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Contrast enhanced duplex ultrasound for early postoperative follow-up after endovascular aneurysm repair: Relation to patient's initial risk of complications.

OBJECTIVES
Current guidelines recommend initial postoperative follow-up with computed tomography angiography (CTA) after endovascular aneurysm repair (EVAR). However, CTA has risks associated with ionizing radiations and nephrotoxic contrast agents. We investigated possibilities to replace the initial postoperative CTA with contrast enhanced duplex ultrasound (CE-DUS) in selected patients.


METHODS
Out of the 273 consecutive patients who underwent EVAR, 173 were excluded and the 100 patients who underwent CTA and CE-DUS imaging concurrently (≤1 month interval between CTA and CE-DUS imaging) within 60 days after EVAR were analyzed. Patients who underwent EVAR outside the manufacturer's instructions for use or who had endoleaks discovered on intraoperative angiography were classified as the high-risk group, otherwise, they were classified as the low-risk group. Measurements of diagnostic values of CE-DUS ​​related to the detection of complications were calculated using CTA as the gold standard. McNemar's test was performed to compare these values and Pearson correlation coefficient was derived to compare CE-DUS measurements of sac diameters with CTA.


RESULTS
In the low-risk group, no difference was observed between CE-DUS and CTA in the detection of EVAR-related complications (sensitivity = 0.95, specificity = 0.93). In the high-risk group, CE-DUS was not as accurate as CTA for the detection of overall EVAR-related complications (sensitivity = 0.57, specificity = 0.86, p = 0.04) and for the detection of complications other than endoleaks (p = 0.02). Regarding sac diameter measurement, there was good agreement between CE-DUS and CTA (r = 0.92, p < 0.001).


CONCLUSIONS
First postoperative CE-DUS was reliable for the evaluation of EVAR-related complications compared to CTA in selected patients. Individualized EVAR follow-up strategy using CE-DUS based on the initial risk of EVAR-related complications should be considered.