Preventing Type II Endoleak in Endovascular Aneurysm Repair: The Role of nBCA Injection

Injection n-Butyl-2-Cyanoacrylate into Abdominal Aortic Aneurysm Sac during Endovascular Aortic Repair prevent Type II Endoleaks Caused by Lumbar Arteries

Clinical question

Can the occlusion of target lumbar arteries using n-butyl-2-cyanoacrylate (nBCA) injection during endovascular aneurysm repair (EVAR) reduce the incidence of Type II endoleak (T2EL) after EVAR?

Take away point

Concomitant nBCA injection during EVAR significantly reduces the incidence of T2EL, offering a simple yet effective strategy to reduce T2EL incidence and improve long-term outcomes in treating AAA.

Reference

Miura S, Kurimoto Y, Maruyama R, et al. Injection of n-Butyl-2-Cyanoacrylate into the Abdominal Aortic Aneurysm Sac during Endovascular Aortic Repair to Prevent Type II Endoleaks Caused by Lumbar Arteries. J Vasc Interv Radiol. 2024;35(5):676-686. doi:10.1016/j.jvir.2023.12.573

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Study design

Retrospective, non-randomized, single-center, observational cohort study

Funding Source

None

Setting

Academic setting

Figure

Figure 2. Concomitant n-butyl-2-cyanoacrylate (nBCA) injection during endovascular aneurysm repair. (a) After coil embolization of the patent inferior mesenteric artery (star) and deployment of stent-grafts, a 5-F catheter was inserted into the abdominal aortic aneurysm (AAA) sac from the contralateral side of the femoral artery (arrowheads), and patent lumbar arteries (LAs) branching from the AAA were confirmed by digital subtraction angiography (DSA) injecting within the sac. (b) nBCA/ethiodized oil mixture was injected near origins of targeted LAs by pointing the catheter tip toward the posterior wall of the aneurysm (white dotted circle). During nBCA injection, the proximal neck was occluded by an aortic occlusion balloon (asterisk) to prevent excessive distal embolization of LAs. Limited flow into a targeted LA was observed after nBCA injection (arrow). (c) Preprocedural and postprocedural computed tomography (CT) images confirmed nBCA in a previously patent left LA (arrow).

Summary

Endovascular aneurysm repair (EVAR) offers a minimally invasive alternative to open surgical repair for abdominal aortic aneurysms (AAA). However, this efficacy may be hindered by type II endoleak, a common complication involving retrograde blood flow into the aneurysm sac from patent lumbar or inferior mesenteric arteries. There is a notable disparity in the perception of type II endoleak between Asian and Western regions. While Japan reported a type II endoleak of 29%, Western countries exhibited a lower range of 10-19%. This discrepancy may be due to differences in coagulopathy, high perioperative warfarin, or antiplatelet medication rates. Furthermore, while most type II endoleaks resolve within six months post-EVAR in Western countries, they tend to persist for longer durations in Asia. This disparity prompted this investigation aimed at devising strategies to prevent type II endoleak and improve EVAR outcomes.

This study assessed the efficacy of injecting n-butyl-2-cyanoacrylate (nBCA) into the aneurysmal sac during EVAR to embolize the target lumbar arteries as a preventive measure against type II endoleak. This study involved 187 patients undergoing EVAR for infrarenal AAA between 2013 and 2020, with 106 receiving nBCA injections and 81 undergoing standard EVAR. Patient data was collected via a comprehensive review of medical records focusing on procedural details and postoperative outcomes. Selective catheterization during EVAR was performed to administer the nBCA injections into the aneurysmal sac. A balloon occlusion to prevent nBCA spillage was utilized when necessary to ensure the precise delivery of nBCA. Additionally, coil embolization of patent inferior mesenteric arteries was performed to mitigate nBCA-related adverse events. Statistical analyses included t-tests, Fisher exact tests, and multivariate regression to identify factors associated with type II endoleak incidence. Results demonstrated a significant reduction in type II endoleak occurrence and aneurysmal diameter in patients receiving nBCA injections. 2 cases of transient lower-limb motor dysfunction (1.9%) were observed, likely due to nBCA-related ischemia of the psoas or gluteus maximus muscles rather than spinal cord injury.

The study’s clinical significance lies in the potential of nBCA injection to decrease type II endoleak incidence, preventing future repeated interventions to correct type II endoleak, and improve long-term outcomes post-EVAR. Both the simplicity and efficacy of nBCA injection make it promising. These findings also align with prior research in EVAR, contributing to the ongoing discussion regarding the influence of type II endoleak on EVAR outcomes. However, limitations such as the study’s retrospective nature and sample size were acknowledged, emphasizing the need for further research to validate findings and assess safety and cost-effectiveness of nBCA injection in EVAR procedures compared to other interventions.

Commentary

This study has addressed a major issue in the management of AAA with EVAR, namely the prevention of type II endoleak. Efficacy of nBCA into the aneurysmal sac during EVAR as a preventive measure against type II endoleak and its influence on long-term outcomes (decreased incidence of sac enlargement and reintervention) for patients with AAA was demonstrated. However, its retrospective design and limited sample size may restrict the external validity or broader applicability of these findings. Furthermore, attention should be paid to the study’s specific patient population (Japan, Asian) and practice pattern (nBCA has been categorized as reimbursable since 2023 and on-label; Onyx has not been approved). Overall, this study presents encouraging findings regarding the efficacy of nBCA injections in enhancing EVAR outcomes. But to integrate this preventive measure into clinical practice, additional information about the long-term safety, cost-effectiveness, and comparison with other preventive measures from larger prospective studies are necessary.

Post Author
Danielle Millner Balagtas, BA
MD Candidate, Class of 2027
University of Massachusetts Chan Medical School
@daniellelmb