Johns Hopkins Stroke Dept. Live Blogs About “Thrombolysis Guided by Perfusion Imaging up to 9 Hours after Onset of Stroke”
Burton J. Tabaac, MD
The following discussion is documented via “LIVE Blogging,” a Journal Club held at Johns Hopkins Hospital in Baltimore, Maryland, on May 14, 2019. The journal article presented is “Thrombolysis Guided by Perfusion Imaging up to 9 Hours after Onset of Stroke,” published in The New England Journal of Medicine on May 9, 2019. The Journal Club presentation and discussion was led by Dr. Rebecca Gottesman, a neurology professor, cerebrovascular specialist, and International Stroke Conference 2019 award recipient.
Current American Heart Association/American Stroke Association guidelines for ischemic stroke limit the time to initiate intravenous thrombolytic therapy to within 4.5 hours after the onset of stroke. Representatives from the EXTEND trial and collaborators from the University of Melbourne, Royal Melbourne Hospital, in Australia published an article that challenges this limit. By carefully selecting the appropriate patient population using advanced imaging, patients who have salvageable brain tissue beyond 4.5 hours may benefit from treatment via IV thrombolysis! The authors tested the hypothesis that “intravenous thrombolysis with alteplase initiated between 4.5 and 9.0 hours after stroke onset or on awakening with stroke symptoms (for which the time of onset was not known) would provide a benefit in patients who had a small core volume of cerebral infarction that was disproportionate to a larger area of hypoperfusion.”
This paradigm change to carefully select the appropriate patients who may benefit from therapy outside current guidelines parallels a similar historical trajectory to that of endovascular intervention in treating large vessel occlusion. For an epoch, the standard of care in approaching embolectomies relied on the patient presenting to clinical attention within 6 hours of onset and a favorable ASPECTS score on “dry” CT brain imaging. This limit was breached via conclusions drawn from the DAWN and DEFUSE 3 trials. By carefully selecting the appropriate patient population in concordance with advanced imaging (e.g., CTP, hyperacute MRI), offerable treatment was readily introduced to a much larger eligible patient population.