Thromboembolic Events after the Coverage of Anterior Cerebral Artery with Flow Diversion: A Single Institution Series and Systematic Review

Background Advances in the use of flow diversion (FD) now extend to bifurcation aneurysms; herein, we compare thromboembolic events in patients with ICA aneurysms treated with and without exclusion of the ACA. Methods Retrospective analysis of aneurysms in the terminal ICA treated with FD from 2013 to 2023 at a single-center. Procedures were classified according to the coverage at the origin of the ACA, and compared through bivariate-analysis. A review was also carried on PubMed, Web of Science, and EMBASE until April 2024, adhering to the PRISMA reporting guidelines. Results Ninety-five patients harboring 113 aneurysms treated in 102 procedures were evaluated. Fifty-eight were treated covering the ACA origin. Dual antiplatelet regimens included aspirin-clopidogrel (50%), aspirin-ticagrelor (44.1%), and aspirin-prasugrel (4.9%). Thromboembolic events occurred in six patients (5.9%), presenting with large vessel occlusion of the ICA, but without reaching statistical difference in the two treated cohorts (p=0.46). At a median clinical follow-up of 5.95 months, there were no differences in the functional outcomes in the two groups (p=0.22). Contralateral angiographic runs post-treatment after covering the ACA origin demonstrated increase in the A1 (median: 0.45mm; IQR=0.4-1.2) and ICA diameter (median: 0.55mm; IQR=0.1-1.2). After pooling data from literature and our cohort, complete side branch occlusion after the coverage of ACA was seen in 25% of branches (95%CI=0.16-0.36), and thromboembolic events were observed after 3% (95%CI=0.01-0.04) of procedures. Conclusion Thromboembolic events can occur in distal ICA aneurysms treated with FD, but no significant association was seen with covering the ACA origin.