Preoperative Mural Thrombus Volume Ratio Predicts Aneurysm Enlargement in Type 2 Endoleak after Endovascular Aortic Repair

Abstract

Objectives: This study aimed to identify anatomical predictors of aneurysm enlargement in patients with lumbar artery (LA)-related type 2 endoleak (T2EL) after endovascular aortic Methods: This retrospective observational cohort study included 59 patients with infrarenal abdominal aortic aneurysms who developed T2EL caused exclusively by LAs after EVAR between January 2019 and July 2024. Computed tomography-based anatomical parameters, including mural thrombus volume ratio, calcified volume ratio, aneurysm diameter, and LA anatomy, were analyzed. Results: During a median follow-up of 33 months, aneurysm enlargement occurred in 9 patients (15.3%). Patients with aneurysm enlargement had a significantly lower mural throm0.06-0.84; p = 0.026) and mural thrombus volume ratio (HR, 0.88 per 1% increase; 95% CI, 0.80-0.96; p = 0.003) were significantly associated with aneurysm enlargement, whereas LA anatomy was not. Receiver operating characteristic analysis identified an optimal cutoff value of 29.2% (area under the curve, 0.82). Conclusions: A low preoperative mural thrombus volume ratio was associated with aneurysm enlargement in patients with LA-related T2EL after EVAR. This parameter may serve as a practical imaging biomarker to support selective consideration of preemptive embolization.