This is the current release of the guideline.

This version updates a previously published guideline: U.S. Preventive Services Task Force. Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. Chapter 6, Screening for abdominal aortic aneurysm. p. 67-72.

The U.S. Preventive Services Task Force (USPSTF) grades its recommendations (A, B, C, D, or I) and the quality of the overall evidence for a service (good, fair, poor). The definitions of these grades can be found at the end of the "Major Recommendations" field.

The USPSTF recommends one-time screening for abdominal aortic aneurysm (AAA) by ultrasonography in men aged 65 to 75 who have ever smoked. B recommendation

The USPSTF found good evidence that screening for AAA and surgical repair of large AAAs (5.5 cm or more) in men aged 65 to 75 who have ever smoked (current and former smokers) leads to decreased AAA-specific mortality. There is good evidence that abdominal ultrasonography, performed in a setting with adequate quality assurance (i.e., in an accredited facility with credentialed technologists), is an accurate screening test for AAA. There is also good evidence of important harms of screening and early treatment, including an increased number of surgeries with associated clinically-significant morbidity and mortality, and short-term psychological harms. Based on the moderate magnitude of net benefit, the USPSTF concluded that the benefits of screening for AAA in men aged 65 to 75 who have ever smoked outweigh the harms.

The USPSTF makes no recommendation for or against screening for AAA in men aged 65 to 75 who have never smoked. C recommendation

The USPSTF found good evidence that screening for AAA in men aged 65 to 75 who have never smoked leads to decreased AAA-specific mortality. There is, however, a lower prevalence of large AAAs in men who have never smoked compared with men who have ever smoked; thus, the potential benefit from screening men who have never smoked is small. There is good evidence that screening and early treatment leads to important harms, including an increased number of surgeries with associated clinically-significant morbidity and mortality, and short-term psychological harms. The USPSTF concluded that the balance between the benefits and harms of screening for AAA is too close to make a general recommendation in this population.

The USPSTF recommends against routine screening for AAA in women. D recommendation.

Because of the low prevalence of large AAAs in women, the number of AAA-related deaths that can be prevented by screening this population is small. There is good evidence that screening and early treatment result in important harms, including an increased number of surgeries with associated morbidity and mortality, and psychological harms. The USPSTF concluded that the harms of screening women for AAA outweigh the benefits.

Clinical Considerations

• The major risk factors for AAA include age (being 65 or older), male sex, and a history of ever smoking (at least 100 cigarettes in a person's lifetime). A first-degree family history of AAA requiring surgical repair also elevates a man's risk for AAA; this may also be true for women but the evidence is less certain. There is only a modest association between risk factors for atherosclerotic disease and AAA.
• Screening for AAA would most benefit those who have a reasonably high probability of having an AAA large enough, or that will become large enough, to benefit from surgery. In general, adults younger than age 65 and adults of any age who have never smoked are at low risk for AAA and are not likely to benefit from screening. Among men aged 65 to 74, an estimated 500 who have ever smoked - or 1,783 who have never smoked - would need to be screened to prevent 1 AAA-related death in the next 5 years. As always, clinicians must individualize recommendations depending on a patient's risk and likelihood of benefit. For example, some clinicians may choose to discuss screening with male nonsmokers nearing age 65 who have a strong first-degree family history of AAA that required surgery.
• The potential benefit of screening for AAA among women aged 65 to 75 is low because of the small number of AAA-related deaths in this population. The majority of deaths from AAA rupture occur in women aged 80 or older. Because there are many competing health risks at this age, any benefit of screening for AAA would be minimal. Individualization of care, however, is still required. For example, a clinician may choose to discuss screening in the unusual circumstance in which a healthy female smoker in her early 70s has a first-degree family history for AAA that required surgery.
• Operative mortality for open surgical repair of an AAA is 4% to 5%, and nearly one-third of patients undergoing this surgery have other important complications (e.g., cardiac and pulmonary). Additionally, men having this surgery are at increased risk for impotence.
• Endovascular repair of AAAs (EVAR) is currently being used as an alternative to open surgical repair. Although recent studies have shown a short-term mortality and morbidity benefit of EVAR compared with open surgical repair, the long-term effectiveness of EVAR to reduce AAA rupture and mortality is unknown. The long-term harms of EVAR include late conversion to open repair and aneurysmal rupture. EVAR performed with older-generation devices is reported to have an annual rate of rupture of 1% and conversion to open surgical repair of 2%. The conversion to open surgical repair is associated with a peri-operative mortality of about 24%. The long-term harms of newer-generation EVAR devices are yet to be reported.
• For most men, 75 years may be considered an upper age limit for screening. Patients cannot benefit from screening and subsequent surgery unless they have a reasonable life expectancy. The increased presence of comorbidities for people aged 75 and older decreases the likelihood that they will benefit from screening.
• Ultrasonography has a sensitivity of 95% and specificity of nearly 100% when performed in a setting with adequate quality assurance. The absence of quality assurance is likely to lower test accuracy. Abdominal palpation has poor accuracy and is not an adequate screening test.
• One-time screening to detect an AAA using ultrasonography is sufficient. There is negligible health benefit in re-screening those who have normal aortic diameter on initial screening.
• Open surgical repair for an AAA of at least 5.5 cm leads to an estimated 43% reduction in AAA-specific mortality in older men who undergo screening. However, there is no current evidence that screening reduces all-cause mortality in this population.
• In men with intermediate-sized AAAs (4.0-5.4 cm), periodic surveillance offers comparable mortality benefit to routine elective surgery with the benefit of fewer operations. Although there is no evidence to support the effectiveness of any intervention in those with small AAAs (3.0-3.9 cm), there are expert opinion-based recommendations in favor of periodic repeat ultrasonography for these patients.

Definitions:

Strength of Recommendations

The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):

A

The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.

B

The USPSTF recommends that clinicians provide [the service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.

C

The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.

D

The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.

I

The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.

Strength of Evidence

The U.S. Preventive Services Task Force (USPSTF) grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):

Good

Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.

Fair

Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.

Poor

Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.

None provided

The type of evidence supporting the recommendations is identified in the "Major Recommendations" field.

Not applicable: The guideline is not adapted from another source.

1996 (revised 2005)

United States Preventive Services Task Force - Independent Expert Panel

United States Government

U.S. Preventive Services Task Force (USPSTF)

The U.S. Preventive Services Task Force has an explicit policy concerning conflict of interest. All members and evidence-based practice center (EPC) staff disclose at each meeting if they have an important financial conflict for each topic being discussed. Task Force members and EPC staff with conflicts can participate in discussions about evidence, but members abstain from voting on recommendations about the topic in question.

From: Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow, CD, Teutsch SM, Atkins D. Current methods of the U.S. Preventive Services Task Force: a review of the process. Methods Work Group, Third U.S. Preventive Services Task Force. Am J Prev Med 2001 Apr;20(3S):21-35.

This is the current release of the guideline.

This version updates a previously published guideline: U.S. Preventive Services Task Force. Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. Chapter 6, Screening for abdominal aortic aneurysm. p. 67-72.

This summary was completed by ECRI on June 30, 1998. The information was verified by the guideline developer on December 1, 1998. This NGC summary was updated by ECRI on January 20, 2005. The updated information was verified by the guideline developer on January 31, 2005.