Table 3. Abbreviations in This Guideline ACC American College of Cardiology AHA American Heart Association AIS Acute ischemic stroke ARD Absolute risk difference ASA American Stroke Association ASCVD Atherosclerotic cardiovascular disease ASPECTS Alberta Stroke Program Early Computed Tomography Score BP Blood pressure CEA Carotid endarterectomy CeAD Cervical artery dissection CMB Cerebral microbleed COR Class of recommendation CPAP Continuous positive airway pressure CS Conscious sedation CT Computed tomography CTA Computed tomographic angiography CTP Computed tomographic perfusion DTN Door-to-needle DVT Deep vein thrombosis DW-MRI Diffusion-weighted magnetic resonance imaging ED Emergency department EMS Emergency medical services EVT Endovascular therapy GA General anesthesia GWTG Get With The Guidelines HBO Hyperbaric oxygen HR Hazard ratio HT Hemorrhagic transformation ICH Intracerebral hemorrhage IPC Intermittent pneumatic compression IV Intravenous LDL-C Low-density lipoprotein cholesterol LMWH Low-molecular-weight heparin LOE Level of evidence LVO Large vessel occlusion M1 Middle cerebral artery segment 1 M2 Middle cerebral artery segment 2 M3 Middle cerebral artery segment 3 MCA Middle cerebral artery MI Myocardial infarction MR Magnetic resonance MRA Magnetic resonance angiography MRI Magnetic resonance imaging mRS Modified Rankin Scale mTICI Modified Thrombolysis in Cerebral Infarction NCCT Noncontrast computed tomography NIHSS National Institutes of Health Stroke Scale NINDS National Institute of Neurological Disorders and Stroke OR Odds ratio OSA Obstructive sleep apnea PFO Patent foramen ovale RCT Randomized clinical trial RR Relative risk rt-PA Recombinant tissue-type plasminogen activator SBP Systolic blood pressure sICH Symptomatic intracerebral hemorrhage TIA Transient ischemic attack UFH Unfractionated heparin Table 3. Continued (Continued) Powers et al 2019 Guidelines for Management of AIS e349 1. Prehospital Stroke Management and Systems of Care 1.1. Prehospital Systems 1.2. EMS Assessment and Management 1.2. EMS Assessment and Management COR LOE New, Revised, or Unchanged The use of a stroke assessment tool by first aid providers, including EMS dispatch personnel, is recommended. 