Contrast Enhanced Ultra Sound (CEUS) for EVAR Monitoring: A New First Line Method for Post-operative Surveillance? A Single Center Experience

Abstract

Introduction: EVAR (Endo Vascular Aortic Repair) is the first line therapy for the treatment of abdominal aortic aneurysms (AAA). The most frequent post-operative complications of EVAR are endoleaks (EL) that occur when blood leaks back into the aneurysm sac. Type II EL is the most frequent complication requiring lifelong surveillance by radiological imaging. Nowadays, according to guidelines, Computed Tomography Angiography (CTA) scan represents the gold standard modality of imaging to detect EL. CEUS (Contrast Enhanced Ultra Sound) is playing an emerging role in EL detection that could change the follow up algorithm in the near future, reducing the need for CTA imaging to selected cases. Methods: The purpose of the study is to evaluate the role of CEUS in detecting endoleaks after EVAR. Between 2014-2018, 111 patients treated with EVAR for AAA were collected, the mean follow up was 25 months; 14 patients (group 1) were enrolled in the group monitored by CT scan at 1, 6, 12 months and then once per year; 19 patients (group 2) in the group monitored by CEUS and CT scan at 1 month, by CEUS at 6 months and then by Ultrasound Scan (US) yearly; 59 patients (group 3) in the group monitored by CEUS at 1 and 6 months and then, in case of absence of complications, by US yearly. CTA was performed only in case of AAA sac's growth. During the follow-up, 2 patients died in peri-operative period for causes not related to EVAR and 17 patients have been dropped out (5 in group 1, 2 in group 2, 10 in group 3). Results: At the first month we reported 4 EL type II and 1 EL type 1b in group 1 (35%, 5/14), 6 EL type II and 1 EL 1b in group 2 (36%, 7/19) , 12 EL type II, 1 EL type 1b (22% 13/59) and 1 graft thrombosis of left iliac branch in group 3. Patients with type I EL have been promptly treated. All patients with type II EL have been monitored at 6 months, according to clinical and ultrasound presentation. We did not report deaths or major complication in patients with EVAR monitored only by CEUS. Five patients with type II EL and growth of the sac underwent to embolization with resolution of EL in 4 cases, while all the others EL type 2 resolved spontaneously or did not develop AAA growth. Conclusion: CEUS can provide additional contents in terms of dynamic images and flow patterns created by EL inside the AAA sac. The main disadvantages of this technique are operator dependency, lack of quantification, interpretation difficulties in complex anatomies and in high body mass index patients. Anyway, our results highlight the role of CEUS, compared to CT scan, in EVAR surveillance in terms of low cost, good diagnostic performance and, mostly, reduction of exposure to radiations and risk development of contrast medium induced nephropathy for patients needing a lifelong follow-up. Disclosure: Nothing to disclose