High Blood Pressure in the Portal Vein to the Liver in Dogs

The liver is an essential part of the body’s digestive system and filters toxins by way of the portal vein. As a matter of fact, the liver gets 25% of the cardiac output and supplies about 77% of the blood supply through the portal vein. Once the blood gets to the liver through the portal vein, it branches out into smaller veins, which take it through even smaller channels to go through the liver.

If your dog has portal hypertension, eventually the body will develop new veins to pass by the liver rather than go through the resistance in the liver. These new vessels do not remove toxins and other waste from the body as it would if it went through the liver, and they go into the esophagus, where they will eventually cause the vessels to burst because of the pressure. Your dog will show signs of liver damage such as yellowing of the skin and eyes and fluid accumulation, among other symptoms. If you suspect your dog has portal hypertension you should see your veterinarian right away.

High blood pressure in the portal vein to the liver (portal hypertension) is elevated blood pressure in the large vein going from the intestine to the liver. It can also affect the veins from the spleen, stomach, and pancreas going to the liver. There are three types of portal hypertension, which are prehepatic, intrahepatic, and posthepatic. This disorder may be caused by liver damage from other disorders and can lead to swollen veins in the esophagus, rectum, umbilicus, and stomach, which is a life threatening complication.

• Jaundice (yellow color in the whites of the eyes and skin)
• Fluid retention (seen as swollen belly)
• Coughing (gagging)
• Exhaustion (tired all the time)
• Breathing difficulty (labored or erratic breathing)
• Diarrhea (runny stool)
• Pain in the abdomen (guarding the belly)
• Appetite loss (refusal to eat)
• Weight loss
• Excessive sleepiness
• Not wanting to play or exercise

 Types

• Prehepatic portal hypertension (portal vein) can be described as resistance in the extrahepatic portal vein
• Intrahepatic portal hypertension (liver) is increasing resistance in the portal vein branches, sinuses, and hepatic veins
• Posthepatic portal hypertension (heart, vena cava, hepatic vein) is known as blockage of the larger hepatic veins, vena cava, or right atrium

Prehepatic Portal Hypertension

• Congenital (Cocker Spaniels, Doberman Pinschers, Rottweilers)
• Cirrhosis
• Pancreatitis
• Blood clot
• Constricted blood vessel
• Peritonitis
• Abdominal neoplasia
• Small portal vein
• Corticosteroids
• Enlarged lymph nodes
• Cancer
• Side effect of shunt repair operation

 Intrahepatic Portal Hypertension

• Congenital (German Shepherd, Terriers, Dalmation, Cocker Spaniel, Doberman Pinscher, Retrievers)
• Recurrent bile duct blockage
• Excess fibrous tissues in the liver
• Liver cirrhosis
• Cancer
• Chronic inflammation
• Fistula in the liver

 Posthepatic Portal Hypertension

• Heart disease (congestive heart failure)
• Heartworms
• Tumor in the heart
• Pericardial effusion (fluid in the pericardium)
• Serious blood clot in lung

Your dog’s veterinarian will need to do a complete thorough physical examination including blood pressure and body temperature. You should also be prepared to give the veterinarian as much information about your dog’s symptoms and when they started. The veterinarian will also need your dog’s complete medical history, including all dietary and physical changes as well as changes in shampoos or soap. The veterinarian will also run some tests on your dog. Some of these tests are:

• CBC (anemia, platelet cell counts)
• Coagulation parameters (blood clotting time, fibrinogen, antithrombin, and protein)
• Urinalysis
• Fine needle aspiration of abdominal fluid
• Liver enzyme (increase of liver enzyme activity)
• Liver function (blood ammonia, total serum bile acid)
• Portal vein pressure
• Digital radiographs (x-rays)

If these tests are inconclusive or show signs of a problem that needs clarification, the veterinarian will run some more tests to verify his suspicions. These tests are:

• Liver biopsy
• CT scans
• Ultrasound
• Scintigraphy (portosystemic hepatic bypass)
• Angiography (hepatic arteriovenous fistula)

The main thing the veterinarian will be concerned with is treating the complications, such as fluid retention and electrolyte imbalance. Your veterinarian will probably hospitalize your dog to reduce the fluid built up in the abdomen with diuretic medication. It is essential to watch your dog and give him fluid therapy while he is initially treated so there is no dehydration. The overall treatment depends on the cause of the portal hypertension.

• Portal vein issues can be treated with surgery (glue embolization of the fistula) or medication (Isosorbide 5-mononitrate)
• Liver disorders can be treated with surgery (liver lobectomy) or medications (nadolol)
• Heart failure can be treated with surgery (stents, embolectomy) or medication (thrombolytic, anticoagulant)