The Impact of Iliac Artery Anatomy on Distal Landing Zone After EVAR During the 12-Month Follow-Up.

ABSTRACT

BACKGROUND: Proximal sealing zone has been the main interest in endovascular abdominal aortic aneurysm repair (EVAR), although the distal landing zone remodeling may also affect EVAR durability. The aim of this study was to assess iliac anatomy and its potential impact on distal landing zone adverse events after EVAR during the 12-month follow-up. METHODS: A prospective data collection of patients treated with standard bifurcated EVAR devices for abdominal aortic aneurysm was undertaken between 2017 and 2019. Patients that received extension to the external iliac artery were excluded. Follow-up included computed tomography angiography (CTA) at the 1st and 12th month postoperatively. The common iliac artery (CIA) diameter was assessed in three levels origin (just below the aortic bifurcation), distally (just above the iliac bifurcation) and the middle of the distance between these two landmarks. Iliac angle, tortuosity indexes, relining and oversizing were also analyzed. Distal landing zone-related adverse events were any limb related re-intervention, endoleak type Ib, graft migration, limb stenosis, or occlusion. RESULTS: In total, 268 iliac limbs (134 patients) were included. In all three levels, the mean iliac artery diameters increased at 12-month follow-up. At the origin of the CIA, the diameter increased from 18.7 ± 10.5 mm to 19.9 ± 9.4 mm (P = 0.04), at the middle portion of the CIA, the diameter changed significantly from 15.5 ± 5.1 mm to 17.4 ± 5.4 mm (P < 0.001) and at the distal CIA, from 14.6 ± 3.3 mm to 15.1 ± 3.9 mm (P = 0.03). The iliac angle remained stable (P = 0.14) while the CIA index decreased significantly from 1.17 ± 0.13 to 1.11 ± 0.09 (P < 0.001). The mean value of oversizing was 21.5 ± 14.5% and affected distal iliac diameter increase (P < 0.001). The composite outcome of distal landing zone adverse events was not associated to diameter changes at any level. In 57 cases, a distal iliac diameter ≥18 mm was recorded. The estimated oversizing was lower (16.3 ± 11.8%) compared to <18 mm arteries (22.5 ± 14.9%, P = 0.01). At 12-month follow-up, iliac diameters remained stable in the ≥18 mm group. Endoleak type Ib was more common in iliac arteries ≥18 mm [3 (5.3%) vs. 1 (0.5%) (P = 0.04)] at 12-months. CONCLUSIONS: Post-EVAR iliac artery dilation does not seem to have an impact on distal landing zone adverse events during the 12-month follow-up. Aggressive oversizing may be related to iliac dilation. EVAR patients with iliac arteries ≥18 mm are at higher risk for ET Ib.