Objective To evaluate risk factors for acute ischemic stroke following treatment of paraclinoid aneurysms using flow diverters. Methods Between September 2015 and July 2018, 205 consecutive patients with 229 paraclinoid aneurysms were treated with Pipeline embolization device (PED) at Department of Interventional Neuroradiology, Beijing Tiantan Hospital, Capital Medical University. The aneurysm size and parent artery size were measured. According to the length, proximal and distal diameter of the parent artery, appropriate size of PED was deployed with or without coiling. Various potential risk factors associated with acute ischemic stroke following PED treatment were documented. Univariate and multivariate logistic regression analyses were applied to identify risk factors. Results Among the 205 patients with 229 paraclinoid aneurysms, 110 aneurysms were treated by PED and 119 aneurysms received PED with coiling, all PED were delivered and implanted successfully. Eighteen (8.8%) patients with 20 aneurysms had acute ischemic stroke after PED deployment. Univariate analysis suggested that ADP inhibition, high MA-ADP value, clopidogrel non-response, application of complex intraoperative techniques, and long operation time were associated with the acute ischemic stroke following PED treatment (all P<0.05). Further multivariate logistic regression analysis showed the clopidogrel non-response (OR=6.161, 95% CI: 1.480-25.649, P=0.012), application of complex intraoperative techniques (OR=8.405, 95% CI: 1.437-49.146, P=0.018) and operation time (OR=1.011, 95% CI: 1.002-1.020, P=0.022) were independent factors for acute ischemic stroke following PED treatment. Conclusions Clopidogrel non-response, application of complex intraoperative techniques and long operation time may increase the risk of ischemic events. Key words: Intracranial aneurysm; Stroke; Factor analysis, statistical; Flow diverter; Paraclinoid