Serial VerifyNow P2Y12 platelet reactivity units in cerebral aneurysm patients treated with ticagrelor surrounding stent-coiling or flow diversion

Introduction: Platelet function testing using serial VerifyNow P2Y12 platelet reactivity units (PRUs) is established for guiding clopidogrel antiplatelet therapy in cerebral aneurysm stenting procedures. However, for ticagrelor, the impact of serial PRU testing and the identification of safe PRU ranges remains unexplored. Methods: Flow diversion stenting (n = 232) and stent-assisted coiling procedures (n = 83) performed 05/2017-12/2021 were reviewed. Out of these, 31 flow diversion and 18 stent-coiling procedures were performed on 44 patients using ticagrelor. Baseline demographics, ticagrelor PRUs, and clinical outcomes were assessed. Results: Collectively, 257 ticagrelor P2Y12 PRUs were obtained. PRUs were <100 in 192/257 (74.7%) tests. Only 11/257 (4.3%) PRUs were >200. The overall median ticagrelor PRU was 38 (IQR 11-101). Among the 49 procedures, median PRUs before the procedure (25, IQR 10-67), on the day of the procedure (68, IQR 44-117), and on the day after the procedure (37, IQR 21-79) did not show the significant differences between the groups. A total of seven thromboembolic complications occurred. Median PRUs surrounding the thromboembolic complications (median 182, IQR 148-235) were significantly higher than preprocedural (p < .001), day of surgery (p < .01), and postprocedural PRUs (p < .01). All seven procedures harbored demographic, anatomic, or procedural features increasing the risk for thromboembolic complications. Discussion: The majority of periprocedural ticagrelor PRUs were <100. PRUs at the time point of thromboembolic complications were >120. Despite procedure-complicating features in each thromboembolic case, it raises the question whether safe ticagrelor PRU levels might be lower than those commonly applied for clopidogrel.