Role of duplex scan in endoleak detection after endoluminal abdominal aortic aneurysm repair

Objective: to validate the role of duplex scan in endoleak detection in pos toperative surveillance of endoluminal abdominal aneurysm repair (EAAR). Patients and methods: between April 1997 and March 1999, 103 patients were eligible for duplex and computed tomography (CT) scan after EAAR. Mean foll ow-up was 8 months (range 1-24 months). The study protocol comprised concur rent examination with colour-duplex and CT scan at 1, 6, and 12 months afte r EAAR, for a total of 198 concurrent examinations. All duplex scan examina tions were performed by two vascular surgeons with the same machine (ATL HD I 3000). Interobserver agreement in endoleak detection (kappa = 1) and in t ype of endoleak (kappa = 0.7) was evaluated in 50 random duplex examination s. Endoleak detection was examined comparatively in duplex and CT scan, the latter being the gold standard. Sensitivity and specificity tests together with negative- and positive-predictive values (NPV and PPV) were calculate d. Results: duplex scan was not feasible in one patient. On CT scan the endole ak rate was 4% at one month, 3% at 6 months, and 4% at one year. Overall, C T scan detected 12 endoleaks. With respect to endoleak detection, duplex sc an revealed a great ability in ruling out false-negative results (sensitivi ty 91.7%, NPV 99.4%), but overestimated the presence of endoleak (specifici ty 98.4%, PPV 78.6%). Regarding type of endoleak, the ability of duplex sca n to identify the source of endoleak was low (sensitivity 66.7%). Conclusions: duplex scan, if validated, appears to be a reliable means for excluding the presence of endoleak after EAAR.