Percutaneous transvenous coil embolization of portosystemic shunts

Percutaneous transvenous coil embolization of portosystemic shunts

Jan 01, 2012

A congenital portosystemic shunt (PSS) is a vascular anomaly connecting the portal venous system with the central venous system, allowing nutrient-rich blood to bypass the liver, avoid detoxification and enter the systemic circulatory system, leading to a variety of biochemical and clinical sequellae. See how a minimally invasive procedure helped this puppy.

Initial findings

  • Signalment: 5-month-old 22-kg intact male Labrador retriever
  • Presenting complaint: Hepatoencephalopathy due to suspected PSS
  • Pertinent history: Three-month history of intermittent ataxia, poor growth, exercise intolerance and reduced appetite; owners report some improvement with antibiotics
  • Medications: Ampicillin
  • Physical examination findings: Quiet, alert and responsive; heart rate = 70 beats/min; body condition score 3/9; no murmurs auscultated; no neurologic abnormalities; abdominal palpation unremarkable; rectal examination normal (no melena)

Diagnostic evaluation

  • Complete blood count: Moderately elevated white blood cell count with mature neutrophilia, with a nonregenerative microcytic anemia (mean corpuscular volume = 54, hematocrit = 31 percent)
  • Serum chemistry profile: Alanine transaminase = 154, aspartate transaminase = 87, blood urea nitrogen 3, albumin = 1.9, globulin = 2.2, cholesterol = 125
  • Bile acids: Pre-prandial = 119, post-prandial = 244
  • Protein concentration: 44
  • Urinalysis urine culture: Urine specific gravity = 1.016, ammonium biurate crystalluria; culture results pending
  • Abdominal ultrasonography: Declined in favor of future computed tomography (CT) angiography

Initial treatment decisions

After an intrahepatic PSS was diagnosed, a medical regimen was recommended to reduce the clinical signs associated with the hepatic dysfunction and gastrointestinal upset, including lactulose (dosed to produce soft but formed bowel movements), metronidazole (7.5 mg/kg b.i.d.), omeprazole (1 mg/kg b.i.d.) and a low-protein diet compatible with liver disease. The patient was discharged with instructions to return in about one month for CT angiography. The delay in further imaging was done to maximize the patient's medical regimen in order to reduce any potential risks associated with general anesthesia.

CT angiography and treatment options

The patient returned one month later with reports that it had dramatically improved on these medications. It had gained 4.5 kg and was having no further neurologic or ataxic episodes. A dual-phase CT angiogram was performed, which demonstrated a large, left divisional intrahepatic PSS. Portal perfusion to the liver was substantially diminished, and the liver was small. The kidneys were mildly enlarged with mild renal pelvic mineralization or nephrolithiasis.

Medical, surgical and interventional management was discussed with the owners. Understanding that medical management would likely be temporary and concerned about the risk associated with traditional open surgery, the owners opted for a minimally invasive approach using percutaneous transvenous coil embolization.