The pivotal role of timing of intravenous thrombolysis bridging treatment prior to endovascular thrombectomy

Background: The role of intravenous thrombolysis (IVT) as bridging treatment prior to endovascular thrombectomy (EVT) is under debate and better patient selection is needed. Objectives: As the efficacy and safety of IVT diminish with time, we aimed to examine the impact of bridging treatment within different time frames from symptom onset. Design: A retrospective registry study. Methods: Data were extracted from ongoing prospective EVT registries in two large tertiary centers. The current study included IVT-eligible patients with onset to door (OTD) < 4 h. We examined the efficacy and safety of bridging treatment through a comparison of the IVT + EVT group with the direct-EVT group by different time frames. Results: In all, 408 patients (age 71.1 +/- 14.6, 50.6% males) were included, among them 195 received IVT + EVT and 213 underwent direct EVT. Both groups had similar characteristics. In the IVT + EVT group only, longer OTD was associated with lower rates of favorable outcome (p = 0.021) and higher rates of hemorrhagic transformation (HT; p = 0.001). In patients with OTD <= d2 h, IVT + EVT compared to direct EVT had higher rates of TICI 2b-3 (86.2% versus 80.7%, p = 0.038). In patients with OTD > 2 h, IVT + EVT had lower rates of favorable outcome (33.3% versus 56.9%, p = 0.021), worse discharge National Institutes of Health Stroke Scale [7 (2-13) versus 3 (1-8), p = 0.024], and higher rates of HT (34.0% versus 8.5%, p < 0.001). Discussion: In this study, we found OTD times to have a significant effect on the impact of IVT bridging treatment. Our study shows that among patients with OTD < 2 h bridging treatment may be associated with higher rates of successful recanalization. By contrast, in patients with OTD > 2 h, bridging treatment was associated with worse outcomes. Further time-sensitive randomized trials are needed.