Association of Brain Injury Biomarkers and Circulatory Shock Following Moderate-Severe Traumatic Brain Injury: A TRACK-TBI Study

INTRODUCTION

Early circulatory shock following traumatic brain injury (TBI) is a multifactorial process; however, the impact of brain injury biomarkers on the risk of shock has not been evaluated. We examined the association between neuronal injury biomarker levels and the development of circulatory shock following moderate-severe TBI.

METHODS

In this retrospective cohort study, we examined adults with moderate-severe TBI (Glasgow Coma Scale score <13) enrolled in the TRACK-TBI study, an 18-center prospective TBI cohort study. The exposures were day-1 levels of neuronal injury biomarkers (glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1 [UCH-L1], S100 calcium-binding protein B [S100B], neuron-specific enolase), and of an inflammatory biomarker (high-sensitivity C-reactive protein). The primary outcome was the development of circulatory shock, defined as cardiovascular Sequential Organ Failure Assessment Score ≥2 within 72 hours of admission. Association between day-1 biomarker levels and the development of circulatory shock was assessed with regression analysis.

RESULTS

The study included 392 subjects, with a mean age of 40 years; 314 (80%) were male and 165 (42%) developed circulatory shock. Median (interquartile range) day-1 levels of UCH-L1 (994.8 [518.7 to 1988.2] pg/mL vs. 548.1 [280.2 to 1151.9] pg/mL; P <0.0001) and S100B (0.47 μg/mL [0.25 to 0.88] vs. 0.27 [0.16 to 0.46] μg/mL; P <0.0001) were elevated in those who developed early circulatory shock compared with those who did not. In multivariable regression, there were associations between levels of both UCH-L1 (odds ratio, 1.63 [95% confidence interval, 1.25-2.12]; P <0.0005) and S100B (odds ratio, 1.73 [95% confidence interval 1.27-2.36]; P <0.0005) with the development of circulatory shock.

CONCLUSION

Neuronal injury biomarkers may provide the improved mechanistic understanding and possibly early identification of patients at risk for early circulatory shock following moderate-severe TBI.

Complications of Intravenous Tenecteplase Versus Alteplase for the Treatment of Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Prior systematic reviews have compared the efficacy of intravenous tenecteplase and alteplase in acute ischemic stroke, assigning their relative complications as a secondary objective. The objective of the present study is to determine whether the risk of treatment complications differs between patients treated with either agent.

METHODS

We performed a systematic review including interventional studies and prospective and retrospective, observational studies enrolling adult patients treated with intravenous tenecteplase for ischemic stroke (both comparative and noncomparative with alteplase). We searched MEDLINE, Embase, the Cochrane Library, Web of Science, and the www.

CLINICALTRIALS

gov registry from inception through June 3, 2022. The primary outcome was symptomatic intracranial hemorrhage, and secondary outcomes included any intracranial hemorrhage, angioedema, gastrointestinal hemorrhage, other extracranial hemorrhage, and mortality. We performed random effects meta-analyses where appropriate. Evidence was synthesized as relative risks, comparing risks in patients exposed to tenecteplase versus alteplase and absolute risks in patients treated with tenecteplase.

RESULTS

Of 2226 records identified, 25 full-text articles (reporting 26 studies of 7913 patients) were included. Sixteen studies included alteplase as a comparator, and 10 were noncomparative. The relative risk of symptomatic intracranial hemorrhage in patients treated with tenecteplase compared with alteplase in the 16 comparative studies was 0.89 ([95% CI, 0.65-1.23]; I2=0%). Among patients treated with low dose (<0.2 mg/kg; 4 studies), medium dose (0.2-0.39 mg/kg; 13 studies), and high dose (≥0.4 mg/kg; 3 studies) tenecteplase, the RRs of symptomatic intracranial hemorrhage were 0.78 ([95% CI, 0.22-2.82]; I2=0%), 0.77 ([95% CI, 0.53-1.14]; I2=0%), and 2.31 ([95% CI, 0.69-7.75]; I2=40%), respectively. The pooled risk of symptomatic intracranial hemorrhage in tenecteplase-treated patients, including comparative and noncomparative studies, was 0.99% ([95% CI, 0%-3.49%]; I2=0%, 7 studies), 1.69% ([95% CI, 1.14%-2.32%]; I2=1%, 23 studies), and 4.19% ([95% CI, 1.92%-7.11%]; I2=52%, 5 studies) within the low-, medium-, and high-dose groups. The risks of any intracranial hemorrhage, mortality, and other studied outcomes were comparable between the 2 agents.

CONCLUSIONS

Across medium- and low-dose tiers, the risks of complications were generally comparable between those treated with tenecteplase versus alteplase for acute ischemic stroke.

Abstract 13 A Randomized, Placebo-Controlled, Phase II Trial of Intravenous Allogeneic Umbilical Cord Blood Infusion for Adults with Ischemic Stroke

Introduction

Stroke is the fifth leading cause of death in the United States. Tissue plasminogen activator and mechanical thrombectomy are the only effective treatments, but many patients are ineligible for these treatments.

Objective

The objective of this study was to determine whether an intravenous infusion of a non-HLA matched, unrelated donor umbilical cord blood (UCB) would improve functional outcomes.

Methods

We conducted a phase II multicenter, randomized (2:1), placebo controlled, double-blinded trial of UCB in adults with acute ischemic stroke. Patients had to have adequate immune function. Cord blood units were selected from U.S. public cord banks based on blood type, race, and cell dose. Study product was infused 3-10 days post stroke. Participants were randomized within strata of National Institutes of Health Stroke Scale Score (NIHSS) (&lt;12 vs ≥12), and study center. The primary endpoint was change in Modified Rankin Scale (mRS) (baseline minus day 90). The study was powered at 80% (odds ratio of 2). Key secondary outcomes included functional independence at day 90 (mRS &lt;2), NIHSS, the Barthel Index, infusion reactions, and adverse events.

Results

Seventy-nine participants were enrolled at 6 centers when the trial was closed early due to slow accrual related to COVID19; 73 participants (47 randomized to UCB) were included in the safety and efficacy analyses. The median (range) of the change in mRS was 1 (–2, 3) in UCB and 1 (–1, 4) in placebo. A shift analysis based on the proportional odds model showed an odds ratio of 0.9 (95% CI: 0.4, 2.3) after adjustment for baseline mRS and randomization strata. No differences were observed on the key secondary outcomes. There were 17 mild infusion reactions (27.6% UCB; 15.4% placebo). The distribution of serious and non-serious adverse events was similar between arms.

Discussion

This study demonstrated the safety of infusing non-HLA matched UCB to adults with acute ischemic stroke. Feasibility and logistics were challenging. The primary efficacy endpoint did not demonstrate benefit in this underpowered sample size. In a secondary ad hoc analysis, a trend of improved functional outcomes at day 90 in recipients of UCB more than 5 days post stroke (Figure 1) could be explored in future trials.

Tolerability and Pharmacokinetics of Single Escalating and Repeated Doses of CN-105 in Healthy Participants

PURPOSE

CN-105 is an IV, apolipoprotein E-mimetic pentapeptide. Preclinical studies have reported that CN-105 effectively down-regulates neuroinflammatory responses in microglia and mitigates neuronal excitotoxicity following acute brain injury. The CN-105 Phase I and II trials that have been done in the United States have demonstrated that CN-105 was well tolerated in US participants. Thus, the main objective of the present Phase I study was to investigate the tolerability and pharmacokinetic (PK) profiles of CN-105 in healthy Chinese participants.

METHODS

This randomized, double-blind, placebo-controlled, dose-escalation study was performed in healthy participants using sequential 30-minute IV administration of single and multiple doses of CN-105 (four times daily for 13 doses). Forty volunteers were randomly assigned, in an 8:2 ratio, to one of four dosing groups, receiving either CN-105 (0.03, 0.1, 0.3, or 1 mg/kg), or placebo. Serial blood samples were collected for the measurement of plasma concentrations of CN-105. Tolerability was also assessed.

FINDINGS

After single-dose administration, the plasma CN-105 concentration rapidly reached the peak by the end of infusion. The mean elimination half-life of CN-105 ranged from 2.3 to 3.6 hours. During single- and multiple-dosing paradigms, exposure to CN-105 (AUC) exhibited linear dependency on dose. Steady state was reached by the fourth dose, with minimal accumulation. The PK properties of CN-105 with single and multiple dosing were comparable to those observed in US participants. CN-105 was generally well tolerated in Chinese participants. A total of 13 adverse events were reported in 30% of subjects (12/40) at the 0.03 mg/kg (6/8), 0.1 mg/kg (1/8), 0.3 mg/kg (2/8), 1 mg/kg (0/8) doses and with placebo (3/8). All adverse events were mild or moderate in severity and self-limited, with no dose relationship observed.

IMPLICATIONS

CN-105 was well tolerated in these healthy Chinese participants at doses of 0.1 to 1 mg/kg with single and multiple IV administrations. The PK characteristics of CN-105 were comparable among Chinese and Western subjects. A Phase II study in patients with intracranial hemorrhage is being planned in China.

CLINICALTRIALS

gov identifiers: NCT02670824 and NCT03168581; Chinese Clinical Trial Registration identifier: CTR20202397.

Epidemiology and Outcomes of Acute Respiratory Distress Syndrome Following Isolated Severe Traumatic Brain Injury

Patients with traumatic brain injury (TBI) are at risk for extra-cranial complications, such as the acute respiratory distress syndrome (ARDS). We conducted an analysis of risk factors, mortality, and healthcare utilization associated with ARDS following isolated severe TBI. The National Trauma Data Bank (NTDB) dataset files from 2007-2014 were used to identify adult patients who suffered isolated [other body region-specific Abbreviated Injury Scale (AIS) < 3] severe TBI [admission total Glasgow Coma Scale (GCS) from 3 to 8 and head region-specific AIS >3]. In-hospital mortality was compared between patients who developed ARDS and those who did not. Utilization of healthcare resources (ICU length of stay, hospital length of stay, duration of mechanical ventilation, and frequency of tracheostomy and gastrostomy tube placement) was also examined. This retrospective cohort study included 38,213 patients with an overall ARDS occurrence of 7.5%. Younger age, admission tachycardia, pre-existing vascular and respiratory diseases, and pneumonia were associated with the development of ARDS. Compared to patients without ARDS, patients that developed ARDS experienced increased in-hospital mortality (OR 1.13, 95% CI 1.01-1.26), length of stay (p = <0.001), duration of mechanical ventilation (p = < 0.001), and placement of tracheostomy (OR 2.70, 95% CI 2.34-3.13) and gastrostomy (OR 2.42, 95% CI 2.06-2.84). After isolated severe TBI, ARDS is associated with increased mortality and healthcare utilization. Future studies should focus on both prevention and management strategies specific to TBI-associated ARDS.

Bone marrow T cell sequestration as a novel mode of CNS immune privilege

The central nervous system (CNS), although a site of relative immune “privilege,” is continuously monitored by immune cells. The CNS must possess means for limiting excess inflammation that can otherwise cause irreparable damage or death. Recently, we characterized a unique mode of cancer-induced immunosuppression whereby T cells become sequestered in high numbers in the bone marrow (BM) of humans and mice with intracranial tumors. Sequestration of T cells is mediated in part by the loss of sphingosine-1-phosphate receptor 1 (S1P1) from the T cell surface. Interestingly, this phenomenon occurs only when tumors are located intracranially, but not peripherally. This suggests that sequestration is not mediated by brain tumors themselves, but instead represents tumors usurping of a novel mechanism for CNS immune privilege designed to limit T-cell access to the CNS. Consequently, we investigated whether BM T cell sequestration occurs in other CNS disorders, such as stroke. In a murine model of stroke, immune alterations recapitulated those observed in intracranial tumors. These changes include severe but transient lymphopenia, lymphoid organ shrinkage, and BM T cell sequestration. As with intracranial tumors, BM T cell sequestration was mediated by loss of surface S1P1 on T cells. A mechanistic understanding of CNS-driven BM T cell sequestration will enable the development of novel therapeutics to limit neuroinflammation and damage in the context of CNS pathologies.

Speckle Tracking Analysis of Left Ventricular Systolic Function Following Traumatic Brain Injury: A Pilot Prospective Observational Cohort Study

BACKGROUND

Systolic dysfunction and reduction in left ventricular ejection fraction (LVEF) has been documented after traumatic brain injury (TBI). Speckle tracking is an emerging technology for myocardial strain assessment which has been utilized to identify subclinical myocardial dysfunction, and is most commonly reported as global longitudinal strain (GLS). We examined myocardial strain and regional strain patterns following moderate-severe TBI.

MATERIALS AND METHODS

We conducted a prospective cohort study of moderate-severe TBI patients (Glasgow Coma Scale≤12) and age/sex-matched controls. Transthoracic echocardiography was performed within the first day and 1 week following TBI. Myocardial function was assessed using both GLS and LVEF, and impaired systolic function was defined as GLS >-16% or LVEF ≤50%. Regional strain patterns and individual strain trajectories were examined.

RESULTS

Thirty subjects were included, 15 patients with TBI and 15 age/sex-matched controls. Among patients with adequate echocardiographic windows, systolic dysfunction was observed in 2 (17%) patients using LVEF and 5 (38%) patients using GLS within the first day after TBI. Mean GLS was impaired in patients with TBI compared with controls (-16.4±3.8% vs. -20.7±1.8%, P=0.001). Regional myocardial examination revealed impaired strain primarily in the basal and mid-ventricular segments. There was no improvement in GLS from day 1 to day 7 (P=0.81).

CONCLUSIONS

Myocardial strain abnormalities are common and persist for at least 1 week following moderate-severe TBI. Speckle tracking may be useful for the early diagnosis and monitoring of systolic dysfunction following TBI.

Lymphopenia and bone marrow T cell sequestration accompanying stroke are mediated by T cell S1P1 loss

Sequestration of T cells in bone marrow is a phenomenon recently characterized by our group in the setting of intracranial tumors, regardless of histology. It is accompanied by lymphopenia and lymphoid organ regression and is mediated by loss of S1P1 receptor from the T cell surface. We now reveal that this phenomenon is not unique to tumors, but accompanies additional intracranial pathologies, most notably stroke. In this study, blood, bone marrow, and spleens were collected from mice at day 2, 5, 7 or 14 following stroke via middle cerebral artery occlusion (MCAO) or sham surgery and analyzed by flow cytometry. T cell S1P1 levels were assessed, as were T cell counts in each compartment. S1P1 receptor stabilization was achieved with a knock-in model in which receptor internalization is inhibited. Following stroke, T cells accumulated in the bone marrow of injured mice. T cell numbers peaked at day 7 post-stroke before returning to normal by day 14. Bone marrow accumulation was accompanied by transient lymphopenia and splenic involution following stroke. T cells in the bone marrow yielded decreased levels of S1P1 on their surface. Conversely, mice with genetically stabilized T cell S1P1 protected against sequestration, lymphopenia, and splenic regression following stroke. In conclusion, bone marrow T cell sequestration occurs transiently following stroke and is mediated by the S1P-S1P1 axis. This may be prove an adaptive mechanism to limit intracranial inflammation following an initial insult. Better understanding of this phenomenon may uncover a novel mechanism of immune privilege and allow for therapeutic modulation in the setting of stroke, brain tumor, and other types of intracranial injury.

Abstract WP372: International Comparison of Patient Characteristics and Quality of Care for Ischemic Stroke

Background and Purpose: Adherence to evidence-based guidelines is an important indicator of hospital stroke care quality; yet, there is lack of assessment of patient characteristics and performance measures in acute ischemic stroke for most world regions.

Methods: We analyzed data of 19,604 acute ischemic stroke patients in China National Stroke Registry and 194,876 patients in GWTG-Stroke registry in US between 2012 to 2013 and compare their baseline characteristics and hospital performance measures.

Results: Compared with US, Chinese patients were younger and had lower prevalence of comorbidities except for history of stroke/TIA or smoking. NIHSS was similar (China vs. US: median 4 [IQR 2-7] vs. 4 [1-10]). Chinese patients were more likely to have delays from last-known-well to hospital arrival (median 1,318 minutes [330-3,209] vs. 644 [142-2,055]), less likely to receive thrombolytic therapy (2.5% vs. 8.1%), and were more likely to experience treatment delays (door-to-needle time 95 minutes [72-112] vs. 62 [49-85]). Adherence to early and discharge antithrombotics, smoking cessation counseling, and dysphagia screening were relatively high (e.g.>80%) in both countries. However, large gaps existed in administration of intravenous thrombolytics within 3 hours (18.3% vs. 83.6%), door-to-needle time ≤60 minutes (14.6% vs. 48.0%), deep vein thrombosis prophylaxis (65.0% vs. 97.8%), anticoagulation for atrial fibrillation (21.0% vs. 94.4%), lipid treatment for low-density lipoprotein > 100 mg/dL (66.3% vs. 95.8%), and rehabilitation assessment (58.8% vs. 97.4%). Door-to-CT ≤25 minutes was relatively low in both countries (26.4% vs. 27.9%).

Conclusions: We found significant differences in clinical characteristics and gaps in adherence for certain performance measures between China and US. Additional efforts are needed for continued improvements in acute stroke care and secondary prevention in both nations, especially China.

The Effect of the Relationship of APOE Polymorphisms and Cerebral Vasospasm on Functional Outcomes in Children With Traumatic Brain Injury

BACKGROUND

Pediatric traumatic brain injury (TBI) is a leading cause of death and disability. Polymorphisms in the apolipoprotein E ( APOE) gene have been linked to cerebral vasospasm (CV) and poor outcomes in adults with TBI, yet these associations remain poorly defined in children.

OBJECTIVE

We examined the effect of the relationship between APOE polymorphisms and CV on functional outcomes in children with a TBI.

METHOD

This prospective, descriptive study examined 60 children (aged 10 days to 15 years) with a TBI. Data included demographic information, genetic sampling for the APOE gene and single-nucleotide polymorphisms (SNPs; rs405509, rs429358, rs7412), and daily transcranial Doppler ultrasounds to evaluate for CV. We examined Glasgow Outcome Scale-Extended Pediatrics (GOS-E Peds) scores at the time of discharge and 4-6 weeks after discharge.

RESULTS

More than half (56.7%) of the 60 children ( M_age = 5.9 years) were male. Twenty-six participants (43.3%) experienced an occurrence of CV. There were significant differences in injury mechanism (unadjusted p = .048) and age (unadjusted p = .02) between those with and without CV. Also, the noncoding promoter SNP rs405509 T/T, when considered with injury severity, appeared to modify the relationship of APOE genotype to CV. The relationship between APOE and CV had no significant effect on GOS-E Peds scores.

CONCLUSION

Injury severity and the APOE noncoding promoter SNP rs405509 may modify the relationship between APOE and CV in children with TBI. More studies are needed to understand the role of APOE polymorphisms in outcomes in children with TBI.

Abstract TP102: Apolipoprotein E Mimetic Pentapeptide (CN 105) Improves Outcome in a Murine Model of Ischemic Stroke

Introduction: Apolipoprotein E (apoE) is an endogenous brain protein synthesized in response to brain injury and modifies neuroinflammatory responses by downregulating glial activation and release of inflammatory mediators. Due to its size, however, the intact apoE holoprotein does not cross the blood brain barrier, and thus has limited therapeutic potential. We have demonstrated that a small 5 amino acid apoE-mimetic peptide (CN-105) derived from the receptor-binding region of apoE retains the neuroprotective effects of the intact holoprotein, is well tolerated, and effectively crosses the blood brain barrier. This study investigates whether CN105 improves functional and histological outcomes in a murine model of transient focal ischemia and reperfusion.

Methods: We used the transient middle cerebral artery occlusion murine model of ischemic stroke for all our experiments. Thirty-minutes ischemic occlusion time was used for infarct volume and survival analysis at 72 hours while 15 minutes ischemic occlusion time was used for functional outcome analysis performed 7 days post stroke. A dose of CN-105 (0.1mg/kg) in 100 μl volume was administered as a single dose 30 minutes post-perfusion via tail vein injection. Motor-sensory functional outcomes were evaluated using daily rotarod assessment for 7 days and 4-limb wire hanging test on days 2 and 7 days post injury. Infarct volume was evaluated using 2,3,5-Triphenyltetrazolium chloride staining method. Independent t-test was used for infarct volume analysis, repeated measures ANOVA was used for functional outcomes evaluation and log-rank test was used for survival evaluation. Experiments were performed in a randomized and blinded fashion.

Results: Administration of CN-105 improved motor and sensory functional outcomes at 7 days in rotarod (p = 0.035) and 4-limb wire hanging test (p=0.013) when compared to vehicle. There was also a survival benefit (n = 8 (66.7%) vs n = 3 (25%), p=0.037) and a significant reduction of infarct volumes (79 ± 43 mm 3 ) compared to vehicle (127 ± 31 mm 3 ) (p = 0.039) at 72 hours.

Conclusion: Intravenous administration of CN-105 is associated with functional, survival, and histological benefits in a murine ischemic stroke model when given at 30 minutes post-reperfusion.

Multicenter cohort study on association of genotypes with prospective sports concussion: methods, lessons learned, and recommendations

BACKGROUND

Approximately 3.8 million sports related TBIs occur per year. Genetic variation may affect both TBI risk and post-TBI clinical outcome. Limited research has focused on genetic risk for concussion among athletes. We describe the design, methods, and baseline characteristics of this prospective cohort study designed to investigate a potential association between genetic polymorphisms of apolipoprotein E gene, APOE promoter G-219T, and Tau gene exon 6 polymorphisms (Ser53 Pro and Hist47Tyr) with: 1) the risk of prospective concussion; 2) concussion severity; and 3) postconcussion neurocognitive recovery.

METHODS

The prospective cohort study included a final population of 2947 college, high school, and professional athletes. Baseline data collection included a concussion/medical history questionnaire, neuropsychological (NP) testing, and genetic sampling for the genetic polymorphisms. Data collection on new concussions experienced utilized post-concussion history/mental status form, Lovell post-concussion symptom score, Standardized Assessment of Concussion (SAC) and/or the Sports Concussion Assessment Tool (SCAT)-1/SCAT-2, and post-concussion NP testing.

RESULTS

This paper is focused on discussing the important methodological considerations, organizational challenges and lessons learned in the completion of a multi-center prospective cohort study. A total of 3740 subjects enrolled, with a total of 335 concussions experienced.

CONCLUSIONS

Of critical importance to the success of a study of this type is to successfully recruit committed institutions with qualified local study personnel, obtain "buy-in" from study sites, and cultivate strong working relationships with study sites. The use of approved incentives may improve study site recruitment, enhance retention, and enhance compliance with study protocols. Future publications will detail the specific findings of this study. Collaborative research is very likely needed given the nature of this study population.

Abstract 276: Asymmetric Dimethylarginine Is A Potential Risk Factor For Transient Ischemic Attack

Objective: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase which has been shown to be involved in the pathogens of atherosclerosis. Vascular endothelial growth factor (VEGF) is apleiotropic growth factor involved in neurovascular remodeling in the cerebral ischemia disease. ADMA has been validated to be a risk marker of stroke and transient ischemic attack (TIA). VEGF has been demonstrated associated with risk of stroke. This pilot study aimed to verify the correlation between serum ADMA, VEGF levels and ABCD2 score which has been validated to predict short term risk of stroke following transient ischemic attack (TIA).

Methods: TIA was defined as a transient episode of neurologic dysfunction caused by focal brain, spinal cord or retinal ischemia, without acute infarction even the focal transient neurologic symptoms last less than one hour. We enrolled 40 TIAs and 40 healthy controls in Peking University Third Hospital Neurology wards and clinics since May to July 2013. The TIA diagnosis and ABCD2 score evaluation is conducted by the same neurology physician. The mean age of TIAs and controls was 61.9±12.9yrs and 63.4±10.9yrs respectively (P=0.544). Blood samples were drawn within 24 hours after the TIA diagnosis clarified. ADMA and VEGF levels were measured by ELISA.

Result: The ADMA levels in TIAs and control group are 0.52±0.06mmol/L and 0.23±0.04mmol/L (t=24.14, P<0.01). The VEGF levels in TIAs and control group are 272.01±26.36mmol/L and 148.87±21.05mmol/L (t=24.65, P<0.01). In the non-stroke history TIAs (23 cases) sub-group the spearman correlation coefficient between ADMA and ABCD2 score is 0.6(P=0.002).

Conclusion: ADMA and VEGF are absolutely increased in TIAs. There is no correlation between ADMA, VEGF, age, sex, blood pressure, glucose and ABCD2 in this small sample size population. But ADMA is probably associated with risk of TIA with no-stroke history. Thus, these findings reveal a possibly new challenging potential of the ADMA and VEGF role in the pathogenesis of TIA.

Cardiovascular manifestations of neurologic disease

Cardiac manifestations of neurologic diseases are common in clinical practice. There are numerous anatomic and pathophysiologic links between the normal and abnormal function of both systems. There are a number of brain-heart interactions which affect the care of patients as well as help guide therapeutic development. This is exemplified in the area of vascular neurology where knowledge of the brain-heart connection is essential not only for bedside management but where collaborative efforts between neurology and cardiology are key in developing new strategies for ischemic stroke prevention and treatment, atrial fibrillation, and interventional techniques. This chapter will focus on cardiac manifestations of neurologic disease, with special emphasis on vascular and intensive care neurology, epilepsy, and neurodegenerative and peripheral nervous system diseases.

Abstract 234: Prior Warfarin Treatment and Intracranial Hemorrhage among Patients With Acute Ischemic Stroke Treated With Intravenous Tissue Plasminogen Activator: A Meta-analysis

Background and Purpose: The risk for bleeding complications after intravenous thrombolysis for ischemic stroke in patients on warfarin with international normalized ratio [INR] ≤1.7) remains unclear. The aim of the current study is to perform a meta-analysis to determine whether there is an association between warfarin and risk of symptomatic intracranial hemorrhage (sICH).

Methods: We searched MEDLINE, Web of Science and EBSCO databases for articles published through Jul 2012. A random-effects model was used to compute the pooled risk estimate.

Results: Overall, 11 observational studies were identified that met our study inclusion criteria. This included 29,283 stroke participants treated with tPA; of which 2129 (7.3%) patients were on home warfarin prior treatment. Warfarin pretreatment was associated with an increased crude OR for symptomatic intracranial hemorrhage (sICH) (combined OR=1.77; 95% CI, 1.07~2.93;P=0.03).Of these studies, 7 studies had conducted a multivariate adjusted analyses, which demonstrated no association between warfarin use and increased risk of sICH following tPA use (combined adjusted OR=1.73; 95% CI, 0.91-3.28; p=0.10).

Conclusions: These data suggested that the risk of sICH after thrombolytic therapy is not increased in patients using warfarin with sub therapeutic INR levels.

Stroke after primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction: timing, characteristics, and clinical outcomes

BACKGROUND

Stroke is a rare but potentially devastating complication of acute myocardial infarction. Little is known about stroke timing, characteristics, and clinical outcomes in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We studied 5372 patients enrolled in the Assessment of Pexelizumab in Acute Myocardial Infarction (APEX-AMI) trial. We analyzed stroke incidence, type, timing, and association with the prespecified 90-day clinical outcomes. Cox proportional hazards modeling was performed to assess the relationship between stroke and outcomes, after adjusting baseline characteristics and analyzing stroke as a time-dependent covariate. Stroke occurred in 69 primary patients with PCI (1.3%). A third of strokes were ischemic (n=23; 33%), 12% (n=8) were hemorrhagic, and the remaining 55% (n=38) were of uncertain type. The median (25th, 75th percentile) time of stroke occurrence was 6 (3, 14) days. Overall, 43% of strokes occurred within 48 hours of PCI, and all hemorrhagic strokes occurred within 48 hours. Stroke was associated with an increased risk of 90-day death (unadjusted hazard ratio [HR], 8.0; 95% confidence interval [CI], 4.8-13.5), congestive heart failure (unadjusted HR, 3.2; 95% CI, 1.3-7.8), and 30-day hospital readmission (unadjusted HR, 3.2; 95% CI, 2.0-5.1). After adjustment, stroke was still strongly associated with 90-day death (adjusted HR, 5.6; 95% CI, 3.2-9.8) and the combination end point of death, congestive heart failure, or cardiogenic shock at 90 days (adjusted HR, 2.4; 95% CI, 1.2-4.7).

CONCLUSIONS

Stroke is an infrequent complication in the setting of ST-segment elevation myocardial infarction treated with primary PCI but is associated with increased morbidity and mortality. Studies to determine mechanisms that may be responsible for strokes that occur >48 hours from primary PCI are warranted.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00091637.

NIH Roundtable on Opportunities to Advance Research on Neurologic and Psychiatric Emergencies

STUDY OBJECTIVE

The Institute of Medicine Committee on the Future of Emergency Care in the United States Health System (2003) identified a need to enhance the research base for emergency care. As a result, a National Institutes of Health (NIH) Task Force on Research in Emergency Medicine was formed to enhance NIH support for emergency care research. Members of the NIH Task Force and academic leaders in emergency care participated in 3 Roundtable discussions to prioritize current opportunities for enhancing and conducting emergency care research. We identify key research questions essential to advancing the science of emergency care and discuss the barriers and strategies to advance research by exploring the collaboration between NIH and the emergency care community.

METHODS

Experts from emergency medicine, neurology, psychiatry, and public health assembled to review critical areas in need of investigation, current gaps in knowledge, barriers, and opportunities. Neurologic emergencies included cerebral resuscitation, pain, stroke, syncope, traumatic brain injury, and pregnancy. Mental health topics included suicide, agitation and delirium, substances, posttraumatic stress, violence, and bereavement.

RESULTS

Presentations and group discussion firmly established the need for translational research to bring basic science concepts into the clinical arena. A coordinated continuum of the health care system that ensures rapid identification and stabilization and extends through discharge is necessary to maximize overall patient outcomes. There is a paucity of well-designed, focused research on diagnostic testing, clinical decisionmaking, and treatments in the emergency setting. Barriers include the limited number of experienced researchers in emergency medicine, limited dedicated research funding, and difficulties of conducting research in chaotic emergency environments stressed by crowding and limited resources. Several themes emerged during the course of the roundtable discussion, including the need for development of (1) a research infrastructure for the rapid identification, consent, and tracking of research subjects that incorporates innovative informatics technologies, essential for future research; (2) diagnostic strategies and tools necessary to understand key populations and the process of medical decisionmaking, including the investigation of the pathobiology of symptoms and symptom-oriented therapies; (3) collaborative research networks to provide unique opportunities to form partnerships, leverage patient cohorts and clinical and financial resources, and share data; (4) formal research training programs integral for creating new knowledge and advancing the science and practice of emergency medicine; and (5) recognition that emergency care is part of an integrated system from emergency medical services dispatch to discharge. The NIH Roundtable "Opportunities to Advance Research on Neurological and Psychiatric Emergencies" created a framework to guide future emergency medicine-based research initiatives.

CONCLUSION

Emergency departments provide the portal of access to the health care system for most patients with acute neurologic and psychiatric illness. Emergency physicians and colleagues are primed to investigate neurologic and psychiatric emergencies that will directly improve the delivery of care and patient outcomes.

Apolipoprotein E protects against oxidative stress in mixed neuronal-glial cell cultures by reducing glutamate toxicity

Apolipoprotein E (ApoE) deficiency has been shown to adversely affect outcome after transient cerebral ischemia and head trauma. Since oxidative stress contributes to these injuries, the ability of ApoE to reduce irreversible oxidative damage was studied in primary mixed neuronal-glial cell cultures. Cells (13-16 days in vitro) were exposed to 50 microM hydrogen peroxide (H2O2) for 30 min, and toxicity was determined by the release of lactate dehydrogenase (LDH) 24 h after exposure. The presence of recombinant human ApoE2 (100, 300, or 1000 nM) in the culture media partially protected against oxidative injury. This protection was not reversed by pre-treatment with receptor associated protein. The NMDA receptor antagonist, MK-801, also provided partial protection against H2O2 toxicity. The degree of protection was similar to that conferred by ApoE treatment. The protective effects of ApoE and MK-801 were not additive; no ApoE protection was observed in cultures treated with MK-801 prior to H2O2 exposure. ApoE treatment had no effect on H2O2 stimulated glutamate release, but did increase the rate of glutamate uptake via the high affinity glutamate transporter in H2O2 treated cultures. Pre-treatment with ApoE also conferred partial protection against glutamate-induced LDH release. Taken together, these findings suggest that ApoE protects mixed neuronal-glial cell cultures against irreversible oxidative injury from H2O2 by reducing secondary glutamate excitotoxicity.

Acute visual loss and other disorders of the eyes

This article outlines neuro-ophthalmic findings and diseases which may present in an emergency setting. The abnormal optic disc, visual loss, double-vision and disorders of gaze, skew deviation, and the neuro-ophthalmology of vascular lesions, intracerebral hemorrhage, increased intracranial pressure, neuromuscular emergencies, metabolic disturbances, and trauma are all reviewed.

Magnetic resonance imaging of the cauda equina in Guillain-Barré syndrome

We report three patients (two children and one adult) with Guillain-Barré syndrome and magnetic resonance imaging evidence of gadolinium enhancement of the cauda equina and lumbar nerve roots. All three patients exhibited symmetric ascending paralysis and areflexia, and two (one child, one adult) suffered urinary incontinence and retention. Similar enhancement has been observed in patients with chronic inflammatory demyelinating polyneuropathy and suggests proximal nerve inflammation. Magnetic resonance imaging in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy may have diagnostic utility.

In vivo stereological assessment of human cerebellar volume: effects of gender and age

Intermediate T2-weighted MR images and a systematic sampling stereological method were used in 37 normal volunteers, 24 to 79 years old, to assess the effects of age and sex on cerebellar volume. Female subjects (n = 21) had significantly smaller cerebellar volumes compared with males (n = 16) of similar age (t = -3.9, p less than .0008, two-tail t test). Using straight-line, univariate regression, we determined that age was not a significant predictor of cerebellar volume (R2 = 0.07, t = -1.66, p = 0.11), whereas gender did appear to account for a significant amount of variability in cerebellar volume (R2 = 0.33, t = -4.13, p = .0002). The mean absolute cerebellar volume in this study was 112 ml (SD +/- 16) for all subjects, 104 ml (SD +/- 10) for females, and 122 ml (SD +/- 16) for males. This study demonstrates the feasibility of using MR images along with a systematic stereological method to assess in vivo human cerebellar volume, thereby providing a research tool to correlate cerebellar morphology with cognitive and neuromotor function.