Association of a platelet function testing-guided intensified antiplatelet strategy with thromboembolic events after EP2 stent-assisted coil embolization in patients with unruptured intracranial aneurysms

Introduction To evaluate the association of Platelet Function Testing (PFT)-guided intensified antiplatelet strategy with the incidence of thromboembolic events and bleeding rates in patients with Unruptured Intracranial Aneurysms (UIA) undergoing stent-assisted coil embolization, compared with standard fixed-dose Dual Antiplatelet Therapy (DAPT). Methods In this retrospective study, 368 patients from two centers between January 2019 and September 2024 were enrolled and categorized into a Monitored Group ( n = 219) and a Non-monitored Group ( n = 149). Both groups initially received a fixed-dose DAPT regimen of clopidogrel 75 mg and aspirin 100 mg daily. Within 24 h prior to the procedure, the Monitored Group underwent PFT. Patients exhibiting High On-Treatment Platelet Reactivity (HPR) to clopidogrel were administered a single 300 mg clopidogrel loading dose and received short-term perioperative tirofiban. For patients with HPR to aspirin, the aspirin dose was increased to 200 mg daily. The Non-monitored Group did not undergo platelet function testing and dose adjustment. To control for confounding, propensity score matching (PSM) and multivariable Cox regression were performed. The primary outcome was the composite thromboembolic event rate within 7 days post-procedure. Secondary outcomes included the composite thromboembolic event rate within 30 days, and the safety outcome was the composite bleeding event rate within 30 days. Results In the original cohort, the monitored strategy was associated with a lower incidence of the primary 7-day composite thromboembolic outcome (3.20% vs. 8.05%; unadjusted HR = 0.388, 95%CI 0.153–0.985, p = 0.045; adjusted HR = 0.391, 95%CI 0.154–0.994, p = 0.048). The association remained directionally consistent in the propensity score-matched cohort (115 pairs, 4.35% vs. 8.70%; HR = 0.487, 95%CI 0.166–1.424, p = 0.189). The secondary 30-day composite thromboembolic outcome showed similar patterns (original cohort: adjusted HR = 0.412, 95%CI 0.187–0.909, p = 0.028; PSM cohort: HR = 0.446, 95%CI 0.169–1.172, p = 0.101). No statistically significant association was observed for the 30-day composite bleeding event rates between the two groups in either the original or matched analyses. Subgroup analyses identified no significant association modifiers. Conclusion A PFT-guided intensified antiplatelet strategy was associated with a lower incidence of early post-procedural thromboembolic events without a significant increase in major bleeding in UIA patients treated with EP2 stent-assisted coiling. These findings support the potential utility of this comprehensive strategy, although the independent contribution of each component requires further investigation in larger prospective studies.