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Am Fam Physician. 2022;106(2):165-172

This clinical content conforms to AAFP criteria for CME.

Author disclosure: No relevant financial relationships.

Abdominal aortic aneurysm is a pathologic condition with progressive abdominal aortic dilatation of 3.0 cm or more that predisposes the abdominal aorta to rupture. Most abdominal aortic aneurysms are asymptomatic until they rupture, although some are detected when an imaging study is performed for other reasons. The risk factors for abdominal aortic aneurysm include hypertension, coronary artery disease, tobacco use, male sex, a family history of abdominal aortic aneurysm, age older than 65 years, and peripheral artery disease. Abdominal ultrasonography is the preferred modality to screen for abdominal aortic aneurysm because of its cost-effectiveness and lack of exposure to ionizing radiation. Abdominal aortic aneurysm can be managed medically or surgically, depending on the patient's symptoms and the size and growth rate of the aneurysm. Medical management is appropriate for asymptomatic patients and smaller aneurysms and includes tobacco cessation and therapy for cardiovascular risk reduction. Surgical management, which includes open and endovascular aneurysm repair, is indicated when the aneurysm diameter is 5.5 cm or larger in men and 5.0 cm or larger in women. Surveillance of abdominal aortic aneurysm depends on the size and growth rate of the aneurysm. The most serious complication of abdominal aortic aneurysm is rupture, which requires emergent surgical intervention. The U.S. Preventive Services Task Force recommends that men with a history of smoking who are 65 to 75 years of age should undergo one-time abdominal aortic aneurysm screening with ultrasonography.

Abdominal aortic aneurysm (AAA) is the abnormal dilatation of the infrarenal abdominal aorta of 3.0 cm or more.1 It occurs when the abdominal aortic wall weakens, causing it to bulge or balloon, resulting in permanent and progressive focal dilatation of the abdominal aorta2 (Figure 1). AAA is the 14th leading cause of mortality in the United States, resulting in 4,500 deaths each year.3 Approximately 45,000 surgeries for AAA repair are performed annually.1,3 AAA affects about 1.5% of men older than 60 years and 1% of women older than 64 years.4 Women are known to have worse outcomes with AAA than men. This is likely due to the lack of screening and late presentation associated with larger aneurysms that tend to grow faster and have a four times higher risk of rupture at diameters of 5.0 cm to 5.9 cm.5 The average annual risk of rupture for aneurysms that are 6.0 cm or larger is more than 10%.6 A ruptured AAA is associated with high mortality rates. Between 59% and 83% of patients die before they reach a hospital or have surgery.1

A history of smoking is responsible for 75% of AAAs.7 In 2005, the U.S. Preventive Services Task Force (USPSTF) recommended one-time ultrasonography to screen for AAA in men 65 to 75 years of age who had ever smoked. This recommendation was updated in 2014 and 2019 and is supported by the American Academy of Family Physicians. Epidemiologic literature defines a patient with a history of smoking as someone who has smoked 100 or more cigarettes in their lifetime.8 Although the recommendations are stratified by men and women, the net benefit is driven by biological sex rather than gender identity.


AAA occurs from the degenerative process of smooth muscle cell loss and structural deterioration of the aortic wall, specifically within the elastic media and adventitia.9 Matrix metalloproteinase, a proteolytic enzyme released by T and B lymphocytes, macrophages, and other chronic inflammatory cells, destroys the elasticity and collagen of smooth muscle.10,11

Risk Factors

Cigarette smoking is the greatest risk factor for developing AAA. Other risk factors include a family history of AAA and conditions that are associated with cardiovascular disease such as hypertension, coronary artery disease, atherosclerosis, and stroke (Table 1).6,12 Although diabetes mellitus alone is not a risk factor for AAA, when associated with coronary artery disease and peripheral artery disease, it is linked to AAA growth and rupture.13

Major risk factors
Male sex*
Older than 65 years*
Tobacco use*
Additional risk factors
Cerebrovascular disease
Coronary artery disease
Family history (i.e., first-degree relatives) of abdominal aortic aneurysm
History of aneurysm on a peripheral vessel
Peripheral artery disease


Most AAAs are asymptomatic until they rupture, although some may be identified during an evaluation of abdominal symptoms. AAA is often detected as an incidental finding when ultrasonography, computed tomography of the abdomen, or magnetic resonance imaging is performed for other purposes. For patients who present with unexplained abdominal discomfort, such as pain that radiates to the back, flank, and groin, abdominal palpation is reasonably accurate in diagnosing AAA and does not increase the risk of rupture.12 One study reported that the sensitivity of abdominal palpation increases significantly with AAA diameter, ranging from 29% for aneurysms 3.0 cm to 3.9 cm, 50% for those 4.0 cm to 4.9 cm, and 75% for those 5.0 cm or larger.14 The most common finding on the abdominal examination is a pulsatile mass around the umbilicus. A bruit can sometimes be heard on the pulsatile mass. Patients with popliteal artery aneurysms have a high prevalence of AAA and vice versa.15 Therefore, examining both popliteal arteries and the abdominal aorta is important when an arterial aneurysm is suspected. One study found that abdominal obesity can decrease the sensitivity of palpation.14 Physical examination has been used in practice but has low sensitivity (39% to 68%) and specificity (75%) and is not recommended for screening in patients who are obese.

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