Thromboembolic Events in the Posterior Circulation After Flow Diversion—A Closer Look at Coverage of the Posterior Cerebral Artery

Abstract

Flow diversion (FD) for bifurcation aneurysms requires excluding one of the branches from the parent artery, raising concern for ischemic events. Herein, we evaluate thromboembolic events and their relation with covering the origin of the posterior cerebral artery (PCA). This retrospective analysis included patients with confirmed basilar and proximal PCA aneurysms treated with FD between 2013 to 2023. Procedures were classified according to the coverage of the origin of the PCA. Thromboembolic events associated with the excluded PCA were evaluated. Out of the total 28 aneurysms included, 7 were at the basilar-tip, 16 in the basilar trunk, and 5 in the P1-segment; fifteen were treated excluding one of the PCA. DAPT included aspirin-ticagrelor (57.1%), aspirin-clopidogrel (35.7%), and aspirin-prasugrel (3.57%). Complete and near-complete aneurysm occlusion was achieved in 80.8% of aneurysms treated in a median follow-up of 12.31 months. Thromboembolic complications occurred in three patients, two basilar perforator stroke and one basilar in stent thrombosis; but there was no statistically significant difference in these events between patients with PCA coverage and those without (p=0.46). Diminished and lack of flow was seen in eight and seven of the covered vessels. mRS≤2 was reported in 89.3% of patients in a median clinical follow-up of 5.5 months. Thromboembolic events are high in distal basilar and proximal PCA aneurysms, but PCA coverage was not associated with their occurrence. There was no difference in post-procedural disability between patients whose aneurysms were treated excluding one of the PCAs, and those who did not.