Is there Still a Time Window in the Treatment of Acute Stroke

It has become evident that strict time-based criteria are not optimal in selecting patients for acute stroke intervention, leaving the majority of patients untreated due to missing universal time-based criteria. We discuss the pathophysiologic basis for a shift of focus from time to the imaging evidence of salvageable tissue, as well as clinical and imaging tools. There is strong evidence for the benefit of thrombectomy in patients with a sustained salvageable tissue presenting within 24 h. Although evidence of benefit is limited in patients presenting longer than 24 h, those patients will have a poor functional outcome if untreated. MRI-based approaches to choose patients for thrombolytic therapy later than 4.5 h are relatively safe and modestly effective. Defining a patient-based therapeutic window to replace strict time windows and therefore refining patient exclusion and inclusion criteria is possible through understanding pathophysiology of acute ischemic stroke in individual patients.