Optimal transfer paradigm for emergent large vessel occlusion strokes: recognition to recanalization in the RACECAT trial.

Of the various forms of stroke, emergent large vessel occlusion (ELVO) stroke produces the majority of disability and death after stroke,1 but now represents a target for highly efficacious endovascular thrombectomy (EVT).2 Intravenous tissue plasminogen activator (IV tPA) remains otherwise the standard of care for all qualifying patients with ischemic stroke, with or without ELVO, within 4.5 hours of onset.2 Regardless of the treatment, outcome after ischemic stroke is heavily dependent on time from onset of symptoms to reperfusion therapy.3 Hence, the objective of stroke systems of care is to rapidly identify symptomatic patients, and reduce time from onset to definitive treatment. Three factors are to be considered when attempting to optimize stroke systems of care—type of stroke, stroke center, and transfer paradigm. Identification and characterization of stroke poses challenges. Delays in activation of emergency medical services (EMS) are common in the population and the source of treatment delay.4 A deficit that appears clinically vascular in origin may not be a stroke at all. If a stroke, the cause may be hemorrhagic or ischemic, and acute ischemic stroke may or may not harbor a large vessel occlusion. To aid identification in the field, a range of prehospital stroke scales have been developed for use by EMS, assessing for both the presence of a stroke and the likelihood of a large vessel occlusion.5 The greater the clinical deficit, the more likely an ELVO stroke. One such scale, the Rapid Arterial Occlusion Evaluation (RACE) scale, demonstrates a sensitivity of 0.85 and a specificity of 0.68 for ELVO using a threshold of RACE scale ≥5.6 The presence and severity of stroke may influence where a patient receives the most appropriate stroke care. Stroke care provided at stroke centers is stratified into endovascular thrombectomy capable stroke centers …