A 13-month-old, female, mixed-breed cat weighing 4.0 kg was referred to the Animal Medical Center at the Tokyo University of Agriculture and Technology with chronic decreased appetite, loss of vigour and intermittent vomiting from 7 months of age. Physical examination revealed no cyanosis or wasting, and no heart murmur was auscultated. Arterial blood pressure was within the normal range (139/98 mmHg [mean arterial pressure 113 mmHg]). Complete blood count revealed mild anaemia with haematocrit (Hct) 22.5%, and serum biochem-istry revealed elevated levels of aspartate aminotrans-ferase (114 U/l), alanine aminotransferase (366 U/l) and preprandial serum ammonia (109 microg/dl). Levels of albumin (3.1 g/dl) and total bile acid (TBA) (preprandial, 3.3 micromol/l; postprandial, 3.6 micromol/l levels) were within normal limits. Abdominal ultrasonography revealed dilation of an intrahepatic portal vein branch and an intrahepatic saccular dilation (maximum diameter 10.3 mm) showing pulsatile mosaic perfusion. Contrast-enhanced (4 ml iodine contrast agent; Iopamidol injection [Konica Minolta Health Care]) CT confirmed dilation of a portal vein branch (diameter 6.7 mm) in the left lateral hepatic lobe with several tortuous vessels that appeared continuous with the hepatic artery and a nidus visible around the associated portal vein branch (Figure 1). CT also confirmed the presence of multiple shunt vessels.
Moderate splenomegaly and ascites were also present. Based on these findings, hepatic arteriovenous fistula/hepatic artery-portal vein fistula with multiple acquired portosystemic shunts was strongly suspected. The cat was medically controlled using antibiotics (ampicillin sodium, 15 mg/kg q12h), liver-protecting agent (ursodeoxycholic acid, 50 mg q12h) and a low-protein diet with blood transfusions. However, because medical treatment proved ineffective, coil embolisation was performed on day 11 using a hybrid approach via the mesenteric vein.
Intravenous (IV) ampicillin sodium was administered at 30 mg/kg (ampicillin Na injection; Kyoritsu Seiyaku) to prevent infection, with IV buprenorphine hydro-chloride at 0.01 mg/kg (Lepetan 0.2 mg; Otsuka Pharmaceutical) as pain relief. Following preadministration of a subcutaneous injection of atropine sulfate at 0.02 mg/kg, general anaesthesia was induced using 5% isoflurane (Isoflurane for Animal Use; Intervet). Coil embolisation was performed via a transperitoneal approach under general anaesthesia maintained with isoflurane inhalation (3.5-4.0%). For the midline transperitoneal approach, the mesenteric vein was cannulated with an IV catheter, and portal venous pressure was 26/24 mmHg (mean pressure 24 mmHg) (portal venous pressure in anaesthetised cats is 8.9 +- 0.35 mmHg, with a mean of 7.38 +- 2.7 mmHg). A wide area of greater omentum was pale and the colour of the intestines suggested congestion. Anterograde angiography with iodine contrast agent (4 ml) showed that the contrast medium injected into the portal vein branch immediately diverted into the mesenteric vein, and multiple shunts were visible in the abdominal cavity. Congestion, dark-red colouration and varicose projections were apparent in part of the right medial hepatic lobe, which presented an extremely irregular texture. However, no abnormalities in external appearance were observed in the quadrate or left medial lobes. A small amount of pale-yellow ascites fluid was accumulated in the abdominal cavity. The splenic head was enlarged and dark red, and splenectomy to improve anaemia was performed using a vessel-sealing system (LigaSure; Covidien). After splenectomy, a 3 Fr sheath was inserted in the proximal mesenteric vein and a 0.018 inch guidewire was introduced. A microcatheter (Virtus 2Marker microcatheter; Boston Scientific Japan) was then inserted under fluoroscopic guidance as far as the region of the arterioportal fistula. A detachable coil (interlocking detachable coil, 12 mm, 20 cm x 1 coil; Boston Scientific Japan) was deployed inside the portal vein branch under fluoroscopic guidance. Portal venous pressure was measured and peristaltic movements and colour of the intestines were checked, then five push-up coils (Cook push-up coils: 10 mm, 14.2 cm; Cook Japan) were added in order to embolise the intrahepatic portal vein (Figures 2 and 3). Portal venous pressure after coil embolisation was 27/23 mmHg (mean pressure 25mmHg). Recovery from anaesthesia was uneventful, and appetite was evident 3 h postoperatively. Postoperative condition was improved, with no diarrhoea or vomiting. The day after the operation (day 12), pulsatile mosaic perfusion on abdominal ultrasonography was decreased in the intrahepatic branches of the portal vein. The animal was discharged on day 15. On day 92, the animal was vigorous and showed a good appetite, with no sign of diarrhoea or ascites. Postprandial serum ammonia (197 microg/dl) showed no decrease and remained medically controlled using ursodeoxycholic acid, but no sign of hepatic encephalopathy was identified and the cat exhibited good levels of activity and a stable condition. In addition, anaemia was improved (Hct 30.9%). On day 113, abdominal ultrasonography revealed that the mosaic pattern around the site of coil placement was nearly undetectable.