Early major ischemic changes on computed tomography should not preclude use of tissue plasminogen activator.

Abstract

Early major ischemic changes on CT should not preclude use of tPA. In 1997, Prof von Kummer and his colleagues in ECASS greatly advanced stroke neurology by showing us the importance of early ischemic changes (EIC) on computed tomography.1 They devised the so-called one third rule and taught us to estimate whether EIC subsumed more or less than one third of the territory of the middle cerebral artery (MCA). In the NINDS study, we missed this important finding. In our trial, we focused on treating half our patients within 90 minutes, and the remainder within 3 hours; there was only time to review the scans for hemorrhage, perform a history and physical, and obtain informed consent prior to mixing up the drug.2 Following the regulatory approval of intravenous (IV) thrombolysis in the United States, physicians have tried to implement CT reading and to learn to read EIC and use the one third rule.1 Although FDA approval was based primarily on NINDS, the approval language and package insert incorporated the ECASS warning about EIC and the one third rule. Listening to neurologists and emergency medicine physicians debate the importance …