Portosystemic Shunts: Page 3 of 3

In rare cases, no portal vein (portal atresia) exists. No surgical treatment has been established for this condition. If this is the case for your pet, you should discuss medical therapy and diet adjustment with your veterinarian to keep your pet comfortable. Multiple portosystemic shunts are also impossible to close surgically, however other techniques to improve blood flow through the liver such as vena cava banding have been attempted. If multiple shunts are diagnosed, your veterinarian may suggest a liver biopsy to try and diagnose the underlying liver disease. Results may help determined the appropriate medical treatment for your pet and his or her long-term prognosis.

Surgery for some single intrahepatic shunts is similar to that of a single extrahepatic shunt. Because the abnormal vein is inside the liver, it is more difficult for the surgeon to see, making surgery more difficult. There are newer surgical methods that are being developed for some of these shunts that involve the placement of many small metal coils within the shunt vessels to try to close off the flow of blood through them. These are performed with the aid of real-time radiographs (fluoroscopy) and catheters that are advanced into the abnormal vessel.

urrent treatment options for liver shunts are continuing to evolve and there are many different factors that help determine what treatment is best for each individual patient. Be sure to reach out to your veterinarian with any questions regarding your pet’s treatment options, as you are your pet’s best advocate.

There is risk involved in every surgery. Although complications are uncommon, they can be severe. A specific complication of portosystemic shunt surgery is portal hypertension, which in its most severe form causes rapid, progressive fluid accumulation within the abdomen, shock, and bloody diarrhea within a few hours of closure of a shunt. The only treatment is surgical removal of the ligature and the prognosis is extremely guarded. Moderate portal hypertension can occur with gradual occlusion devices, resulting in distension of the abdomen with fluid within days to weeks after surgery. Fluid distension in the abdomen generally resolves within a few weeks.

Seizures are another possible complication of portosystemic shunt surgery. These are often severe and can be continuous. They generally develop within three days after surgery. Pets that do not have seizures before surgery can develop seizures immediately afterward. These seizures can be difficult to control and their cause is still unknown. There is a high death rate associated with these seizures. Researchers are continuing to investigate the cause of seizures post-surgical ligation, as removing the ligature does not resolve the problem. When dogs or cats develop seizures after surgery, the prognosis can be guarded. Your pet may also experience generalized bleeding or systemic infection (sepsis).

The overall mortality rate for surgery for portosystemic shunts is about 10%. Other potential complications include hemorrhaging, and tearing or bleeding from the shunt. Both of these complications can be life threatening.

Ascites, or fluid leakage into the abdomen, may accumulate postoperatively anywhere from a few days to ten days after surgery. This usually resolves by itself, but sometimes a diuretic (medicine that makes the body shed water) is needed to decrease the fluid. Even after surgery, you will have to feed your pet a special prescription or homemade diet until the liver has had a chance to improve its function.

Unfortunately, some dogs with congenital liver shunts also have another underlining liver disease that makes them unable to handle the added blood flow though the liver that closing the shunt vessel provides. Encouraging your veterinarian to run tests prior to surgery (blood tests, ultrasound, possible liver biopsy, etc.) is recommended to try to determine if your pet is a good candidate for surgery.

After surgery, you should expect your pet to be monitored in the ICU for at least 24 hours. This means that your pet will stay overnight. Furthermore, since your pet had abdominal surgery, you should prevent your pet from jumping or exercising up to two weeks after surgery.

In general, though, postoperative care depends on the nature of the shunt and the severity of clinical signs. In most cases, broad spectrum antibiotics and low protein diet will be recommended. Bile acid tests are usually rechecked periodically after surgery. Some patients clinically improve, yet don't have a significant decrease in bile acids following the surgery. Other medical treatments may be recommended depending on the patient's condition.


The good news is, despite the risks of surgery and gravity of the medical condition, the long-term outlook for many dogs and cats with portosystemic shunts treated either medically or surgically can be favorable with a good quality of life for many years. For those dogs that are deemed to be good candidates for surgery, the long-term prognosis for single extrahepatic portosystemic shunts can be positive. For pets in which the shunt was able to be completely closed successfully, the long-term prognosis is excellent. The prognosis for dogs with intrahepatic shunts and in cats is more guarded, although many can still do very well. The outlook for pets in which the shunt was partially closed down is more variable and depends on the amount of blood still bypassing the liver via the shunt.