Antiplatelet drug resistance did not increase the thromboembolic events after stent-assisted coiling of unruptured intracranial aneurysm: a single center experience of 99 cases

We aimed to evaluate the correlation between aspirin or clopidogrel resistance and the risk of thromboembolic events (TEs). Between June 2011 and April 2015, we reviewed clinical and angiographic characteristics, and TEs in the patients undergoing stent-assisted coil embolization (SAC) of unruptured intracranial aneurysms (UIA) at our institution. We did not modify antiplatelet medication in patients with resistance. The relationships between antiplatelet resistance and the occurrence of acute symptomatic TEs, any diffusion-positive lesions, multiple diffusion-positive lesions, or delayed TEs were investigated. Ninety-nine endovascular treatments with stent-assisted technique were performed on 99 patients. The prevalence of aspirin resistance was 12% and clopidogrel resistance was 62.6%. Acute symptomatic TEs were demonstrated in 4 patients (4%). Diffusion-positive lesions were found in 82 patients [82.1%; 36 patients were group I (≤5) and 46 patients were group II (>5)]. Delayed TEs were demonstrated in 10 patients (10.1%). Neither aspirin resistance nor clopidogrel resistance was relevant to the development of acute symptomatic TEs, any diffusion-positive lesions, multiple diffusion-positive lesions, and delayed TEs (P_logistic = not available, 0.448, 0.362, and 0.829 for aspirin resistance and P_logistic = 0.607, 0.367, 0.278, and 0.245 for clopidogrel resistance). Without modification of antiplatelet medication, we demonstrated 4% of acute symptomatic TEs and 10% of delayed TEs. Aspirin or clopidogrel resistance did not show significant relationships with acute and delayed TEs in the SAC of UIA.