What is an aortic aneurysm?
Abnormal enlargement or bulging of the aorta, the largest blood vessel of the body, is not an unusual condition. Health-care professionals refer to this as aneurysm of the great vessel, or aortic aneurysm. The enlargement usually affects only a small part of the vessel, so bulge is a more accurate description.
An aneurysm occurs when a segment of the vessel becomes weakened and expands. The pressure of the blood flowing through the vessel creates a bulge at the weak spot, much as an overinflated inner tube can cause a bulge in a tire. The bulge usually starts small and grows as the pressure continues. Aneurysms are dangerous because they can rupture, causing internal bleeding. Bulging can occur in any artery in the body. It is most common in the arteries of the brain and in the abdominal aorta. Bulges in an artery are classified as true aneurysm, false aneurysm, or dissection.
- In the aorta, bulging can occur anywhere along the entire vessel.
- It is most common in the abdominal aorta, where it is known as abdominal aortic aneurysm (triple AAA).
- If it occurs in the thoracic aorta, it is known as thoracic aortic aneurysm.
- A true aneurysm involves all three layers of the blood vessel wall.
- A false aneurysm of the artery is contained only by the two outer layers of the blood vessel wall and clot. This is a very fragile condition with high risk of bursting. False aneurysms are usually a result of an infection.
- Because the abdominal aorta is such a large vessel, a ruptured abdominal aneurysm is a life-threatening event.
- Fortunately, not all aneurysms rupture right away. Many grow very slowly and cause no symptoms or problems for many years.
- When detected in time, most aneurysms can be electively repaired with an operation so they do not rupture.
- Most aneurysms occur in people aged 65 years or older.
- The number of aneurysms in the United States is increasing as the population increases and ages.
- Aneurysms are more common in men than in women.
- A related but different condition is aortic dissection. Dissection refers to a separation of the vessel wall, which allows blood to leak between the layers of the vessel. This further damages and weakens the vessel, placing it at much greater risk of bursting (rupture).
Last Reviewed 11/20/2017
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