Ultrasound Surveillance of Common Iliac Artery Aneurysms

Abstract

The surveillance of patients with common iliac artery aneurysms (CIAA) does not follow a defined protocol such as the one adopted for the management of abdominal aortic aneurysms. This study explores CIAA growth rate, and seeks to determine correlations with related parameters which may serve to influence aneurysm expansion with the view of devising an effective local surveillance protocol. Vascular laboratories across the UK were invited to participate in an online survey. Questions were designed to assess current clinical practice in regards to the surveillance of patients with CIAA. Additionally, a retrospective audit was performed using the clinical reports of patients attending a regional vascular laboratory to undergo an aorto-iliac duplex scan (USS). Expansion rate of aneurysms was studied in patients who had ≥2 USS scans; data was recorded at 6 and/or 12 monthly intervals up to 5years. Kaplan Meier estimates of patient mortality (all cause) and intervention rate during the surveillance period were performed. Patient age, initial CIAA diameter, bilateral/unilateral CIAA and coinciding aortic aneurysm diameter were recorded to determine if these specific features were associated with CIAA growth rates. Pearson's correlation coefficient was used to determine the strength of association between variables. Nine hundred and ninety-five of one thousand and sixty patient records were suitable for review: 21.6% (215/995) of patients had a CIAA. Isolated CIAA accounted for 23% (50/215). Mean CIAA growth was 1.5±0.3mm/year. A strong correlation was found between CIAA diameter versus time from diagnosis (r=0.820; P=0.004); CIAA with smaller initial diameters (15-20mm) expanded more rapidly than those of larger diameter at diagnosis (r=0.871; P=0.005). CIAA measured at >30mm demonstrated an unpredictable growth trajectory which was also evident in those CIAA coinciding with larger AAA (>50mm; r=0.208; P=0.655). The results obtained in this study may form the basis for a dedicated CIAA surveillance protocol.