Detection of Stroke with Retinal Microvascular Density and Self-Supervised Learning Using OCT-A and Fundus Imaging.

Acute cerebral stroke is a leading cause of disability and death, which could be reduced with a prompt diagnosis during patient transportation to the hospital. A portable retina imaging system could enable this by measuring vascular information and blood perfusion in the retina and, due to the homology between retinal and cerebral vessels, infer if a cerebral stroke is underway. However, the feasibility of this strategy, the imaging features, and retina imaging modalities to do this are not clear. In this work, we show initial evidence of the feasibility of this approach by training machine learning models using feature engineering and self-supervised learning retina features extracted from OCT-A and fundus images to classify controls and acute stroke patients. Models based on macular microvasculature density features achieved an area under the receiver operating characteristic curve (AUC) of 0.87-0.88. Self-supervised deep learning models were able to generate features resulting in AUCs ranging from 0.66 to 0.81. While further work is needed for the final proof for a diagnostic system, these results indicate that microvasculature density features from OCT-A images have the potential to be used to diagnose acute cerebral stroke from the retina.

Exposure to Neurointervention During Neurology Training.

There is an urgent need to include a dedicated neurointerventional rotation in the curriculum of neurology residency and vascular neurology fellowship based on the paradigm shift in recent years of stroke workflow. The recent changes coupled with growing body of evidence about lack of neurointerventional exposure in current curriculum makes it imperative for us to restructure the training for future neurologists. The exposure will prepare the neurology house-staff for the contemporary management of cerebrovascular diseases and will lead to high quality, patient-centric care.

Call to Action: SARS-CoV-2 and CerebrovAscular DisordErs (CASCADE).

BACKGROUND AND PURPOSE: The novel severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), now named coronavirus disease 2019 (COVID-19), may change the risk of stroke through an enhanced systemic inflammatory response, hypercoagulable state, and endothelial damage in the cerebrovascular system. Moreover, due to the current pandemic, some countries have prioritized health resources towards COVID-19 management, making it more challenging to appropriately care for other potentially disabling and fatal diseases such as stroke. The aim of this study is to identify and describe changes in stroke epidemiological trends before, during, and after the COVID-19 pandemic. METHODS: This is an international, multicenter, hospital-based study on stroke incidence and outcomes during the COVID-19 pandemic. We will describe patterns in stroke management, stroke hospitalization rate, and stroke severity, subtype (ischemic/hemorrhagic), and outcomes (including in-hospital mortality) in 2020 during COVID-19 pandemic, comparing them with the corresponding data from 2018 and 2019, and subsequently 2021. We will also use an interrupted time series (ITS) analysis to assess the change in stroke hospitalization rates before, during, and after COVID-19, in each participating center. CONCLUSION: The proposed study will potentially enable us to better understand the changes in stroke care protocols, differential hospitalization rate, and severity of stroke, as it pertains to the COVID-19 pandemic. Ultimately, this will help guide clinical-based policies surrounding COVID-19 and other similar global pandemics to ensure that management of cerebrovascular comorbidity is appropriately prioritized during the global crisis. It will also guide public health guidelines for at-risk populations to reduce risks of complications from such comorbidities.

Racial disparities in post-stroke functional outcomes in young patients with ischemic stroke.

BACKGROUND AND PURPOSE: Recent studies show rising incidence of stroke in the young, for which risk factors are not well characterized. There is evidence of increased risk in certain racial and ethnic groups. We assessed racial differences in risk factors, stroke etiology, and outcomes among young stroke patients. METHODS: Using data from our inpatient registry for ischemic stroke, we reviewed patients aged 18-50 who were admitted 01/2013 to 04/2018. Race/ethnicity were characterized as non-Hispanic White (NHW), non-Hispanic Black (NHB), Hispanic (HIS). For univariate comparisons Chi-square and Kruskal-Wallis tests were performed as appropriate. Multivariable logistic regression was used to assess impact of race on day seven modified Rankin score (mRS). RESULTS: Among 810 patients with race and outcome data who were admitted in the study period, median age was 43, 57.1% were male, and 36.5% NHW, 43.2% NHB, 20.2% HIS. History of hypertension (HTN), type II diabetes (DM II), smoking, heart failure (CHF), prior stroke, and end-stage renal disease varied significantly by race. Compared to NHW, NHB had higher odds of HTN (OR 2.28, 1.65-3.15), CHF (OR 2.17, 1.06-4.46), and DM II 1.92 (1.25-2.94) while HIS had higher odds of DM II (OR 2.52, 1.55-4.10) and lower odds of smoking (OR 0.56, 0.35-0.90). Arrival NIHSS was higher in NHB, but etiology and rates of tpA treatment and thrombectomy did not vary by race. Compared to NHW patients, NHB (OR 0.50 CI (0.31-0.78)) and HIS (OR 0.37 CI (0.21-0.67)) were less likely to have good functional outcome (mRS <2) at day 7 in adjusted analyses. CONCLUSIONS: In this study, there was a higher prevalence of several modifiable risk factors in NHB and HIS young stroke patients and early functional outcome was worse in these groups. Our study suggests a need for targeted prevention efforts for younger populations at highest risk for stroke.

Development of a Standardized Grading Scale for Atherosclerotic Disease of the Head and Neck.

OBJECTIVE: For research and risk factor analysis, a reproducible method quantifying atherosclerosis is necessary. Our aim was to develop a computed tomography (CT) angiography grading system to quantify atherosclerotic disease of the head and neck. METHODS: Institutional review board-approved, retrospective analysis was performed on 152 patients who underwent head/neck CT angiography. A grading scale was designed to calculate plaque burden at multiple sites with the sum referred to as atherosclerosis score. Three radiologists calculated scores with an overlap of cases to calculate the intraclass correlation coefficient. RESULTS: Without any prior training, the intraclass correlation coefficient between readers was considered fair. After a short tutorial, intraclass correlation coefficient was recalculated using separate patients, showing excellent correlation.Statistically significant positive correlation was found between atherosclerosis scale and age, hyperlipidemia, hypertension, and diabetes, but no correlation with sex or smoking status. CONCLUSIONS: A simple, visual grading scale for atherosclerosis in head/neck CT angiography was used to standardize reporting and better characterize a patient's risk of stroke.

No Weekend or After-Hours Effect in Acute Ischemic Stroke Patients Treated by Telemedicine.

BACKGROUND: Stroke outcomes have been shown to be worse for patients presenting overnight and on weekends (after-hours) to stroke centers compared with those presenting during business hours (on-hours). Telemedicine (TM) helps provide evaluation and safe management of stroke patients. We compared time metrics and outcomes of stroke patients who were assessed and received intravenous recombinant tissue plasminogen activator (IV-tPA) via TM during after-hours with those during on-hours. METHODS: Analysis of our TM registry from September 2015 to December 2016, identified 424 stroke patients who were assessed via TM and received IV-tPA. We compared baseline characteristics, clinical variables, time metrics, and outcomes between the after-hours (5 pm-7:59 am, weekends) and on-hours (weekdays 8 am-4:59 pm) patients. RESULTS: Of the 424 patients, 268 were managed via TM during after-hours, and 156 during on-hours. Baseline characteristics and clinical variables were similar between the groups. Importantly, there were no differences in all relevant time metrics including door to IV-tPA bolus time. IV-tPA complications (including all intracerebral hemorrhage (ICH), any systemic bleeding, and angioedema), discharge disposition, and 90-day modified Rankin Scale were also similar in the groups. CONCLUSIONS: There was no difference in IV-tPA treatment times, acute stroke evaluation times, or mortality between the patients treated after-hours versus on-hours. Unlike in-person neurology coverage at many centers, the coverage provided by TM does not differ depending on the hour or day. Access to stroke specialists 24/7 via TM can ensure dependable and timely clinical care for acute stroke patients regardless of the time of day or day of the week.

Telemedicine Can Replace the Neurologist on a Mobile Stroke Unit.

BACKGROUND AND PURPOSE: The BEST-MSU study (Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit) is a comparative effectiveness trial in patients randomized to mobile stroke unit or standard management. A substudy tested interrater agreement for tissue-type plasminogen activator eligibility between a telemedicine vascular neurologist and onboard vascular neurologist. METHODS: On scene, both the telemedicine vascular neurologist and onboard vascular neurologist independently evaluated the patient, documenting their tissue-type plasminogen activator treatment decision, National Institutes of Health Stroke Scale score, and computed tomographic interpretation. Agreement was determined using Cohen κ statistic. Telemedicine-related technical failures that impeded remote assessment were recorded. RESULTS: Simultaneous and independent telemedicine vascular neurologist and onboard vascular neurologist assessment was attempted in 174 patients. In 4 patients (2%), the telemedicine vascular neurologist could not make a decision because of technical problems. The telemedicine vascular neurologist agreed with the onboard vascular neurologist on 88% of evaluations (κ=0.73). CONCLUSIONS: Remote telemedicine vascular neurologist assessment is reliable and accurate, supporting either telemedicine vascular neurologist or onboard vascular neurologist assessment on our mobile stroke unit. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02190500.

A call for formal telemedicine training during stroke fellowship.

During the 20 years since US Food and Drug Administration approval of IV tissue plasminogen activator for acute ischemic stroke, vascular neurology consultation via telemedicine has contributed to an increased frequency of IV tissue plasminogen activator administration and broadened geographic access to the drug. Nevertheless, a growing demand for acute stroke coverage persists, with the greatest disparity found in rural communities underserved by neurologists. To provide efficient and consistent acute care, formal training in telemedicine during neurovascular fellowship is warranted. Herein, we describe our experiences incorporating telestroke into the vascular neurology fellowship curriculum and propose recommendations on integrating formal telemedicine training into the Accreditation Council for Graduate Medical Education vascular neurology fellowship.

Variety is the spice of life: strategies for promoting fruit and vegetable acceptance during infancy.

The present manuscript describes two experimental studies that were conducted to explore the effects of an 8-day exposure to a particular food or a variety of foods between and/or within meals on fruit and vegetable acceptance in 74 infants. Whether the dietary experience modified acceptance depended on the flavors of foods experienced, whether the experience occurred between or within meals or both, and whether the target food was a fruit or vegetable. In the first study, we found that 8 days of dietary exposure to pears or a variety of fruits between meals (not including pears) resulted in greater consumption of pears by the infants but this increased acceptance did not generalize to green beans. In the second study, we found that 8 days of vegetable variety both between and within meals led to increased acceptance of green beans, carrots and spinach. Those infants who experienced green beans alone or a variety of vegetables between meals also tended to eat more green beans after the exposure. These findings suggest that not only can infants clearly discriminate flavors but repeated opportunities to taste a particular or a variety of foods may promote willingness to eat fruits and vegetables, the consumption of which is generally low in the pediatric population and the acceptance of which is difficult to enhance beyond toddlerhood.

PTK, MAPK, and NOC/oFQ impair hypercapnic cerebrovasodilation after hypoxia/ischemia.

This study characterized the contributions of protein tyrosine kinase (PTK) and mitogen-activated protein kinase (MAPK) in nociceptin/orphanin FQ (NOC/oFQ)-induced impairment of hypercapnic pial artery dilation (PAD) after hypoxia/ischemia (H/I) in piglets equipped with a closed cranial window. NOC/oFQ (10(-10) M cerebrospinal fluid H/I concentration) impaired hypercapnic PAD (21 +/- 2% vs. 13 +/- 1%). Coadministration of either of the PTK inhibitors genistein or tyrphostin A23 or the MAPK inhibitors U-0126 or PD-98059 with NOC/oFQ (10(-10) M) partially prevented the inhibition of hypercapnic PAD compared with that observed in their absence (21 +/- 2% vs. 17 +/- 1% for genistein). After exposure to H/I, PAD in response to hypercapnia was impaired, but pretreatment with either genistein, tyrphostin A23, U-0126, or PD-98059 partially protected such impairment (17 +/- 1% vs. 4 +/- 1% vs. 9 +/- 1% for sham control, H/I, and H/I + genistein pretreatment, respectively). These data show that PTK and MAPK activation contribute to NOC/oFQ-induced impairment of hypercapnic PAD. These data suggest that activation of PTK and MAPK is also involved in the mechanism by which NOC/oFQ impairs hypercapnic PAD after H/I.