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 i dentify 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 po pulation of 1011 men was offered screening as they reached age 65. If a nor mal aorta was identified in this sub-group, further scans were offered at t wo-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 cau se of death were recorded. Results: a total of 2212 men attended screening in the randomised trial; th e overall compliance was 74%, and prevalence of AAA was 7.7%. Compliance de creased, and prevalence increased, with age. Mortality from ruptured AAA wa s reduced by 68% at 5 years (screened group compared to the age-matched con trol population), and by 42% in the study arm (screened and refusers) compa red with controls. The benefit persisted at ten years (53% and 21% respecti vely). 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 a ortic 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 initial ly 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 A AA that are of clinical significance and can identify a large population at low risk from rupture who do not require surveillance. This policy has bee n effective when combined with selective treatment in reducing the risk of rupture for ten years in those who attend the screening programme.