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Liver Shunt in Dogs

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • A liver shunt lets blood bypass the liver, so toxins build up.
  • Small breeds get shunts outside the liver; large breeds inside it.
  • Signs start before age 1: poor growth, odd behavior after meals and bladder stones.
  • Surgery to close the shunt has an excellent outlook if the dog recovers well from surgery.
  • Some dogs live for years on diet and medicine alone, though results vary.

Table of Contents

Research Types Signs Diagnosis Surgery Medical care Life expectancy Cost FAQ Sources

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A liver shunt (portosystemic shunt) is an abnormal blood vessel that lets blood from the intestines bypass the liver, so toxins such as ammonia aren't filtered out.1,2 Most shunts are present from birth. Small breeds such as Yorkshire Terriers, Maltese, Shih Tzus, Miniature Schnauzers and Pugs usually have a single shunt outside the liver (extrahepatic), while large breeds such as Labrador and Golden Retrievers and Irish Wolfhounds usually have one inside it (intrahepatic).2,3 Signs usually start before 1 year of age and include poor growth, behavior changes that often worsen after meals, and bladder stones.2,3 Shunts are diagnosed with bile acid and ammonia tests and imaging such as ultrasound or CT.2 Surgery to gradually close the shunt has an excellent outlook if the dog recovers well from surgery, and some dogs also live for years on diet and medicine alone, though results vary.3,4,5

Go to a vet urgently if a puppy or a dog with a shunt has:

  • Seizures, collapse, blindness, head pressing or severe confusion3,6
  • Repeated vomiting or refusal to eat2
  • Straining to urinate or blood in the urine, which can mean bladder stones3,2

Seizures in the first few days after shunt surgery are rare but serious and need immediate care.3

What the Research and Guidelines Say

  • Surgery is safe in experienced hands. In a 2023 study of 110 dogs with extrahepatic shunts, 3.5% to 3.8% died around the time of surgery, and owners rated quality of life a median of 10 out of 10 afterward.7
  • Medical management can last years. A 2020 study of 78 dogs managed with diet, with or without medicine, estimated median survival at 38.5 months.4
  • Less invasive options. In a 2023 study, closing extrahepatic shunts with coils placed through a vein worked in 95% of 42 dogs without a second procedure.8
  • The evidence is still limited. A 2022 evidence review found only retrospective studies comparing surgery with medical care for nerve signs.9

Types of Liver Shunts

  • Congenital extrahepatic shunts: a single vessel outside the liver, mostly in small and toy breeds2,3
  • Congenital intrahepatic shunts: a vessel inside the liver, mostly in large breeds2,3
  • Acquired shunts: usually several small vessels that form because of high blood pressure in the liver from chronic liver disease3,2
  • Microvascular dysplasia: tiny abnormal vessels within the liver, common in small breeds. Most dogs have no signs and a normal lifespan.2

Congenital shunts are reported in about 0.18% of all dogs.10

Signs of a Liver Shunt

  • Being the smallest of the litter, poor growth and poor muscle development2,5
  • Episodes of dullness, staring, circling, head pressing, wobbliness, blindness or seizures, often a few hours after eating3,6
  • Vomiting, diarrhea, eating non-food items, and drinking and urinating more2,3
  • Bladder stones made of ammonium urate, which are sometimes the only sign2
  • Slow recovery from anesthesia3

About 10% to 20% of dogs with a shunt show no signs.2

Diagnosis

Vets measure bile acids before and after a meal, which are usually markedly high in dogs with a shunt, and blood ammonia.2,3 High bile acids can occur with any liver disease, so imaging is needed to find the shunt.3 Doppler ultrasound can detect many shunts, and CT has largely replaced older contrast x-ray studies for mapping the vessel before surgery.2

Surgery

Surgeons usually close the shunt gradually, because closing it completely all at once can cause dangerous high blood pressure in the intestines.3,2 Options include:

  • An ameroid ring constrictor or a thin-film (cellophane-type) band, which close the vessel gradually3,2
  • Suture ligation, complete in dogs that tolerate it or partial with possible later surgery7,3
  • Coil embolization through a vein, often used for intrahepatic shunts2,11

Dogs usually get diet and medicine for several weeks before surgery to stabilize them.12,13 Bladder stones can be removed at the same time.3 After surgery, risks include high portal blood pressure and seizures, which affect a small percentage of dogs, most often toy breeds in the first 1 to 2 days.3,2 Some dogs develop new acquired shunts later.2

Medical Management Without Surgery

Dogs that can't have surgery, or are waiting for it, are treated with a prescription liver diet, a non-absorbed sugar laxative and sometimes an antibiotic.2,3 Most dogs improve quickly.5 Long-term results vary: a 2020 study estimated median survival of 38.5 months, while VCA reports that more than half of medically treated dogs are euthanized within 10 months of diagnosis.4,5 ACVS calls medical management "an acceptable first-line option," though surgery is linked to better long-term survival.3

Life Expectancy

For dogs with a single extrahepatic shunt, ACVS reports that "the prognosis is excellent if the animal survives the immediate postoperative period."3 Merck cites median survival of about 7 years (2,555 days) after surgery in one large group of dogs, and about 5.8 years (2,109 days) for medically treated dogs in the same group, a difference that wasn't significant.2 In a 2023 study, only 10% of dogs whose shunt was completely tied off still needed a special diet or medicine 6 months or more later.7

How Much Does Liver Shunt Surgery Cost?

Costs vary widely. One US veterinary teaching hospital estimated $5,408 to $7,571 for evaluation and surgery for an extrahepatic shunt in 2026, and $10,600 to $12,309 for coil treatment of an intrahepatic shunt.12 Another estimated $12,000 to $14,000 for stent and coil placement.11 Ask your vet or referral hospital for a written estimate.

Frequently Asked Questions

Can a dog live a normal life with a liver shunt?

Many do, especially after successful surgery. Some live for years on diet and medicine.

What are the early signs of a liver shunt in puppies?

Poor growth, odd behavior after meals, seizures and bladder stones.

What should a dog with a liver shunt eat?

Usually a prescription liver diet, often with dairy or soy protein. See our liver diet page.

Can a liver shunt be cured?

Often, if the shunt can be fully closed with surgery.

Do small breeds get liver shunts more often?

Small breeds most often get shunts outside the liver, and large breeds shunts inside it.

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Sources and further reading

This article was rewritten and fact-checked on October 23, 2026 against current veterinary references and specialist guidelines:

  1. Martin RA, King MD, Tobias K, Hunt GB, Hardie EM, Fingeroth JM. Liver, Biliary System, Pancreas. In: Current Techniques in Small Animal Surgery, 5th ed. (IVIS, 2021).
  2. Center SA. Hepatic Portal Venous Hypoperfusion in Small Animals. Merck Veterinary Manual, updated July 2026.
  3. American College of Veterinary Surgeons. Portosystemic Shunts. ACVS, updated January 2025.
  4. Favier RP, de Graaf E, Corbee RJ, Kummeling A. Outcome of non-surgical dietary treatment with or without a non-absorbed sugar laxative in dogs with congenital portosystemic shunts (title paraphrased). Veterinary Quarterly, 2020.
  5. Weir M, Williams K, Ward E. Portosystemic Shunt in Dogs. VCA Animal Hospitals, updated March 2025.
  6. Braund KG. Endogenous Metabolic Disorders. In: Braund's Clinical Neurology in Small Animals, 2002 (IVIS).
  7. Lipscomb V, Cassie C, Ritchie B, Greenhalgh S, Tivers M. A prospective comparison of complete suture ligation and partial thin film band attenuation of congenital extrahepatic portosystemic shunts in dogs. Veterinary Sciences, 2023.
  8. Ishigaki K, Asano K, Tamura K, et al. Percutaneous transvenous coil embolization for single extrahepatic portosystemic shunts in dogs. BMC Veterinary Research, 2023.
  9. Smachlo J, Gordon-Evans WJ. Does surgical or medical management of extrahepatic portosystemic shunts in dogs carry a better prognosis for the resolution and reduction of neurological dysfunction? Veterinary Evidence, 2022.
  10. Tobias KM. Portosystemic Vascular Anomalies. In: Mechanisms of Disease in Small Animal Surgery, 3rd ed., 2013 (IVIS).
  11. Texas A&M Veterinary Medical Teaching Hospital. Intrahepatic shunt attenuation (information sheet). Interventional Radiology & Endoscopy Service, 2024.
  12. University of Tennessee College of Veterinary Medicine. Portosystemic Shunt Evaluation/Surgery Guidelines and Estimate. UTCVM Veterinary Medical Center, updated June 2026.
  13. Kummeling A. A Portosystemic Shunt In A Dog: Has Its Treatment Changed? EVC Voorjaarsdagen proceedings, The Hague, 2018 (IVIS).

About this article

Last updated : fully rewritten using the Merck Veterinary Manual, the American College of Veterinary Surgeons, university hospital estimates and 2022 to 2023 surgical studies, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.

This page is for general information and is not a substitute for an exam by your veterinarian.