Abstract P345: Perfusion-Guided Bridging Therapy in Strokes With Unknown Time of Onset and Large Vessel Occlusion

Introduction: Endovascular treatment (EVT) is the therapy of choice, in patients with unknown stroke onset (unwitnessed and wake-up strokes) and large vessel occlusion (LVO) with a favorable perfusion pattern. Whether bridging therapy (intravenous thrombolysis (IVT) and EVT) is superior to EVT alone remains unknown. Material and Methods: We retrospectively included all patients admitted to the Geneva University Hospital from 01.2016 to 06.2020 with i) stroke of unknown onset, due to ii) anterior circulation occlusion, with iii) favorable CT perfusion pattern based on the DEFUSE criteria (ischemic core volume< 70ml; mismatch ratio >= 1.8 and mismatch volume >= 15ml), and iv) treated < 4.5 hours after symptom recognition. As a standard of care, the patients fulfilling these inclusion criteria were treated with EVT and IVT or EVT alone when IVT was contraindicated. Outcome measures were any intracerebral bleeding (symptomatic or asymptomatic), mortality and favorable outcome (mRS 0-1) at three months. Results: 32 patients were included (17 treated with EVT alone and 15 with EVT and IVT). Mean age was 69±18 yo. Median NIHSS was 16 (IQR 12-20) and median time from symptom recognition to treatment was 184 (146-226) minutes. Median hypoperfused tissue volume (Tmax > 6s) was 119 ml (80-151) and infarcted core (CBF ratio <30%) 8 ml (0-27). After propensity score weighting, bridging therapy was not associated with an increased risk of intracerebral bleeding (p=0.72) or mortality (p=0.55). The proportion of favorable outcomes at three months was similar between treatment groups (p=0.78). Conclusion: These results suggest that IVT before EVT is a safe therapeutic option in patients with unknown stroke onset selected on perfusion imaging and treated <4.5 hours after symptom recognition. Early administration of IVT may be particularly relevant before interhospital transfer to a comprehensive stroke center for EVT.