Risk of clopidogrel resistance in endovascular aneurysm stenting

Background: Thromboembolic complications remain a significant risk in endovascular aneurysm stenting, with clopidogrel resistance implicated as a major contributing factor. The efficacy of ticagrelor as an alternative in clopidogrel non-responders requires further evaluation. The objective of this study is to evaluate thromboembolic outcomes in clopidogrel-resistant patients undergoing endovascular aneurysm stenting and to assess whether switching to ticagrelor mitigates these risks. Methods: This single-center retrospective cohort study included 228 patients treated between 2020 and 2024. All patients underwent P2Y12 testing before the procedure. Clopidogrel non-responders (<40% inhibition) were switched to ticagrelor. The primary endpoint was thromboembolic complication, defined as radiological or clinical infarct, aiming to capture all patients with thromboembolic complication, whether symptomatic or not. Secondary analyses evaluated aneurysm characteristics and associated risk factors. Results: Of the 228 patients, a significant 122 patients (54%) were found to be non-responders and switched to ticagrelor. No statistically significant differences were observed in rates of clinical infarct (13% vs. 11%, P = 0.7) between clopidogrel responders and ticagrelor-treated non-responders. Evidence of radiological infarct was included to incorporate any asymptomatic patients and also was found to have no difference between groups (19% vs. 12%, P = 0.2). Larger aneurysm size correlated with both higher number of radiological ( P = 0.011) and clinical infarcts ( P = 0.002). Diabetes and advanced age were associated with multiple aneurysms. Younger patients with prior subarachnoid hemorrhage were more likely to undergo stent-assisted coiling. Conclusion: Preoperative platelet function testing and switching clopidogrel non-responders to ticagrelor resulted in comparable thromboembolic complication rates to clopidogrel responders. These findings support the role of routine platelet function testing and individualized antiplatelet management in endovascular aneurysm treatment.