Abstract
We were delighted to read the study by Niagara et al. regarding 47 patients post-EVAR implantation, showing that contrast-enhanced CT is not required for endoleak evaluation when Dmax is measured over 6 months post EVAR (1). We are in agreement that there is no need for contrast-enhanced CT surveillance. However we champion the use of duplex ultrasound surveillance, which reduces not only exposure of the patient to nephrotoxic contrast but also completely reduces the radiation exposure, which we know can be cumulatively harmful to patients particularly after long-term surveillance.
In our hands, as supported by the literature (2–13), duplex ultrasound is sensitive to detect these sac size increases and this, in conjunction with clinical symptoms of patients, is satisfactory for surveillance program. Do the authors have any experience of using ultrasound for surveillance? Did any patients have more than one type of endoleak at any one time? In these patients were there Dmax changes and a greater number of endoleak present? Were patients with Dmax increases more clinically symptomatic? There is no description of the correlation of these findings in this paper. In our hands we found that those with the largest expanding aortic sacs are more symptomatic and therefore clinical evaluation provides valuable information to expedite further imaging and re-interventions. We also noted that the endoleak rate of 36% was particularly high in this small series of 47 patients. Were there any particular technical difficulties that led to this?
Overall, we found this study particularly informative and useful in our quest to reduce contrast CT surveillance that EVAR patients are exposed to. However, we believe that the use of ultrasound may ultimately be the answer, particularly with the addition of microbubble contrast in selected cases.