Long-Term Remodeling of Aortoiliac Vessels After Standard EVAR, the Reality to Be Considered

Background/Objectives: The aim of our study was to document and analyze the long-term geometric alterations that occur in the infrarenal aorta and iliac arteries over time after a successful elective standard endovascular abdominal aneurysm repair (EVAR) as well as to investigate the potential relationship of aortoiliac remodeling with the long-term complications of EVAR. Methods: The prospectively collected clinical and computed tomography angiography (CTA) data from 168 patients treated with elective standard EVAR between 2013 and 2018 were retrospectively analyzed. Follow-up assessments were performed at 1, 24, and 60 months postoperatively. Primary anatomical variables included 11 measurements: total right and left aortoiliac lengths, infrarenal aortic length, right and left aortoiliac angles on the frontal CTA plane, right and left intra-iliac angles, inter-iliac angle, infrarenal aortic body angle on the sagittal CTA plane, and right and left aortoiliac angles on the sagittal CTA plane. Secondary variables were the mean percentage changes in anatomical measurements between the follow-up time intervals. The primary clinical endpoint was the occurrence of any complication related (ARC) to the index EVAR or reinterventions. Secondary endpoints included any graft migration (AM) observed in proximal aortic or distal iliac sealing zones, and failure of aneurysm sac regression (FSR) or an increase in sac diameter by >5 mm. Six different bifurcated endografts were used. For subgroup analysis, the primary differentiating feature among grafts was the presence or absence of suprarenal fixation with hooks. Results: Median follow-up was 77 months, with an interquartile range (IQR) of 24.0 months. Observed EVAR-related mortality was 2.4%. Twenty-seven (16.1%) ARC events occurred, and migration was detected in 21 (12.5%) patients, combined with endoleak in 20 of them. The incidence of FSR was 43.5%, and approximately a third of ARCs and AMs occurred after the 60th month of follow-up. Across all measured lengths and the inter-iliac angle on the frontal CTA plane, a significant increase was observed, while all other angles demonstrated a significant decrease over time. The pattern of aortoiliac remodeling followed a linear progression for the first 24 months, transitioning to either a quadratic or cubic trend by the 60-month mark. Linear regression analysis revealed that an excessive increase in length variables was significantly associated with lower AAA sac regression rates. Furthermore, multivariate analysis identified that suprarenal fixation with hooks was the only factor associated with a reduced likelihood of AMs and a five-fold decrease in FSRs. Conclusions: Despite a fully successful EVAR, significant aortoiliac geometrical remodeling is evident over time. Extensive remodeling of aortoiliac lengths appears to be associated with lower rates of AAA sac regression. Suprarenal proximal aortic fixation with hooks may serve as a protective mechanism, reducing the likelihood of long-term complications. Life-long follow-up remains an essential measure for early detection of long-term EVAR failures.