Abstract
Surveillance for endoleak, blood flow into the residual aneurysmal sac, is required post-endovascular repair (EVAR). Te Whatu Ora Southern utilises duplex ultrasound imaging at 1-, 6- and 12-months, then life-long annual scans. A reduced regime is proposed: surveillance at 5-year intervals if endoleak was not detected at first follow-up. This study aimed to determine the timing and occurrence of endoleak within our post-EVAR cohort and assess the suitability of the modified surveillance regime.
A retrospective audit of post-EVAR surveillance was conducted from January 2008-2023. Descriptive characteristics from 298 patients are shown with continuous data shown as mean (95% CI or ± SD). Sub-group analysis was conducted stratified to with/without endoleak. Differences were determined by Fisher's exact or unpaired Student's t-test, with significance set at P < 0.05.
Endoleak was detected in 138/298 (46.3%) patients with 6%, 2%, 40.9%, 3.7%, 0.7% for types 1a, 1b, 2, 3, 4/5, respectively. Further intervention was clinically indicated in 42.5% cases of endoleak; 36/38 cases of type 1 or 3, and 32/122 type 2. Resolution of endoleak (i.e. not observed on the last scan) was observed in 62% of cases. No differences in patient characteristics or initial aneurysmal sac size were observed between those with/without endoleak. On average, endoleak was detected at 2.2 (1.7-2.6) years. Endoleak was detected at first visit (early) in 54/138, and at scans ≥6 months in 74/138 with separate incidences of early and late endoleak observed in 10 patients. Scans conducted between 0.5 - <5 years, i.e. the time frame excluded within the modified surveillance, detected a large number of endoleak 32% type 1 (a or b) and 96% type 2.
Therefore, our data shows that the proposed modified surveillance regime would result in a missed opportunity to identify many occurrences of endoleak in our cohort, including cases deemed to require intervention.