Delayed Recanalization-How Late Is Not Too Late?

Stroke has become the second most prevalent cause of mortality in the world. Currently, the treatment of ischemic stroke is based on thrombolytic and thrombectomy therapy shortly after the ischemic event (<= 4.5 h for thrombolytic strategies; <= 6 h for thrombectomy strategies). However, the majority of patients are unable to receive prompt treatment, particularly in undeveloped countries. Alternative solutions are lacking for those patients that miss the optimal window of opportunity for treatment. Recently, new developments in imaging techniques and intravascular interventional devices enable the expansion of the window of opportunity for treating stroke patients. Clinical studies have reported that delayed recanalization at 24 h, or even more than 1 month, was beneficial for some patients. However, the mechanisms of neuroprotection that underly the delayed recanalization in these ischemic stroke patients remain unclear. In this review, we will summarize the clinical studies of delayed recanalization, and organize them according to the duration of occlusion. Additionally, we will discuss the changing guidelines and possible mechanisms based on animal research, and attempt to draw conclusions and future perspectives.

Automated summary

Stroke is the second leading cause of mortality worldwide, and the treatment of ischemic stroke typically involves thrombolytic therapy within 4.5 hours and thrombectomy within 6 hours. Many patients are unable to receive timely treatment, and alternative solutions are lacking for those who miss the optimal treatment window. Recent studies have shown that delayed recanalization may benefit some stroke patients, but the neuroprotective mechanisms underlying this phenomenon are still unclear.