Outcomes and safety of endovascular treatment from 6 to 24 hours in patients with a pre-stroke moderate disability (mRS 3): a multicenter retrospective study

Background Approximately 30% of patients presenting with acute ischemic stroke (AIS) due to large vessel occlusion have pre-stroke modified Rankin Scale (mRS) scores >= 2. We aimed to investigate the safety and outcomes of endovascular treatment (EVT) in patients with AIS with moderate pre-stroke disability (mRS score 3) in an extended time frame (ie, 6-24 hours from the last time known well). Methods Data were collected from five centers in Europe and the USA from January 2018 to January 2023 and included 180 patients who underwent EVT in an extended time frame. Patients were divided into two groups of 90 each (Group 1: pre-mRS 0-2; Group 2: pre-mRS 3; 71% women, mean age 80.3 +/- 11.9 years). Primary outcomes were: (1) 3-month good clinical outcome (Group 1: mRS 0-2, Group 2: mRS 0-3) and Delta mRS; (2) any hemorrhagic transformation (HT); and (3) symptomatic HT. Secondary outcomes were successful and complete recanalization after EVT and 3-month mortality. Results No between-group differences were found in the 3-month good clinical outcome (26.6% vs 25.5%, P=0.974), any HT (26.6% vs 22%, P=0.733), and symptomatic HT (8.9 vs 4.4%, P=0.232). Unexpectedly, Delta mRS was significantly smaller in Group 2 compared with Group 1 (1.64 +/- 1.61 vs 2.97 +/- 1.69, P<0.001). No between-group differences were found in secondary outcomes. Conclusion Patients with pre-stroke mRS 3 are likely to have similar outcomes after EVT in the extended time frame to those with pre-stroke mRS 0-2, with no difference in safety.