1092 Timing, Type and Impact of Thromboembolic Events Caused by Flow Diversion: A Ten-Year Experience

INTRODUCTION: Thromboembolic (TE) events are among the most feared complications after flow diversion (FD) and reported to occur even with adequate dual antiplatelet therapy. METHODS: A retrospective analysis of aneurysms treated with FD at a single institution in the US was performed from 2013 to 2023. We documented the emergence of intraprocedural and postoperative TE events. A survival analysis and a Cox regression model was conducted to identify predictors associated with these events. RESULTS: We included 651 procedures performed on 593 patients to treat 748 aneurysms. TE events occurred in 38 of performed procedures (5.8%), causing permanent morbidity in 20 patients, four of whom died. Eleven cases presented with acute stent thrombosis, 11 with large vessel occlusion, and 9 with perforator strokes. At a median follow-up of 9.5 months, 66.7% of patients with an ischemic event had an mRS = 2. Three of the deaths were secondary to occlusion at the basilar trunk and vertebral artery. In the anterior circulation, six out of ten patients with MCA occlusion and eight out of eleven patients with ICA occlusion achieved independence. Time-to-event Cox regression analysis demonstrated that TE events were more frequent in patients exhibiting aspirin resistance (HR=2.66; 95% CI=1.10-6.70), and when multiple devices were used (HR=3.25; 95% CI=1.00-11.00). CONCLUSIONS: TE events after FD result from multiple factors, including age, aneurysm characteristics, aneurysm location, antiplatelet resistance, and procedural factors. In our cohort, we found the highest morbidity for patients with TE events presenting with LVO at the middle cerebral artery, and vertebrobasilar system.