Aortic Aneurysm

Types

Aortic aneurysms are classified by shape, location along the aorta, and the process that leads to their formation.

The aortic wall consists of three layers: a thin inner layer of smooth cells called the endothelium, a muscular middle layer that includes elastic fibers, and a tough outer layer.

If the aneurysm is still contained in all three layers of the aortic wall, it is called a true aneurysm. If only the outer layer of the aortic wall remains, the aneurysm is called a pseudoaneurysm. Pseudoaneurysms may occur as a result of trauma when the inner layers are torn apart.

Abdominal Aneurysm

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Abdominal Aortic Aneurysms

Nearly 75 percent of aortic aneurysms are abdominal.

Abdominal aortic aneurysms are located along the portion of the aorta that passes through the abdomen, carrying blood to the vital organs until it splits off into two smaller arteries that supply blood to the pelvis and legs.

Abdominal aortic aneurysms can affect anyone, but most often occur in men ages 40 to 80. Most abdominal aortic aneurysms are caused by atherosclerosis (hardening of the arteries.)

Learn more about abdominal aortic aneurysm treatment.

Thoracic Aortic Aneurysms

Approximately 25 percent of aortic aneurysms are thoracic.

Thoracic aneurysms can occur anywhere along the aorta above the diaphragm (the partition separating the chest from the abdomen), including the ascending aorta, the aortic arch, and the descending thoracic aorta.

They can result from connective tissue disorders such as Marfan syndrome, previous dissection (separation of the layers of the wall) of the aorta, prolonged hypertension (high blood pressure) and trauma (usually falls or motor vehicle accidents). Thoracic aortic aneurysms also may occur in people who have bicuspid aortic valves, a condition in which two cusps, instead of the normal three, seal the valves when they're closed.

Learn more about thoracic aortic aneurysm treatment.

Dissecting Aneurysm

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Fusiform Aneurysm

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Saccular Aneurysm

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Dissecting Aneurysms

Dissecting aneurysms occur when a tear begins within the wall of the aorta, causing its three layers to separate. Dissection weakens the wall of the aorta, which enlarges. Dissection may cause aneurysms, but an existing aneurysm may also dissect.

Dissections may occur anywhere along the aorta. Treatment depends on the location. Dissections involving the ascending aorta (in the front near the heart) often are treated with emergency surgery. Dissections involving the descending thoracic aorta (in the back) are treated with medication.

Although uncommon, dissections are the most common aortic syndrome that causes acute (severe) signs and symptoms. Dissections can be lethal if not treated by surgeons and physicians with expertise in treating this disorder.

Learn more about dissecting aneurysm treatment.

Fusiform Aneurysms

Most fusiform aneurysms are true aneurysms. The weakness often is located along an extended section of the aorta and involves the aorta's entire circumference. The weakened portion appears as a nearly symmetrical bulge.

Saccular Aneurysms

A saccular aneurysm appears to be a small blister on the side of the aorta. It is asymmetrical (uneven). Saccular aneurysms typically are caused by trauma such as a car accident or by a penetrating aortic ulcer.