Population screening for abdominal aortic aneurysm: evaluating the evidence against screening criteria

Screening for abdominal aortic aneurysm (AAA) has been initiated in the United Kingdom and United States. Screening using abdominal ultrasound scans allows AAAs to be detected and electively repaired before rupture. There is currently no policy for AAA screening in New Zealand (NZ). We reviewed literature to assess current evidence for AAA screening against standard criteria used to evaluate population-based screening programmes. AAA rupture has high mortality, and people of Maori ethnicity are disproportionately affected. Abdominal ultrasound is a valid screening tool, and elective repair is an effective treatment. Screening reduces AAA-related mortality by about 40% in elderly men. However, the age and comorbidities of AAA patients means rupture risk has to be weighed against elective repair risk. Overtreatment is likely, given most individuals with AAA will not experience rupture in their lifetime. AAA screening appears to be cost-effective. It is unclear if the health system could support all the elements of a AAA screening pathway. AAA appears to be an appropriate condition for which to consider population screening. We recommend research into the prevalence of AAA in NZ, the comorbidity profile of individuals with AAA, drivers of high mortality among Maori, and acceptability of AAA screening to the New Zealand public.