What is an Abdominal Aortic Aneurysm?

An aneurysm is a bulge in a blood vessel where the vessel wall has become weak or thin. As the wall weakens, that part of the vessel loses the ability to support the force of blood flow and begins to expand. Left untreated, the aneurysm may grow to several times the size of a normal vessel and could eventually rupture or burst. When the aneurysm occurs in the abdomen, it is called an Abdominal Aortic Aneurysm, commonly abbreviated as AAA.
The aorta is the body’s main artery that carries oxygenrich blood from the heart to the lower portion of the body. It extends from the chest to the abdomen where it divides into two arteries (the iliac arteries) that carry blood down into the legs. Aneurysms may occur in any blood vessel, but are most common in the aorta and iliac arteries.

What causes an AAA?

It is not fully clear why an aneurysm forms in the aorta. Aneurysms can affect men or women of any age. However, they are most common in men aged 65 and over. This can occur in about 1 out of 25 men. Not all aneurysms will be of a significant size; only 1 in 100 will be large enough (>5mm in diameter) to require surgery. Men are at higher risk than women, they are six times more likely to have an aneurysm.
As people age, they may lose some of the supporting tissue in the aortic wall . This explains why aneurysms are more common in older people. Your genetic make-up also plays a role as you have a much higher chance of developing an AAA if one of your immediate relatives (parent, brother or sister) has or had one. Other risk factors that increase the chance of getting an aneurysm include smoking, high blood pressure, high cholesterol, emphysema and obesity.

What is concerning about an AAA?

The main concern is that the aneurysm might rupture. The wall of the aneurysm is weaker than a normal artery wall and may not be able to withstand the pressure of blood inside. If a rupture does occur, it may lead to severe internal bleeding which is often fatal. Most AAAs do not rupture.

What are the symptoms of an AAA?

In most cases there are no symptoms with an AAA, when diagnosed, 7 in 10 people will not have had any symptoms due to the aneurysm. The expansion of the aneurysm does not cause any symptoms unless it becomes large enough to put pressure on nearby structures. Symptoms that do occur are likely to be mild abdominal or back pains. There are many other causes of these types of pains, which can lead to the delay in diagnosis unless the aneurysm is large enough to be felt by a doctor when he or she examines your abdomen.