The force of blood pushing against the walls of an artery combined with damage or injury to the artery’s walls can cause an aneurysm.
Many conditions and factors can damage and weaken the walls of the aorta and cause aortic aneurysms. Examples include aging, smoking, high blood pressure, and atherosclerosis (ath-er-o-skler-O-sis). Atherosclerosis is the hardening and narrowing of the arteries due to the buildup of a waxy substance called plaque (plak).
Rarely, infections—such as untreated syphilis (a sexually transmitted infection)—can cause aortic aneurysms. Aortic aneurysms also can occur as a result of diseases that inflame the blood vessels, such as vasculitis (vas-kyu-LI-tis).
A family history of aneurysms also may play a role in causing aortic aneurysms.
In addition to the factors above, certain genetic conditions may cause thoracic aortic aneurysms (TAAs). Examples of these conditions include Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome (the vascular type), and Turner syndrome.
These genetic conditions can weaken the body’s connective tissues and damage the aorta. People who have these conditions tend to develop aneurysms at a younger age than other people. They’re also at higher risk for rupture and dissection.
Trauma, such as a car accident, also can damage the walls of the aorta and lead to TAAs.
Researchers continue to look for other causes of aortic aneurysms. For example, they’re looking for genetic mutations (changes in the genes) that may contribute to or cause aneurysms.