Richard T. Benson

Screening with MRI for Accurate and Rapid Stroke Treatment: SMART

Objective: The objective of this study was to demonstrate the feasibility of timely multimodal MRI screening before thrombolysis in acute stroke patients. Methods: Quality improvement processes were initiated in 2013 to reduce door-to-needle (DTN) time at the 2 hospitals where the NIH stroke team provides clinical care. Acute ischemic stroke (AIS) patients who received IV tissue plasminogen activator (tPA) ≤4.5 hours from last known normal were identified. Demographic and clinical characteristics and timing metrics were analyzed comparing the time periods before, during, and after the quality improvement processes. Results: There were 157 patients treated with IV tPA for AIS during 2012–2013, of whom 135 (86%) were screened with MRI. DTN time was significantly reduced by 40% during this period from a median of 93 minutes in the first half of 2012 to 55 minutes in the last half of 2013 (p < 0.0001) with a significant 4-fold increase in the proportion of treated patients with DTN time ≤60 minutes from 13.0% to 61.5%, respectively (p < 0.00001). Improvement in DTN time was associated with reduced door-to-MRI time, and there were no differences in demographic or clinical characteristics (p = 0.21–0.76). Conclusions: It is feasible and practical to consistently and rapidly deliver IV tPA to AIS patients within national benchmark times using MRI as the routine screening modality. The processes used in the SMART (Screening with MRI for Accurate and Rapid Stroke Treatment) Study to reduce DTN time have the potential to be widely applicable to other hospitals.

Identification of Reversible Disruption of the Human Blood–Brain Barrier Following Acute Ischemia

Background and Purpose— Animal models of acute cerebral ischemia have demonstrated that diffuse blood–brain barrier (BBB) disruption can be reversible after early reperfusion. However, irreversible, focal BBB disruption in humans is associated with hemorrhagic transformation in patients receiving intravenous thrombolytic therapy. The goal of this study was to use a magnetic resonance imaging biomarker of BBB permeability to differentiate these 2 forms of BBB disruption. Methods— Acute stroke patients imaged with magnetic resonance imaging before, 2 hours after, and 24 hours after treatment with intravenous tissue-type plasminogen activator were included. The average BBB permeability of the acute ischemic region before and 2 hours after treatment was calculated using a T2* perfusion-weighted source images. Change in average permeability was compared with percent reperfusion using linear regression. Focal regions of maximal BBB permeability from the pretreatment magnetic resonance imaging were compared with the occurrence of parenchymal hematoma (PH) formation on the 24-hour magnetic resonance imaging scan using logistic regression. Results— Signals indicating reversible BBB permeability were detected in 18/36 patients. Change in average BBB permeability correlated inversely with percent reperfusion (P=0.006), indicating that early reperfusion is associated with decreased BBB permeability, whereas sustained ischemia is associated with increased BBB disruption. Focal regions of maximal BBB permeability were significantly associated with subsequent formation of PH (P=0.013). Conclusions— This study demonstrates that diffuse, mild BBB disruption in the acutely ischemic human brain is reversible with reperfusion. This study also confirms prior findings that focal severe BBB disruption confers an increased risk of hemorrhagic transformation in patients treated with intravenous tissue-type plasminogen activator.

Embolic Protection Devices in Transcatheter Aortic Valve Replacement

The initially reported periprocedural neurological events rates associated with transcatheter aortic valve replacement raised concerns that ultimately led to the development and to the clinical research of novel embolic protection devices. Although the reduction of clinical stroke is a desired goal, the current research design of embolic protection devices focuses on surrogate markers of the clinical disease, primarily on silent central nervous system lesions observed in postprocedural diffuse-weighted magnetic resonance imaging and cognitive function testing. As the mere presence of particulate debris in brain matter may not correlate with the extent of brain injury, cognitive function, or quality of life, the clinical significance of embolic protection devices has yet to be determined, and interpretation of study results with regard to real-life clinical use should be viewed accordingly. The purpose of this article is to provide an overview of the updated ongoing clinical research on embolic protection devices and present its major caveats.

Deconstructing health disparities: It's not just about race

In view of the sacred covenant of physicians, the Hippocratic Oath, the medical community continually strives to provide timely and appropriate medical care to all patients without consideration of person, place, or insurance status. Some would purport that medical triage, acute care, and long-term follow-up in the United States are ethical, appropriate, and nonbiased, when compared with the rest of the world. However, the reality is that racial, ethnic, geographic, and social disparities continue to exist in this country.1 As the second most common cause of death worldwide, fourth cause of death in the United States, and a leading cause of adult disability, stroke is a disease with global health and economic consequences.2 When looking at race alone, black and Hispanic patients …

An MRI Hyperintense Acute Reperfusion Marker Is Related to Elevated Peripheral Monocyte Count in Acute Ischemic Stroke

Blood–brain barrier (BBB) disruption detected on magnetic resonance imaging (MRI) in acute ischemic stroke as a hyperintense acute reperfusion marker (HARM) is associated with upregulation of matrix metalloproteinase‐9 (MMP‐9). Although activated leukocytes, including monocytes, are the main source of MMPs, limited data exist to support relationship between leukocyte activation and BBB disruption in patients with acute ischemic stroke. The goal of this study is to investigate the relationship between neutrophils, lymphocytes, and monocytes with BBB disruption detected as HARM (+) in patients with acute ischemic stroke.

Global disparities in stroke and why we should care

The World Health Organization lists stroke as the second leading cause of death for people older than 60 years.1 Even more tragically, nearly 6 million people die annually of stroke worldwide. In response to this crisis, the World Stroke Organization launched the World Stroke Campaign to intensify global awareness about the fight against stroke. Major components for winning this fight include understanding the distribution, risk factors, determinants, and disparities in stroke, even in the most remote regions of the world.

Perfusion Deficits and Association with Clinical Outcome in Patients with Anterior Choroidal Artery Stroke

BACKGROUND AND PURPOSE Anterior choroidal artery (AChA) strokes have a varied pattern of tissue injury, prognosis, and clinical outcome. It is unclear whether perfusion deficit in AChA stroke is associated with the clinical outcome. This study aims to determine the frequency of perfusion abnormalities in AChA stroke and association with clinical outcome. METHODS The study cohort was derived from ischemic stroke patients admitted to 2 stroke centers between July 2001 and July 2014. All patients received an acute magnetic resonance imaging (MRI) scan. Patients with ischemic stroke restricted to the AChA territory were included in the study. Lesion size was measured as the largest diameter on diffusion-weighted imaging (DWI) or apparent diffusion coefficient and divided into 2 groups (<20 mm or ≥20 mm). Group comparisons were performed among patients with and without perfusion abnormalities and based on diffusion diameter. Favorable clinical outcome was defined as discharge to home. RESULTS A total of 120 patients were included in the study. Perfusion deficits were identified in 67% of patients. The admission National Institutes of Health Stroke Scale (NIHSS) was higher in patients with perfusion abnormalities (P = .027). Diameter lesion size on DWI was larger among patients with a perfusion deficit median [interquartile range], 1.63 [1.3-2.0], as compared with those without, 1.18 [1.0-1.7], P < .0001. Patients with a perfusion deficit were less likely to be discharged to home than those without (36% versus 60%, P = .013). CONCLUSIONS Two thirds of patients with an AChA stroke have a perfusion deficit on MRI, higher admission NIHSS, and larger DWI lesion size at presentation.