Thoracic Aortic Aneurysm

An aneurysm is a type of vascular disease marked by an abnormal sac-like dilatation in the wall of an artery, vein or heart. It indicates a thin and weakened area in the wall that may later rupture causing dangerous, often fatal internal bleeding. Aneurysms are classified by location, origin and other characteristics. The abdominal aorta is the most common site of aneurysm formation, yet the ascending thoracic aorta can also have aneurysmal expansion with potentially dire outcomes. A dissecting aneurysm is caused by a tear in the innermost coat of blood vessels, which results in bleeding and splitting (dissecting) of the vessel wall, often involving the aorta. Familial aortic aneurysm has been reported in the Leonberger. For both abdominal and thoracic aortic aneurysms, there are no medical treatments.2


In some cases, aortic aneurysms result in a parasitic infestations of the walls of the esophagus. Spirocerca lupi nematode is a major canine parasite in warm regions of the world, classically causing parasitic nodules in the esophagus, aortic aneurysms, and spondylitis. The adult S. lupi occurs in a nodular mass in the wall of the esophagus. The infective larvae penetrate the gastric mucosa, and migrate within the walls of the gastric arteries to the thoracic aorta. About 3-months post-infection, the larvae leave the aorta and migrate to the esophagus where they provoke the development of granulomas as they mature to adults over the next 2 to 3 months. Although quite rare in the United States, the parasite is a serious pathogen of dogs, causing potentially fatal heart, lung, eye and central nervous system disease.4 A case of mycotic aortic aneurysm in a German Shepherd dog has recently been reported. Fungal organisms were identified in the aortic aneurysm as well as from the thoracic vertebrae, lymph nodes, spleen, kidneys, liver, lungs and heart.5 In rare cases, aortic aneurysm may result in the enlargement of the aortic arch.7


  1. Aortic Aneurysm - University of Michigan Cardiac Surgery
  2. Hong Lu, Debra L. Rateri, Lisa A. Cassis, and Alan Daugherty. The Role of the Renin-Angiotensin System in Aortic Aneurysmal Diseases
  3. Todd R. Tams. Handbook of small animal gastroenterology
  4. A. Zajac, Gary A. Conboy. Veterinary clinical parasitology
  5. James Sutherland-Smith, BVSc, Diplomate ACVR and Catherine L. Rogers, DVM, Diplomate ACVECC. Abdominal Aortic Aneurysm Associated with Systemic Fungal Infection in a German Shepherd Dog. Ryan T. Gershenson, DVM, Raffaele Melidone
  6. Efficacy of a combination of imidacloprid 10%/moxidectin 2.5% spot-on (Advocate® for dogs) in the prevention of canine spirocercosis (Spirocerca lupi)
  7. Manual of Canine and Feline Cardiology. Lawrence P. Tilley



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