Changes in Renal-Mesenteric Duplex Ultrasound Velocities after Fenestrated and Branched Endovascular Aortic Aneurysm Repair.

OBJECTIVE: Stenting of renal and mesenteric vessels may result in changes in velocity measurements due to arterial compliance, potentially giving rise to confusion about presence of stenosis during follow-up. The aim of our study was to compare preoperative and post-operative changes in peak systolic velocity (PSV, cm/sec) following placement of the celiac axis (CA), superior mesenteric artery (SMA) and renal artery (RAs) bridging stent-grafts during fenestrated-branched endovascular aortic repair (FB-EVAR) for treatment of complex abdominal aortic aneurysms (cAAAs) and thoracoabdominal aortic aneurysms (TAAAs).

METHODS: Patients were enrolled in a prospective, non-randomized single-center study to evaluate FB-EVAR for treatment of CAAAs and TAAAs between 2013-2020. Duplex ultrasound (DUS) of renal-mesenteric vessels were obtained prospectively pre-operatively and at 6-8 weeks following the procedure. DUS was performed by a single vascular laboratory team using a pre-defined protocol including PSV measurements obtained with <60° angles. All renal-mesenteric vessels incorporated by bridging stent-grafts using fenestrations or directional branches were analyzed. Target vessels with significant stenosis in the preoperative exam were excluded from the analysis. The endpoint was variations in PSV post-stent placement at the origin, proximal and mid segments of the target vessels for fenestrations and branches.

RESULTS: There were 419 patients (292 male, mean age 74±8 years old) treated by FB-EVAR with 1,411 renal-mesenteric targeted vessels, including 260 CAs, 409 SMAs and 742 RAs. No significant variances in the mean PSVs of all segments of the CA, SMA and RAs at 6-8 weeks after surgery were found as compared to the preoperative values (CA: 135 cm/sec vs. 141 cm/sec, p=.056; SMA: 128 cm/sec vs. 125 cm/sec, p=.624; RAs: 90 cm/sec vs. 83 cm/sec, p= .654). Compared with baseline preoperative values, the PSV of the targeted vessels showed no significant difference in the origin and proximal segment of all vessels. However, PSV significantly increased in the mid segment of all target vessels following stent placement.

CONCLUSION: Stent placement in nonstenotic renal and mesenteric vessels during FB-EVAR is not associated with significant increase in PSVs at the origin and proximal segments of the target vessels. While there is a modest but significant increase in velocity measurements in the mid segment of the stented vessel, this is not clinically significant. Furthermore, PSVs in stented renal and mesenteric arteries were well below the threshold for significant stenosis in native vessels. These values provide a baseline or benchmark for expected PSVs following renal-mesenteric stenting during FB-EVAR.