Predictors of Outcomes in Patients With Mild Ischemic Stroke Symptoms: MaRISS

[Figure: see text].

Covalently interconnected transition metal dichalcogenide networks via defect engineering for high-performance electronic devices

Solution-processed semiconducting transition metal dichalcogenides are at the centre of an ever-increasing research effort in printed (opto)electronics. However, device performance is limited by structural defects resulting from the exfoliation process and poor inter-flake electronic connectivity. Here, we report a new molecular strategy to boost the electrical performance of transition metal dichalcogenide-based devices via the use of dithiolated conjugated molecules, to simultaneously heal sulfur vacancies in solution-processed transition metal disulfides and covalently bridge adjacent flakes, thereby promoting percolation pathways for the charge transport. We achieve a reproducible increase by one order of magnitude in field-effect mobility (µ_FE), current ratio (I_ON/I_OFF) and switching time (τ_S) for liquid-gated transistors, reaching 10^-2 cm² V^-1 s^-1, 10⁴ and 18 ms, respectively. Our functionalization strategy is a universal route to simultaneously enhance the electronic connectivity in transition metal disulfide networks and tailor on demand their physicochemical properties according to the envisioned applications.

Trends of Acute Ischemic Stroke Reperfusion Therapies from 2012 to 2016 in the United States

BACKGROUND

American Heart Association/American Stroke Association guidelines recommend endovascular stroke therapy (EST) with recombinant tissue plasminogen activator (rt-PA) for eligible patients in acute ischemic stroke (AIS). Using the National Inpatient Sample database, we evaluated trends in treatment with rt-PA and EST for AIS and their outcomes.

METHODS

This is a cross-sectional observational study of patients with AIS admitted in US hospitals from 2012 to 2016. Patients were grouped into those who received rt-PA alone, EST alone, and rtPA+EST. Survey statistical procedures were performed. Multivariable regression analysis with pairwise comparisons of each treatment group with no treatment group was performed for discharge outcomes.

RESULTS

The study included 2,290,520 patients with AIS with the mean age of 70.46 years. Treatment rates increased from 2012 to 2016 for rt-PA by 7% per year (5.86%-7.67%, odds ratio [OR] = 1.07, 95% confidence interval [CI]: 1.05-1.08) and EST by 38% per year (0.55%-1.75%, OR = 1.38, 95% CI: 1.31-1.45) but not rt-PA+EST (0.54%-0.57%, OR = 1.04, 95% CI: 0.99-1.08). The mean length of stay reduced from 2012 to 2016 for rt-PA (6.07-4.91 days, P < 0.0001) and rt-PA+EST (9.19-7.10 days, P = 0.0067) but not for EST (9.61-8.51 days, P = 0.5074). The odds of patients discharged home increased by 8%, 9%, and 15% among patients who received rt-PA alone, EST alone, and rt-PA+EST, respectively, compared with no treatment group.

CONCLUSION

The utilization of rt-PA alone and EST alone increased but that of rt-PA+EST remained unchanged from 2012 to 2016 in the National Inpatient Sample.

Abstract P310: Impact of COVID-19 Pandemic on Stroke Care at the University of Rochester Medical Center

Introduction: The impact of the COVID-19 pandemic response on medical care for stroke is unknown.

Methods: We used local “Get With The Guidelines” stroke data for patients with ischemic stroke (IS), transient ischemic attack (TIA), and intracerebral hemorrhage/subarachnoid hemorrhage (ICH/SAH) from March 20–April 14, 2020 (study period) and January 1–March 19, 2020 (control period #1) and March 20–April 14, 2019 (control period #2). We examined daily admission rates, transfers, tPA administration, thrombectomy, and time from last well to hospital arrival.

Results: There were 349 patients (n=40 study period, n=225 control period #1, n=84 control period #2); 263 with IS, 37 with TIA, and 49 with ICH/SAH. Overall, 46% were female, 82% white, with median age 70 years (IQR 58-82 years).

Daily admission rates were 1.4 IS/day for the study period compared to 2.1 IS/day (Incident rate ratio [IRR] 1.49 95% CI 1.05-2.13, p=0.027) and 2.2 IS/day (IRR 1.57 1.04-2.37, p=0.033) for control periods #1 and #2 ( Table ), respectively. There was only one admission for TIA in the study period compared to approximately one every 4 days in control period #1 (IRR 7.2 95% CI 1.0-53.7, p=0.053) and one every 2 days in control period #2 (IRR 14.0 95% CI 1.8-106.5, p=0.011). ICH/SAH admissions were fewer in the study period. Transfers were less common with approximately one transfer every four days in the study period compared to one each day of the control periods. Rates of tPA, thrombectomy, and time from last well to first hospital contact did not differ across the epochs.

Conclusions: Our data suggest the COVID-19 pandemic response has led to reduced admission volumes for all stroke types in the University of Rochester Medical Center catchment area, partly due to decreases in hospital transfers. These data raise the question whether fewer patients sought care for stroke symptoms at the height of the COVID-19 pandemic.

Proceedings from the Neurotherapeutics Symposium on Neurological Emergencies: Shaping the Future of Neurocritical Care

Effective treatment options for patients with life-threatening neurological disorders are limited. To address this unmet need, high-impact translational research is essential for the advancement and development of novel therapeutic approaches in neurocritical care. "The Neurotherapeutics Symposium 2019-Neurological Emergencies" conference, held in Rochester, New York, in June 2019, was designed to accelerate translation of neurocritical care research via transdisciplinary team science and diversity enhancement. Diversity excellence in the neuroscience workforce brings innovative and creative perspectives, and team science broadens the scientific approach by incorporating views from multiple stakeholders. Both are essential components needed to address complex scientific questions. Under represented minorities and women were involved in the organization of the conference and accounted for 30-40% of speakers, moderators, and attendees. Participants represented a diverse group of stakeholders committed to translational research. Topics discussed at the conference included acute ischemic and hemorrhagic strokes, neurogenic respiratory dysregulation, seizures and status epilepticus, brain telemetry, neuroprognostication, disorders of consciousness, and multimodal monitoring. In these proceedings, we summarize the topics covered at the conference and suggest the groundwork for future high-yield research in neurologic emergencies.

Prehospital time intervals and management of ischemic stroke patients

OBJECTIVE

Quantify prehospital time intervals, describe prehospital stroke management, and estimate potential time saved if certain procedures were performed en route to the emergency department (ED).

METHODS

Acute ischemic stroke patients who arrived via emergency medical services (EMS) between 2012 and 2016 were identified. We determined the following prehospital time intervals: chute, response, on-scene, transport, and total prehospital times. Proportions of patients receiving the following were determined: Cincinnati Prehospital Stroke Scale (CPSS) assessment, prenotification, glucose assessment, vascular access, and 12-lead electrocardiography (ECG). For glucose assessment, ECG acquisition, and vascular access, the location (on-scene vs. en route) in which they were performed was described. Difference in on-scene times among patients who had these three interventions performed on-scene vs. en route was assessed.

RESULTS

Data from 870 patients were analyzed. Median total prehospital time was 39 min and comprised the following: chute time: 1 min; response time: 9 min; on-scene time: 15 min; and transport time: 14 min. CPSS was assessed in 64.7% of patients and prenotification was provided for 52.0% of patients. Glucose assessment, vascular access initiation, and ECG acquisition was performed on 84.1%, 72.6%, and 67.2% of patients, respectively. 59.0% of glucose assessments, 51.2% of vascular access initiations, and 49.8% of ECGs were performed on-scene. On-scene time was 9 min shorter among patients who had glucose assessments, vascular access initiations, and ECG acquisitions all performed en route vs. on-scene.

CONCLUSIONS

On-scene time comprised 38.5% of total prehospital time. Limiting on-scene performance of glucose assessments, vascular access initiations, and ECG acquisitions may decrease prehospital time.

Abstract WP47: Combined Treatment of Rt-PA With Mechanical Thrombectomy is Associated With Better Outcome Than Mechanical Thrombectomy Alone and Possibly Underutilized - A National Inpatient Sample Study

Background and Purpose: 2015 AHA/ASA guidelines recommend mechanical thrombectomy (MT) with rt-PA for eligible patients within 6 hours of acute ischemic stroke (AIS). We evaluated the real world impact of the guidelines by analyzing trends and outcomes of stroke patients discharged from 2012 to 2016 in National Inpatient Sample database.

Methods: Patients discharged with primary diagnosis of AIS were identified with ICD-9 codes for 2012 to third quarter of 2015 and ICD-10 codes for 2016 and last quarter of 2015. Patients who received only rt-PA, only MT, rt-PA+MT or no treatment were analyzed for discharge outcomes including length of stay (LOS), inpatient mortality and discharge status to home. Survey procedures were used for analysis. Multivariable regression analysis with pairwise comparison of treatment groups with no treatment group was performed to evaluate outcomes controlling for risk factors and all patient refined DRG severity of illness and risk of mortality scores.

Results: A total of 2,290,520 adult AIS patients were in the study with mean age 70.4 years (SE 0.03) and 51.1% (SE 0.08) women. There was a significant increase in treatment with rt-PA (5.86% in 2012 to 7.67% in 2016, OR=1.07, 95% CI 1.05-1.08); and MT (0.55% in 2012 to 1.75% in 2016, OR=1.38, 95%CI 1.31-1.45); but not combination rt-PA+MT (0.54% in 2012 to 0.57% in 2016, OR=1.04, 95% CI 0.99 - 1.08). LOS was significantly reduced for rt-PA (mean 6.07 days in 2012 to 4.91 days in 2016, p<0.0001, 1.7 percent reduction/year), and rt-PA+MT (mean 9.19 days in 2012 to 7.10 days in 2016, p=0.0067, 2.9 percent reduction/year) but not for MT alone (9.61 days in 2012 to 8.51 days in 2016, p=0.50). The odds of patients discharged home was significantly higher by 8%, 9% and 15% among patients who received rt-PA (p<0.0001), MT (p=0.0095) and rt-PA+MT group (p=0.0004), respectively, compared to those who did not receive treatment. There was no significant change in inpatient mortality between the groups.

Conclusion: The utilization of MT increased but that of rt-PA+MT remained unchanged from 2012 to 2016. Patients with AIS have better LOS and discharge disposition to home when treated with rt-PA+MT than MT alone. Combined treatment of rt-PA with MT may be underutilized in clinical practice.

Common Data Elements for Unruptured Intracranial Aneurysms and Aneurysmal Subarachnoid Hemorrhage: Recommendations from the Working Group on Hospital Course and Acute Therapies-Proposal of a Multidisciplinary Research Group

INTRODUCTION

The Common Data Elements (CDEs) initiative is a National Institute of Health/National Institute of Neurological Disorders and Stroke (NINDS) effort to standardize naming, definitions, data coding, and data collection for observational studies and clinical trials in major neurological disorders. A working group of experts was established to provide recommendations for Unruptured Aneurysms and Aneurysmal Subarachnoid Hemorrhage (SAH) CDEs.

METHODS

This paper summarizes the recommendations of the Hospital Course and Acute Therapies after SAH working group. Consensus recommendations were developed by assessment of previously published CDEs for traumatic brain injury, stroke, and epilepsy. Unruptured aneurysm- and SAH-specific CDEs were also developed. CDEs were categorized into "core", "supplemental-highly recommended", "supplemental" and "exploratory".

RESULTS

We identified and developed CDEs for Hospital Course and Acute Therapies after SAH, which included: surgical and procedure interventions; rescue therapy for delayed cerebral ischemia (DCI); neurological complications (i.e. DCI; hydrocephalus; rebleeding; seizures); intensive care unit therapies; prior and concomitant medications; electroencephalography; invasive brain monitoring; medical complications (cardiac dysfunction; pulmonary edema); palliative comfort care and end of life issues; discharge status. The CDEs can be found at the NINDS Web site that provides standardized naming, and definitions for each element, and also case report form templates, based on the CDEs.

CONCLUSION

Most of the recommended Hospital Course and Acute Therapies CDEs have been newly developed. Adherence to these recommendations should facilitate data collection and data sharing in SAH research, which could improve the comparison of results across observational studies, clinical trials, and meta-analyses of individual patient data.

High Performance Na-O2 Batteries and Printed Microsupercapacitors Based on Water-Processable, Biomolecule-Assisted Anodic Graphene

Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g., adenosine monophosphate) as bifunctional agents for the electrochemical exfoliation and dispersion of graphene nanosheets in water. Acting both as exfoliating electrolytes and colloidal stabilizers, these biomolecules facilitated access to aqueous graphene bio-inks that could be readily processed into aerogels and inkjet-printed interdigitated patterns. Na-O₂ batteries assembled with the graphene-derived aerogels as the cathode and a glyme-based electrolyte exhibited a full discharge capacity of ∼3.8 mAh cm^-2 at a current density of 0.2 mA cm^-2. Moreover, shallow cycling experiments (0.5 mAh cm^-2) boasted a capacity retention of 94% after 50 cycles, which outperformed the cycle life of prior graphene-based cathodes for this type of battery. The positive effect of the nucleotide-adsorbed nanosheets on the battery performance is discussed and related to the presence of the phosphate group in these biomolecules. Microsupercapacitors made from the interdigitated graphene patterns as the electrodes also displayed a competitive performance, affording areal and volumetric energy densities of 0.03 μWh cm^-2 and 1.2 mWh cm^-3 at power densities of 0.003 mW cm^-2 and 0.1 W cm^-3, respectively. Taken together, by offering a green and straightforward route to different types of functional graphene-based materials, the present results are expected to ease the development of novel energy storage technologies that exploit the attractions of graphene.

Solvent exfoliation stabilizes TiS2 nanosheets against oxidation, facilitating lithium storage applications

Titanium disulfide is a promising material for a range of applications, including lithium-ion battery (LIB) anodes. However, its application potential has been severely hindered by the tendency of exfoliated TiS2 to rapidly oxidize under ambient conditions. Herein, we confirm that, although layered TiS2 powder can be exfoliated by sonication in aqueous surfactant solutions, the resultant nanosheets oxidise almost completely within hours. However, we find that upon performing the exfoliation in the solvent cyclohexyl-pyrrolidone (CHP), the oxidation is almost completely suppressed. TiS2 nanosheets dispersed in CHP and stored at 4 °C in an open atmosphere for 90 days remained up to 95% intact. In addition, CHP-exfoliated nanosheets did not show any evidence of oxidation for at least 30 days after being transformed into dry films even when stored under ambient conditions. This stability, probably a result of a residual CHP coating, allows TiS2 nanosheets to be deployed in applications. To demonstrate this, we prepared lithium ion battery anodes from nano : nano composites of TiS2 nanosheets mixed with carbon nanotubes. These anodes displayed reversible capacities (920 mA h g-1) close to the theoretical value and showed good rate performance and cycling capability.

Percolation Effects in Electrolytically Gated WS2/Graphene Nano:Nano Composites

Mixed networks of conducting and nonconducting nanoparticles show promise in a range of applications where fast charge transport is important. While the dependence of network conductivity on the loading level of conductive additive is well understood, little is known about the loading dependence of mobility and carrier density. This is particularly important as the addition of graphene might lead to increases in the mobility of semiconducting nanosheet network transistors. Here, we use electrolytic gating to investigate the transport properties of spray-coated composite networks of graphene and WS₂ nanosheets. As the graphene loading is increased, we find that both conductivity and carrier density increase in line with the percolation theory with percolation thresholds (∼8 vol %) and exponents (∼2.5) consistent with previous reporting. Perhaps surprisingly, we find the mobility increases modestly from ∼0.1 cm²/V s (for a WS₂ network) to ∼0.3 cm²/V s (for a graphene network) which we attribute to the similarity between WS₂-WS₂ and graphene-graphene junction resistances. In addition, we find both the transistor on- and off-currents to scale with loading according to the percolation theory, changing sharply at the percolation threshold. Through fitting, we show that only the current in the WS₂ network changes significantly upon gating. As a result, the on-off ratio falls sharply at the percolation threshold from ∼10⁴ to ∼2 at higher loading. Reflecting on these results, we conclude that the addition of graphene to a semiconducting network is not a viable strategy to improve transistor performance as it reduces the on:off ratio far more than it improves the mobility.

Abstract WP245: Demographics, Risk Factors and Outcomes of Stroke in Young Adults Aged 18-45 Years in Comparison With Those Older Than 45 Years

Introduction: The prevalence of stroke in young adults have increased with the prevalence of cerebrovascular risk factors in this population. The objective of this study was to compare stroke prevalence in age groups 18-45 years versus more than 45 years by demographics, risk factors, and outcome.

Methods: We analyzed the National Inpatient Sample Database from the Healthcare Cost and Utilization Project for the years 2008-14. Patients with stroke were identified based on discharge DRG codes 61-66 for acute ischemic stroke with use of thrombolytic therapy, intracranial hemorrhage or cerebral infarction. Demographics, risk factors from comorbid condition codes, and outcomes were analyzed.

Results: Out of a total of 3,624,243 adult patients with stroke hospitalized during the years 2008-14, 189103 (5.21%) hospitalizations were of patients aged 18-45 years. The ratio of stroke hospitalizations to overall hospitalizations increased from 154 to 185 per 10,000 hospitalizations from the year 2008 to 2014 with increase in stroke hospitalizations in both age groups. Stroke in young adults aged 18-45 years was more common in men, Blacks and Hispanics compared to those older than 45 years. Cerebrovascular risk factors were common in young adults with stroke and the prevalence of obesity, arterial malformation, tobacco use or alcohol abuse was higher in stroke patients aged 18-45 years compared to those older than 45 years (Table 1). There was up to 6% increase in the prevalence of cerebrovascular risk factors from 2008 to 2014. Young adults with stroke aged 18-45 years were more likely to be discharged home while older adults were more likely to be discharged to skilled nursing facility.

Conclusions: There are gender and racial differences in stroke among adults aged 18-45 years compared to those older than 45 years age. Modifiable cerebrovascular risk factors are common in young adults with stroke. Most notably, both obesity and smoking were particularly higher in younger patients.