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Aortic Aneurysms (TAA & AAA)

Background

Diagnosis

Screening

Treatment Options

Common Questions & Answers

Glossary

Bibliography

 

 


Common Questions & Answers

What is an aneurysm?

What is an aortic aneurysm?

What are the thoracic and abdominal aorta?

Where do aortic aneurysms tend to develop?

What shape are most aortic aneurysms?

What's inside an aortic aneurysm?

Who is most likely to have an abdominal aortic aneurysm?

What is the most common cause of aortic aneurysms?

What are other causes of aortic aneurysms?

What are the symptoms of an abdominal aortic aneurysm?

How is an abdominal aortic aneurysm diagnosed clinically?

What tests help in the diagnosis of an abdominal aortic aneurysm?

What is the natural history of abdominal aortic aneurysms?

What are the complications with an abdominal aortic aneurysm?

How are abdominal aortic aneurysms repaired?

What is done if an abdominal aortic aneurysm threatens to rupture?

What happens if an abdominal aortic aneurysm ruptures?

Abdominal Aortic Aneurysm At A Glance

 

 

What is an aneurysm?

An aneurysm is an area of a localized widening (dilation) of a blood vessel. (The word "aneurysm" is borrowed from the Greek "aneurysma" meaning "a widening").

What is an aortic aneurysm?

An aortic aneurysm involves the aorta, one of the large arteries that carries blood from the heart to the rest of the body. The aorta bulges at the site of the aneurysm like a weak spot on an old worn tire.

What are the thoracic and abdominal aorta?

The aorta is first called the thoracic aorta as it leaves the heart, ascends, arches, and descends through the chest until it reaches the diaphragm (the partition between the thorax and abdomen). The aorta is then called the abdominal aorta after it has passed the diaphragm and continues down the abdomen. The abdominal aorta ends where it splits to form the two iliac arteries that go to the legs.

Where do aortic aneurysms tend to develop?

Aortic aneurysms can develop anywhere along the length of the aorta. The majority, however, are located along the abdominal aorta. Most (about 90%) of abdominal aneurysms are located below the level of the renal arteries, the vessels that leave the aorta to go to the kidneys. About two-thirds of abdominal aneurysms are not limited to just the aorta but extend from the aorta into one or both of the iliac arteries.

What shape are most aortic aneurysms?

Most aortic aneurysms are fusiform. They are shaped like a spindle ("fusus" means spindle in Latin) with widening all around the circumference of the aorta. (Saccular aneurysms just involve a portion of the aortic wall with a localized out pocketing).

What's inside an aortic aneurysm?

The inside walls of aneurysms are often lined with a laminated blood clot that is layered like a piece of plywood.

Who is most likely to have an abdominal aortic aneurysm?

Abdominal aortic aneurysms are most common after age 60. Males are 5 times more likely than females to be affected. This means men over 60 are at highest risk to develop an abdominal aortic aneurysm. Approximately 5% of men over age 60 develop an abdominal aortic aneurysm.

What is the most common cause of aortic aneurysms?

The most common cause of aortic aneurysms is "hardening of the arteries" called arteriosclerosis. At least 80% of aortic aneurysms are from arteriosclerosis. The arteriosclerosis can weaken the aortic wall and the pressure of the blood being pumped through the aorta causes expansion at the site of weakness.

What are other causes of aortic aneurysms?

Other causes of aortic aneurysms include:

  • Genetic: There is a familial tendency to aortic aneurysms. This tendency is at least in part genetic. Among the inheritable causes of aortic aneurysms are connective tissue disorders such as Ehlers-Danlos syndrome and Marfan's syndrome.
  • Post-traumatic: After physical trauma to the aorta.
  • Arteritis (inflammation of blood vessels) as occurs in Takayasu disease, giant cell arteritis, and relapsing polychondritis.
  • Congenital malformation of the aorta (aneurysms tend to develop just beyond the narrowing of a coarctation of the aorta; also with what is called a ductus diverticulum).
  • End-stage (tertiary) syphilis, which tends to affect the ascending aorta and arch of the aorta.
  • Mycotic (fungal) infection which may be associated with immunodeficiency, IV drug abuse, heart valve surgery.

What are the symptoms of an abdominal aortic aneurysm?

Abdominal aortic aneurysms may cause pain. The pain typically has a deep quality as if it is boring into the person. It is felt most prominently in the lower back region. The pain is usually steady but may be relieved by changing position. The person may also become aware of an abnormally prominent abdominal pulsation. However, many aneurysms are without symptoms. They may become large and even rupture without warning.

How is an abdominal aortic aneurysm diagnosed clinically?

Careful feeling of the abdomen by the doctor may reveal the abnormally wide pulsation of the abdominal aorta. This is characteristically felt on both sides of the aorta which is in the midline. Note that even large aneurysms can be very difficult to detect on physical examination in overweight people. Aneurysms that are rapidly enlarging and on the verge of rupture are often tender.

What tests help in the diagnosis of an abdominal aortic aneurysm?

X-rays of the abdomen show calcium deposits in the aneurysm wall in about 90% of cases. Ultrasonography usually gives a clear picture of the extent and size of an aneurysm. Ultrasound has about 98% accuracy in measuring the size of the aneurysm. CT scanning of the abdomen, particularly with contrast medium, can be highly accurate in determining the size and shape of the aneurysm. MRI scanning is similarly accurate but is rarely necessary. Abdominal aortography shows the origin of the major blood vessels arising from the aorta and reveals the size and extent of any aneurysm. Contrast aortography is especially useful if there is extension of the aneurysm above the renal arteries and in delineating a mural thrombus (a clot clinging to the wall of the aneurysm).

What is the natural history of abdominal aortic aneurysms?

The natural history of abdominal aortic aneurysms depends on their size. Rupture of aneurysms is uncommon when they are less than 5 cm wide. Rupture is far more common in aneurysms that are over 6 cm wide. Surgical repair is therefore usually recommended for all aneurysms over 6 cm wide. Elective repair is also generally recommended for aneurysms between 4 and 6 cm in patients who are good surgical risks.

What are the complications with an abdominal aortic aneurysm?

Rupture is a feared problem. Half of all persons with untreated abdominal aortic aneurysms die of rupture within 5 years. Abdominal aortic aneurysms are the 13th leading cause of death in the U.S. Peripheral embolization of clot within the aneurysm can occur when a piece of clot comes loose and travels further out in the arterial system. This clot fragment can lodge in a smaller artery and block the flow of blood. Infection of aneurysms can occur from turbulent blood flow from the rough inner surface. Spontaneous blockage of the aorta can also occur.

How are abdominal aortic aneurysms repaired?

Traditionally, repair of an aortic aneurysms has been surgical. The surgery has usually consisted of opening the abdomen, removing (excising) the aneurysm, and sewing a synthetic (Dacron) tube in its place.

More recently, "minimally invasive" procedures have been devised using stent grafts that can be guided to the site of the aneurysm without the need to cut open the abdomen. The first stent graft was installed in 1991 by Dr. Juan Parodi in Argentina.

A stent graft developed by Dr. Thomas Fogarty at Stanford is a Dacron tube inside a collapsed metal-mesh cylinder. To install the stent, a small incision is made in the thigh to gain access to the femoral artery. The stent, about 6 inches (15 cm) long, is guided inside a long plastic capsule through the arteries to the lower aorta. Once the stent is in place, the holding capsule is removed. Activated by heat, the stent expands like a spring and becomes anchored to the artery wall. The by-passed aneurysm then is shielded from the blood flow and typically shrinks over time.

According to a U.S. national multi-center study reported by Dr. Christopher Zari from Stanford in 1998, the "minimally invasive" installation of the stent graft carries a lower rate of complications and permits people to get back on their feet faster than traditional open surgery.

What is done if an abdominal aortic aneurysm threatens to rupture?

Threatened rupture of abdominal aneurysms is a surgical emergency. The operative risk for a ruptured aneurysm is about 50%. If kidney failure occurs after surgery, the prognosis (outlook) is particularly poor.

What happens if an abdominal aortic aneurysm ruptures?

Rupture of an abdominal aneurysm is a catastrophe. It is highly lethal and is usually preceded by excruciating pain in the lower abdomen and back, with tenderness of the aneurysm. Rupture of an abdominal aneurysm causes profuse bleeding and leads to shock. Death may rapidly follow.

Abdominal Aortic Aneurysm At A Glance

  • An aneurysm is an abnormal area of localized widening of a blood vessel.
  • The aorta bulges at the site of an aneurysm like a weak spot on a worn tire.
  • Aortic aneurysms are typically spindle-shaped and involve the aorta below the arteries to the kidneys.
  • Five percent of men over 60 develop an abdominal aortic aneurysms.
  • The most common cause of an aneurysm is arteriosclerosis.
  • Abdominal aortic aneurysms often do not cause symptoms. If they do, they may cause deep boring pain in the lower back or abnormally prominent abdominal pulsation.
  • X-rays of the abdomen and other radiologic tests can be used in diagnosing an aneurysm.
  • Rupture of an aortic aneurysm is a catastrophe.
  • Repair of the aneurysm can be done by surgery or by installation of a stent graft.
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