BACKGROUND

Abdominal aortic aneurysms (AAAs) are present in 5 to 10% of men over the age of 65, and elective surgical intervention has long been the mainstay of treatment. There is widespread consensus that operative repair is the treatment of choice in larger AAAs, where the risk of rupture increases with the size of the aneurysm. However, even elective operations carry a significant mortality risk, and the UK small aneurysm trial has shown that for smaller aneurysms (between 4 and 5.5cm) there is no difference in outcome between operation and no intervention. Currently such patients are treated with best medical therapy, but there has been considerable research into finding a pharmacological treatment to prevent aneurysm expansion and rupture.

SCREENING PROGRAMMES

A major obstacle to the prevention of mortality and morbidity associated with aneurysms has been the fact that the majority are asymptomatic, and therefore often remain undetected. Abdominal aortic aneurysms have tended to present either as emergencies or as a result of their increasing size, and it has been shown that larger aneurysms grow more rapidly than their smaller counterparts and are at greater risk of rupture. These patients would therefore benefit most from operative repair rather than medical intervention. In order for a medical treatment to be of benefit, it needs to be targeted at aneurysms that are small and asymptomatic. The most obvious way of doing this would be the initiation of a mass screening programme, and indeed, the Multicentre Aneurysm Screening Study (MASS) has shown that as many as 88% of screen-detected aneurysms are below the threshold for surgery.