Does residual ADP reactivity within the therapeutic range predict intraoperative thromboembolic events during endovascular treatment of intracranial aneurysms?

PURPOSE: Thromboembolic events remain one of the major complications during endovascular treatment of intracranial aneurysms. Platelet function testing is widely used to identify clopidogrel resistance, yet its role in predicting intraoperative thromboembolic complications among pharmacologically responsive patients remains unclear. This study aimed to evaluate the association between preoperative ADP-induced platelet reactivity and intraoperative thromboembolic events in patients undergoing endovascular aneurysm treatment. METHODS: We retrospectively analyzed 196 patients treated for unruptured intracranial aneurysms between March 2017 and March 2020. Patients presenting with subarachnoid hemorrhage or without available preoperative ADP values were excluded. Multiplate platelet function testing was used to measure ADP-induced platelet reactivity. Patients with ADP values > 46 AUC were considered resistant and were switched to ticagrelor or prasugrel before re-testing; resistant cases were excluded from the final analysis. Associations between preoperative ADP values and intraoperative thromboembolic complications were assessed using multivariate logistic regression. RESULTS: The mean age was 55.3 ± 10.9 years, and 72.4% were female. The median preoperative ADP value was 15 (range 0-70). Intraoperative thromboembolic events occurred in 25 patients (12.8%), including material thrombus (6.6%), distal embolism (4.6%), and combined events (1.5%). Female sex was identified as an independent risk factor (OR 3.82, p = 0.045), while patients treated with a flow diverter stent had a lower risk of thromboembolic complications (OR 0.24, p = 0.029). There was no significant association between preoperative ADP reactivity and intraoperative thromboembolic events (p = 0.874). CONCLUSION: In this cohort of 196 patients with adequate preoperative platelet inhibition, residual ADP-induced platelet reactivity was not associated with the risk of intraoperative thromboembolic complications. These findings suggest that residual ADP reactivity within the therapeutic range has limited value for predicting intraoperative thromboembolic events.