The long-term benefits of a single scan for abdominal aortic aneurysm (AAA) at age 65

Aim: to investigate the efficacy of a single ultrasonic scan at age 65 to identify patients at risk from ruptured abdominal aortic aneurysm (AAA). Method: a total of 6058 men aged 64-81 were recruited to a randomised trial, and 3000 were invited to attend a single screening test. An additional population of 1011 men was offered screening as they reached age 65. If a normal aorta was identified in this sub-group, further scans were offered at two-yearly intervals. Follow up and treatment of those identified as having an aortic dilatation of 3 cm or greater was undertaken. All subject groups were monitored for deaths occurring over the study period, and date and cause of death were recorded. Results: a total of 2212 men attended screening in the randomised trial; the overall compliance was 74%, and prevalence of AAA was 7.7%. Compliance decreased, and prevalence increased, with age. Mortality from ruptured AAA was reduced by 68% at 5 years (screened group compared to the age-matched control population), and by 42% in the study arm (screened and refusers) compared with controls. The benefit persisted at ten years (53% and 21% respectively). Of the uncontrolled sample of 1011 men offered a scan at age 65, 681 attended and 649 of these were found to have a normal aortic diameter; re-screening demonstrated new aneurysm development in 4% over ten years. The aortic diameters of the new AAAs were under 4 cm and would therefore have a low risk of rupture.(1) Mortality from rupture in all those with an initially normal aortic diameter was low, at 1 case per 1000 scans over ten years. Conclusion: screening once for AAA at age 65 can identify the majority of AAA that are of clinical significance and can identify a large population at low risk from rupture who do not require surveillance. This policy has been effective when combined with selective treatment in reducing the risk of rupture for ten years in those who attend the screening programme.