Aortic Aneurysm

Types

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

The wall of the aorta consists of three layers: a thin inner layer of smooth cells called the endothelium, a muscular middle layer which has elastic fibers, and a tough outer layer. When the wall of the aneurysm has all three layers, it is called a true aneurysm. If only the outer layer of the aneurysm remains, it 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

Abdominal aortic aneurysms are the most common, comprising up to 75 percent of aortic aneurysms. They are located along the portion of the aorta that passes through the abdomen. The abdominal aorta carries blood down through the abdomen, providing blood to the vital organs until it eventually splits off into two smaller arteries that supply blood to the pelvis and legs.

Abdominal aortic aneurysms can affect anyone, but most often affect men ages 40 to 80. Most abdominal aortic aneurysms are caused by atherosclerosis.

More about abdominal aortic aneurysm treatment.

Thoracic Aortic Aneurysms

The aorta is shaped like a walking cane with the short stem of the curved handle coming out of the heart and curling through the aortic arch, which gives off branches to the head and arms. Then the aorta descends through the chest cavity into the abdomen and separates to provide blood to the abdominal organs and both legs. Thoracic aneurysms can occur anywhere along the aorta above the diaphragm, including the ascending aorta, the aortic arch, and the descending thoracic aorta.

As many as 25 percent of aortic aneurysms are thoracic. They can result from various connective tissue disorders (such as Marfan syndrome), previous dissection of the aorta, prolonged high blood pressure (hypertension), and trauma (usually falls or motor vehicle accidents). They also sometimes occur in people who have bicuspid aortic valves.

More about thoracic aortic aneurysm treatment.

Dissecting Aneurysms

Dissecting Aneurysm

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Fusiform Aneurysm

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Saccular Aneurysm

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Dissecting aneurysms occur when a tear begins within the wall of the aorta causing the three layers to separate. The effect is similar to what happens to plywood left out in the weather. The dissection weakens the wall of the aorta, and the aorta enlarges. Dissections can cause aneurysms, but an existing aneurysm can also dissect.

Dissections can occur anywhere along the aorta, and treatment depends upon the location. Frequently, dissections involving the ascending aorta (in the front near the heart) are treated with emergency surgery while those involving the descending thoracic aorta (in the back) are treated with medication.

Although uncommon, dissections are the most common acute aortic syndrome. They are lethal if not treated and should be treated only by surgeons and physicians with expertise in treating this type of disorder.

More about dissecting aneurysm treatment.

Fusiform Aneurysms

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

Saccular Aneurysms

Saccular aneurysms appear like a small blister or bleb on the side of the aorta and are asymmetrical. Typically they are pseudoaneurysms caused by trauma such as a car accident or by a penetrating aortic ulcer.