Contrast Enhanced Ultrasound Detects Endoleak after EVAR

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Introduction - The major complications of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAA) include endoleak, stentgraft migration and increased aneurysm sac size with subsequent risk of rupture. Thus, EVAR requires lifetime follow-up. Contrast-enhanced computed tomographic angiography (CTA) is considered the gold standard in follow-up after EVAR. However, repeat CTA is potentially harmful due to accumulated radiation1; and the association between contrast agents and reduced renal function. Contrast agents used in contrast-enhanced ultrasound (CEUS) are not nephrotoxic and CEUS has been reported to be able to detect endoleak after EVAR2. The aim of this study was to investigate the preciseness of CEUS vs CTA in follow-up after EVAR. Methods - Ninety-two patients (79 men) operated with EVAR for AAA between Jan 2013 and May 2016 was prospectively, consecutively enrolled. Mean age was 74 years (range 57 – 92). Follow-up was done with CTA and CEUS at one, six, 12 and 24 months. At each follow-up, CTA and CEUS were done the same day. The results from CTA were blinded from the operator doing CEUS and vice versa. A GE Logiq E9 ultrasound machine and an abdominal curvilinear 2-5MHz probe were used for the CEUS. The ultrasound contrast agent used in this study was SonoVue® (2.4ml dispersion intravenous bolus dose). The presence of endoleak was registered as a dichotomous variable and CTA was defined as the gold standard. Statistical analyses were done using crosstabs and chi-square tests (IBM, SPSS Statistics v24). Results - 236 paired CEUS and CTA were performed. In total, 48 endoleaks were documented on CTA. The overall sensitivity of CEUS was 89 % and the specificity 100 %. The number of endoleaks detected at one, six, 12 and 24 months postoperatively are listed in Table 1. At six months, five new endoleaks were found on CTA and two with CEUS. At 12 and 24 months, no new cases of endoleak were detected by either modality. In all four cases of endoleak detected on CTA but missed on CEUS, poor visualization on CEUS due to high body mass index (median 30.5) was reported. All cases of endoleaks were type 2.Table 1Number of patients with paired CTA and CEUS performed during follow-up and the sensitivity and specificity of endoleak detection by CEUSFollow-up, monthsPatients (n)Endoleaks on CEUS vs CTASensitivity (%)Specificity (%)17311/129210066813/1776100126312/1210010024326/6100100 Open table in a new tab Conclusion - In the present study, CEUS showed high sensitivity and specificity for detecting endoleak. CEUS may replace CTA in most patients during follow-up after EVAR.