The most serious complication of an abdominal
aortic aneurysm is rupture. When rupture occurs, more
than half of people die before getting medical attention.
A second complication is the formation of a blood clot in the aorta.
When an aneurysm develops, it may result in damage to the wall of the blood
vessel. The damage leads to clot formation. A blood clot can narrow the
diameter of the aorta, leading to a decrease in blood flow and a resulting lack
of blood and oxygen (ischemia) to areas "downstream" from the clot.
Additionally, pieces of the blood clot can break off and travel through the
bloodstream (embolize) and lodge elsewhere in the bloodstream. This blocks
blood flow and causes damage to tissue beyond the blood clot.
For instance, if a blood clot breaks off and travels to the iliac
artery, which carries blood to the pelvis and legs, it can block blood supply
to the foot or toes and cause a "cold foot" or another manifestation of acute
vascular disease. This usually requires emergency surgery.
An
inflammatory aneurysm can cause complications, such as
fever, weight loss, and symptoms of a chronic disease. A massive inflammatory
response may affect body parts close by, including part of the small intestine
(duodenum), the
ureter, or the veins to the kidney. Any of these
structures can become obstructed by the inflammation.