Segmental caudal vena cava aplasia and porto-azygos shunt in a female shih-tzu dog

Marganit Yaffe*, I. Aroch

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Segmental aplasia of the caudal vena cava (CVC), also termed azygos continuation of the CVC, CVC uniting with the azygos vein, and CVC absence, interruption or discontinuation, is a very rare congenital anomaly in dogs, reported only several times in dogs, and is similar to segmental aplasia of the inferior vena cava (IVC) in humans (also termed IVC atresia). An intact female Shih-Tzu dog, aged 18 months was presented with a history of aimless walking, hematochezia and hypersalivation. Laboratory tests showed hyperammonemia, increased liver enzyme activity and decreased liver functions, suggestive of hepatic encephalopathy. Abdominal ultrasonography and computed tomography (CT) with angiography showed several marked vascular anomalies, including segmental CVC aplasia and porto-azygos shunt. This combined vascular anomaly is an extremely rare congenital condition in dogs, since azygos continuation of the CVC occurs most often in the absence of portosystemic shunting. Based on the imaging findings, surgical correction of this shunt was not an option. The dog was therefore treated conservatively with oral lactulose and a commercial prescription hepatic diet. The dog improved clinically, and was stable over a nine month follow-up period. CT scanning with contrast media angiography was a sensitive tool to detect the portosystemic shunt and to demonstrate this unique and rare combined vascular anomaly.

Original languageAmerican English
Pages (from-to)41-46
Number of pages6
JournalIsrael Journal of Veterinary Medicine
Issue number1
StatePublished - 2021

Bibliographical note

Publisher Copyright:
© 2021, Israel Veterinary Medical Association. All rights reserved.


  • CVC Aplasia
  • Canine
  • Computed Tomography
  • Hepatic Encephalopathy
  • Hyperammonemia
  • Porto-Systemic Shunt


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