Publication Date: June 2021 (Volume 23, Supplement 06)
CME Credits: 4 AMA PRA Category 1 Credits™. CME expires 06/15/2024. This course is included with an Emergency Medicine Practice subscription
Specialty CME Credits: Included as part of the 4 credits, this CME activity is eligible for 4 Stroke CME and 1 Pharmacology CME credits, subject to your state and institutional approval.
Acute ischemic stroke is a leading cause of morbidity and mortality in the United States, and a majority of acute ischemic stroke patients are evaluated for the first time by a clinician in the emergency department. Intravenous tissue plasminogen activator and mechanical thrombectomy are powerful tools for the treatment of acute ischemic stroke. Treatment algorithms for acute ischemic stroke are evolving rapidly, and strokes in select patients can now be treated up to 24 hours after last known well time. However, even in the setting of extended treatment times, the treatment effects of both intravenous tissue plasminogen activator and mechanical thrombectomy are time dependent. The emergency clinician must remain current with the newest treatment algorithms in order to provide expeditious and high-quality care to stroke patients.
Stroke currently ranks fifth among all causes of death in the United States, where a stroke occurs on average every 40 seconds, with an incidence of approximately 795,000 acute strokes every year.1 Of these, the majority are ischemic strokes (87%), with the remainder comprised of hemorrhagic strokes and subarachnoid hemorrhages.1 The incidence of stroke has decreased over time,2 likely due to strong national efforts to improve control of vascular risk factors in outpatient settings. Despite this, the prevalence is expected to increase by 3.4 million individuals by the year 2030, based on projections from data obtained through the National Health and Nutrition Examination Survey (NHANES) and the United States Census Bureau.3 One likely explanation for this observation is the aging population in the United States, as stroke risk increases with age. This rise in stroke prevalence results in a tremendous financial burden, and it is projected that between 2012 and 2030, total direct medical stroke-related costs will more than double, from $71.55 billion to $184.13 billion.3
In 1995, intravenous tissue plasminogen activator (IV tPA) was approved by the United States Food and Drug Administration (FDA) for the treatment of acute ischemic stroke (AIS), after the National Institute of Neurological Disorders and Stroke (NINDS) demonstrated significant improvement in clinical outcomes with IV tPA.4 More recently, endovascular stroke treatment with mechanical thrombectomy has proven to be a powerful and effective therapy as well, allowing select patients to be treated in an extended time window beyond 0 to 3 hours after last known well time.5-11 Despite this extended time window, the effects of both IV tPA and mechanical thrombectomy remain time dependent. A meta-analysis evaluating 9 randomized phase III trials comparing IV tPA to placebo found that earlier treatment with IV tPA increased the odds of a good clinical outcome (defined in the study as no significant disability at 3-6 months, as indicated by a modified Rankin Score of 0 or 1).12 Similarly, a meta-analysis evaluating 5 randomized phase III trials comparing mechanical thrombectomy and medical therapy to medical therapy alone found that earlier treatment with mechanical thrombectomy was associated with lower degrees of poststroke disability.13
In the majority of cases, the initial evaluation of a patient with AIS will occur in the emergency department (ED). In 2015, 640,000 ED visits had stroke as the principal diagnosis.1 Given the time-dependent nature of the treatments that have been proven to improve outcomes significantly in patients presenting with AIS, it is important for emergency clinicians to be able to evaluate these patients rapidly for appropriate treatment.