Risk Factors for Type 2 Endoleak After Preemptive Side Branch Embolization During EVAR for Abdominal Aortic Aneurysm

BACKGROUND: Type 2 endoleak (T2EL) remains the most frequent complication after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm and is associated with sac enlargement and late adverse events. Preemptive embolization of aortic side branches has been introduced to reduce its incidence. This study aimed to evaluate the mid-term outcomes of EVAR with preemptive side branch embolization and to identify factors associated with persistent T2EL. METHODS: We retrospectively reviewed 217 patients who underwent EVAR with preemptive embolization of the inferior mesenteric artery and lumbar arteries (LAs) at our institution between April 2018 and March 2025. Patient characteristics, aneurysm morphology, and procedural details were analyzed. The primary endpoint was the occurrence of T2EL during follow-up. Risk factors were evaluated using univariable and multivariable logistic regression analyses. RESULTS: During a mean follow-up of 43.0 ± 22.6 months, T2EL occurred in 25 patients (11.5%). Sac enlargement ≥5 mm was significantly more frequent in patients with T2EL (36.0% vs. 4.7%, P < 0.001), while complete sac regression was observed only in the non-T2EL group (22.9% vs. 0%, P = 0.007). Multivariable analysis identified angulated neck (OR 2.90, 95% CI 1.10-7.66, P = 0.031) and the number of residual LAs (OR 1.74, 95% CI 1.12-2.70, P = 0.013) as independent predictors of T2EL. CONCLUSION: Persistent T2EL after PBE was associated with unfavorable sac behavior and an increased need for reintervention. Residual LAs and angulated neck anatomy were independent predictors of persistent T2EL, suggesting the importance of complete embolization, particularly in patients with angulated neck anatomy.