Extrahepatic porto-systemic shunts.
This is little Archie.
Archie had a spleno-caval portosystemic shunt. The portal vein takes tributaries from the gastro-intestinal tract, pancreas, spleen etc and then diverts blood into the liver. Hepatic veins then empty into the vena cava. However, if blood is shunted from an anomalous vessel from the portal vasculature straight to the vena cava, then it bypasses the liver (and as we know, blood passing through the liver is important in terms of removing toxins). Typically, due to lesser blood flow, the liver shrinks in size.
Treatment is localising the anomalous vessel and preventing blood flow through it. However, if we do this suddenly, it overwhelms the smaller liver and therefore the portal vasculature and you can get portal hypertension. Signs of this are free abdominal fluid, gastrointestinal bleeding, hypovolemic shock, incisional bleeding, decreased central venous pressure, vomiting, diarrhoea and abdominal pain. Therefore, the vessel needs to close slowly.
The technique I used with Archie, was to place a cellophane band around the anomalous vessel. This results in gradual attenuation of this vessel. The third photo is the cellophane band around the shunt just prior to entry into the caudal vena cava.
Archie is doing well! Surgery increases life span significantly compared to medical management and for dogs that survive the peri-operative period, a normal life-span can be expected.
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