The potential for a selective screening strategy for abdominal aortic aneurysm

To investigate the feasibility of selective screening for abdominal aortic aneurysm (AAA) based on identification of a target group of manageable size defined by risk factors for AAA.

Male residents of Perth, Western Australia, aged 65-83 years, who participated in a randomised controlled trial of ultrasound screening for AAA.

Eligible men were identified from the electoral roll and invited to attend a screening clinic. Those who attended completed a questionnaire, had a limited physical examination, and underwent an ultrasound examination to identify the maximum diameter of the infrarenal aorta. Data on risk factors collected from the first 8995 men seen were used to calculate a multivariate risk score for the remaining 2755 men who were screened. Centiles of the risk score were used to define potential target groups for screening and the sensitivity and specificity of each of these selective screening strategies were calculated. We repeated the calculation separately for AAAs of at least 30 mm, 40 mm, and 50 mm in diameter.

We found that screening half of the male population aged 65-83 years would find approximately 75% of AAAs, regardless of their size, whereas screening only current smokers in this population would find approximately 20% of AAAs.

Selective screening for AAA using easily recognisable risk factors is feasible but is not worthwhile as approximately 25% ofclinically significant cases would be missed.