OBJECTIVES: To assess the safety and efficacy of intra-arterial thrombectomy for patients with acute ischemic stroke due to large vessel occlusion (LVO) treated beyond the traditional 6-hour window, using diffusion-weighted imaging and the Alberta Stroke Program Early CT Score (DWI-ASPECTS) for patient selection. METHODS: A retrospective study was conducted at Hebei General Hospital, involving 263 acute stroke patients treated between November 2022 and August 2024. Patients were categorized into two cohorts based on treatment timing: within 6 hours (n = 156) and beyond 6 hours (n = 107). Outcomes included the modified Rankin Scale (mRS), National Institutes of Health Stroke Scale (NIHSS), degree of vascular recanalization (modified Thrombolysis in Cerebral Infarction [mTICI] scale), coagulation parameters, and adverse event rates as safety measures. RESULTS: Demographics and baseline conditions were comparable across groups. The beyond-6-hour group showed prolonged time from symptom onset to intervention, with slightly higher mRS and NIHSS scores at discharge and 90 days, indicating poorer functional and neurological outcomes (P <
0.05 for both). The beyond-6-hour group had a significantly lower vascular recanalization rate (mTICI ≥ 2b: 84.11%) compared to the within-6-hour group (93.59%, P = 0.013). However, the overall safety profile was similar, with no significant differences in adverse event rates. CONCLUSION: Intra-arterial thrombectomy beyond the standard 6-hour window was feasible, showing substantial efficacy and an acceptable safety profile when guided by DWI-ASPECTS.