Time to Treatment With Intravenous Tissue Plasminogen Activator and Outcome From Acute Ischemic Stroke

NTRAVENOUS (IV) TISSUE-TYPE PLASminogen activator (tPA) is a treatment of proven benefit for select patients with acute ischemic stroke as long as 4.5 hours after onset. 1,2Available evidence suggests a strong influence of time to therapy on the magnitude of treatment benefit.In stroke animal models, time to reperfusion is a dominant determinant of final infarct volume. 3In human patients, imaging studies show the volume of irreversibly injured tissue in acute cerebral ischemia expands rapidly over time, typically consuming 2 million additional neurons per minute until reperfusion is achieved. 4Pooled data from IV tPA clinical trials indicate that therapeutic benefit of tPA is greatest when given very early…