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Conservative AAA Screening Recommendations
Submit responseIn their recent article, the U.S. Preventive Services Task Force (USPSTF) recommended ultrasound screening for abdominal aortic aneurysms (AAAs) only in male smokers age 65-75, excluding other subsets in part based on “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.”(1) I question the evidence regarding harms.
First, the companion review of this topic by Fleming et al concluded that “screening does not appear to be associated with significant physical or psychological harms.”(2) Second, the harm related to morbidity and mortality of “unnecessary” operations requires an unstated assumption that small AAAs identified by screening would be inappropriately repaired before they reach a size of substantial rupture risk. The USPSTF does not provide evidence for this assumption, nor do they indicate the magnitude of this effect on their conclusions. In fact, evidence from randomized trials of AAA screening indicates that >90% of subsequent elective AAA repairs were performed at recommended size criteria.(3)
The USPSTF made separate recommendations for men based on smoking, even though the randomized trials favor screening for all men.(2) They did this based on separate analyses of AAA prevalence, based on risk factors such as smoking. Clearly, screening is more cost-effective if the screened population has a higher prevalence of AAA, so the impact of smoking is an important consideration. Unclear, however, is why they did not evaluate women based on smoking history. Women smokers have the same AAA prevalence as male non-smokers (1.9% for 3 cm AAAs(4)), yet they were bundled into a D-level recommendation against screening for all women, while male smokers received a neutral C-level recommendation. I do not believe that risk factor analysis should be differentially applied based on gender.
Finally, it is disappointing that the USPSTF ignored the importance of a family history of AAA in their overall recommendations. Most studies have found that first degree relatives of patients with AAA have a much higher prevalence of small AAAs (25-43% in brothers, 6-16% in sisters(5)) than the 5.9% prevalence in male smokers (4), for which a B-level recommendation was made for screening by the USPSTF.
Based on these facts, I believe that the USPSTF recommendations were too conservative, in not recommending AAA screening for all men over age 64, for women smokers in this age group, and for men or women of this age with a sibling or parent with an AAA. The Society for Vascular Surgery and the Society for Vascular Medicine and Biology have recommended more comprehensive screening which reflects these concerns.(6)
1. Screening for abdominal aortic aneurysm: recommendation statement. Ann Intern Med 2005; 142:198-202.
2. Fleming C, Whitlock EP, Beil TL, Lederle FA. 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. 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; 360:1531-9.
4. 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; 126:441-9.
5. Frydman G, Walker PJ, Summers K, et al. The value of screening in siblings of patients with abdominal aortic aneurysm. Eur J Vasc Endovasc Surg 2003; 26:396-400.
6. Kent KC, Zwolak RM, Jaff MR, et al. Screening for abdominal aortic aneurysm: a consensus statement. J Vasc Surg 2004; 39:267-9.
Conflict of Interest:
None declared