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Updated: Oct 9, 2026

An Approach to Point-Of-Care Ultrasound Evaluation of the Abdominal Aorta
Published on: September 8, 2023
The incidence of small abdominal aortic aneurysms and the change in normal infrarenal aortic diameter: implications
A B Wilmink1, C S Hubbard, N E Day
1Department of Surgery, Norfolk & Norwich Hospital, Norwich, UK.
Aim:
to study the incidence of small abdominal aortic aneurysms (AAA), and to investigate what proportion of normal infrarenal aortic diameters (IAD) expand with age.
Methods:
longitudinal follow-up in a population-based aneurysm screening programme. The infrarenal aortic diameter (IAD) was measured by ultrasound. A second scan was performed in subjects with a normal aorta after an average of 5.5 years.
Results:
data were analysed from 4072 subjects, 464 with a small AAA and 3608 with a normal aorta. The infrarenal aorta expanded in 15% of subjects, but significant growth (>5 mm) occurred in only 7%. Age and initial diameter were independent predictors for aortic dilatation. The effect of diameter at first screen was non-linear. The relative risk for expansion increased dramatically for IADs over 2.5 cm (test for departure of trend: chi2=52, p<0.0001). The effect of age was also non-linear, the risk of expansion was highest in the 60-69 year old age group; test for departure of trend (chi2=13, p=0.002). The incidence of new aneurysms was 3.5 per 1000 person-years (py) (95% CI: 2.8-4.4). The highest incidence of new aneurysms was found in the 60 to 69 year old age group.
Conclusion:
only a small proportion of the population is prone to aortic dilatation. Patients over 70 with an IAD <2.5 cm can be discharged from follow-up.
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