Background Appropriate periprocedural platelet inhibition is paramount to prevent thromboembolic complications surrounding stent-assisted coiling and flow diversion of cerebral aneurysms. P2Y12-inhibitors represent the cornerstone of antiplatelet therapy in conjunction with aspirin for dual antiplatelet therapy (DAPT). Clopidogrel-hyporesponder status is prevalent in up to 30% of the U.S. population, resulting in centers using platelet function testing or directly prescribing newer P2Y12-inhibitors such as ticagrelor as first line therapy. Here, the authors seek to explore the value of platelet function testing using VerifyNow P2Y12 platelet reactivity units (PRUs) surrounding parent vessel stenting in cerebral aneurysm patients receiving ticagrelor and their association with complications surrounding intracranial stenting.

Methods Patients undergoing cerebral aneurysm treatment with intracranial parent vessel stenting or flow diversion stenting between 05.2017 - 12.2021 were retrospectively reviewed. A total of 232 flow diversion stenting (FDS) and 83 stent-assisted coiling (SAC) procedures were identified. A pharmacy-mediated antiplatelet management protocol is established at the authors´ institution. Clopidogrel and aspirin represent the primary DAPT in conjunction with outpatient lab testing and antiplatelet medication adjustments. Fourty-four patients were treated with FDS or SAC and at least temporarily being treated with ticagrelor and aspirin. Three patients underwent two and one patient underwent three different aneurysm treatments. Baseline demographics, radiographic data, hemorrhaghic and ischemic complications and P2Y12 PRU lab results were collected.

Results A total of 315 intracranial stenting procedures for cerebral aneurysms were identified. Among those, in 31/232 (13.4%) of FDS and in 18/83 (21.7%) of SAC procedures, patients were at least temporarily on ticagrelor and aspirin. In most cases, (36/49, 73.5%), clopidogrel and aspirin wereinitiated as standard of care with subsequent switch to ticagrelor and aspirin. In the remaining 13/49 cases, ticagrelor and aspirin were initiated directly. Among the 49 procedures, clopidogrel-PRUs (n=203) were significantly higher than ticagrelor-PRUs (n=291) (C: median 97, mean 105 ± 90 vs. T: median 43, mean 68 ± 67, respectively; p < 0.001). Seven patients with varying complicating factors (subarachnoid hemorrhage, large, blister or fusiform aneurysms) developed thromboembolic complications. At time of complication the ticagrelor-PRUs in these seven patients were markedly elevated (T: median 182, mean 186 ± 46).

Conclusion Safe PRU ranges are established for clopidogrel. However, safe PRU values for ticagrelor surrounding intracranial stenting of cerebral aneurysms have not yet been established. The authors observed that in the setting of complex aneurysms, with their institutional second line use of ticagrelor, elevated PRUs were associated with thromboembolic complications.

Disclosures T. Bielinski: None. M. Collins: None. C. Griessenauer: None. O. Goren: None. I. Melamed: None. G. Weiner: None. C. Schirmer: None. P. Hendrix: None.