96. Hepatic Vascular Anomalies Flashcards
What is the primary function of the portal vein in the liver?
To supply 75% to 80% of the afferent blood volume and 50% of the oxygen supply to the liver.
Name two clinical signs associated with hepatic encephalopathy in dogs.
Seizures and ataxia.
What is the main blood vessel supplying oxygenated blood to the liver apart from the portal vein?
Hepatic artery.
What type of portosystemic shunt is most common in small or toy breed dogs?
Extrahepatic portosystemic shunt.
What congenital vascular anomaly is characterized by multiple arterial and venous communications within the liver?
Hepatic arteriovenous malformation.
Which vein in dogs typically divides into right and left branches 0.5 to 1.0 cm beyond its gastroduodenal tributary?
Portal vein.
What condition is characterized by small intrahepatic portal vessels and may be accompanied by fibrosis?
Primary hypoplasia of the portal vein without portal hypertension (previously known as microvascular dysplasia).
What is the major neurotoxic substance thought to play a role in hepatic encephalopathy?
Ammonia.
In dogs with congenital portosystemic shunt (PSS), which breed has the highest reported odds ratio for this condition?
Yorkshire Terrier.
Which dietary adjustment is recommended to manage hepatic encephalopathy in dogs with PSS?
Protein restriction with high-quality protein sources, such as milk or vegetable protein.
What imaging modality is considered the gold standard for evaluating the portal venous system in humans?
Computed tomographic angiography.
Name a condition that commonly presents with similar signs to hepatic vascular anomalies in small breed dogs.
Toy-breed hypoglycemia.
What is the purpose of bile acids in liver function tests for animals with PSS?
To evaluate liver function by measuring the liver’s ability to process and recirculate bile acids.
What breed is associated with intrahepatic portosystemic shunt (PSS) in large dogs?
Irish Wolfhound.
What enzyme’s activity is often measured to differentiate between PSS and portal vein hypoplasia without portal hypertension?
Protein C.
What is a common histologic finding in dogs with congenital PSS?
Bile duct proliferation and hypoplasia of intrahepatic portal tributaries.
Name one clinical sign specific to cats with congenital PSS.
Ptyalism (excessive salivation).
Which vein in the liver receives blood from the papillary process of the caudate lobe in dogs?
Left portal vein.
What imaging technique uses technetium for detection of portosystemic shunts?
Nuclear scintigraphy.
Name the blood test most commonly used to screen for liver dysfunction in animals with hepatic vascular anomalies.
Serum bile acids test.
What is the cause of microcytic anemia often seen in dogs with PSS?
Hypoferremia.
Which condition in dogs may present with signs of urolithiasis due to ammonium urate crystalluria?
Congenital portosystemic shunt.
What medical therapy is often used to reduce ammonia levels in hepatic encephalopathy?
Lactulose.
Name a coagulation disorder common in dogs with PSS.
Prolonged prothrombin time (PT).
What type of biopsy is often recommended at the time of congenital shunt attenuation if liver enzyme values are elevated?
Liver biopsy.
Which artery supplies the caudate and right lateral hepatic lobes in dogs?
Right lateral branch of the hepatic artery.
What is the most common location for extrahepatic PSS to terminate?
Caudal vena cava or azygos vein.
What vitamin deficiency is commonly associated with coagulation issues in liver disease?
Vitamin K deficiency.
In what percentage of dogs with congenital PSS are ammonium urate crystals reported?
26% to 57%.
Which imaging technique is useful for detecting radiolucent uroliths in dogs and cats with hepatic vascular anomalies?
Ultrasonography.
Which diet is found beneficial for dogs with hepatic encephalopathy, soy-based or meat-based?
Soy-based diet.
What histologic change is common in cats with congenital PSS?
Portal vein hypoplasia.
Name an antioxidant commonly used as a liver supportive therapy for animals with hepatic vascular anomalies.
S-adenosyl-methionine (SAMe).
What breed is prone to developing hepatic arteriovenous malformations?
No specific breed, it can occur in any breed.
Which nerve supplies the lips and cheeks in dogs?
Facial nerve (CN VII).
What is the typical survival time for dogs with PSS managed medically without surgery?
Median survival time is approximately 9.9 months.
What type of anemia is commonly seen in animals with PSS?
Microcytic anemia.
What is the primary effect of protein C deficiency in animals with liver disease?
Increased risk of thrombosis.
What is the effect of excessive bile acid concentrations in animals with PSS?
Bile acids enter the systemic circulation, reflecting liver dysfunction.
Which amino acid imbalance is associated with hepatic encephalopathy?
Increased aromatic amino acids and decreased branched-chain amino acids.
What is the role of endothelin in the ductus venosus closure?
It promotes contraction of the ductus venosus in response to reduced blood flow.
In which breed is the ductus venosus closure delayed compared to others?
Irish Wolfhound.
Which laboratory finding is typical in dogs with congenital PSS?
Hypoalbuminemia.
Name a neurotransmitter involved in hepatic encephalopathy due to ammonia toxicity.
Glutamate.
What enzyme is primarily involved in the detoxification of ammonia in the liver?
Urea cycle enzymes (e.g., ornithine transcarbamylase).
Which imaging modality allows a detailed 3D image of the liver vasculature?
Magnetic resonance angiography (MRA).
What treatment is recommended for severe hypoalbuminemia in small dogs with PSS?
Administration of plasma or human serum albumin.
Name one breed overrepresented with extrahepatic PSS in cats.
Domestic shorthairs.
Which condition can lead to glomerulosclerosis secondary to hepatic vascular anomalies?
Immune-mediated glomerulonephritis due to antigen accumulation.
What is the typical response in blood ammonia levels after surgical attenuation of a congenital PSS?
Decrease in blood ammonia levels.
Which type of portosystemic shunt is most commonly seen in small or toy breed dogs? A) Intrahepatic PSS B) Extrahepatic PSS C) Acquired PSS D) Hepatic Arteriovenous Malformation
B) Extrahepatic PSS
What is the primary source of blood ammonia in animals with hepatic encephalopathy? A) Muscle tissue B) Liver C) Kidneys D) Gastrointestinal tract
D) Gastrointestinal tract
Which breed is most commonly associated with congenital portosystemic shunts? A) Labrador Retriever B) German Shepherd C) Yorkshire Terrier D) Golden Retriever
C) Yorkshire Terrier
What percentage of blood volume to the liver is supplied by the portal vein? A) 50% B) 60% C) 70% D) 75%-80%
D) 75%-80%
What condition is characterized by excessive ammonia in the bloodstream due to reduced liver function? A) Hepatic fibrosis B) Hepatic encephalopathy C) Portal vein hypoplasia D) Hepatic neoplasia
B) Hepatic encephalopathy
Which imaging modality is preferred for detailed pre-surgical planning of hepatic vascular anomalies? A) Radiography B) Ultrasound C) Computed Tomographic Angiography D) Scintigraphy
C) Computed Tomographic Angiography
In dogs, which liver lobe is primarily supplied by the right lateral branch of the hepatic artery? A) Right lateral lobe B) Left medial lobe C) Quadrate lobe D) Left lateral lobe
A) Right lateral lobe
Which factor is often considered the primary neurotoxic substance in hepatic encephalopathy? A) Ammonia B) GABA C) Glutamine D) Bilirubin
A) Ammonia
Which hepatic vein is typically the largest and most cranial in dogs? A) Caudate vein B) Right hepatic vein C) Left hepatic vein D) Central vein
C) Left hepatic vein
What is a common clinical finding in cats with congenital portosystemic shunts? A) Hypertension B) Ptyalism C) Polydipsia D) Ascites
B) Ptyalism
What is the typical urine specific gravity finding in dogs with congenital PSS? A) Hyposthenuric B) Hypersthenuric C) Isosthenuric D) Hypertonic
A) Hyposthenuric
Which abnormality is most commonly seen on abdominal radiographs of dogs with PSS? A) Hepatomegaly B) Splenomegaly C) Microhepatia D) Renal atrophy
C) Microhepatia
What blood test is most commonly used to evaluate liver function in animals with PSS? A) Ammonia concentration B) ALT C) Bile acids D) Albumin levels
C) Bile acids
Which type of PSS is most commonly associated with larger dog breeds? A) Extrahepatic PSS B) Intrahepatic PSS C) Portal hypoplasia D) Acquired PSS
B) Intrahepatic PSS
Which enzyme is typically increased in dogs with portosystemic shunts? A) ALT B) AST C) Amylase D) Lipase
A) ALT
In dogs with congenital PSS, low concentrations of which substance are commonly noted? A) Glucose B) Urea C) Bile D) Bilirubin
B) Urea
Which breed is overrepresented in cases of primary hypoplasia of the portal vein without portal hypertension? A) Doberman Pinscher B) Golden Retriever C) Cairn Terrier D) Maltese
C) Cairn Terrier
What is a common histopathologic finding in dogs with congenital PSS? A) Necrosis B) Hyperplasia of arterioles C) Thrombosis D) Lymphoid hyperplasia
B) Hyperplasia of arterioles
Which venous system contributes to the formation of the portal vein during embryologic development? A) Cardinal veins B) Subcardinal veins C) Umbilical veins D) Vitelline veins
D) Vitelline veins
Which diagnostic test is contraindicated in animals with baseline elevated ammonia? A) Bile acids test B) Protein C test C) Liver biopsy D) Ammonia tolerance test
D) Ammonia tolerance test
Which artery provides blood to the left lateral and medial liver lobes in dogs? A) Right lateral branch B) Hepatic artery C) Left hepatic artery D) Left portal vein
C) Left hepatic artery
What is the major anatomical effect of hepatic arteriovenous malformations? A) Fibrosis of hepatic veins B) Hepatofugal blood flow C) Hyperplasia of Kupffer cells D) Portal vein thrombosis
B) Hepatofugal blood flow
What percentage of afferent blood supply to the liver is provided by the portal vein? A) 50-55% B) 60-65% C) 75-80% D) 85-90%
C) 75-80%
Which breed of dog is most likely to present with congenital portosystemic shunts? A) Golden Retriever B) Yorkshire Terrier C) Labrador Retriever D) Beagle
B) Yorkshire Terrier
What is the primary clinical sign associated with hepatic encephalopathy? A) Gastrointestinal signs B) Neurologic abnormalities C) Respiratory distress D) Cardiac arrhythmias
B) Neurologic abnormalities
Which vein is the largest tributary of the portal vein in dogs? A) Splenic vein B) Gastroduodenal vein C) Cranial mesenteric vein D) Caudal mesenteric vein
C) Cranial mesenteric vein
What is the most common type of congenital portosystemic shunt in small breed dogs? A) Extrahepatic shunt B) Intrahepatic shunt C) Portoazygos shunt D) Arteriovenous malformation
A) Extrahepatic shunt
In which species does the portal vein divide into right, central, and left branches? A) Dogs B) Cats C) Horses D) Pigs
B) Cats
Which liver lobe is primarily supplied by the right portal vein in dogs? A) Left medial lobe B) Quadrate lobe C) Right lateral lobe D) Caudate lobe
C) Right lateral lobe
What role does vascular endothelial growth factor (VEGF) play in hepatic vascular anomalies? A) Inhibits vascular growth B) Stimulates vascular growth C) Prevents apoptosis D) Decreases inflammation
B) Stimulates vascular growth
What is the predominant blood flow direction in hepatic arteriovenous malformations? A) Hepatofugal B) Hepatopetal C) Cranial-caudal D) Caudal-cranial
A) Hepatofugal
Which imaging technique is the ‘gold standard’ for evaluating the portal venous system? A) Ultrasonography B) CT angiography C) MRI D) Radiography
B) CT angiography
What is the primary cause of hepatic encephalopathy in patients with portosystemic shunts? A) Increased ammonia levels B) Dehydration C) Hypoglycemia D) Hypocalcemia
A) Increased ammonia levels
What type of shunt is more common in larger breed dogs? A) Extrahepatic shunt B) Intrahepatic shunt C) Multiple acquired shunt D) Portal hypoplasia
B) Intrahepatic shunt
Which artery supplies 50% of the oxygen supply to the liver? A) Hepatic artery B) Portal artery C) Splenic artery D) Gastroduodenal artery
A) Hepatic artery
Which dietary component is recommended to be restricted in animals with hepatic encephalopathy? A) Carbohydrates B) Protein C) Fats D) Fiber
B) Protein
In dogs, which hepatic vein is the largest and most cranial? A) Right hepatic vein B) Left hepatic vein C) Caudal vena cava D) Central hepatic vein
B) Left hepatic vein
Which diagnostic test is 100% sensitive for detecting portosystemic shunts in dogs and cats? A) Bile acids test B) Ammonia tolerance test C) Transsplenic scintigraphy D) Abdominal ultrasound
C) Transsplenic scintigraphy
Which protein’s activity is used to help differentiate between portosystemic shunts and PVH-MVD? A) Albumin B) Protein C C) Fibrinogen D) C-reactive protein
B) Protein C
What is a common clinical finding in cats with portosystemic shunts? A) Ptyalism B) Vomiting C) Coughing D) Diarrhea
A) Ptyalism
What does the term ‘hepatofugal flow’ refer to? A) Blood flow towards the liver B) Blood flow away from the liver C) Blood flow towards the heart D) Blood flow towards the stomach
B) Blood flow away from the liver
What liver histopathologic feature is commonly seen in dogs with congenital portosystemic shunts? A) Bile duct proliferation B) Lymphoid hyperplasia C) Necrosis D) Abscess formation
A) Bile duct proliferation
Which nutrient should be increased in the diet of animals with portosystemic shunts? A) Protein B) Fat C) Zinc D) Copper
C) Zinc
Which imaging technique is commonly used to diagnose hepatic arteriovenous malformations? A) Scintigraphy B) MRI C) Ultrasound D) CT angiography
D) CT angiography
What is a recommended drug for medical management of hepatic encephalopathy? A) Lactulose B) Aspirin C) Ibuprofen D) Paracetamol
A) Lactulose
Which condition involves a high-pressure arterial and low-pressure venous communication? A) Hepatic arteriovenous malformation B) Portal vein hypoplasia C) Congenital PSS D) Primary hypoplasia
A) Hepatic arteriovenous malformation
Which cranial vein segment becomes the hepatic portion of the caudal vena cava during development? A) Left vitelline vein B) Right vitelline vein C) Left umbilical vein D) Right umbilical vein
B) Right vitelline vein
What percentage of dogs with congenital PSS are hypercoagulable according to thromboelastography? A) 10% B) 20% C) 40% D) 43%
D) 43%
What is the common cause of portal hypertension in dogs with acquired PSS? A) Hepatic fibrosis B) Low protein intake C) Physical trauma D) Bacterial infection
A) Hepatic fibrosis
What is the primary purpose of clipping the ventral neck before surgery in patients with portosystemic shunts? (A) Aesthetic reasons, (B) Placement of a jugular catheter, (C) Decreasing infection risk, (D) Easing ventilation
B) Placement of a jugular catheter
Which method is recommended for preventing hypothermia during surgery? (A) Ice packs, (B) Fans, (C) Conductive or forced warm air blankets, (D) Heating lamps
C) Conductive or forced warm air blankets
Which catheter placement is often needed for intraoperative central venous pressure measurements? (A) Femoral vein, (B) Jugular vein, (C) Radial artery, (D) Carotid artery
B) Jugular vein
For a congenital portosystemic shunt, which type of occlusion is often not tolerated? (A) Gradual partial occlusion, (B) Complete acute occlusion, (C) Hydraulic occlusion, (D) Ligature occlusion
B) Complete acute occlusion
What is the preferred method of shunt attenuation for congenital portosystemic shunts? (A) Complete acute occlusion, (B) Gradual attenuation, (C) Partial acute ligation, (D) Embolization
B) Gradual attenuation
Which method is commonly used for gradual shunt occlusion? (A) Ameroid constrictor, (B) Suture ligation, (C) Coil embolization, (D) Catheterization
A) Ameroid constrictor
When extrahepatic portocaval shunts are occluded, where is the typical location of occlusion? (A) Terminal end on the caudal vena cava, (B) Middle of the hepatic vein, (C) Left renal vein, (D) Near the diaphragm
A) Terminal end on the caudal vena cava
What is a key consideration before beginning surgery for congenital portosystemic shunt repair? (A) Skin preparation from the pubis to the neck, (B) Preparation for cranial vena cava access, (C) Clipping hair only on the abdomen, (D) Using intravenous dye for vessel mapping
A) Skin preparation from the pubis to the neck
Which technique is sometimes used to identify multiple congenital portosystemic shunts intraoperatively? (A) MRI, (B) Ultrasonography, (C) Endoscopy, (D) X-ray
B) Ultrasonography
What is recommended if intrahepatic portosystemic shunts are not visible during surgery? (A) Perform a transdiaphragmatic tube insertion, (B) Use intraoperative mesenteric portography, (C) Avoid any intervention, (D) Administer antibiotics
B) Use intraoperative mesenteric portography
What should be done to visualize portoazygos shunts passing through the diaphragm? (A) Retract the liver and stomach to the left, (B) Enter the omental bursa, (C) Perform a ventral neck incision, (D) Clamp the diaphragm
B) Enter the omental bursa
Which of these is NOT a recommended surgical treatment for portosystemic shunts? (A) Complete occlusion with ligatures, (B) Gradual occlusion with cellophane bands, (C) Stent placement, (D) Gradual occlusion with hydraulic occluders
C) Stent placement
What is a reason for avoiding complete occlusion in most animals with congenital shunts? (A) Risk of blood loss, (B) High tolerance for complete occlusion, (C) Risk of postoperative complications, (D) Requirement for long recovery time
C) Risk of postoperative complications
What is the purpose of the ameroid constrictor in portosystemic shunt surgery? (A) Rapid shunt closure, (B) Slow shunt closure, (C) Complete acute closure, (D) Preventing infection
B) Slow shunt closure
If portal vein atresia is present, what is the recommended action? (A) Partial shunt attenuation, (B) Complete shunt ligation, (C) Avoid shunt attenuation, (D) Shunt attenuation with coil embolization
C) Avoid shunt attenuation
In portosystemic shunt surgery, where is the portal vein typically located? (A) Within the mesoduodenum, (B) Near the hepatic artery only, (C) Behind the diaphragm, (D) Adjacent to the renal vein
A) Within the mesoduodenum
In cases with small gastric vein branches joining the shunt, what should be considered? (A) Dissection of the diaphragm, (B) Avoidance of any surgery, (C) Cessation of portal vein catheterization, (D) Occlusion of branches
A) Dissection of the diaphragm
In intrahepatic shunts, which technique helps locate the shunt if it’s not visible? (A) Ultrasound-guided palpation, (B) MRI, (C) Fluoroscopy, (D) Thermal imaging
A) Ultrasound-guided palpation
During shunt attenuation surgery, portal pressure should ideally not exceed: (A) 15 cm H2O, (B) 20 cm H2O, (C) 8 cm H2O, (D) 5 cm H2O
B) 20 cm H2O
To prevent seizure activity after shunt surgery, which sedative is preferred? (A) Diazepam, (B) Ketamine, (C) Acepromazine, (D) Morphine
C) Acepromazine
Which vessel is most commonly accessed for portal pressure catheterization? (A) Femoral artery, (B) Jugular vein, (C) Jejunal vein, (D) Cephalic vein
C) Jejunal vein
Which type of band is used for gradual occlusion due to its ability to cause inflammatory response? (A) Stainless steel band, (B) Cellophane band, (C) Rubber band, (D) Nylon band
B) Cellophane band
Which blood parameter is often monitored after surgery to assess liver function? (A) Serum glucose, (B) Bile acids, (C) Hemoglobin, (D) Uric acid
B) Bile acids
For interventional procedures involving intrahepatic PSS, which vein is often accessed? (A) Right hepatic vein, (B) Jugular vein, (C) Left renal vein, (D) Portal vein
B) Jugular vein
To prevent portal hypertension during surgery, which is an acceptable portal pressure limit? (A) 12 cm H2O, (B) 15 cm H2O, (C) 17 cm H2O, (D) 24 cm H2O
D) 24 cm H2O
Which surgical approach may improve intraoperative exposure for treating portosystemic shunts? A. Lateral thoracotomy B. Caudal sternotomy C. Dorsal diaphragmatic incision D. Cranial sternotomy
B. Caudal sternotomy
What is clipped to allow placement of a jugular catheter during surgery? A. Ventral neck B. Abdominal area C. Lumbar region D. Hindlimb
A. Ventral neck
Which fluid may be administered during surgery for central venous pressure support? A. Saline B. Hetastarch C. Dextrose D. Lactated Ringer’s
B. Hetastarch
What warming method is recommended to prevent hypothermia during surgery? A. Hot water bags B. Conductive warming blankets C. Heating lamps D. Radiant heaters
B. Conductive warming blankets
Where is vascular access typically obtained for interventional procedures involving intrahepatic PSS? A. Jugular veins B. Femoral veins C. Carotid arteries D. Saphenous veins
A. Jugular veins
Which surgical method is generally preferred for shunt occlusion in congenital PSS? A. Complete acute occlusion B. Gradual attenuation C. Immediate ligation D. Catheter embolization
B. Gradual attenuation
Which is a common method used for gradual shunt occlusion? A. Suture ligation B. Cellophane bands C. Silk thread D. Nylon bands
B. Cellophane bands
What surgical approach is recommended for portoazygos shunts that require further exposure? A. Cranial midline B. Transdiaphragmatic C. Caudal midline D. Lateral incision
B. Transdiaphragmatic
What structure must be avoided during portoazygos shunt attenuation to prevent nerve damage? A. Right phrenic nerve B. Left vagus nerve C. Cervical sympathetic trunk D. Median nerve
B. Left vagus nerve
How are portocaval shunts typically located in surgery? A. X-ray B. Direct visualization C. MRI D. Endoscopy
B. Direct visualization
Which incision is recommended for midline celiotomy for PSS location? A. Mid-abdomen B. Sternum to pubis C. Thorax D. Pelvic region
B. Sternum to pubis
In which condition is complete shunt occlusion generally not tolerated? A. Extrahepatic portocaval shunts B. Intrahepatic shunts C. Portoazygos shunts D. Portal hypertension
D. Portal hypertension
Which imaging method is often used intraoperatively for locating PSSs? A. MRI B. Ultrasound C. Mesenteric portography D. CT scan
C. Mesenteric portography
What is the recommended method for attenuating congenital PSSs? A. Clipping B. Gradual constriction near insertion site C. Immediate occlusion D. Vessel ablation
B. Gradual constriction near insertion site
Where do extrahepatic portocaval shunts commonly terminate? A. Cranial to renal veins B. Near the left atrium C. Distal vena cava D. Close to the esophageal hiatus
A. Cranial to renal veins
What is typically done to prevent ameroid constrictor movement post-surgery? A. Secure with metal wire B. Use minimal dissection C. Fix with suture D. Apply adhesive gel
B. Use minimal dissection
What is the purpose of placing a jugular catheter for intraoperative procedures? A. Blood pressure monitoring B. Central venous pressure measurements C. Heart rate monitoring D. Direct portal measurement
B. Central venous pressure measurements
Which type of anesthesia is commonly used in intraoperative PSS repair? A. Local anesthesia B. Regional block C. General anesthesia D. Conscious sedation
C. General anesthesia
How should ameroid constrictors be sterilized before use? A. Boiling water B. Gas sterilization C. Ethanol wash D. Steam sterilization
B. Gas sterilization
Where should animals undergoing intrahepatic shunt surgery be clipped preoperatively? A. Over the hindlimbs B. From sternum to pubis C. On the neck only D. Only at the incision site
B. From sternum to pubis
What is used for portal pressure measurement intraoperatively? A. Blood pressure cuff B. Water manometer C. Glucometer D. Spirometer
B. Water manometer
Which vascular anomaly may involve multiple arteries communicating with the portal vein? A. Portoazygos shunt B. Hepatic arteriovenous malformation C. Gastrophrenic shunt D. Splenogonadal shunt
B. Hepatic arteriovenous malformation
What is the standard device used for portal pressure monitoring during PSS attenuation? A. Manometer B. Thermometer C. Glucometer D. Capnometer
A. Manometer
Which of these is a potential postoperative complication of PSS surgery? A. Hypoglycemia B. Hypertension C. Hyperkalemia D. Hypothermia
A. Hypoglycemia
Which imaging tool is commonly used intraoperatively to assist in identifying PSS? A. Doppler ultrasonography B. X-ray C. CT scan D. Endoscopy
A. Doppler ultrasonography
What is the main purpose of using a jugular catheter during PSS surgery?
For central venous pressure measurements and fluid administration.
What type of catheter might be placed for measuring portal pressure?
A jejunal or splenic vein catheter.
Why is hypothermia a concern during PSS surgery?
Because it can impact recovery and is common in long or complex surgeries.
What technique is recommended for finding PSSs during surgery?
Midline celiotomy and abdominal exploration.
What complication may arise if shunt dissection is too extensive?
Postoperative movement of the constrictor ring leading to acute occlusion.
Why might a surgeon extend the incision cranially through the diaphragm in a PSS surgery?
For better exposure of intrahepatic shunts.
Which animals are more likely to experience shunt spasms during surgery?
Animals with portoazygos shunts.
What is a common characteristic of the portal vein in dogs with congenital extrahepatic PSS?
It is usually smaller than normal.
What method is often used to improve visibility of intrahepatic PSS during surgery?
Intraoperative Doppler ultrasonography.
How can the portal vein be identified during exploratory laparotomy?
By retracting the duodenum to the left.
What vessel characteristic indicates an intrahepatic PSS?
Dilated hepatic and portal vein branches with turbulent blood flow.
What is a potential consequence of complete acute occlusion of a shunt?
Postoperative complications due to intolerance.
Where do gastrophrenic shunts typically terminate?
On the phrenic vein, which then joins the left hepatic vein or caudal vena cava.
Which procedure allows indirect suture passage for ligating intrahepatic shunts?
Using a Doppler ultrasound-guided method.
What approach is commonly used for challenging intrahepatic PSS attenuation?
Extravascular or intravascular dissection techniques.
What is a primary postoperative risk associated with shunt attenuation?
Portal hypertension.
What procedure might be used if a shunt is not located during surgery?
Intraoperative mesenteric portography.
What are potential sites for multiple acquired PSSs?
Near the kidneys and within the intestinal mesentery.
What kind of catheter is used in mesenteric portography?
A transsplenic portal catheter.
How is portal hypertension evaluated post-shunt ligation?
By measuring portal pressures using a manometer or transducer.
What clinical sign might indicate postoperative portal hypertension?
Abdominal distention or pain.
Why are central venous pressure measurements useful during PSS surgery?
To assess portal hypertension risk.
What condition commonly accompanies multiple acquired PSSs?
Ascites due to portal hypertension.
What dietary measure is often recommended post-shunt surgery?
A protein-restricted diet.
What is the purpose of using lactulose postoperatively in shunt cases?
To reduce ammonia production and prevent hepatic encephalopathy.
Why is the peritoneum sometimes opened during PSS surgery?
To improve exposure for shunt occlusion.
What is one of the main complications of gradual shunt attenuation devices like cellophane bands?
Persistent shunt flow due to reduced inflammatory response in some species.
What is a primary benefit of gradual attenuation for PSS occlusion?
Reduced risk of portal hypertension.
What factor often influences the choice of constrictor size in shunt attenuation?
The shunt diameter.
Why is portal pressure important to monitor during shunt attenuation surgery?
To determine tolerance to shunt closure and prevent complications.
Which vessel must be retracted to expose the epiploic foramen during surgery?
The duodenum.
What imaging method might help confirm shunt vessel placement during surgery?
Fluoroscopic guidance.
What potential postoperative complication may lead to seizures?
Hypoglycemia.
What method is used to measure portal pressure with a jejunal vein catheter?
By attaching the catheter to a water manometer or pressure transducer.
Why might dogs with PSS have low portal vein size?
Due to decreased resistance from congenital shunts.
What type of shunt is often managed with interventional radiology rather than open surgery?
Intrahepatic portosystemic shunts.
Why are jugular catheters placed in PSS surgery involving the diaphragm?
For central venous access during extensive shunt management.
What should be anticipated when performing intrahepatic shunt dissection?
High risk of intraoperative hemorrhage.
What is a commonly used contrast agent for intraoperative mesenteric portography?
Iodinated contrast materials.
What type of venous access is preferred for hepatic arteriovenous malformation surgery?
The femoral artery.
What specific anesthetic recovery issue is monitored post-PSS attenuation surgery?
Delayed anesthetic recovery.
Why might gastric protectants be used postoperatively in PSS surgeries?
To prevent gastrointestinal bleeding associated with portal hypertension.
What liver change is commonly noted in dogs with multiple acquired PSS?
The liver may appear small and firm with nodular texture.
What indicates a better clinical outcome after gradual shunt occlusion?
Reduced portal pressures with hepatopetal blood flow direction.
Which animals generally have a poor prognosis after developing multiple acquired shunts?
Those with chronic liver disease.
What is a possible outcome if intrahepatic shunts are completely occluded?
Improved liver function and reduced shunt flow.
What is the purpose of placing a stent in a transjugular coil embolization for intrahepatic PSS?
To prevent coil migration.
How does cellophane banding gradually occlude PSSs?
By causing an inflammatory response that leads to fibrous tissue formation.
What approach may reduce the need for repeat surgery in gradual shunt attenuation?
Ensuring close placement of occlusion devices near the shunt insertion.
What dietary supplements might benefit patients postoperatively in hepatic encephalopathy?
Probiotics or live active cultures.
