Endovascular Aneurysm Repair With Inferior Mesenteric Artery Embolization for Preventing Type II Endoleak: A Prospective Randomized Controlled Trial

OBJECTIVE:This study aimed to evaluate the effect of inferior mesenteric artery (IMA) embolization during endovascular aneurysm repair (EVAR) in patients at high risk of type II endoleak (T2EL) in randomized controlled trial (RCT). SUMMARY BACKGROUND DATA:Several studies have demonstrated a reduction of T2EL by IMA embolization before EVAR. However, there have been no RCT confirming the efficacy of IMA embolization. METHODS:Patients scheduled for elective EVAR between April 2014 and March 2018 were eligible. 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 occurrence of T2EL during follow-up. Secondary endpoints included aneurysmal sac changes, adverse events from IMA embolization, and reintervention rate due to T2EL. This trial is registered with the University Hospital Medical Information Network, number UMIN000022147. RESULTS:One hundred thirteen patients had high risk and 106 were randomized. In the intention-to-treat analysis, the incidence of T2EL was significantly lower in the embolization group [24.5% vs 49.1%; P = 0.009, absolute risk reduction = 24.5%; 95% confidence interval (CI), 6.2–40.5, number needed to treat = 4.1; 95% CI, 2.5–16.1]. The aneurysmal sac shrunk significantly more in the embolization group (−5.7 ± 7.3 mm vs −2.8 ± 6.6 mm; P = 0.037), and the incidence of aneurysmal sac growth related to T2EL was significantly lower in the embolization group (3.8% vs 17.0%; P = 0.030). There were no complications related to IMA embolization or reinterventions associated with T2EL. CONCLUSIONS:Our 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.