Safety of antiplatelet medication discontinuation more than 12 months after stent-assisted coil embolization: a non-interventional, multicenter, observational study

Background: Antiplatelet maintenance is essential to avoid ischemia following stent-assisted coiling (SAC) procedures. However, indications for antiplatelet medication discontinuation (AMD) remain controversial, and optimal timing of cessation has yet to be determined. Our goal, which we achieved through a multicenter, prospectively enrolled, non-interventional study, was to investigate the safety of AMD conducted more than 12 months after SAC. Methods: Data were retrieved from the records of 495 consecutive patients prospectively enrolled at 10 institutions during a 3-year period (between January 2021 and December 2023). Each subject had discontinued antiplatelet therapy >12 months after SAC. Maintenance duration and cessation were both at physician discretion, based on patient clinical status. We investigated clinical outcomes for at least 6 months after AMD. Results: A majority of patients engaged in AMD (292/495, 59.0%) were not at high risk for ischemia. Mean±SD time to AMD was 20.0±12.9 months after SAC. Treated aneurysms were largely confined to the internal carotid artery (332/495, 67.1%), followed by the anterior (95/495, 19.2%) and middle (43/495, 8.7%) cerebral arteries. A laser-cut open-cell stent was most often applied (60.5%); laser-cut closed-cell (22.2%) and braided closed-cell (17.3%) stents were used to a lesser extent. Four patients underwent double stenting. Despite sizeable (41.0%) high-risk group representation, there were no ischemic events in relation to AMD. Conclusion: Our results suggest that AMD >12 months after SAC procedures is safe in patients who are not at high risk for ischemia. Randomized controlled trials are warranted to confirm these results.