Continuum : lifelong learning in neurology
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The article "Update on Treatment of Acute Ischemic Stroke" by Dr Rabinstein was first published in the February 2017 Cerebrovascular Disease issue of Continuum: Lifelong Learning in Neurology as "Treatment of Acute Ischemic Stroke" and has been updated by Dr Rabinstein for this issue at the request of the Editor-in-Chief. ⋯ PURPOSE OF REVIEWThis article provides an update on the state of the art of the treatment of acute ischemic stroke with particular emphasis on the indications for reperfusion therapy.RECENT FINDINGSIn addition to the previously established indications for intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rtPA) within 4.5 hours of stroke symptom onset and endovascular therapy with mechanical thrombectomy for patients with large artery occlusion who can be treated within 6 hours of symptom onset, recent randomized controlled trials have now established new indications for emergency reperfusion in patients with wake-up stroke or delayed presentation (up to 24 hours from last known well in the case of mechanical thrombectomy). Identification of patients who may benefit from acute reperfusion therapy within this extended time window requires screening with perfusion brain imaging or, in the case of IV thrombolysis for wake-up strokes, emergency brain MRI. Collateral status and time to reperfusion remain the primary determinants of outcome.SUMMARYTimely successful reperfusion is the most effective treatment for patients with acute ischemic stroke. Recent evidence supports the expansion of the time window for reperfusion treatment in carefully selected patients.
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This article reviews the actual indications for mechanical thrombectomy in patients with acute ischemic stroke and how the opportunities for endovascular therapy can be expanded by using the concept of clinical-imaging or perfusion-imaging mismatch (as a surrogate for salvageable tissue) rather than time of ischemia. ⋯ For patients with acute ischemic stroke and a large vessel occlusion in the proximal anterior circulation who can be treated within 6 hours of stroke symptom onset, mechanical thrombectomy with a second-generation stent retriever or a catheter aspiration device should be indicated regardless of whether the patient received treatment with intravenous (IV) recombinant tissue plasminogen activator (rtPA) in patients with limited signs of early ischemic changes on neuroimaging. Two clinical trials completely disrupted the time window concept in acute ischemic stroke, showing excellent clinical outcomes in patients treated up to 24 hours from symptom onset. Time of ischemia is, on average, a good biomarker for tissue viability; however, the window of opportunity for treatment varies across different individuals because of a range of compensatory mechanisms. Adjusting time to the adequacy of collateral flow leads to the concept of tissue window, a paradigm shift in stroke reperfusion therapy.