Abstract Number: Esoc2026a461 Outcome by Vessel Occlusion Site in the Attest-2 Trial

Abstract Background and aims Tenecteplase may have superior fibrinolytic efficacy compared to alteplase but findings among patients with large vessel occlusion (LVO) are inconsistent. ATTEST-2 found non-inferiority of tenecteplase compared to alteplase in acute ischaemic stroke treated 4.5 hours from last known well. We explored the influence of vessel occlusion presence and site on outcomes in ATTEST-2. Methods Thrombolysis eligible adults were randomized in ATTEST-2 to tenecteplase 0.25 mg/kg or alteplase 0.9 mg/kg. All patients underwent baseline and 24 hours non-enhanced CT, a subset also had baseline CT angiography (CTA). CTAs were reviewed centrally by expert raters, masked to clinical details, for vessel occlusion and site. We compared 90-day disability outcomes (modified Rankin Score, mRS) in subgroups of LVO, medium or distal vessel occlusion (MDVO), and no occlusion (NO) using logistic or ordinal regression. Results CTA was available in 1110/1777 patients (253 LVO, 212 MDVO, 645 NO) with matched baseline characteristics between treatment groups. There was a significant interaction between treatment group and occlusion site for mRS 0-2 (p = 0.001), mRS 0-1 (p = 0.001) and mRS distribution (P = 0.003). Adjusting for age and thrombectomy use, mRS 0-2 at 90 days was not different with tenecteplase compared to alteplase in patients with LVO (OR1.00,(0.58-1.71),P = 0.99) or NO (OR0.83,(0.56-1.23),P = 0.35) but was significantly more likely in MDVO patients with tenecteplase (OR2.33,(1.28-4.25),P = 0.006). Results were consistent for mRS 0-1 and mRS distribution. Conclusions Tenecteplase was associated with improved functional outcomes compared to alteplase among ATTEST-2 participants with MDVO visible on CTA but not LVO or NO. Conflict of interest n/a. Figure 1 - belongs to Results