Endoleak after Endovascular Aneurysm Repair: Duplex Ultrasound is Better than CT at Determining the Need for Intervention

Objectives:
Computed tomography (CT) scan is reported as the gold standard for the detection of endoleak but it is not a test without risk. Duplex ultrasound (US) is a noninvasive alternative to CT. The purpose of this study is to compare CT and US in the detection of endoleak requiring intervention after endovascular aneurysm repair (EVAR). Standard statistical methods were applied.
Methods:
A retrospective review of all EVARs performed at our institution from 1996 to 2007 was conducted. US and CT results were recorded as was the presence of endoleak. Clinical follow up was reviewed and interventions for endoleak were recorded. Interventions were performed for Type I, Type II with sac enlargement, and for Type III endoleaks.
Results:
During the time period reviewed, 540 patients underwent EVAR, 236 of these had both US and CT follow up studies paired within six months of each other. Follow up ranged from <1 month to 111 months with a mean follow up of 17 months. A total of 988 studies or 494 pairs were reviewed. Twenty patients (8.4%) required intervention for 22 endoleaks. Type I (n=7), Type II (n=14), and Type III (n=1). All Type I and III endoleaks were treated with endovascular cuff or limb extension placement. Type II endoleak was treated with open ligation in 4 while coil or glue embolization was used in 10. Early endoleak, within one month, occurred in 2 versus late endoleak in 20 (mean 19.2 months with a range of 0.7 to 54 months). US detected endoleak requiring intervention in all cases while CT detected endoleak in only 68%. The ability to correctly identify the type of endoleak as confirmed at time of intervention was 72% with US compared to 41% by CT. US, for the detection of endoleak requiring intervention, had a sensitivity of 100% and specificity of 81% while CT had a sensitivity of 68% and specificity of 87%.
Conclusions:
Duplex ultrasound has a high sensitivity in detecting endoleak requiring intervention, is better at identifying type of endoleak, and is an excellent test for graft surveillance after endovascular aneurysm repair. When compared to CT scan, US in our experience is the preferred test on which to base an intervention for endoleak.