Type II Endoleak after EVAR: The Sac Behavior-Anatomy-Driven Management (SADM) Framework

Type II endoleak (T2EL) is the most common complication following endovascular abdominal aortic aneurysm repair (EVAR), although its clinical significance remains debated. While often benign, a subset of cases is associated with aneurysm sac enlargement and may require intervention. This review summarizes current evidence on the diagnosis, surveillance, and management of T2EL, with emphasis on decision-making guided by aneurysm sac behavior. Beyond summarizing available evidence, this review introduces and operationalizes the Sac Behavior-Anatomy-Driven Management (SADM) framework that integrates heterogeneous guideline recommendations and anatomical considerations into a unified, clinically applicable decision support strategy for T2EL management. T2EL occurs in approximately 10-30% of patients after EVAR, but only a minority demonstrate clinically relevant sac enlargement. Surveillance strategies are primarily driven by sac dynamics rather than the presence of T2EL alone. Intervention should be considered in cases of persistent endoleak with sac enlargement. Endovascular embolization remains the main treatment approach, although no single technique has demonstrated clear superiority in the absence of high-quality comparative data, and recent randomized evidence has not demonstrated a clear benefit for routine prophylactic inferior mesenteric artery embolization during EVAR. The proposed SADM framework provides a practical, clinically applicable approach to T2EL management by separating treatment indication from procedural strategy and aligning decision-making with aneurysm sac behavior and anatomical feasibility.