An aneurysm is when a blood vessel becomes abnormally large or balloons outward. The abdominal aorta is a large blood vessel that supplies blood to your abdomen, the pelvis, and legs.

The exact cause is unknown, but risk factors for developing an aortic aneurysm include:

• High blood pressure
• Smoking
• High cholesterol
• Obesity
• Emphysema
• Genetic factors
• Male gender

An abdominal aortic aneurysm can develop in anyone, but it is most frequently seen in males over 60 with one or more risk factors. The larger the aneurysm, the more likely it is to rupture.

When an abdominal aortic aneurysm ruptures, it is a true medical emergency. Aortic dissection occurs when the innermost lining of the artery tears and blood leaks into the wall of the artery. This most commonly occurs in the aorta within the chest.

Aneurysms develop slowly over many years and often have no symptoms. If an aneurysm expands rapidly, tears open (ruptured aneurysm), or blood leaks along the wall of the vessel (aortic dissection), symptoms may develop suddenly.

The symptoms of rupture include:

• Pulsating sensation in the abdomen
• Pain in the abdomen or back -- severe, sudden, persistent, or constant. The pain may radiate to groin, buttocks, or legs.
• Abdominal rigidity
• Anxiety
• Nausea and vomiting
• Clammy skin
• Rapid heart rate when rising to a standing position
• Shock
• Abdominal mass

Your doctor will examine your abdomen. The exam also will include an evaluation of pulses and sensation in your legs.

Abdominal aortic aneurysm may be diagnosed with these tests:

• Abdominal ultrasound
• CT scan of abdomen
• Angiography of aorta

If the aneurysm is small and there are no symptoms (for example, if it was discovered during a routine physical), your doctor may recommend periodic evaluation. This usually includes a yearly ultrasound, to see if the aneurysm is getting bigger.

Aneurysms that cause symptoms usually require surgery to prevent complications.

Surgery is recommended for patients with aneurysms bigger than 5.5 cm in diameter and aneurysms that rapidly increase in size. The goal is to perform surgery before complications or symptoms develop.

There are two approaches to surgery. In a traditional (open) repair, a large cut is made in your abdomen. The abnormal vessel is replaced with a graft made of synthetic material, such as Dacron.

The other approach is called endovascular stent grafting. An endovascular stent graft is a tube made of metal mesh that helps support the artery. Small, hollow tubes called catheters are inserted through arteries in your groin. The stent graft is sent through a catheter, and permanently placed into the artery. Endovascular stent grafting can be done without making a large cut in your abdomen, so you may get well faster. However, not all patients with abdominal aortic aneurysms can have this type of surgery.

The outcome is usually good if an experienced surgeon repairs the aneurysm before it ruptures. However, less than 40% of patients survive a ruptured abdominal aneurysm.

• Aortic rupture
• Hypovolemic shock
• Arterial embolism
• Kidney failure
• Heart attack
• Stroke
• Aortic dissection

Go to the emergency room or call 911 if you develop severe abdominal pain or any of the other symptoms of an aneurysm.

Exercise, eat well, and avoid tobacco to reduce the risk of developing aneurysms. Get regular physical exams. If you have any risk factors, insist upon a screening abdominal aortic ultrasound.