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This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for abdominal aortic aneurysm (AAA) and the supporting scientific evidence, and updates the 1996 recommendations contained in the Guide to Clinical Preventive Services, second edition.1
Summary of Recommendations
|Task Force Ratings
Strength of Recommendations and Quality of Evidence
- The major risk factors for abdominal aortic aneurysm (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 percent, 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 percent and conversion to open surgical repair of 2 percent. The conversion to open surgical repair is associated with a peri-operative mortality of about 24 percent. 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 percent and specificity of nearly 100 percent 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-percent 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.
By definition, an AAA is present when the infrarenal aortic diameter exceeds 3.0 cm.5 Large AAAs are associated with approximately 9,000 deaths annually in the United States.6 The prevalence of AAAs found in population-based ultrasonography screening studies from various countries is about 4 percent to 9 percent in men and 1 percent in women.7-12 The prevalence of an AAA greater than 5.0 cm in men aged 50 to 79 is estimated to be 0.5 percent.13 Almost all deaths from ruptured AAAs occur in men older than 65; most AAA-related deaths occur in men younger than 80; and most AAA-related deaths in women occur when they are older than 80.14,15
The strongest risk factor for the rupture of an AAA is maximal aortic diameter.16,17 The natural history of clinically apparent AAAs of 5.5 cm or more is difficult to determine, since most large aneurysms are surgically repaired. Results of one study showed that 1-year incidence rates of rupture were 9 percent for AAAs of 5.5 to 5.9 cm; 10 percent for AAAs of 6.0 to 6.9 cm; and 33 percent for AAAs > 7.0 cm.18 A rapid rate of aneurysm expansion (> 1.0 cm/year) is commonly used in making decisions about the elective repair of AAAs < 5.5 cm; however, the predictive value of expansion as an index of rupture risk is less clear.19
The major risk factors for AAA include male sex, a history of ever smoking (defined in surveys as 100 cigarettes in a person's lifetime), and age 65 or older. Other lesser risk factors include family history, coronary heart disease, claudication, hypercholesterolemia, hypertension, cerebrovascular disease, and increased height.3 Factors associated with decreased risk include female sex, diabetes mellitus, and black race.
The USPSTF review identified four randomized controlled trials (RCTs) of screening for AAA; these RCTs predominantly screened white men aged 65 and older.2,3 A good-quality RCT of 67,800 white men aged 65 to 74 was conducted to evaluate screening for AAA.8 Screening was performed by ultrasonography and surgery in men with AAAs greater than 5.4 cm. The study showed AAA related-mortality was reduced by an average of 42 percent (95 percent CI, 22 percent-58 percent) in the screened population compared with the non-screened population; the absolute reduction in AAA-specific mortality was 0.14 percent (0.33 percent in the non-screened group and 0.19 percent in the screened group).3
A fair-quality RCT selected 15,775 white men and women aged 65 to 80 from family medical practices.21 This was the only one of the four RCTs that studied women. The prevalence of AAA in women was one-sixth of that in men. The incidence of AAA rupture was the same in the screened and control groups of women. This trial lacked adequate power and reported a non-statistically significant 41 percent reduction in AAA-related mortality in screened men and no reduction in AAA-related mortality in screened women. A fair-quality hospital-based RCT of 12,658 men aged 65 to 73 showed a 69 percent statistically significant reduction in AAA-specific mortality.22 Another RCT was population-based and included 38,704 men aged 65 to 83. After 5 years of follow-up, 18 men in the group invited to be screened, and 25 in the control group, died of causes associated with AAA (odds ratio [OR], 0.72; 95 percent CI, 0.39-1.32). In a subgroup analysis, there was a statistically significant reduction in AAA-related mortality in men aged 65 to 75, but not in older men.23 A meta-analysis of these trials showed a relative risk reduction of 43 percent in AAA-related deaths by screening for AAA, although there was no change in all-cause mortality.2,3
Death from AAA rupture after negative results on a single ultrasound scan at age 65 is rare. Studies have shown that the incidence rate for new AAAs in a period of 10 years is low, ranging from 0 to 4 percent; none of the incident AAAs exceeded a diameter of 4.0 cm.15,24-26 Based on these studies, negative results on a single ultrasound examination around the age of 65 appears to virtually exclude the risk for future AAA rupture or death.
Two randomized trials showed no statistically significant mortality benefit from immediate surgical repair compared with frequent surveillance for intermediate-sized AAAs (4.0-5.4 cm).27,28 Additionally, about 39 percent fewer AAA-related surgical repairs needed to be performed in the surveillance group.
Two randomized trials reported that the 30-day mortality rate for EVAR was significantly reduced compared with open surgical repair (about 1.5 percent vs. 4.5 percent, respectively).29,30 While there are short-term mortality and morbidity benefits of performing EVAR compared with open surgical repair, the magnitude of long-term potential harms is not well known. Long-term potential harms of EVAR may occur because of device failure, which could cause bleeding into the aneurysmal sac around the device or from retrograde flow into the aneurysmal sac through collateral blood vessels. These events may require late conversion to open repair or may lead to aneurysmal rupture. Studies of the EUROSTAR (EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair) registry report an annual rupture rate of 1 percent and conversion to open repair at an annual rate of 2 percent, with a 24-percent peri-operative mortality rate for the conversion.31,32
Although open surgical repair remains the only proven intervention that leads to decreased AAA mortality in the long term, there are major harms associated with this procedure. One study showed in-hospital mortality rates for patients undergoing open repair to be 4.2 percent.33 The complication rate of elective surgery is about 32 percent and includes myocardial infarction, respiratory failure, renal failure, ischemic colitis, spinal cord ischemia, and prosthetic graft infections.3
There is a short-term impact of AAA screening on quality-of-life measures. Those testing positive for AAA initially had more anxiety and lower physical and mental health scores (measured by the Short Form-36) than those testing negative. Those who underwent surgery, compared with those on continued surveillance, had slightly lower Short Form-36 scores but higher self-rated health scores 3 months after surgery. These negative psychological measures returned to normal levels within 12 months after screening or surgery.8
The USPSTF review of four relevant cost-effectiveness studies of AAA yielded an estimated cost-effectiveness ratio of population-based AAA screening (compared with no screening) that is in the same range as that of other cost-effective preventive services.4
The pathogenesis of AAA formation is complex and multifactorial; more studies are needed to clarify AAA's natural history of formation and expansion. A number of areas require further study, including the lack of a strong association between AAA and atherosclerotic disease; the prevalence and natural history of AAA in women; the efficacy of screening and treatment in nonwhite male populations; the efficacy and periodicity of surveillance of small AAAs (3.0-4.0 cm); and the long-term efficacy of EVAR as an alternative to open surgical repair, especially for AAAs less than 4.0 cm. There also is a need for a high-quality, cost-effectiveness analysis of AAA screening conducted from the U.S. societal perspective.
Recommendations of Other Groups
The Society for Vascular Surgery and the Society for Vascular Medicine and Biology recommend screening all men aged 60 to 85 for AAA; women aged 60 to 85 with cardiovascular risk factors; and men and women aged 50 and older with a family history of AAA. These groups further recommend the following courses of action after screening: no further testing if aortic diameter is less than 3.0 cm; yearly ultrasonographic screening if aortic diameter is between 3.0 to 4.0 cm; ultrasonography every 6 months if aortic diameter is between 4.0 to 4.5 cm; and referral to a vascular specialist if aortic diameter is greater than 4.5 cm.34
1. U.S. Preventive Services Task Force. Guide to Clinical Preventive Services, 2nd ed. Washington, DC: Office of Disease Prevention and Health Promotion; 1996.
2. Fleming C, Whitlock EP, Beil T, Lederle F. Screening for abdominal aortic aneurysm: a best-evidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med 2005;142:203-11.
3. Fleming C, Whitlock EP, Beil T, Lederle F. Primary Care Screening for Abdominal Aortic Aneurysm. Evidence Synthesis No. 35 (Prepared by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024.) Rockville, MD: Agency for Healthcare Research and Quality. February 2005. (Available on the AHRQ Web site at: http://www.uspreventiveservicestaskforce.org/serfiles.htm.)
4. Meenan RT, Fleming C, Whitlock EP, Beil TL, Smith P. Cost-effectiveness analyses of population-based screening for abdominal aortic aneurysm: evidence synthesis. Rockville, MD: Agency for Healthcare Research and Quality; February 2005. Available at: http://www.uspreventiveservicestaskforce.org/uspstf/uspstopics.htm.
5. Johnston KW, Rutherford RB, Tilson MD, Shah DM, Hollier L, Stanley JC. Suggested standards for reporting on arterial aneurysms. Subcommittee on Reporting Standards for Arterial Aneurysms, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery. J Vasc Surg 1991;13(3):452-8.
6. Gillum RF. Epidemiology of aortic aneurysm in the United States. J Clin Epidemiol 1995;48(11):1289-98.
7. Bengtsson H, Bergqvist D, Ekberg O, Janzon L. A population based screening of abdominal aortic aneurysms (AAA). Eur J Vasc Surg 1991;5(1):53-7.
8. Ashton HA, Buxton MJ, Day NE, et al. The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet 2002;360(9345):1531-9.
9. Lindholt JS, Henneberg EW, Fasting H, Juul S. Mass or high-risk screening for abdominal aortic aneurysm. Br J Surg 1997;84(1):40-2.
10. Morris GE, Hubbard CS, Quick CR. An abdominal aortic aneurysm screening programme for all males over the age of 50 years. Eur J Vasc Surg 1994;8(2):156-60.
11. Simoni G, Pastorino C, Perrone R, et al. Screening for abdominal aortic aneurysms and associated risk factors in a general population. Eur J Vasc Endovasc Surg 1995;10(2):207-10.
12. Smith FC, Grimshaw GM, Paterson IS, Shearman CP, Hamer JD. Ultrasonographic screening for abdominal aortic aneurysm in an urban community. Br J Surg 1993;80(11):1406-9.
13. Lederle FA, Johnson GR, Wilson SE, et al. Prevalence and associations of abdominal aortic aneurysm detected through screening. Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Group. Ann Intern Med 1997;126(6):441-9.
14. Scott RA, Bridgewater SG, Ashton HA. Randomized clinical trial of screening for abdominal aortic aneurysm in women. Br J Surg 2002;89(3):283-5.
15. Scott RA, Vardulaki KA, Walker NM, Day NE, Duffy SW, Ashton HA. The long-term benefits of a single scan for abdominal aortic aneurysm (AAA) at age 65. Eur J Vasc Endovasc Surg 2001;21(6):535-40.
16. Nevitt MP, Ballard DJ, Hallett JW Jr. Prognosis of abdominal aortic aneurysms. A population-based study. N Engl J Med 1989;321(15):1009-14.
17. Glimaker H, Holmberg L, Elvin A, et al. Natural history of patients with abdominal aortic aneurysm. Eur J Vasc Surg 1991;5(2):125-30.
18. Lederle FA, Johnson GR, Wilson SE, et al. Rupture rate of large abdominal aortic aneurysms in patients refusing or unfit for elective repair. JAMA 2002;287(22):2968-72.
19. Wilmink AB, Quick CR. Epidemiology and potential for prevention of abdominal aortic aneurysm. Br J Surg 1998;85(2):155-62.
20. van der Vliet JA, Oomen AP. Abdominal aortic aneurysm: screening and treatment. [Dutch]. Ned Tijdschr Geneeskd 1993;137(23):1155.
21. Scott RA, Wilson NM, Ashton HA, Kay DN. Influence of screening on the incidence of ruptured abdominal aortic aneurysm: 5-year results of a randomized controlled study. Br J Surg1995;82(8):1066-70.
22. Lindholt JS, Juul S, Fasting H, Henneberg EW. Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial. Eur J Vasc Endovasc Surg 2002;23(1):55-60.
23. Norman PE, Jamrozik K, Lawrence-Brown MM, et al. Population based randomised controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ 2004;329:1259-62.
24. Crow P, Shaw E, Earnshaw JJ, Poskitt KR, Whyman MR, Heather BP. A single normal ultrasonographic scan at age 65 years rules out significant aneurysm disease for life in men. Br J Surg 2001;88(7):941-4.
25. Emerton ME, Shaw E, Poskitt K, Heather BP. Screening for abdominal aortic aneurysm: a single scan is enough. Br J Surg 1994;81(8):1112-3.
26. Lederle FA, Johnson GR, Wilson SE, et al. Yield of repeated screening for abdominal aortic aneurysm after a 4-year interval. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med 2000;160(8):1117-21.
27. Lederle FA, Wilson SE, Johnson GR, et al. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med 2002;346(19):1437-44.
28. The UK Small Aneurysm Trial Participants. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. Lancet 1998;352(9141):1649-55.
29. The EVAR trial participants. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 2004;364:843-8.
30. Prinssen M, Verhoeven ELG, Buth J, et al. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 2004;351:1607-18.
31. Harris PL, Vallabhaneni SR, Desgranges P, Becquemin JP, van Marrewijk C, Laheij RJ. Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European Collaborators on Stent/graft techniques for aortic aneurysm repair. J Vasc Surg 2000;32(4):739-49.
32. Vallabhaneni SR, Harris PL. Lessons learnt from the EUROSTAR registry on endovascular repair of abdominal aortic aneurysm repair. Eur J Radiol 2001;39(1):34-41.
33. Huber TS, Wang JG, Derrow AE, et al. Experience in the United States with intact abdominal aortic aneurysm repair. J Vasc Surg 2001;33(2):304-10.
34. Kent KC, Zwolak RM, Jaff MR, et al. Screening for abdominal aortic aneurysm: A consensus statement. J Vasc Surg 2004;39:267-9.
Members of the Task Force
Members of the U.S. Preventive Services Task Force* are Ned Calonge, M.D., M.P.H., Chair, USPSTF (Acting Chief Medical Officer and State Epidemiologist, Colorado Department of Public Health and Environment, Denver, CO); Janet D. Allan, Ph.D., R.N., C.S., Vice-chair, USPSTF (Dean, School of Nursing, University of Maryland, Baltimore, Baltimore, MD); Alfred O. Berg, M.D., M.P.H. (Professor and Chair, Department of Family Medicine, University of Washington, Seattle, WA); Paul S. Frame, M.D. (Family Physician, Tri-County Family Medicine, Cohocton, NY, and Clinical Professor of Family Medicine, University of Rochester, Rochester, NY); Leon Gordis, M.D., M.P.H., Dr.P.H. (Professor, Epidemiology Department, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD); Kimberly D. Gregory, M.D., M.P.H. (Director, Women's Health Services Research and Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA); Russell Harris, M.D., M.P.H. (Associate Professor of Medicine, Sheps Center for Health Services Research, University of North Carolina School of Medicine, Chapel Hill, NC); Mark S. Johnson, M.D., M.P.H. (Professor and Chair, Department of Family Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ); Jonathan D. Klein, M.D., M.P.H. (Associate Professor, Department of Pediatrics, University of Rochester School of Medicine, Rochester, NY); Carol Loveland-Cherry, Ph.D., R.N. (Executive Associate Dean, Office of Academic Affairs, University of Michigan School of Nursing, Ann Arbor, MI); Virginia A. Moyer, M.D., M.P.H. (Professor, Department of Pediatrics, University of Texas Health Science Center, Houston, TX); Judith K. Ockene, Ph.D. (Professor of Medicine and Chief of Division of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, MA); Diana B. Petitti, M.D., M.P.H. (Senior Scientific Advisor for Health Policy and Medicine, Regional Administration, Kaiser Permanente Southern California, Pasadena CA); Albert L. Siu, M.D., M.S.P.H. (Professor and Chairman, Brookdale Department of Geriatrics and Adult Development, Mount Sinai Medical Center, New York, NY); Steven M. Teutsch, M.D., M.P.H. (Executive Director, Outcomes Research and Management, Merck & Company, Inc., West Point, PA); and Barbara P. Yawn, M.D., M.Sc. (Director of Research, Olmstead Research Center, Rochester, MN).
* Members of the Task Force at the time this recommendation was finalized. For a list of current Task Force members, go to http://www.uspreventiveservicestaskforce.org/about.htm.
Contact the Task Force
Address correspondence to: Ned Calonge, M.D., M.P.H., Chair, U.S. Preventive Services Task Force, c/o Program Director, 540 Gaither Road, Rockville, MD 20850.
The complete information on which this statement is based, including evidence tables and references, is included in the summary of evidence,2 evidence synthesis,3 and in the cost-effectiveness analyses review4 on this topic, available on the USPSTF Web site (http://www.uspreventiveservicestaskforce.org).
Recommendations made by the USPSTF are independent of the U.S. Government. They should not be construed as an official position of AHRQ or the U.S. Department of Health and Human Services.
Source: U.S. Preventive Services Task Force. Screening for Abdominal Aortic Aneurysm. Ann Intern Med 2005;142:198-202.
Copyright and Electronic Dissemination
This document is in the public domain within the United States. Requests for linking or to incorporate content in electronic resources should be sent via the USPSTF contact form.
AHRQ Publication No. 05-0569-A
Current as of February 2005
U.S. Preventive Services Task Force. Screening for Abdominal Aortic Aneurysm: Recommendation Statement. AHRQ Publication No. 05-0569-A, February 2005. http://www.uspreventiveservicestaskforce.org/uspstf05/aaascr/aaars.htm