What are the guidelines for abdominal aortic aneurysm (AAA) screening?

From the Guidelines

Abdominal aortic aneurysm (AAA) screening is recommended as a one-time ultrasound for men aged ≥65 years with a history of smoking to reduce the risk of death from ruptured AAA. This recommendation is based on the most recent and highest quality study, which suggests that screening for AAA with duplex ultrasound (DUS) is recommended in men aged ≥65 years with a history of smoking 1.

Key Points

• The screening test is a simple, painless abdominal ultrasound that measures the diameter of the aorta, with an aortic diameter of 3.0 cm or greater considered aneurysmal.
• Early detection through screening is important because AAAs are typically asymptomatic until rupture, which carries a high mortality rate.
• If an AAA is detected, management depends on its size - small aneurysms (3.0-5.4 cm) are typically monitored with periodic ultrasounds, while larger aneurysms (≥5.5 cm) or rapidly growing ones may require surgical repair.
• Risk factor modification, including smoking cessation, blood pressure control, and cholesterol management, is essential for all patients with identified AAAs to prevent growth and rupture.

Specific Recommendations

• Screening for AAA with DUS is recommended in men aged ≥65 years with a history of smoking 1.
• Screening may be considered in men aged ≥75 years (irrespective of smoking history) or in women aged ≥75 years who are current smokers, hypertensive, or both 1.
• Family AAA screening with DUS is recommended for first-degree relatives of patients with AAA aged ≥50, unless an acquired cause can be clearly identified 1.

Rationale

The rationale for these recommendations is based on the balance of benefits and harms of screening for AAA. The benefits of screening include reduced mortality from ruptured AAA, while the harms include increased risk of surgical complications and psychological distress. The most recent and highest quality study suggests that the benefits of screening outweigh the harms in men aged ≥65 years with a history of smoking 1.

From the Research

AAA Screening Guidelines

• The US Preventive Services Task Force (USPSTF) recommends one-time screening for abdominal aortic aneurysm (AAA) with ultrasonography in men aged 65 to 75 years who have ever smoked 2.
• The USPSTF also recommends that clinicians selectively offer screening for AAA with ultrasonography in men aged 65 to 75 years who have never smoked, rather than routinely screening all men in this group 2.
• For women aged 65 to 75 years who have never smoked and have no family history of AAA, the USPSTF recommends against routine screening for AAA with ultrasonography 2.
• The evidence is insufficient to determine the net benefit of screening for AAA in women aged 65 to 75 years who have ever smoked or have a family history of AAA 2.

Risk Factors for AAA

• Smoking is a significant risk factor for AAA, and cessation of smoking can reduce the risk of AAA 3, 4.
• Other risk factors for AAA include increasing age, male gender, family history, and cardiovascular disease 3.
• A healthy lifestyle, including exercise and consumption of nuts, vegetables, and fruits, may be associated with reduced risk of AAA 3.

Screening Effectiveness

• Screening for AAA can reduce mortality from ruptured AAA, with one study showing a 68% reduction in mortality at 5 years and a 42% reduction at 10 years 5.
• The prevalence of AAA is lower than expected in some populations, such as 70-year-old men, which may affect the cost-effectiveness of screening 6.
• Re-screening of men with a normal aortic diameter at age 65 can identify new aneurysms, but the risk of rupture is low in this group 5.