Risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair

PURPOSE We aimed to identify the risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair (EVAR). METHODS We retrospectively reviewed contrast-enhanced computed tomography (CT) images of 143 patients who were followed for >= 6 months after EVAR. Sac expansion was defined as an increase in sac diameter of 5 mm relative to the preoperative diameter. Univariate and multivariate analyses were performed to identify associated risk factors for late sac expansion after EVAR from the following variables: age, gender, device, endoleak, antiplatelet therapy, internal iliac artery embolization, and preprocedural variables (aneurysm diameter, proximal neck diameter, proximal neck length, suprarenal neck angulation, and infrarenal neck angulation). RESULTS Univariate analysis revealed female gender, endoleak, aneurysm diameter >= 60 mm, suprarenal neck angulation >45 degrees, and infrarenal neck angulation >60 degrees as factors associated with sac expansion. Multivariate analysis revealed endoleak, aneurysm diameter >= 60 mm, and infrarenal neck angulation >60 degrees as independent predictors of sac expansion (P < 0.05, for all). CONCLUSION Our results suggest that patients with small abdominal aortic aneurysms (<60 mm) and infrarenal neck angulation <= 60 degrees are more favorable candidates for EVAR. Intraprocedural treatments, such as prophylactic embolization of aortic branches or intrasac embolization, may reduce the risk of sac expansion in patients with larger abdominal aortic aneurysms or greater infrarenal neck angulation.