Ultrasound surveillance is feasible after Endovascular Aneurysm Repair.

INTRODUCTION: Surveillance after endovascular aneurysm repair (EVAR) is traditionally done with computed tomography angiography (CTA) scans that exposes patient to radiation, nephrotoxic contrast media, and potentially increased risk for cancer. Ultrasound (US) is less labor intensive and expensive and might thus provide a good alternative for CTA surveillance. The aim of this study was to evaluate in real-life patient cohorts whether US is able to detect post-EVAR aneurysm-related complications similarly to CTA.

METHODS: This retrospective study compared the outcome of consecutive patients who underwent EVAR for intact abdominal aortic aneurysm (AAA) and were surveilled solely by CTA (CTA-only cohort, n= 168) in 2000-2010 or by combined CTA and US (CTA/US cohort, n= 300) in 2011-2016, as a standard surveillance protocol in department of vascular surgery, Helsinki University Hospital. The CTA-only patients were imaged at 1, 3, and 12 months and annually thereafter. The CTA/US patients were imaged with CTA at 3 and 12 months, US at 6 months and annually thereafter. If there were suspicion of >5 mm aneurysm growth, CTA scan was performed. The patients were reviewed for imaging data, reinterventions, aneurysm ruptures, and death until December 2018. The two groups were compared for secondary rupture, aneurysm- and cancer-related death, reintervention related to AAA, and maximum aneurysm diameter increase >5 mm. The mean follow-up in the CTA-only cohort was 67 months and in CTA/US cohort 43 months.

RESULTS: The two cohorts were alike for basic characteristics and for the mean aneurysm diameter. The total number of CT scans for detecting aneurysm was 84.1/100 patient years in the CTA-only cohort compared to 74.5/100 patient years for US/CTA-cohort. 40 % of patients under combined CTA/US surveillance received one or more additional CTA scans. The two cohorts did not differ for 1-, 5- and 8-year freedom from aneurysm related death, secondary sac rupture, nor the incidence of rupture preventing interventions.

CONCLUSION: Based on the follow up data of this real-life cohort of 468 patients, combined surveillance with US and additional CTA either per protocol or due to suspicion of aneurysm-related complications had comparable outcome with sole CTA-surveillance. Thus, US can be considered a reasonable alternative for the CTA. However, our study showed also that the need of additional CTAs due to suspicion of endoleak or aneurysm non-related reasons is substantial.