What causes an aortic aneurysm?

Mark J. Russo, MD
Thoracic Surgery (Cardiothoracic Vascular)

Thoracic aortic aneurysms may be caused by different disease processes, especially in respect to their location. Examples of different locations of thoracic aortic aneurysms and their causes may include, but are not limited to, the following:

Ascending Thoracic Aneurysm

  • cystic medial degeneration (necrosis): breaking down of the tissue of the aortic wall. This is the most common cause of this type of thoracic aortic aneurysm.
  • genetic disorders which affect the connective tissue, such as Marfan's syndrome and Ehlers-Danlos syndrome
  • family history of thoracic aortic aneurysm with no incidence of Marfan's syndrome
  • atherosclerosis: hardening of the arteries caused by a build-up of plaque in the inner lining of an artery. This is a rare cause of ascending thoracic aortic aneurysm.
  • infection, syphilis (rare causes of thoracic aortic aneurysm)

Aortic Arch Thoracic Aneurysm

  • Takayasu's arteritis: a type of vasculitis that causes inflammation of the arteries
  • atherosclerosis
  • continuation of an ascending and/or descending aortic aneurysm

Descending Thoracic and Abdominal Aortic Aneurysm - Atherosclerosis is most often associated with descending aneurysms and is thought to play an important role in aneurysmal disease. The following risk factors associated with atherosclerosis such as:

  • age (greater than 55)
  • male gender
  • family history (first-degree relatives such as father or brother)
  • genetic factors
  • hyperlipidemia (elevated fats in the blood)
  • hypertension (high blood pressure)
  • smoking
  • diabetes
The most common causes of aortic aneurysm are atherosclerosis and high blood pressure. At highest risk are males over the age of 60 who smoke and people with a family history of abdominal aortic aneurysm. If you're at risk, you should be evaluated early and monitored regularly.
William J. Quinones Baldrich, MD
Vascular Surgery
It is not known what causes aneurysms. Although most aortic aneurysms are associated with atherosclerosis, they are actually degenerative in nature. Degradation of the proteins within the wall of the aorta leads to weakening of the artery, dilation of the segment and formation of the aneurysm. Other causes of aneurysms may include genetic defect, infection or disruption of a previously placed aortic graft with a small bleed covering what is called a false aneurysm. Aortic aneurysms are not associated with brain aneurysms.
The exact cause of an aortic aneurysm is often difficult to determine, but many factors potentially can contribute to the development of an aortic aneurysm. Some of the most common conditions associated with aneurysm formation are:
  • congenital or genetic causes for weakness of the artery wall (present from birth)
  • changes in the aorta due to advanced age
  • connective tissue disorders such as Marfan or Ehlers-Danlos syndrome
  • inflammation of the aorta
  • hardening of the arteries (atherosclerosis) where fat, cholesterol, and other substances (plaque) clog the arteries
  • injury from falls or motor vehicle accidents
  • untreated infection such as syphilis or salmonella
In some cases, aneurysms run in families and are classified as “familial," so several members of extended families may be affected by aneurysms in different locations.

This content originally appeared online in "The Patient Guide to Heart, Lung, and Esophageal Surgery" from the Society of Thoracic Surgery.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.