Liver shunt (PSS) surgery in Louisville and Lexington, Kentucky

A portosystemic shunt (PSS), or liver shunt, is an abnormal blood vessel that lets blood from the intestines bypass the liver. Because the liver can't filter that blood, toxins build up, and the liver may stay small and underdeveloped. Most shunts are congenital and found in young dogs and cats; small breeds such as Yorkshire Terriers often have a single shunt outside the liver (extrahepatic), while large breeds more often have one inside the liver (intrahepatic).

Under general anesthesia, the shunt vessel is located and a device is placed around it that closes it slowly over several weeks, giving the liver time to adapt to the increased blood flow. Dr. Bruce prefers an ameroid constrictor in most cases, though a cellophane band is also an option, and liver biopsies are taken. Before surgery, pets should be on medical management for at least 2 weeks: a low-protein diet, lactulose, antibiotics, and often levetiracetam (Keppra). One study found that starting levetiracetam before surgery lowered the risk of seizures afterward, though later, larger studies have not found the same benefit, so it can't be counted on to prevent them. This matters because if signs of hepatic encephalopathy don't improve with medication, there's a good chance they won't improve with surgery either.

Patients are monitored closely for the first week, since a small number develop complications such as seizures (about 8% of dogs in a large study) or high blood pressure in the portal system after surgery. Many patients need 24-hour hospital care for a day or two, since some can develop seizures, which can be life-threatening. Diet and medications are usually continued and then tapered once follow-up bile acids show the liver is working better. Bile acids are rechecked within the first few months after surgery to measure improvement, and sutures come out at 2 weeks.