547 Postoperative Outcomes Are Significantly Worse Among Patients Undergoing Repair of Ruptured Versus Unruptured Iliac Artery Aneurysms – a 10-Year Longitudinal Cohort Study

Aim

The European Society for Vascular Surgery defines iliac artery aneurysms (IAA) as beyond 1.5 times its normal diameter. Common iliac arteries (CIA) beyond 1.8cm in men and 1.5cm in women are considered aneurysmal. This study aimed to assess outcomes following IAA rupture as their natural history is poorly understood and treatment recommendations based on low-level evidence.

Method

Patients with IAAs 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 aneurysm rupture, rupture diameter, post-operative complications, 30-day, 1-year and 5-year mortality rates. Statistical analysis with SPSS® was performed using chi-squared tests.

Results

Of 203 patients included, 90.6% were men and median(IQR) age at detection was 77 (71–83). Co-morbidities included hypertension (54.2%), hyperlipidaemia (42.9%) and ischaemic heart disease (35.5%). IAA were in the CIA (85.2%), IIA (21.7%) and EIA (2.0%), mostly asymptomatic (78.8%). Overall IAA rupture rate was 7.9% with CIA (81.2%) and EIA (18.8%). Mean (SD) diameters at rupture were 4.6 (2.4)cm for CIA and 4.6 (3.0)cm for IIA. Post-operative major adverse cardiovascular events (MACE) more frequently occurred following repair of ruptured compared to unruptured IAA (33.3% vs 3.5%, p=.011). Mortality at 30-days, 1-year and 5-years postoperatively were higher following repair of ruptured vs unruptured aneurysms (88.9%, 88.9%, 100% vs 1.2%, 10.6%, 36.1% respectively).

Conclusions

Early detection and elective treatment of IAA aneurysms before they approach 4.6cm may reduce rupture risk, morbidity and mortality associated with emergency repair following rupture.

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

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.