Abdominal aortic aneurysm
three white arrows pointing to an enlargement of the abdominal aorta
CT reconstruction image of an abdominal aortic aneurysm (white arrows)
Specialty Vascular surgery
Symptoms None, abdominal, back, or leg pain
Usual onset Over 50 years old males
Risk factors Smoking, high blood pressure, other heart or blood vessel diseases, family history, Marfan syndrome
Diagnostic method Medical imaging (abdominal aorta diameter > 3 cm
Prevention Not smoking, treating risk factors
Treatment Surgery (open surgery or endovascular aneurysm repair)
Frequency ~5% (males over 65 years)
Deaths 168,200 aortic aneurysms (2015)
Abdominal aortic aneurysm (AAA or triple A) is a localized enlargement of the abdominal aorta such that the diameter
is greater than 3 cm or more than 50% larger than normal diameter.They usually cause no symptoms except when ruptured.
Occasionally, abdominal, back, or leg pain may occur.Large aneurysms can sometimes be felt by pushing on the abdomen.
Rupture may result in pain in the abdomen or back, low blood pressure, or loss of consciousness, and often results in
AAAs occur most commonly in those over 50 years old, in men, and among those with a family history.
Additional risk factors include smoking, high blood pressure, and other heart or blood vessel diseases.
Genetic conditions with an increased risk include Marfan syndrome and Ehlers-Danlos syndrome.
AAAs are the most common form of aortic aneurysm.
About 85% occur below the kidneys with the rest either at the level of or above the kidneys.
In the United States, screening with abdominal ultrasound is recommended for males between 65 and 75 years of
age with a history of smoking.In the United Kingdom, screening all men over 65 is recommended.
Once an aneurysm is found, further ultrasounds are typically done on a regular basis.
Not smoking is the single best way to prevent the disease.Other methods of prevention include treating high
blood pressure, treating high blood cholesterol and not being overweight. Surgery is usually recommended
when an AAA’s diameter grows to >5.5 cm in males and >5.0 cm in females.Other reasons for repair include
the presence of symptoms and a rapid increase in size (more than one centimeter per year).Repair may be
either by open surgery or endovascular aneurysm repair (EVAR). As compared to open surgery, EVAR has a lower
risk of death in the short term and a shorter hospital stay, but may not always be an option.There does not
appear to be a difference in longer term outcomes between the two. With EVAR there is a higher need for repeat
AAAs affect between 2 and 8% of males over the age of 65.Rates among women are one-fourth as high.
In those with an aneurysm less than 5.5 cm the risk of rupture in the next year is less than 1%.
Among those with an aneurysm between 5.5 and 7 cm, the risk is about 10%, while for those with an aneurysm greater
than 7 cm the risk is about 33%.Mortality if ruptured is 85% to 90%.During 2013, aortic aneurysms resulted in 168,200
deaths, up from 100,000 in 1990.In the United States AAAs resulted in between 10,000 and 18,000 deaths in 2009.
Signs and symptoms
Abdominal aortic aneurysm location
The vast majority of aneurysms are asymptomatic. However, as abdominal aortic aneurysms expand,
they may become painful and lead to pulsating sensations in the abdomen or pain in the chest, lower back, or
scrotum.The risk of rupture is high in a symptomatic aneurysm, which is therefore considered an indication
for surgery. The complications include rupture, peripheral embolization, acute aortic occlusion, and aortocaval
(between the aorta and inferior vena cava) or aortoduodenal (between the aorta and the duodenum) fistulae. On
physical examination, a palpable and pulsatile abdominal mass can be noted. Bruits can be present in case of renal
or visceral arterial stenosis.