Abstract Number: Esoc2026a2348 a Survey of Clinical Equipoise for Late Window Intravenous Thrombolysis Before Transfer to Thrombectomy Centres in the Uk

Background and aims Intravenous thrombolysis alone can improve outcomes up to 24 hours after patients are last known well when selected by imaging criteria, but there is continuing uncertainty about its use amongst patients also undergoing thrombectomy within extended time windows. This survey evaluated the degree of clinical equipoise in preparation for the TIMELESS-TNT* UK trial, which plans to randomise patients in the extended window at primary stroke centres to Tenecteplase or routine care, before transfer for thrombectomy. Methods An electronic survey was circulated to all clinicians at UK stroke centres through the National Institute of Health and Care Research Regional Research Delivery Network (NIHR RRDN) and Hyperacute Stroke Research Centres (HSRCs). The survey assessed willingness to randomise to a trial, based upon perfusion mismatch or ASPECTS scores, in the extended window. Results 62 responses were received over the 5-week survey period, the majority from clinicians including nurses (n=60, 96.7%), 42% of whom were based at primary centres. Based upon mismatch, 90% of overall respondents supported randomisation of the target trial population in the presence of anterior circulation LVOs and 89% for basilar occlusions. Based on an ASPECTS cut-off ≥7, 65% of respondents were in favour of randomising for anterior circulation LVOs and 66% for basilar occlusions. Conclusions There is high prevailing uncertainty regarding use of tenecteplase for late window patients being transferred for thrombectomy. This provides further support for the TIMELESS TNT trial, currently funded in France, with plans to extend recruitment to the UK. Conflict of interest Nothing to disclose