A Narrative Review on Contrast-Enhanced Ultrasound in Aortic Endograft Endoleak Surveillance

Abstract

Endovascular repair of abdominal aortic aneurysms have been performed successfully since 1991. However, 20% to 50% of these patients may develop an endoleak or continued aneurysmal sac expansion or perfusion despite stent graft coverage. Current recommendations suggest lifelong surveillance with computed tomographic angiography (CTA) at least 1 month after intervention and yearly after that. In select patients with a stable aneurysm sac on computed tomography performed 1 year after treatment, future screening could be performed with ultrasonography. However, color Doppler ultrasound can fail to detect as many as 31% of endoleaks. Contrast-enhanced ultrasound (CEUS) provides an alternative approach to excluded aneurysm sac follow-up imaging. The Society for Vascular Surgery notes a need for further research on the role of CEUS in endovascular aortic repair surveillance. The European Federation of Societies for Ultrasound in Medicine and Biology suggests that early results are promising. Meta-analyses report pooled sensitivities and specificities of CEUS compared with CTA for the detection of endoleak between 89% and 98% and 86% and 88%, respectively. Owing to the dynamic flow information it provides, CEUS may actually be more sensitive than CTA at detection and characterization in select circumstances. Challenges with adoption, patient selection, and operator dependency remain, but current and future research suggests a role for CEUS in endoleak surveillance.

Pseudoendoleak: A post‐endovascular aortic repair ultrasound surveillance pitfall – Single institution case series

“…Computed tomography angiography (CTA) and CDUS assess changes in aneurysm sac size and for the presence of endoleaks. While literature demonstrates decreased sensitivity of CDUS compared with CTA, there are distinct advantages of ultrasound with a lack of ionising radiation, potentially nephrotoxic contrast and improved temporal resolution 6 . The typical schedule at our institution (assuming an uncomplicated course) would involve baseline studies approximately 1‐month postintervention, followed by annual assessments, typically with CDUS, in line with SVS guidelines 7 .…”

“…While literature demonstrates decreased sensitivity of CDUS compared with CTA, there are distinct advantages of ultrasound with a lack of ionising radiation, potentially nephrotoxic contrast and improved temporal resolution. 6 The typical schedule at our institution (assuming an uncomplicated course) would involve baseline studies approximately 1‐month postintervention, followed by annual assessments, typically with CDUS, in line with SVS guidelines. 7 In the event of increasing sac size or findings suggesting endoleak, further imaging would be performed.…”

Validation of computed tomography angiography using mean arterial pressure gradient as a reference in stented superior mesenteric artery

“…Since angiography is invasive and exposes patients and personnel to radiation, the European Society of Vascular Surgery (ESVS) recommend colour Doppler ultrasound (CDU) of the mesenteric arteries as first line examination [4] and performance of CDU when using MAP gradient as a reference was recently found to be good [5]. However, CDU is a more operator-dependant modality in comparison to CTA [6]. Ultrasound is challenged by the rapid evolution of high-resolution computed tomography angiography (CTA) imaging available around the clock, especially in the subacute and acute setting.…”

Use of contrast ultrasound in differentiating thrombosed pseudoaneurysm from sarcoma, prior to surgery

“…Less common indications include vascular structure evaluation [4] . Endoleak evaluation after abdominal aortic aneurysm repair utilizing contrast ultrasound has been shown to be similar to gold standard computed tomography angiography to determine the presence and type of endoleak [ 5 , 6 ]. Contrast ultrasound is also able to differentiate bland versus tumor thrombus within the portal vein, in the setting of cirrhosis and hepatocellular carcinoma, respectively [7] .…”