Could Four-dimensional Contrast-enhanced Ultrasound Replace Computed Tomography Angiography During Follow up of Fenestrated Endografts? Results of a Preliminary Experience

Objective: To evaluate four-dimensional contrast-enhanced ultrasound (4D-CEUS) as an alternative imaging method to computed tomography angiography (CTA) during follow up of fenestrated endovascular aneurysm repair (FEVAR) for juxta- and para-renal abdominal aortic aneurysms (AAA). Methods: Between October 2011 and March 2012, all consecutive patients who underwent FEVAR follow up were included in the study and evaluated with both 4D-CEUS and CIA. The interval between the two examinations was always <= 30 days. Endpoints were the comparison of postoperative AAA diameter, AAA volume, presence of endoleaks, revascularized visceral vessel (RVV) visualization, and patency. Comparative analysis was performed using Bland-Altman plots and McNemar's Chi-square test. Results: Twenty-two patients (96% male, 4% female; mean age 74 7 years; American Society of Anesthesiologists grade III/IV 82%/18%) were enrolled. Seventy-eight RVV (fenestrations: 60; scallops: 17; branches: 1) were analyzed. The mean AAA diameter evaluated by 4D-CEUS and CIA was 45 10 mm (range 30-69 mm) and 48 +/- 9 mm (range 32-70 mm), respectively. The mean difference was 3 +/- 3 mm. The mean AAA volume evaluated by 4D-CEUS and CIA was 150 +/- 7 cc (range 88-300 cc) and 159 +/- 68 cc (range 80-310 cc), respectively. The mean difference was 7 4 cc; a Bland-Altman plot revealed agreement in AAA diameter and volume evaluation (p < .01) between 4D-CEUS and CIA. The observed agreement for the detection of endoleaks was 95%. McNemar's Chi-square test confirmed that 4D-CEUS and CIA were equivalent (p > .05) at detecting endoleaks. The first segment of six (8%) RVVs (four renal and two superior mesenteric arteries) was not directly visualized by 4D-CEUS owing to obesity, but the contrast enhancement into the distal part of vessel or into the relative parenchyma gave indirect information about their patency. McNemar's Chi-square test demonstrated the superiority of CIA (p = .031) in visualizing RVVs. The patency of 77/78 RVVs was confirmed with both techniques. McNemar's Chi-square test confirmed that 4D-CEUS and CIA were equivalent in their ability to detect visceral vessel patency. Conclusions: The data suggest that 4D-CEUS is as accurate as CIA in the evaluation of postoperative AAA diameter and volume, endoleak detection, and RVV patency after FEVAR. Four-dimensional CEUS could provide hemodynamic information regarding RVVs, and reduce radiation exposure and renal impairment during follow up. Obesity limits the diagnostic accuracy of 4D-CEUS. (C) 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.