The Impact of Dual Antiplatelet Therapy Duration on Unruptured Aneurysm Occlusion after Flow Diversion: A Multicenter Study

Objective: The objective of this study is to assess the impact that the type and duration of DAPT has on aneurysm occlusion rates and iatrogenic complications following endoluminal flow diversion with a single flow diverting stent. Methods: A retrospective review of a multicenter aneurysm database was performed from 2012 to 2020 to identify unruptured intracranial aneurysms treated with single device flow diversion and >12-month follow-up. Clinical and radiologic data were analyzed with aneurysm occlusion as a function of DAPT duration serving as a primary outcome measure. Results: A total of 205 patients underwent flow diversion with a single pipeline embolization device. During the study period, 12.7% of treated aneurysms remained non-occluded. There were no significant differences in aneurysm morphology or type of DAPT used between occluded and non-occluded groups. Non-occluded aneurysms received a longer mean duration of DAPT (9.4 vs 7.1 mo, p=0.016) with ANOVA demonstrating a significant effect of DAPT duration on the observed aneurysm occlusion rate (F(2, 202)=4.2, p=0.016). An exploratory analysis demonstrated the optimum DAPT discontinuation time to minimize aneurysm non-occlusion rates was 7.9 months (95% CI: 6-11 months). There was no significant difference in the rate of complications or delayed ischemic strokes observed between patients receiving short (<6 mo) and prolonged duration (>6 mo) DAPT (7.9% vs 9.3%, p=0.76). Conclusions: Following endovascular flow-diversion, an abbreviated duration of DAPT lasting 6 months may be most appropriate before transitioning to low-dose aspirin monotherapy to promote timely aneurysm occlusion while minimizing delayed thromboembolic complications.