Automobile-induced obstruction of the intrathoracic caudal vena cava in a dog.

A two-year-old labrador retriever was examined after a year's history of persistent ascites and exercise intolerance that began shortly after the dog was struck by an automobile. Contrast venography showed tortuosity of the intrathoracic caudal vena cava with partial obstruction caused by kinking of the vessel. Surgical resection of a fibrous connective band that was found to be tethering the intrathoracic vena cava ventrally, creating a partial obstruction, was performed. A hypothesis of the aetiology of this phenomenon is presented.