Risk Factors after Reduction to Single Antiplatelet Therapy for Postoperative Ischemia of Intracranial Stent-assisted Coil Embolization

Objective: There are concerns regarding ischemic events associated with stent-assisted coil embolization. It is important to evaluate the risk factors for delayed thromboembolic events. This study evaluated risk factors after reduction to singleantiplatelet therapy 140–365 days after embolization. Methods: We conducted a retrospective and cross-sectional study of patients who underwent stent-assisted coil embolization. Sixty eight aneurysms in 67 patients with unruptured intracranial aneurysms or the chronic phase of ruptured intracranial aneurysms between July 2010 and April 2014 were evaluated. Results: Dual-antiplatelet therapy was administered for 157 ± 65 days. Three patients who were administered the single-antiplatelet agent experienced postoperative ischemic events. One patient experienced cerebral infarction 143 days after the procedure. One patient with over 50% in-stent stenosis experienced cerebral infarction 194 days after the procedure. The final patient experienced transient ischemic attack (TIA) 223 days after the procedure, and reembolization was performed 209 days after the procedure. Postoperative ischemic events occurred more frequently in severe in-stent stenosis patient (P <0.05). Conclusions: However, severe in-stent stenosis may be a risk factor after reduction to single-antiplatelet therapy, relatively few ischemic events occurred after cessation of dual-antiplatelet therapy.