Influence of Aortoiliac Geometry on Non-Occlusive Thrombotic Risk Following Endovascular Repair of Abdominal Aortic Aneurysms

Objectives: This study investigated the impact of aortoiliac geometry on thrombotic complication following aortic endovascular aneurysm repair (EVAR). Methods: Data from 54 patients who received abdominal EVAR between January 2015 and December 2023, in which 18 developed unilateral iliac limb in-stent thrombus, were retrospectively reviewed. Clinical data, including cardiovascular risk factors, laboratory findings, and geometrical factors, including iliac diameter, sectional area, limb angles, and tortuosity, were collected. Aortoiliac geometry analyses were performed on the 3D model reconstructed from abdominal aortic computed tomography angiography (CTA) using semi-automated software (MIMICS version 25.0). Results: Compared to non-thrombotic limbs, thrombotic iliac limbs showed larger maximum diameters (17.48 ± 0.95 mm vs. 14.14 ± 0.62 mm, p = 0.006), lower graft limb angles (117.52° ± 5.61° vs. 148.54° ± 4.31°, p < 0.001), lower aortoiliac angles (123.48° ± 4.66° vs. 141.96° ± 4.76°, p = 0.009), and higher iliac tortuosities (0.2 ± 0.03 vs. 0.12 ± 0.02, p = 0.02). Paired comparisons between normal and diseased limbs in 18 patients with thrombotic events also showed statistical differences in terms of iliac limb maximum diameter, graft limb angle, aortoiliac angle, and iliac tortuosity. Conclusions: Thrombosis formation following EVAR in iliac limbs was associated with limb diameter, graft limb angle, aortoiliac angle, and tortuosity.