548 A 10-Year Longitudinal Cohort Study Assessing Growth Rates and Surveillance Intervals for Common Iliac Artery Aneurysms

Abstract

Aim The European Society for Vascular Surgery defines common iliac artery (CIA) aneurysms as greater than 1.8cm in men and 1.5cm in women. Their reported growth rate is 1–4mm/year depending on their diameter. This study aimed to assess the natural history and surveillance intervals for CIA aneurysms as intervention threshold is based on low-quality evidence. Method Patients diagnosed with an IAA at a single vascular centre between 1st January 2010 and 31st August 2021 were identified from a prospectively collected departmental database and Caldicott-approved data collection performed. The primary outcomes included diameter-based mean aneurysm growth rates and median surveillance intervals. Statistical analysis with SPSS® was performed using chi-squared tests. Results Of the 203 patients included, 90.6% were men and median (IQR) age at detection was 77 (71–83). IAA were located in the CIA (85.2%), IIA (21.7%) and EIA (2.0%) with the majority being asymptomatic (78.8%). CT was most frequently used as the imaging modality for IAA surveillance (66.3%), followed by ultrasound scan (29.8%) and MRA (3.9%). Growth rate for CIA aneurysms measuring 1.0–1.9cm were -2.1mm/year, 2.0–2.9cm were 0.8mm/year, 3.0–3.9cm were 3.5mm/year, 4.0–4.9cm were 9.4mm/year, 5.0–5.9cm were 2.9mm/year and >6.0cm were 13.8mm/year. Median surveillance intervals for CIA aneurysms at 1.0–1.9cm were 12-monthly, 2.0–2.9cm were 11-monthly, 3.0–3.9cm were 5-monthly, 4.0–4.9cm were 5-monthly, 5.0–5.9cm were 5.5-monthly and >6.0cm were 14.5-monthly. Mean(SD) CIA diameter at rupture was 4.6 (2.4)cm. Conclusions CIA aneurysms demonstrate faster growth rates as they enlarge and may require more frequent clinical assessments, surveillance, and consideration for repair prior to rupture.