BACKGROUND: Current guidelines have not recommended an upper age limit for endovascular thrombectomy (EVT) in patients with large vessel occlusion (LVO) stroke. However, elder age links to an increased risk of poor outcome. This study aimed to investigate the efficacy of EVT in elderly versus non-elderly patients and determine the respective factors of poor outcome. METHODS: Three hundred and two consecutive patients with LVO-stroke who underwent EVT were included, and we used sensitivity analysis with restricted cubic spline to define 75 years as the inflexion point. Participants were thus dichotomized into elderly (≥75 years) and non-elderly (<
75 years) groups. Brain frailty on neuroimaging was evaluated using the global cortical atrophy (GCA) scale and the Fazekas scale for white matter lesions (WML). The primary outcome was 3-month functional outcome, and the secondary outcomes were EVT efficacy and safety. RESULTS: Elderly patients had significantly higher incidences of hypertension, diabetes mellitus, atrial fibrillation, and more severe GCA and WML. The rate of good outcome in elderly patients was 32%, significantly lower than non-elderly patients (54%, CONCLUSION: GCA and WML play pivotal roles for the functional outcomes in elderly patients undergoing EVT for LVO-stroke, providing valuable and practical information for early prediction of long-term prognosis.