The use of color-flow duplex scan for the detection of endoleaks

Objective: Computed tomographic (CT) scan represents the criterion standard for surveillance of endoleaks after endoluminal repair of abdominal aortic aneurysms (erAAAs). Given need for surveillance, risks, and expense of CT scan, the accuracy of color-flow duplex (CFD) scan after erAAA was determined. Methods: During a 43-month period, patients enrolled in phase II and III of the AneuRx Multicenter Clinical Trial at our institution underwent CFD scan 1 month after erAAA. Patients with CFD scan results that were positive for endoleak underwent CT scanning at 3 months after erAAA, and those with CFD scan results that were negative for endoleak underwent CT scanning at 6 months after erAAA. Results: Seven of 79 patients (9%) who underwent CFD and CT scanning had the diagnosis of endoleak. All endoleaks that were diagnosed with CT scan were detected with CFD scan. One patient had positive results for endoleak with CFD scan at 1 month and then negative results with CT scan at 3 months. Although this may represent resolution of endoleak, this case was counted as a false-positive result. When compared with CT scan, CFD scan had a sensitivity of 100%, specificity of 99%, positive predictive value of 88%, negative predictive value of 100%, and accuracy of 99%. Conclusion: CFD scan is an accurate test for the detection of endoleak after erAAA. In addition, most endoleaks diagnosed with CFD scan at 1 month continued to be present at 6 months. This important finding increases the emphasis on the use of this noninvasive test and may initiate earlier intervention of endoleak.