Screening for Abdominal Aortic Aneurysm

This document updates a report published December 17, 2003.

Summary and Conclusions

SBU’s appraisal of the evidence

Aneurysm of the abdominal aorta is common in older men. An aortic diameter of 30 millimeters, or more, is defined as an abdominal aortic aneurysm. As an aneurysm becomes larger the risk for rupture increases, often with fatal consequences. Screening to detect the condition at an early stage is one approach toward reducing mortality from abdominal aortic aneurysm.

• Screening for abdominal aortic aneurysm leads to reduced mortality related to abdominal aortic aneurysm in men (Evidence Grade 1)*. The method is cost-effective (Evidence Grade 1)*.
• Scientific evidence is insufficient* as regards the effects of screening for abdominal aortic aneurysm in women.
• Screening for abdominal aortic aneurysm is ethically defensible, provided that the screening programs are designed to satisfy fundamental ethical principles and that the information given in conjunction with the initial examination and followup is objective and easily understood.

*Criteria for Evidence Grading SBU’s Conclusions
Evidence Grade 1 – Strong Scientific Evidence. The conclusion is corroborated by at least two independent studies with high quality, or a good systematic overview.
Evidence Grade 2 – Moderately Strong Scientific Evidence. The conclusion is corroborated by one study with high quality, and at least two studies with medium quality.
Evidence Grade 3 – Limited Scientific Evidence. The conclusion is corroborated by at least two studies with medium quality.
Insufficient Scientific Evidence – No conclusions can be drawn when there are not any studies that meet the criteria for quality.
Contradictory Scientific Evidence – No conclusions can be drawn when there are studies with the same quality whose findings contradict each other.

Technology and target group

Annually, around 600 men and just over 200 women in Sweden die as a result of rupture of an abdominal aortic aneurysm. Aneurysm is detected either through ultrasound or computed tomography (CT) examination of the abdomen, or after the aneurysm has ruptured. Aneurysms can be repaired surgically for preventive purposes. Surgery of this type is associated with a mortality risk probably below 3%.

Since the condition is less prevalent in women, discussions concerning screening have centered primarily on men. However, studies are under way to assess the effects of screening aimed at women. Screening of all men at 65 years of age is the recommended approach. A screening model of this type, covering all of Sweden, would invite approximately 50 000 men per year for examination. Results from studies in other countries show that approximately 75% of those invited actually participate in the screening program. However, experiences from current screening programs in Uppsala and Östergötland county councils suggest that participation could be higher in Sweden.

It has been estimated that approximately 5% of those examined have an abdominal aortic aneurysm. Of these, approximately 1 in 10 have an aortic diameter that is sufficiently large to motivate direct surgical intervention, while the others can be followed by regularly recurring examinations.

Primary questions

• Can screening reduce the risk for mortality from abdominal aortic aneurysm?
• Is screening for abdominal aortic aneurysm a cost-effective strategy?
• Is screening for abdominal aortic aneurysm ethically defensible?

Patient benefit

A meta-analysis showed that mortality from abdominal aortic aneurysm was lower among those randomized to screening. The analysis included 3 controlled studies that, in all, involved approximately 125 000 individuals aged 65 to 83 years in screening programs.

The largest study, the MASS study, was conducted in England. It included 67 800 men aged 65 to 74 years. After 4 years of followup, mortality from abdominal aortic aneurysm was 42% lower in the study group than in the control group. The absolute risk was 0.19% and 0.33% respectively. Hence, to avoid a single death from aneurysm, approximately 700 men would need to undergo a screening examination. The two remaining studies showed similar results. After 7 years of followup, the MASS study showed that also total mortality was lower in the screened group.

Economic aspects

Introducing screening for abdominal aortic aneurysm involves costs related to the screening examination itself, which is usually performed with ultrasound. Further costs would be incurred from the greater number of preventive operations. Concurrently, however, the costs for acute operations would decrease.

An analysis based on data from the MASS study showed that after 7 years of followup the cost per life-year saved was 19 500 US dollars (USD), corresponding to approximately 117 000 Swedish kronor (SEK). Model studies have analyzed the cost-effectiveness of a screening program that is limited to 65-year-old men, showing a somewhat lower cost per life-year saved.

Ethical aspects

Actively searching for a condition in a symptom-free population – where the treatment offered is associated with a mortality risk up to 3% and some postsurgical morbidity – is ethically controversial. Even if screening leads to an overall reduction in the number of deaths, the treatment itself will lead to premature death in some patients. Not implementing a screening program that is apparently effective and can be delivered at a reasonable cost may, however, also be ethically controversial. Some have claimed that screening for abdominal aortic aneurysm is ethically called for, providing that certain conditions are met, eg, that screening does not crowd out other more urgent needs.

In certain cases, screening detects aneurysms that are too small to motivate preventive surgery. The knowledge that one has an aneurysm, but that it will not be treated until it grows larger, could be a psychological burden.

Hence, prior to examination and possible treatment, it is important for participants in the screening program to receive information that clarifies the issues in an objective and easily understood manner. Also, participants should be given an opportunity to weigh different options in consultation with their attending physicians, family members, and others.

This summary is based on a report prepared at SBU in collaboration with Jesper Swedenborg, MD, Emeritus Professor, Karolinska University Hospital, Stockholm. It has been reviewed by David Bergqvist, MD, Professor, Uppsala University Hospital, Uppsala. Project manager: Helene Törnqvist, SBU.

The complete report is available only in Swedish.

SBU Alert is a service provided by SBU in collaboration with the Medical Products Agency, the National Board of Health and Welfare, and the Swedish Association of Local Authorities and Regions.

References

1. Wanhainen A, Björck M, Boman K, Rutegård J, Bergqvist D. Influence of diagnostic criteria on the prevalence of abdominal aortic aneurysm. J Vasc Surg 2001;34(2):229-35.
2. Blanchard JF. Epidemiology of abdominal aortic aneurysms. Epidemiol Rev 1999;21(2):207-21.
3. 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.
4. Collin J, Araujo L, Walton J, Lindsell D. Oxford screening programme for abdominal aortic aneurysm in men aged 65 to 74 years. Lancet 1988;2(8611):613-5.
5. Lucarotti M, Shaw E, Poskitt K, Heather B. The Gloucestershire Aneurysm Screening Programme: the first 2 years’ experience. Eur J Vasc Surg 1993;7(4):397-401.
6. Vardulaki KA, Prevost TC, Walker NM, Day NE, Wilmink AB, Quick CR et al. Incidence among men of asymptomatic abdominal aortic aneurysms: estimates from 500 screen detected cases. J Med Screen 1999;6(1):50-4.
7. Johansson G, Swedenborg J. Little impact of elective surgery on the incidence and mortality of ruptured aortic aneurysms. Eur J Vasc Surg 1994;8(4):489-93.
8. Bengtsson H, Bergqvist D, Ekberg O, Ranstam J. Expansion pattern and risk of rupture of abdominal aortic aneurysms that were not operated on. Eur J Surg 1993;159(9):461-7.
9. Swedvasc SK. Årsrapport 2008.
10. Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomised controlled trial. EVAR trial participants. Lancet 2005;365(9478):2179-86.
11. Hultgren R, Granath F, Swedenborg J. Different disease profiles for women and men with abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2007;33(5):556-60.
12. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. The UK Small Aneurysm Trial Participants. Lancet 1998;352(9141):1649-55.
13. Lederle FA, Wilson SE, Johnson GR, Reinke DB, Littooy FN, Acher CW et al. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med 2002;346(19):1437-44.
14. Powell JT, Brown LC, Forbes JF, Fowkes FG, Greenhalgh RM, Ruckley CV et al. Final 12-year follow-up of surgery versus surveillance in the UK Small Aneurysm Trial. Br J Surg 2007;94(6):702-8.
15. Lindholt JS, Vammen S, Juul S, Henneberg EW, Fasting H. The validity of ultrasonographic scanning as screening method for abdominal aortic aneurysm. Eur J Vasc Endovasc Surg 1999;17(6):472-5.
16. Pentikäinen TJ, Sipilä T, Rissanen P, Soisalon-Soininen S, Salo J. Cost-effectiveness of targeted screening for abdominal aortic aneurysm. Monte Carlo-based estimates. Int J Technol Assess Health Care 2000;16(1):22-34.
17. 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.
18. Wanhainen A, Lundkvist J, Bergqvist D, Björck M. Cost-effectiveness of screening women for abdominal aortic aneurysm. J Vasc Surg 2006;43(5):908-14; discussion 914.
19. Earnshaw JJ, Shaw E, Whyman MR, Poskitt KR, Heather BP. Screening for abdominal aortic aneurysms in men. BMJ 2004;328(7448):1122-4.
20. 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.
21. Ashton HA, Buxton MJ, Day NE, Kim LG, Marteau TM, Scott RA 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.
22. Brady AR, Thompson SG, Fowkes FG, Greenhalgh RM, Powell JT. Abdominal aortic aneurysm expansion: risk factors and time intervals for surveillance. Circulation 2004;110(1):16-21.
23. 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.
24. Norman PE, Jamrozik K, Lawrence-Brown MM, Le MT, Spencer CA, Tuohy RJ et al. Population based randomised controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ 2004;329(7477):1259.
25. 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 Surg 1995;82(8):1066-70.
26. Cosford PA, Leng GC. Screening for abdominal aortic aneurysm. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD002945. DOI: 10.1002/14651858.CD002945.pub2. 2007.
27. Kim LG, P Scott RA, Ashton HA, Thompson SG. A sustained mortality benefit from screening for abdominal aortic aneurysm. Ann Intern Med 2007;146(10):699-706.
28. Ashton HA, Gao L, Kim LG, Druce PS, Thompson SG, Scott RA. Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms. Br J Surg 2007;94(6):696-701.
29. Heather BP, Poskitt KR, Earnshaw JJ, Whyman M, Shaw E. Population screening reduces mortality rate from aortic aneurysm in men. Br J Surg 2000;87(6):750-3.
30. Wilmink AB, Quick CR, Hubbard CS, Day NE. Effectiveness and cost of screening for abdominal aortic aneurysm: results of a population screening program. J Vasc Surg 2003;38(1):72-7.
31. Swedenborg J, Björck M, Wanhainen A, Bergqvist D. Screening för bukaortaaneurysm räddar liv till rimlig kostnad. Läkartidningen 2003;100(21):1886-91.
32. Multicentre aneurysm screening study (MASS): cost effectiveness analysis of screening for abdominal aortic aneurysms based on four year results from randomised controlled trial. Multicentre Aneurysm Screening Study Group. BMJ 2002;325(7373):1135.
33. Kim LG, Thompson SG, Briggs AH, Buxton MJ, Campbell HE. How cost-effective is screening for abdominal aortic aneurysms? J Med Screen 2007;14(1):46-52.
34. Lindholt JS, Juul S, Fasting H, Henneberg EW. Cost-effectiveness analysis of screening for abdominal aortic aneurysms based on five year results from a randomised hospital based mass screening trial. Eur J Vasc Endovasc Surg 2006;32(1):9-15.
35. Boll AP, Severens JL, Verbeek AL, van der Vliet JA. Mass screening on abdominal aortic aneurysm in men aged 60 to 65 years in The Netherlands. Impact on life expectancy and cost-effectiveness using a Markov model. Eur J Vasc Endovasc Surg 2003;26(1):74-80.
36. Frame PS, Fryback DG, Patterson C. Screening for abdominal aortic aneurysm in men ages 60 to 80 years. A cost-effectiveness analysis. Ann Intern Med 1993;119(5):411-6.
37. Lee TY, Korn P, Heller JA, Kilaru S, Beavers FP, Bush HL et al. The cost-effectiveness of a ”quick-screen” program for abdominal aortic aneurysms. Surgery 2002;132(2):399-407.
38. St Leger AS, Spencely M, McCollum CN, Mossa M. Screening for abdominal aortic aneurysm: a computer assisted cost-utility analysis. Eur J Vasc Endovasc Surg 1996;11(2):183-90.
39. Henriksson M, Lundgren F. Decision-analytical model with lifetime estimation of costs and health outcomes for one-time screening for abdominal aortic aneurysm in 65-year-old men. Br J Surg 2005;92(8):976-83.
40. Wanhainen A, Lundkvist J, Bergqvist D, Björck M. Cost-effectiveness of different screening strategies for abdominal aortic aneurysm. J Vasc Surg 2005;41(5):741-51; discussion 751.
41. Lindholt JS, Vammen S, Fasting H, Henneberg EW. Psychological consequences of screening for abdominal aortic aneurysm and conservative treatment of small abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2000;20(1):79-83.
42. Wanhainen A, Rosén C, Rutegård J, Bergqvist D, Björck M. Low quality of life prior to screening for abdominal aortic aneurysm: a possible risk factor for negative mental effects. Ann Vasc Surg 2004;18(3):287-93.
43. Liss PE, Lundgren F. Etiska skäl talar för screening för bukaortaaneurysm hos 65-åriga män. Den aneurysmrelaterade dödligheten kan halveras. Läkartidningen 2005;102(32-33):2216-9.