ABSTRACT NUMBER: ESOC2026LT70 LT70 - ADJUNCTIVE INTRA-ARTERIAL HYPOTHERMIA WITH ENDOVASCULAR THROMBECTOMY FOR ACUTE ANTERIOR CIRCULATION STROKE (CHILL-ART): A RANDOMISED, CONTROLLED, MULTICENTRE TRIAL

Abstract Background and aims Endovascular thrombectomy achieves high recanalisation rates in acute ischaemic stroke due to large-vessel occlusion, yet many patients do not regain functional independence. We assessed whether adjunctive intra-arterial selective hypothermia improves outcomes. Methods CHILL-ART was a multicentre, randomised, open-label, blinded-endpoint trial at 26 comprehensive stroke centres in China. Adults aged 18–85 years with anterior circulation large-vessel occlusion within 24 h of last known well and a National Institutes of Health Stroke Scale score of 6 or higher were randomly assigned (1:1) to thrombectomy plus intra-arterial infusion of 350 mL saline at 4°C (hypothermia) or 350 mL room-temperature saline (normothermia). Randomisation was stratified by age and Alberta Stroke Program Early CT Score category. The primary outcome was functional independence (modified Rankin Scale 0–2) at 90 days in the intention-to-treat population. Safety outcomes included symptomatic intracranial haemorrhage within 72 h and 90-day mortality. Results Between January and June 2025, 262 patients were randomised (129 hypothermia; 133 normothermia). Functional independence at 90 days occurred in 70 of 128 patients in the hypothermia group versus 53 of 133 in the normothermia group (adjusted risk ratio 1·36, 95% CI 1·05–1·76; p=0·018). Rates of symptomatic intracranial haemorrhage (7·0% vs 9·0%) and 90-day mortality (13·3% vs 18·0%) were similar. Other serious adverse events did not differ between groups. Conclusions Adjunctive intra-arterial selective hypothermia during thrombectomy improved 90-day functional independence without increasing adverse events, supporting focal cooling as a scalable neuroprotective strategy. Conflict of interest