Gauged attenuation of congenital portosystemic shunts: Results in 160 dogs and 15 cats

Abstract

SUMMARYPortosystemic shunts were ligated over a gauged stainless steel rod in 160 dogs and 15 cats, using a midline celiotomy. The diameter of the rod varied with the size of the shunt and the diameter of the portal vein cranial to the shunt. Shunts were narrowed to the smallest diameter that did not cause signs of portal hypertension such as cyanosis of the stomach, pancreas, and small intestine. A slight discoloration was accepted only if the heart rate, end-expiratory CO2%, or arterial blood pressure (if available) did not deviate more than 15% from the values that were recorded at the beginning of the surgical procedure. The perioperative mortality (0-30 days) was 29%. The most common cause of death was euthanasia because of hypoplasia of the portal vein cranial to the shunt. Animals with intrahepatic shunts had a significantly lower probability of survival than animals with extrahepatic portocaval or portoazygos shunts. In dogs, large breed and a high body weight were also significant risk factors for non-survival. Age had a significant effect on risk of non-survival, with an increased risk for older dogs, irrespective of the breed of the dog (large breed vs. small breed). The probability of survival without recurrence of hepatoencephalopathy (HE) after 1 and 4 years was 61.3% and 55.7%, respectively. The only variable that was significantly associated with non-recurrence of HE was the breed of the dog, there being a lower probability for large breeds. Among the animals that survived surgery for more than 30 days, there was a significant higher probability of recurrence of HE in cats than in dogs.

Soy Protein Isolate versus Meat‐Based Low‐Protein Diet for Dogs with Congenital Portosystemic Shunts

“…Surgical approaches for CPSS carry a high mortality risk because of postsurgical hypertension, coagulopathies because of impaired liver function, and anesthetic problems related to central neurotransmitter imbalances. 5,6,10,11 Moreover, long-term effects reported to occur in surviving dogs are due to inadequate growth of the portal vascular system resulting in permanent postsurgical portal hypertension. 5,6,23 Recently, in a nonrandomized study of dogs with CPSS, dietary management appeared to have comparable long-term success as surgery.…”

“…The ameroid constrictor has been shown to result in shorter surgery times and less complication than other surgical approaches. [6][7][8][9] One of the complicating factors is the high anesthetic risk because of central neurotransmitter dysfunction mainly associated with hyperammonemia. [10][11][12] Decreased production of clotting factors causes coagulopathy as an additional risk factor at surgery.…”

Prognostic Implications of the Degree of Shunt Narrowing and of the Portal Vein Diameter in Dogs with Congenital Portosystemic Shunts

“…When there is hypoplasia of the portal venous circulation cranial to the shunt, the CPS is closed to the maximum degree of attenuation (partial ligation) that can be tolerated without fatal portal hypertension. [3][4][5][6][7] An alternative method is to use surgical techniques that achieve gradual progressive closure of the CPS such as perivascular ameroid constrictors, cellophane banding, and intravascular thrombogenic coils. [8][9][10][11][12][13][14][15] The prognosis after surgical intervention remains unpredictable and recurrence or persistence of clinical disease has been documented with all techniques used for shunt attenuation.…”

Evidence of Inheritance of Intrahepatic Portosystemic Shunts in Irish Wolfhounds

“…Two months after surgery the patency of the shunting vessel, which was left open partially during surgery, was tested with echo-Doppler examination and ammonia tolerance tests. 6 These tests showed that there was no remaining functional portosystemic shunting in any of the 3 littermates. The dogs were fed a standard commercial dog food and were further kept as companion animals in the foster families.…”

“…1,4,5 Both parents were unaffected, but the 6 offspring included 1 affected male, 2 affected females, and 3 unaffected males. All 3 affected dogs were treated successfully by surgical attenuation of the shunt 6 at an age of 3-4 months.…”