Rates of growth of abdominal aortic aneurysms in an Irish population.

INTRODUCTION: An Abdominal Aortic Aneurysm is a disease with a high mortality and morbidity in both acute and elective settings and thus the timing of intervention and surveillance is of high importance. These are derived from historical growth patterns. However, real-world expansion rates may vary between populations. Indeed there has been no published study examining this in an Irish population. This study aimed to evaluate AAA growth in a local surveillance cohort and assess concordance with assumptions underlying the 2024 ESVS surveillance guidance. METHODS: A retrospective analysis was performed using a prospectively maintained database of patients undergoing ultrasound surveillance for AAA. Aneurysm diameter at first presentation and sequential measurements were recorded. Annualised growth rates were calculated where serial measurements were available. Patients were stratified by baseline aneurysm diameter into, < 3 cm, 3-4 cm, 4-5 cm, 5-6 cm cohorts and > 6 cm, and growth rates were compared across groups. RESULTS: A total of 341 patients were included. The mean age was 73.4 ± 9.2 years, and the mean aneurysm diameter was 4.02 ± 1.09 cm (median 4.1 cm). Follow-up data suitable for growth-rate analysis were available for 214 patients. The mean aneurysm growth rate was 0.2 ± 0.274 cm/year (median 0.167 cm/year; 95% CI 0.169-0.243 cm/year). There was a predominance of males (85%). Stratified analysis demonstrated increasing growth with larger baseline diameter. Mean growth was < 0.1 cm/year for those under 3 cm 0.1 cm/year for aneurysms measuring 3-4 cm, 0.24 cm/year for 4-5 cm, and over 0.28 cm/year for aneurysms > 5 cm and 0.37 cm for those > 6 cm.