An abdominal aortic aneurysm (AAA) is an enlarged lower part of the aorta, the major blood vessel that supplies oxygen-rich blood from the heart to the organs. The aorta is usually 2 cm wide, but in case of AAA, it can swell over 5.5 cm. This happens when the aortic wall weakens.

AAA incidence is higher than other types of aneurysms, such as thoracic aortic aneurysms (that develop in the upper part of the aorta).

The size of AAA varies. Small ones are difficult to detect. However, if once detected, constant monitoring is necessary because they can expand and large AAA may rupture. Ruptured abdominal aortic aneurysm is life-threatening.



The exact causes of AAA are not known. However, there are several factors that possibly play a role, such as: age, being male, smoking, high blood pressure and cholesterol, atherosclerosis, family history of aortic aneurysms (increased risk of developing one yourself).



Abdominal aortic aneurysms can show different symptoms for different size of the aneurysm. Small aneurysms may stay small, giving no symptoms. Some, may expand over time. In this case, the symptoms could be pain or pulsating feeling in the abdomen or constant back pain.

If it is large AAA in question, then there is a risk of its rupture. If this happens, there is a sudden and severe pain in the abdomen, because of the internal bleeding. The bleeding is usually fatal. The symptoms of a ruptured AAA include: sudden and intense abdominal or back pain, sweatiness, dizziness, nausea, vomiting, fast pulse, low blood pressure, shortness of breath, or loss of consciousness.


Risk factors

Abdominal aortic aneurysm risk factors are:

  • Age. AAA occurs most often in people age 65+. In UK, for e.g., men over 65 are invited to screening test (by ultrasound)
  • Being male. Men develop AAA more frequently than women do.
  • Atherosclerosis. Atherosclerosis damages the blood vessel lining, increasing the risk of an aneurysm.
  • Tobacco use. The longer you've smoked, the greater your risk of AAA.
  • Family history. People with a family history of aneurysms tend to develop aneurysms at a younger age, including the higher risk of rupture.



The main complications of AAA are tears in the wall of the aorta. If the AAA ruptures, there is internal bleeding, which is often fatal.

Another complication is the risk of blood clots. Blood clots can block a blood vessel anywhere in the body, blocking the blood flow to the legs, toes, kidneys or abdominal organs.