Interfacility Transfer for Thrombectomy: A Promising Therapeutic Window.

Currently, most acute ischemic stroke patients presenting with a large vessel occlusion are first evaluated at a nonthrombectomy-capable center before transfer to a comprehensive stroke center that performs thrombectomy. Interfacility transfer is a complex process that requires extensive coordination between the referring, transporting, and receiving facilities. As a result, long delays are common, contributing to poor clinical outcomes. In this review, we summarize the accumulating literature about the clinical as well as radiological-infarct growth, collateral change, arterial recanalization, and hemorrhagic transformation-changes during interfacility transfer for thrombectomy. Recent evidence shows that clinical/radiological changes during transfer are heterogeneous across patients and impact long-term functional outcomes, highlighting the urgent need to optimize care during this time window. We review some of the most promising therapeutic strategies-for example, penumbral protection to reduce infarct growth-that may improve clinical outcome in patients being transferred to thrombectomy-capable centers. Finally, we discuss key methodological considerations for designing clinical trials aimed at reducing infarct growth during transfer.