IYSC03 - Use of dynamic triggered computed tomography angiogram for the assessment of branched-fenestreated endovascular aortic repair

Objectives: To conduct a geometric and kinetic analysis of the endograft-bridging stent complex in in patients treated by fenestrated (FEVAR) and branched (BEVAR) endovascular aortic repair.

Methods: We conducted a single-center prospective study (2022-2024) on patients treated by FB-EVAR. Only patients receiving d-CTA within 30 days from FBEVAR were included in the analysis. Dt-CTA was acquired for the duration of a cardiac cycle, with implementation of appropriate reconstructions for each target vessel. The αf angle (between the aorta and bridging stent axis), the bridging length, and the βf angle (between the target vessel and bridging stent axis) were measured in target vessels incorporated by FEVAR. The total bridging length, the αb angle (between the aorta and the branch), and the βb angle (between the branch and the bridging stent axis) were measured for target vessels included by BEVAR (Figure 1). Each measure was performed along the cardiac cycle, to determine the angular excursion (∆). Linear regression was implemented to identify factors associated with angular excursion.
Primary endpoint was the mobility of the endograft-bridging stent complex. Secondary endpoint was to identify any association between dynamic changes and target vessel instability.

Results: Eighty target vessels (60 fenestrations and 20 branches) form 20 patients were included. In tFEVAR, the average ∆αf was 4.21°±0.63°, ∆ β f was 3.45°±0.51°, and the most mobile vessel was the celiac artery (∆αf=5.04°±1.80°; P=.045). In BEVAR, the average ∆αb and ∆β were 4.63°±0.87° and 6.40°±2.71°, respectively. The distal end of the bridging stent was the point with the greatest angular excursion the entire endograft complex (coeff=1.99, P=.021).
In the overall cohort, the celiac-mesenteric arteries appeared to have greater mobility compared to the renals (coeff=1.21, P=.045), as well as BEVAR compared to FEVAR (coeff=1.31, P=.030). In BEVAR, the total bridging length (coeff=0.80, P=.032) and branch upward orientation (coeff=0.75, P< 001) were associated with greater angular excursion. Type of bridging stent (coeff=0.23, P=.123) was not associated with kinetic measurements.
Freedom from target vessel instability at 1 year was 95±2%. A greater angular excursion was associated with target vessel instability of renal arteries incorporated by a directional branch (coeff=0.56, P=.039).

Conclusions: The study demonstrates that the dynamic mobility of the endograft-bridging stent complex in FB-EVAR can be effectively analyzed using Dt-CTA. The findings suggest greater mobility in BEVAR compared to FEVAR and in the celiac-mesenteric arteries compared to the renals, with specific factors such as branch orientation and bridging length influencing this mobility.