Multicentre Randomised Controlled Trial to Evaluate the Efficacy of Pre-emptive Inferior Mesenteric Artery Embolisation during Endovascular Aortic Aneurysm Repair on Aneurysm Sac Change.

Objective: Persistent type II endoleak (T2EL) following endovascular aortic aneurysm repair (EVAR) has been identified as a cause of aneurysm sac expansion, leading to re-intervention and aneurysm rupture. The role of pre-emptive inferior mesenteric artery (IMA) embolisation to prevent T2EL and sac expansion remains controversial. This study aimed to evaluate the influence of IMA embolisation on aneurysm sac change after EVAR.

Methods: The CLARIFY IMA study was a multicentre randomised controlled trial conducted at 24 centres and was registered in the UMIN Clinical Trials Registry (UMIN000035502). Patients with fusiform abdominal aortic aneurysms (AAAs) were randomised to undergo EVAR with or without pre-emptive IMA embolisation. The primary outcome was the percent change in computed tomography (CT) assessed aneurysm sac volume at 12 months, with secondary outcomes including sac diameter changes, prevalence of T2EL, freedom from re-intervention, and overall survival at six, 12, and 24 months. All CT data were evaluated at the core laboratory using a 3D workstation.

Results: In total, 138 patients with AAA (mean age ± standard deviation 76 ± 8 years; 117 men) were randomised to the IMA embolisation (n = 70) or control groups (n = 68). IMA embolisation was successful in 63 (90%) of 70 patients, without any adverse events. At 12 months there was no statistically significant difference in aneurysm sac volume change between the embolisation group (mean -3.90 ± 14.19%) and control group (mean -3.56 ± 13.91%) (p = .89). Furthermore, no statistically significant differences were observed in sac diameter change, rates of T2EL, freedom from re-intervention, and overall survival at any follow up time.

Conclusions: Pre-emptive embolisation of the IMA did not significantly impact the change in aneurysm sac volume, rates of T2EL, or re-intervention compared with controls at 24 month follow up. Further research may be necessary to fully assess the impact of pre-emptive IMA embolisation on clinical outcomes following EVAR.