Effect of AAA Size on Mortality and Morbidity After Endovascular Aortic Repair

<b>Objectives:</b> To analyze the effect of abdominal aortic aneurysm (AAA) diameter on late complication occurrence and survival in patients following endovascular aneurysm repair (EVAR). <b>Methods:</b> The study was a retrospective cohort analysis with a prospective follow-up of 176 patients diagnosed with unruptured AAA who underwent EVAR from 2016 to 2024. Preoperative computed tomography (CT) images were used to measure maximal aneurysm diameter. Prospective follow-up data were collected post-EVAR at 1 month, 6 months, and annually through clinical evaluations and imaging studies. The mean follow-up duration was 26 months. For statistical purposes, the group was divided into tertiles based on aneurysm size. This study was intentionally focused on aneurysm size as an isolated imaging parameter, and did not incorporate other known predictors of complications, such as neck morphology or device-related variables. As such, key limitations include the single-center design, relatively small sample size, and lack of data on anatomical features beyond maximum diameter. <b>Results:</b> Kaplan-Meier survival analysis demonstrated that patients in the highest tertile of aneurysm size experienced significantly higher rates of long-term adverse outcomes compared to those in the lower two tertiles, both in terms of late complications (log-rank <i>p</i> = 0.049) and all-cause mortality at 36 months (<i>p</i> = 0.022). In multivariate logistic regression, the occurrence of late complications was independently associated with symptomatic presentation (<i>p</i> = 0.003, OR = 3.616, 95% CI: 1.533-8.529) and acute admission (<i>p</i> = 0.033, OR = 0.345, 95% CI: 0.130-0.916). The largest aneurysms were significantly associated with late endoleak (<i>p</i> = 0.041, OR = 5.365, 95% CI: 1.071-26.871). <b>Conclusions:</b> This study demonstrates that AAA size is an independent predictor of both late complications and long-term survival following EVAR. Patients with larger aneurysm diameters experienced significantly higher rates of late complications and reduced overall survival.