Circulation: Cardiovascular Quality and Outcomes

Abstract

E ach year in the United States, approximately 800 000 men and women are affected by stroke, which equates to one incident of stroke every 40 seconds. 1 Stroke is the fourth leading cause of death nationally and is one of the foremost contributors to functional disability. 2 The cost to the US healthcare system is substantial. Specifically, in 2010 medical treatment for stroke cost approximately $54 billion and is expected to exceed $1 trillion by 2050. 3 The burden of stroke is not limited to US alone; mortality from stroke is responsible for ~9% of all deaths worldwide and is the second most common cause of death following ischemic heart disease. 4 While the overall risk of stroke has declined by 25% in the last decade, 5 disability from stroke is now emerging as a major public health problem, particularly in the elderly, as we observe an increase in aging of the population. Accordingly, in this month's topic review in Circulation: Cardiovascular Quality and Outcomes, we concentrate on contemporary issues around stroke and transient ischemic attack (TIA). Significant knowledge and practice gaps continue to exist across the continuum of stroke care. First, risk factor modification for stoke remains suboptimal. The most important modifiable risk factor for prevention of stroke is hypertension (HTN), with the lowering of blood pressure associated with a more than 25% reduction in the relative risk (RR) of stroke. 6,7 Modification of other risk factors such as diabetes, hypercholesterolemia, smoking cessation and atrial fibrilla-tion (AF), 8 have also been shown to reduce the incidence of stroke. 9 However, appropriate identification of patients at risk and ensuring adherence to prevention strategies presents many challenges. For example, numerous patients with HTN are not on therapy and many of those who are treated have suboptimal blood pressure (BP) control. Second, optimal antithrombotic therapy for stroke prevention in patients with AF remains challenging. Warfarin is the most commonly used and reduces RR of recurrent stroke in those with TIA/ minor stroke by ~70%. 10 However, warfarin can be difficult to dose and monitor and carries a significant risk of major bleeding. Novel anticoagulants have since been proposed over warfarin such as Dabigatran and Apixaban, which also reduce the risk of stroke in patients with AF. 11,12 These medications provide many potential benefits as they do not require monitoring of INR, while offering similar efficacy in preventing ischemic events. Lastly, guidelines established by the AHA/ASA advocate the initiation of fibrinolytic therapy for patients presenting within 3 hours of symptom onset and up to 4.5 hours for selected patients. 13 Although fibrinolytic therapy is effective in reducing disability, it does not improve mortality. 14 However, at present, only a fraction of patients receive fibrinolytic therapy on time and thus establishing systems to rapidly diagnose and treat eligible patients is a key challenge. Furthermore, novel rehabilitation programs for stroke have also recently showed promise; administrating these programs, preferably within the first 24 hours, and, if possible, within a specialized stroke center is a key goal. 15,16 Appropriately, in this topic review for Circulation: Cardiovascular Quality and Outcomes we have included papers that evaluate (1) stroke epidemiology, risk factors and outcomes, (2) therapeutic strategies for the treatment and prevention of stroke, and (3) health system interventions to improve stroke care. Stroke Epidemiology, Risk Factors, and Outcomes Stroke is one of the leading causes of disability and mortality worldwide and there is great variation in risk factors and outcomes in different populations. 17,18 The epidemiology of stroke in the US has changed over time, and death attributable to stroke has declined 1,19 due to changes in the landscape of risk factors and therapies and the implementation of guidelines and stroke systems of care. 20,22 Despite these improvements, the disease burden is still substantial with close to 800 000 Americans suffering from stroke each year 3 and many questions remain about the variation in risk factors and delivery of care. Antithrombotic therapy has played a major role in the prevention of death and disability from stroke, and the last decade has seen the emergence of many new antithrombotic agents. On the other hand, thrombolytics are the mainstay for the acute treatment of stroke and we are now seeing the advent of promising newer endovascular procedures. With the evolution of therapies for prevention and treatment of stroke it is important to be able to identify both appropriate patients for the use of available treatments and those that may be harmed. There is a need to develop accurate measures for estimating risk, therapeutic efficacy, and outcomes. Better understanding The following are highlights from the new series, Circulation: Cardiovascular Quality and Outcomes Topic Review. This series will summarize the most important manuscripts, as selected by the Editor, that have published in the Circulation portfolio. The objective of this new series is to provide our readership with a timely, comprehensive selection of important papers that are relevant to the quality and outcomes, and general cardiology audience. The studies included in this article represent the most significant research related to stroke and transient ischemic attack. of these issues is critical to further reduce the burden of stroke and improve outcomes. The following section is a collection of contemporary articles addressing the epidemiology, risk factors and outcomes of acute ischemic stroke including variation in burden of stroke and its risk factors, predictive models for estimating risk of stroke and mortality.