How best to diagnose and manage abdominal aortic aneurysms

One critique of the USPSTF recommendations is that they fail to detect a significant portion of patients with AAA and AAA rupture. For example, in a retrospective analysis of 55,197 patients undergoing AAA repair, only 33% would have been detected by the USPSTF grade “B” recommendation to screen male smokers ages 65 to 75 years, and an analysis of AAA-related fatalities found 43% would be missed by USPSTF criteria.^9,21

Screening guidelines from the Society for Vascular Surgery (SVS) are broader than those of the USPSTF, in an attempt to capture a larger percentage of the population at risk for AAA-related disease by extrapolating from epidemiologic data. The SVS guidelines include screening for women ages 65 to 75 years with a smoking history, screening men and women ages 65 to 75 years who have a first-degree relative with AAA, and consideration of screening patients older than 75 years if they are in good health and have a first-degree relative with AAA or a smoking history and have not been previously screened.⁴ However, these expanded recommendations are not supported by patient-oriented evidence.⁶

Attempts to broaden screening guidelines must be tempered by potential risks for harm, primarily overdiagnosis (ie, diagnosing AAAs that would not otherwise rise to clinical significance) and overtreatment (ie, resulting in unnecessary imaging, appointments, anxiety, or surgery). Negative psychological effects on quality of life after a diagnosis of AAA have not been shown to cause significant harm.^6,18

A recent UK analysis found that screening programs for AAA in women modeled after those in men are not cost effective, with an NNS to prevent 1 death of 3900 in women vs 700 in men.^15,18 Another recent trial of ultrasound screening in 5200 high-risk women ages 65 to 74 years found an AAA incidence of 0.29% (95% CI, 0.18%-0.48%) in which only 3 large aneurysms were identified.²²

Smoking is the most potent modifiable risk factor for abdominal aortic aneurysm.

In the United States, rates of screening for AAA remain low.²³ One study has shown electronic medical record–based reminders increased screening rates from 48% to 80%.²⁴ Point-of-care bedside ultrasound performed by clinicians also could improve screening rates. Multiple studies have demonstrated that screening and diagnosis of AAA can be performed safely and effectively at the bedside by nonradiologists such as family physicians and emergency physicians.^25-28 In 1 study, such exams added < 4 minutes to the patient encounter.²⁶ Follow-up surveillance schedules for those identified as having a AAA are summarized in TABLE 2.⁴

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