Screening for Abdominal Aortic Aneurysm Urged for Older Male Smokers

Abdominal aortic aneurysm (AAA), a risk factor for smokers, affects an estimated 3.9% to 7.2% of men and 1% to 1.3% of women ≥50 years of age. In an update to the 2005 recommendation on AAA screening, the United States Preventive Services Task Force (USPSTF) has issued a statement recommending 1-time screening for AAA with ultrasonography in men 65 to 75 years of age who have ever smoked and selective screening for men in this age group who have never smoked. The recommendation statement, which applies to asymptomatic adults ≥50 years of age, was published in Annals of Internal Medicine [2014; DOI:10.7326/M14-104].

USPSTF noted that it is important to consider potential screening strategies for AAA because most AAAs are symptomatic until they rupture. While the risk for rupture varies greatly by aneurysm size, the associated risk for death is as high as 75% to 90%. For the updated recommendation, USPSTF commissioned a systematic review that assessed the evidence on the benefits and harms of screening for AAA and strategies for managing small (3-5.4 cm) screen-detected AAAs. Conventional abdominal duplex ultrasonography was the primary method used in the available AAA screening trials and is widely accepted as the standard approach to AAA screening among clinicians and vascular surgeons. For this recommendation, an “ever-smoker” was defined as an individual who has smoked at least 100 cigarettes in his or her lifetime.

Based on the evidence from 4 large, population-based, randomized, controlled trials, the researchers found that 1-time screening for AAA with ultrasonography in older men was associated with reduced AAA-specific mortality. In the 2 highest-quality trials, the relative reduction in AAA-specific mortality after 13 years dropped by 42% to 66%. USPSTF reported that these aneurysms are most common among men who have ever smoked, with 6% to 7% of this population having the condition.

Screening men overall reduces AAA-specific death, rupture, and emergency surgery. Given that the low prevalence of men who have never smoked (approximately 2%) significantly reduces the absolute benefit in men 65 to 75 years of age, USPSTF recommends selective screening for AAA in this population.

Clinicians should consider the benefits and harms for the individual and risk factors other than smoking, including older age, a first-degree relative with AAA, history of vascular aneurysms, and coronary artery disease.

The biggest change to the updated statement is that instead of 1 “D” recommendation for screening for AAA in all women, the USPSTF now has 2 recommendations: an “I statement” for women 65 to 75 years of age who have ever smoked and a “D” recommendation for women in this age group who have never smoked. Among women who have ever smoked, USPSTF found insufficient evidence in favor or against screening for AAA in this group. Only 1 randomized, controlled screening for AAA included
women. The findings showed most screen-detected AAAs in women were small (3-3.9 cm), and AAA-specific mortality was low in screened and unscreened women (<0.2%) after 10 years.

USPSTF also identified areas of more research and outlined clinical considerations. Without new trial data, USPSTF suggested “high-quality modeling studies should be done to determine whether screening is beneficial in women who smoke or in men and women with a family history of AAA.” Several risk-scoring tools have been developed and, if prospectively validated, could be used to identify patients most likely to benefit from screening. Additionally, alternative strategies to reduce AAA growth, such as antibiotics, statins, or other pharmacologic agents, need to be explored. Effective strategies for smoking cessation may also improve care of patients with small AAAs.—Eileen Koutnik-Fotopoulos