dL), hypoalbuminemia (2.2 g/dL; reference range, 2.5 to 4.0 g/dL), hypocholesterolemia (94 mg/dL; reference range, 111 to 290 mg/dL), and mildly high activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), all of which were supportive of a diagnosis of a portosystemic shunt. The referring veterinarian initiated medical treatment with lactulose (3 mL, PO, q 24 h) and metronidazole (12 mg/kg [5.5 mg/lb], PO, q 24 h); the dog was fed a commercially available low-protein diet. The owners believed that the dog’s clinical signs had decreased in severity with medical treatment. On physical examination, the dog was quiet and had signs of depression. Abdominal ultrasonography revealed microhepatica, dilatation of the caudal vena cava at the porta hepatis, and crystals in the urinary bladder. Triple phosphate crystalluria and cystitis were identified via urinalysis. The dog was referred to the surgery service for further diagnostic testing and treatment. On the basis of the findings to date, examination of the liver vasculature was considered necessary, and an exploratory laparotomy was scheduled with, if required, contrast portal angiography. The dog was anesthetized, and ventral midline celiotomy was performed. Microhepatica was confirmed, and a focal area in the right lateral liver lobe that was palpably softer than the rest of the liver and fluctuant upon compression was observed. No extrahepatic shunt vessel was identified. After catheterization of a mesenteric vein, mesenteric venous portography was performed. A C-shaped, dilated vessel connecting the portal vein to the caudal vena cava extended through the liver to the right of the midline (Fig 1). Because of the long duration of anesthesia, a decision was made to perform ovariohysterectomy at this time and repair the portosystemic shunt during a subsequent surgery. During the postoperative period, the dog was monitored in the Critical Care Unit and received pain medication, lactulose, cefazolin, and metronidazole. Forty-eight hours later, the dog was returned to