Late Time Window Strategy

초록

Late Time Window Strategy Joung-Ho Rha, Inha University Hospital Neurology Endovascular thrombectomy (EVT) for hyperacute ischemic stroke within 6 hours has been established after 5 landmark trials were published in 2015. Three years later, 2 pivotal trials of DAWN and DEFUSE-3, extended the time window upto 24 hours and changed the current guideline. However, compared to the early window trials which focused on the small ischemic core and relevant artery occlusion, these late window trials used rather strict inclusion criteria according to the RAPID software to prove the target mismatch profile. So only limited portion of late window patients can have benefit of EVT. Thereafter, many efforts have been made to broaden the selection criteria of late window EVT, mostly evaluating collateral status by vessel imaging. The “late window paradox”, which means greater effect size of EVT for the late window compared to early window, implies that ischemic core growth is very slow in some selected patients, and elucidate the possibility of EVT even after 24 hour window, and there are reports about these cases. Artificial intelligence is getting more and more investigated and used especially in the field of neuroimaging. Many software is competing to support the decision making of stroke neurologist and neurointerventionist, and probably will be one of the essential tool of EVT in the near future. Finally, basilar artery occlusion can also have benefit from EVT even at late time window, but unfortunately there is still little scientific evidence at present. More effort to prove the effectiveness of posterior circulation EVT is warranted.