Screening for Abdominal Aortic Aneurysms

TO THE EDITOR: The U.S. Preventive Services Task Force (USPSTF) recommended screening for abdominal aortic aneurysms (AAAs) with ultrasonography only in male smokers 65 to 75 years of age. Other subsets were excluded in part because of “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 on this topic by Fleming and colleagues (2) concluded that “screening does not appear to be associated with significant physical or psychological harms.” 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 reached a size of substantial rupture risk. The members of the USPSTF do 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 more than 90% of subsequent elective AAA repairs were performed at recommended size criteria (3). The USPSTF made separate recommendations for men on the basis of smoking, even though randomized trials favor screening for all men (2). To do so, the USPSTF relied 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. It is unclear, however, why the USPSTF did not evaluate women on the basis of smoking history. Female smokers have the same AAA prevalence as male nonsmokers (1.9% for 3-cm AAAs [4]), yet they were bundled into a grade D recommendation against screening for all women while male smokers received a neutral grade C recommendation. I do not believe that risk factor analysis should be differentially applied on the basis of sex. Finally, it is disappointing that the USPSTF ignored the importance of a family history of AAA in its overall recommendations. Most studies have found that first-degree relatives of patients with AAA have a much higher prevalence of small AAAs (25% to 43% in brothers, 6% to 16% in sisters [5]) than the 5.9% prevalence in male smokers (4), for whom the USPSTF issued a grade B recommendation for screening. I believe that the USPSTF recommendations were too conservative in not recommending AAA screening for all men older than age 64 years, for female smokers in this age group, and for men or women in this age group whose sibling or parent had an AAA. The Society for Vascular Surgery and the Society for Vascular Medicine and Biology have recommended more comprehensive screening that reflects these concerns (6).