Multicentre randomised controlled trial to evaluate the efficacy of pre-emptive inferior mesenteric artery embolisation during endovascular aortic aneurysm repair on aneurysm sac change: protocol of Clarify IMA study

Abstract

IntroductionType II endoleak (EL) is frequently seen after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) and is often considered responsible for aneurysm sac enlargement if it persists. In order to reduce type II EL and consequent sac enlargement, pre-emptive embolisation of the inferior mesenteric artery (IMA), which is a main source for persistent type II EL, has been introduced in many vascular centres. At present, there is a lack of robust evidence to support the efficacy of pre-emptive embolisation of IMA on reduction of persistent type II EL with subsequent sac shrinkage.Method and analysisThis multicentre, randomised controlled trial will recruit 200 patients who have fusiform AAA ≥50 mm/rapidly enlarging fusiform AAA, with patent IMA, and randomly allocate them either to a pre-emptive IMA embolisation group or non-embolisation control group in a ratio of 1:1. The primary endpoint is the difference of aneurysm sac volume change assessed by CT scans between the pre-emptive IMA embolisation group and the control group at 12 months after EVAR. The secondary endpoints are defined as change of aneurysm sac volume in both groups at 6 and 24 months, freedom from sac enlargement at 12 and 24 months after EVAR, prevalence of type II EL at 1, 6, 12 and 24 months evaluated by contrast-enhanced CT, reintervention rate, aneurysm related mortality, overall survival, perioperative morbidity, volume of contrast media used during EVAR and dosage of radiation.Ethics and disseminationThe protocol has been reviewed and approved by the ethics committee of Nara Medical University (No. 2113). The findings of this study will be communicated to healthcare professionals, participants and the public through peer-reviewed publications, scientific conferences and the University Hospital Medical Information Network Clinical Trials Registry home page.Trial registration numberUMIN000035502.

Risk Analysis of Aneurysm Sac Enlargement Caused by Type II Endoleak after Endovascular Aortic Repair

“…Preembolization of IMA or LAs have been performed to prevent ETII. 21,22 Li Q et al reported that pre-embolization of both IMA and LAs significantly reduced the occurrence of ETII. 22 However, not all of ETII lead to aneurysm sac enlargement, and preoperative intervention of both IMA and LAs may be excessive to prevent aneurysm sac enlargement.…”

Safety of preoperative branch embolization in patients undergoing evar

“… 32 An ongoing multicenter randomized trial will try to clarify the efficacy of preoperative IMA embolization. 33 …”

Long-term Outcomes of the Endurant and Excluder Stent Grafts for Endovascular Aneurysm Repair in a Japanese Cohort

“…25,26 Further evidence from multicenter RCTs, such as the Clarify IMA trial, is awaited. 27 As for history of smoking, it significantly prohibited late complications. Since history of smoking has been validated as inhibiting type II endoleak, 21 this probably led to decrease of late complications in our study.…”