Endoleak after endovascular aneurysm repair: duplex ultrasound imaging is better than computed tomography at determining the need for intervention.

OBJECTIVE: Color duplex ultrasound (CDU) imaging is a noninvasive alternative to computed tomography (CT) for the detection of endoleak. This study compared CT and CDU imaging in the detection of endoleaks requiring intervention after endovascular aneurysm repair (EVAR).

METHODS: All EVARs performed at our institution from 1996 to 2007 were retrospectively reviewed. CDU and CT scans < or =3 months were paired and the presence of an endoleak and its type were recorded. Clinical follow-up was reviewed and interventions for endoleak were recorded. Interventions were performed for type I, for type II with sac enlargement, and for type III endoleaks. The first analysis of clinical test outcomes used the findings of CT scan as a gold standard and the second used the findings at time of intervention as a gold standard.

RESULTS: During the time period reviewed, 496 patients underwent EVAR, and 236 of these had CDU and CT follow-up studies paired < or =3 months of each other. Mean follow-up was 17 months (range, <1-111 months). We reviewed 944 studies or 472 pairs. Eighteen patients (7.6%) required intervention for 19 endoleaks: six type I, 11 type II, and two type III. Early endoleak (< or =1 month) requiring reintervention was detected in 1 vs late endoleak (mean, 28 months; range, 0.6-88 months) in 18. All type I and III endoleaks were treated with endovascular cuff or limb extension placement. Three type II endoleaks were treated with open ligation, and coil or glue embolization was used in eight. CDU imaging detected endoleaks requiring intervention in 89% of cases, whereas CT detected endoleak in 58% (P < .05). The ability to correctly identify the type of endoleak as confirmed at time of intervention was 74% with CDU imaging vs 42% by CT (P < .05). CDU, for the detection of endoleak requiring intervention, had a sensitivity of 90%, specificity of 81%, negative predictive value (NPV) of 99%, and positive predictive value (PPV) of 16%, while CT had a sensitivity of 58%, specificity of 87%, NPV of 98%, and PPV of 15%.

CONCLUSIONS: CDU imaging has a high sensitivity in detecting endoleaks requiring intervention, is better at identifying the type of endoleak, and is an excellent test for graft surveillance after endovascular aneurysm repair. Compared with CT scan, CDU imaging in our experience is the preferred test on which to base an intervention for endoleak.