Rescue mechanical thrombectomy in prolonged time window for early neurological deterioration in ischaemic stroke with large vessel occlusion.

OBJECTIVE: To investigate whether rescue mechanical thrombectomy (MT) was associated with improved clinical outcomes for patients with anterior circulation large-vessel occlusion (LVO) who developed early neurological deterioration (END) beyond the conventional thrombectomy time window. METHODS: We prospectively enrolled anterior circulation LVO cases who initially showed mild deficits (National Institutes of Health Stroke Scale score 1-5) but subsequently developed END between 24 and 72 hours post symptom onset in our stroke centre. Eligible patients underwent multidisciplinary evaluation and received either rescue MT or best medical management (BMM). Functional independence at 90 days (modified Rankin Scale (mRS) score 0-2) was the primary endpoint. RESULTS: From October 2022 to October 2024, 187 patients were enrolled and 180 completed follow-up (121 MT, 59 BMM). The MT group showed significantly higher rates of 90-day mRS 0-2 37.2% (45/121) vs 20.3% (12/59); adjusted risk ratio (aRR) 1.97, 95% CI 1.01 to 3.82, p=0.044. MT also correlated with reduced 90-day all-cause mortality (aRR 0.49, 95% CI 0.24 to 0.99, p=0.048) and higher rate of 90-day mRS 0-3: aRR 2.09 (95% CI 1.38 to 3.18; p=0.001). Logistic regression showed MT independently associated with mRS 0-2 at 90 days. CONCLUSION: Rescue MT was associated with a higher likelihood of favourable functional outcome compared with BMM in an extended time window for patients with anterior circulation LVO and END. These observational findings require confirmation in randomised controlled trials.