Abstract 9371: Effectiveness of Endovascular Aneurysm Repair With Inferior Mesenteric Artery Embolization From Mid-Term Outcome of a Randomized Controlled Trial

Introduction: Adequate management of type II endoleak (T2EL) has been widely discussed, and inferior mesenteric artery (IMA) embolization before endovascular aneurysm repair (EVAR) has been reported to reduce the T2EL. However, there have been no randomized controlled trials (RCT) confirming the efficacy. Thus, this study aimed to evaluate the effect of IMA embolization during EVAR in patients at high risk of T2EL in an RCT. Methods: This study included patients scheduled for elective EVAR between September 2014 and March 2018. Patients at high risk of T2EL (IMA patency with IMA ≥ 3 mm, LAs ≥ 2 mm, or an aortoiliac-type aneurysm) were prospectively randomized to receive EVAR with or without IMA embolization. The primary endpoint was T2EL occurrence during follow-up. The secondary endpoints were aneurysmal sac changes, adverse events from IMA embolization, and reintervention rate due to T2EL. Results: A total of 106 patients were randomized to the embolization group (group A, n = 53) or the nonembolization group (group B, n = 53). The technical success rate of IMA embolization was 88.7%, and no complications related to IMA embolization were observed. During the mean follow-up period—50.2 ± 21.9 months in group A and 52.9 ± 23.1 months in group B—the incidence of T2EL was significantly lower in the embolization group (23.9% in group A vs. 53.8% in group B; P < 0.0001). Sac diameter changes, the incidence of aneurysmal sac growth (≥5 mm) related to T2EL, and freedom from sac enlargement (≥5 mm) related to T2EL at 5 years were –6.5 ± 8.9 mm vs. –1.1 ± 13.1 mm, 6.5% vs. 25.0%, and 97.5% vs. 72.0% in groups A and B, respectively (P = 0.015; P = 0.025; P = 0.018), which show that both shrinkage of aneurysm and freedom from sac enlargement are significantly higher in group A. Although no significant difference was observed in the reintervention rate due to T2EL (0% in group A vs. 2% in group B; P = 0.344), a significant difference in sac enlargement (≥10 mm) related to T2EL was observed (0% in group A vs. 13.5% in group B; P = 0.010), suggesting that reintervention would need to be considered. Conclusions: The results demonstrated the effectiveness of IMA embolization during EVAR in high-risk patients for the prevention of T2EL, which is suggested for avoiding aneurysmal sac enlargement related to T2EL.