What is an abdominal aortic aneurysm?

An abdominal aortic aneurysm, also called AAA or triple A, is a bulging, weakened area in the wall of the aorta (the largest artery in the body) resulting in an abnormal widening or ballooning greater than 50 percent of the normal diameter (width).

The aorta is under constant pressure as blood is ejected from the heart. With each heart beat, the walls of the aorta distend (expand) and then recoil (spring back), exerting continual pressure or stress on the already weakened aneurysm wall. Therefore, there is a potential for rupture (bursting) or dissection (separation of the layers of the aortic wall) of the aorta.  
 
This may cause life-threatening hemorrhage (uncontrolled bleeding). The larger the aneurysm becomes, the greater the risk of rupture.  Sometimes, a tear can occur on the inside layer of the vessel resulting in blood filling in between the layers of the blood vessel wall and creating a dissection. 

Because an aneurysm may continue to increase in size, along with progressive weakening of the artery wall, surgical intervention may be needed. Preventing rupture of an aneurysm is one of the goals of therapy. 

What causes an abdominal aortic aneurysm to form?

An abdominal aortic aneurysm may be caused by multiple factors that result in the breaking down of the well-organized structural components (proteins) of the aortic wall that provide support and stabilize the wall. The exact cause is not fully known.

Atherosclerosis (a build-up of plaque, which is a deposit of fatty substances, cholesterol, cellular waste products, calcium and fibrin in the inner lining of an artery) is thought to play an important role in aneurysmal disease, including the risk factors associated with atherosclerosis. They include:

  • age (greater than 60)
  • male (occurrence in males is four to five times greater than that of females)
  • family history (first degree relatives, such as father or brother)
  • genetic factors
  • hyperlipidemia (elevated fats in the blood)
  • hypertension (high blood pressure)
  • smoking
  • diabetes

Other diseases that may cause an abdominal aneurysm include:
  • genetic disorders of connective tissue (abnormalities that can affect such tissues as bones, cartilage, heart, and blood vessels), such as Marfan's syndrome, Ehlers-Danlos syndrome, Turner's syndrome and polycystic kidney disease
  • congenital (present at birth) syndromes, such as bicuspid aortic valve or coarctation of the aorta
  • giant cell arteritis: a disease that causes inflammation of the temporal arteries and other arteries in the head and neck. This causes the arteries to narrow, reducing blood flow in the affected areas. It may cause persistent headaches and vision loss
  • trauma
  • infectious aortitis (infections of the aorta) due to such infections as syphilis, salmonella, or staphylococcus. These infectious conditions are rare.

What are the symptoms of abdominal aortic aneurysms?

Aortic disease is often insidious. Most people with aortic aneurysms experience no symptoms, unless they are extremely large or an aortic dissection occurs.   About three of every four abdominal aortic aneurysms are asymptomatic.  

When present, symptoms may occur with different types of aneurysms may include, but are not limited to, the following:  constant pain in abdomen, chest, back or groin area or a pulsatile mass in the abdomen.

The pain associated with an abdominal aortic aneurysm may be located in the abdomen, chest, lower back, or groin area. The pain may be severe or dull. The occurrence of pain is often associated with the imminent (about to happen) rupture of the aneurysm.    Acute, sudden onset of severe pain in the back and/or abdomen may represent rupture and is a life-threatening medical emergency.
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How are aneurysms diagnosed?

For most people, their aortic condition is discovered incidentally while being tested for other reasons. An aneurysm may also be discovered by x-ray, computed tomography scan (CT scan), or magnetic resonance imaging (MRI) that is being done for other conditions. Since abdominal aneurysm may be present without symptoms, it is referred to as the "silent killer" because it may rupture before being diagnosed.   

How is an abdominal aneurysm treated?

Treatment options for an aortic aneurysm may include one or more of the following:
  • Controlling or modifying risk factors: such as quitting smoking, controlling blood sugar if diabetic, losing weight if overweight or obese and controlling dietary fat intake may help to slow the progression of the aneurysm
  • Observation:   routine ultrasound, CT, or MRI procedures to monitor the size and rate of growth of the aneurysm
  • Medication: to control factors such as hyperlipidemia (elevated levels of fats in the blood) and/or high blood pressure
  • Open Aneurysm Repair: the diseased area of the aorta if replaced with a fabric graft
  • Stent graft or endograft: used to treat aneurysms of the descending and abdominal aneurysm; it is comprised of a layer of impermeable reinforcement material enclosed by a self-expanding metal support mesh and is placed across the aneurysm site 

Open Aneurysm Repair

An incision is made in the abdomen to directly visualize the abdominal aorta and repair the aneurysm. A cylinder-like tube called a graft may be used to repair the aneurysm. Grafts are made of various materials such as Dacron (textile polyester synthetic graft) or polytetrafluoroethylene (PTFE, non-textile synthetic graft). This graft is sewn to the aorta, connecting one end of the aorta at the site of the aneurysm to the other end. The open repair is considered the surgical standard for an abdominal aortic aneurysm repair.  

Endovascular Aneurysm Repair (EVAR)

EVAR is a procedure that requires only small incisions in the groin, along with the use of x-ray guidance and specially-designed instruments, to repair the aneurysm by inserting a tube, called a stent-graft, inside the aorta. In this minimally invasive procedure, the stent graft (comprised of a layer of impermeable reinforcement material enclosed by a self-expanding metal support mesh) is placed across the aneurysm site. To achieve stent graft placement, the surgeon inserts a catheter through the femoral artery in the groin. The stent graft is then delivered through the catheter in a collapsed state and deployed at the site of the aneurysm. The device replaces and reinforces the diseased aortic wall, ensuring continuity of blood flow. The potential benefits of the procedure include greatly reduced risk, a shorter hospital stay, and a more rapid recovery. Not all aortic aneurysms can be repaired with EVAR.

Specific treatment will be determined by your physician based on: age, overall health and medical history; size, location, and extent of the disease; signs and symptoms; tolerance of specific medications, procedures or therapies; expectations for the course of the disease; and preference.    

Information 
for Patients

The Find the AAAnswers Coalition is an alliance of concerned physician societies that have come together to provide information about abdominal aortic aneurysms (AAA) and advocate for changes in the screening, diagnosis and management of the disease. 

Animation of an Endovascular 
Aneurysm Repair

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Patient Experience 
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