intrahepatic shunts
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Intrahepatic Shunts. James Montgomery, DVM March 30, 2009 Acc # 111557 & 111556. Acc#: 111557. Madeline 3 month old female basset hound Cystoliths Elevated liver enzymes Elevated bile acids Referred for evaluation of shunt. Acc#: 111557. Acc#: 111556. Acc#: 111557. Portal Vein. - PowerPoint PPT PresentationTRANSCRIPT
INTRAHEPATIC SHUNTSJames Montgomery, DVM
March 30, 2009
Acc # 111557 & 111556
Acc#: 111557 Madeline 3 month old female basset hound Cystoliths Elevated liver enzymes Elevated bile acids Referred for evaluation of shunt
Acc#: 111557
Acc#: 111556
Acc#: 111557
Portal Vein Formed within the mesentery dorsal to the right
limb of the pancreas Confluence of cranial and caudal mesenteric
portal branches Receives blood from the GI tract and spleen
Mesenteric veins, gastroduodenal, splenic, and gastric veins
As approaches liver, sweeps from right to left and divides into right and left branches Main right branch – right lateral and caudate
process of caudate lobe Main left branch – all other lobes
Intrahepatic Shunts Almost all intrahepatic shunts occur in
large dogs Connect portal vein branches after their
divergence from the portal vein to the hepatic veins or abdominal vena cava, bypassing the hepatic sinusoids
Many intrahepatic shunts result from failure of the ductus venosus to close in infancy 65% are anatomically considered PDV
Divided into right, left, and central divisional shunts
Fetal Circulation
Dyce, Sack & Wensing, Textbook of Veterinary Anatomy, 2nd ed, p. 249.
Intrahepatic Shunts Right divisional shunts
Pass through either the caudate process of the caudate lobe or the right lateral lobe of the liver before entering the vena cava
Central divisional shunts Pass through either the right medial or
quadrate lobes before entering the vena cava Left divisional shunts
Pass through either the papillary process of the caudate lobe, the left lateral lobe or the medial lobe before entering the vena cava
Madeline1 2
3
Madeline
R
Miller’s Anatomy of the Dog, 3rd ed, p. 453.
Acc#: 111557
Treatment Often requires more than one surgery Surgical techniques described
Posthepatic left hepatic vein attenuation – no clinical effect
Posthepatic direct shunt ligation Intrahepatic direct shunt dissection and ligation with
ultrasound guidance Intravascular placement of embolisation coils Intraluminal closure of the shunt via the thoracic vena
cava Transportal closure of the shunt via portal venotomy
Direct attenuation of the PDV before it enters the venous ampulla is technically less demanding
Treatment The significant blood flow through large
intrahepatic shuts cannot be suddenly obstructed Life threatening portal hypertension would
develop Causes of intraoperative death
Intraoperative shock (hemorrhagic and septic), cardiac arrest, and portal hyper- and hypotension
Postoperative survival rates: 75-89% Peritonitis, portal vein thrombosis, and
portal hypertension are most common postoperative causes of death
Prognosis Predictors for postoperative
complications Low body weight (<10 kg) and
hypoproteinemia or hypoalbuminemia Shunt location had no effect on short or
long-term outcome Partially attenuated shunt survival rates
1 year – 60% 2 year – 55%
After 4 months, euthanasia due to failure to show clinical improvement was most common cause of death
References Mathews KG, Bunch SK. Vascular Liver
Diseases. In Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine, 6th ed (St. Louis, MO: Elsevier, 2005) pp. 1453-64.
White RN, Burton CA. Anatomy of the patent ductus venosus in the dog. Veterinary Record (2000) 146, 425-9.
Whiting PG, Peterson SL. Portosystemic shunts. In Slatter D, ed. Textbook of Small Animal Surgery, 2nd ed (Philadelphia, PA: WB Saunders Co., 1993) pp. 660-74.