Systems-level computational modeling in ischemic stroke: from cells to patients

Ischemic stroke, a significant threat to human life and health, refers to a class of conditions where brain tissue damage is induced following decreased cerebral blood flow. The incidence of ischemic stroke has been steadily increasing globally, and its disease mechanisms are highly complex and involve a multitude of biological mechanisms at various scales from genes all the way to the human body system that can affect the stroke onset, progression, treatment, and prognosis. To complement conventional experimental research methods, computational systems biology modeling can integrate and describe the pathogenic mechanisms of ischemic stroke across multiple biological scales and help identify emergent modulatory principles that drive disease progression and recovery. In addition, by running virtual experiments and trials in computers, these models can efficiently predict and evaluate outcomes of different treatment methods and thereby assist clinical decision-making. In this review, we summarize the current research and application of systems-level computational modeling in the field of ischemic stroke from the multiscale mechanism-based, physics-based and omics-based perspectives and discuss how modeling-driven research frameworks can deliver insights for future stroke research and drug development.

Canadian Stroke Best Practice Recommendations: Acute Stroke Management, 7th Edition Practice Guidelines Update, 2022

The 2022 update of the Canadian Stroke Best Practice Recommendations (CSBPR) for Acute Stroke Management, 7th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by an interdisciplinary team of healthcare providers and system planners caring for persons with an acute stroke or transient ischemic attack. These recommendations are a timely opportunity to reassess current processes to ensure efficient access to acute stroke diagnostics, treatments, and management strategies, proven to reduce mortality and morbidity. The topics covered include prehospital care, emergency department care, intravenous thrombolysis and endovascular thrombectomy (EVT), prevention and management of inhospital complications, vascular risk factor reduction, early rehabilitation, and end-of-life care. These recommendations pertain primarily to an acute ischemic vascular event. Notable changes in the 7th edition include recommendations pertaining the use of tenecteplase, thrombolysis as a bridging therapy prior to mechanical thrombectomy, dual antiplatelet therapy for stroke prevention, the management of symptomatic intracerebral hemorrhage following thrombolysis, acute stroke imaging, care of patients undergoing EVT, medical assistance in dying, and virtual stroke care. An explicit effort was made to address sex and gender differences wherever possible. The theme of the 7th edition of the CSBPR is building connections to optimize individual outcomes, recognizing that many people who present with acute stroke often also have multiple comorbid conditions, are medically more complex, and require a coordinated interdisciplinary approach for optimal recovery. Additional materials to support timely implementation and quality monitoring of these recommendations are available at www.strokebestpractices.ca.

Efficacy and safety of intravenous thrombolytic therapy in patients over eighty years

INTRODUCTION

Intravenous thrombolytic therapy (IVTT) is licensed for patients under 80 years in many countries. In this study, we aimed to demonstrate functional results and complication rates of IVTT in patients over eighty years and whether there is a difference in efficacy and safety between low dose and standard dose recombinant tissue plasminogen activator (rTPA).

METHODS

A retrospective observational study of patients over eighty who admitted to Suleyman Demirel University Faculty of Medicine Hospital between August 2016 and April 2021 and to Isparta City Hospital between April 2017 and April 2021 and diagnosed with acute ischemic stroke were conducted. Third month modified rankin scores (mRS) and mortality rates of patients and hemorrhagic transformations were determined.

RESULTS

There were 29 patients in IVTT group and 25 patients in non-IVTT group. By the third month, it was observed that functional independence (mRS 0-2) ratio was increased more in IVTT group, but it wasn't statistically significant (p: 0.087). In mortality and symptomatic intracerebral hemorrhage rates, there wasn't statistically significant difference between IVTT and non-IVTT groups and low dose and standard dose rTPA groups by the third month.

CONCLUSION

The efficacy and complication rates of IVTT in patients over 80 years were found similar to not receive IVTT. These results support the safety of IVTT in patients over 80 years. In low or standard dose rTPA preference, we observed that there was not statistically significance in efficacy and safety. We believe that these results will be supported by studies with larger number of patients.

The choroid plexus: a door between the blood and the brain for tissue-type plasminogen activator

Background

In the vascular compartment, the serine protease tissue-type plasminogen activator (tPA) promotes fibrinolysis, justifying its clinical use against vasculo-occlusive diseases. Accumulating evidence shows that circulating tPA (endogenous or exogenous) also controls brain physiopathological processes, like cerebrovascular reactivity, blood–brain barrier (BBB) homeostasis, inflammation and neuronal fate. Whether this occurs by direct actions on parenchymal cells and/or indirectly via barriers between the blood and the central nervous system (CNS) remains unclear. Here, we postulated that vascular tPA can reach the brain parenchyma via the blood-cerebrospinal fluid barrier (BCSFB), that relies on choroid plexus (CP) epithelial cells (CPECs).

Methods

We produced various reporter fusion proteins to track tPA in primary cultures of CPECs, in CP explants and in vivo in mice. We also investigated the mechanisms underlying tPA transport across the BCSFB, with pharmacological and molecular approaches.

Results

We first demonstrated that tPA can be internalized by CPECs in primary cultures and in ex vivo CPs explants. In vivo, tPA can also be internalized by CPECs both at their basal and apical sides. After intra-vascular administration, tPA can reach the cerebral spinal fluid (CSF) and the brain parenchyma. Further investigation allowed discovering that the transcytosis of tPA is mediated by Low-density-Lipoprotein Related Protein-1 (LRP1) expressed at the surface of CPECs and depends on the finger domain of tPA. Interestingly, albumin, which has a size comparable to that of tPA, does not normally cross the CPs, but switches to a transportable form when grafted to the finger domain of tPA.

Conclusions

These findings provide new insights on how vascular tPA can reach the brain parenchyma, and open therapeutic avenues for CNS disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00378-0.

Compartmentalized Actions of the Plasminogen Activator Inhibitors, PAI-1 and Nsp, in Ischemic Stroke

Tissue plasminogen activator (tPA) is a multifunctional protease. In blood tPA is best understood for its role in fibrinolysis, whereas in the brain tPA is reported to regulate blood-brain barrier (BBB) function and to promote neurodegeneration. Thrombolytic tPA is used for the treatment of ischemic stroke. However, its use is associated with an increased risk of hemorrhagic transformation. In blood the primary regulator of tPA activity is plasminogen activator inhibitor 1 (PAI-1), whereas in the brain, its primary inhibitor is thought to be neuroserpin (Nsp). In this study, we compare the effects of PAI-1 and Nsp deficiency in a mouse model of ischemic stroke and show that tPA has both beneficial and harmful effects that are differentially regulated by PAI-1 and Nsp. Following ischemic stroke Nsp deficiency in mice leads to larger strokes, increased BBB permeability, and increased spontaneous intracerebral hemorrhage. In contrast, PAI-1 deficiency results in smaller infarcts and increased cerebral blood flow recovery. Mechanistically, our data suggests that these differences are largely due to the compartmentalized action of PAI-1 and Nsp, with Nsp deficiency enhancing tPA activity in the CNS which increases BBB permeability and worsens stroke outcomes, while PAI-1 deficiency enhances fibrinolysis and improves recovery. Finally, we show that treatment with a combination therapy that enhances endogenous fibrinolysis by inhibiting PAI-1 with MDI-2268 and reduces BBB permeability by inhibiting tPA-mediated PDGFRα signaling with imatinib significantly reduces infarct size compared to vehicle-treated mice and to mice with either treatment alone.

Risk of selection bias assessment in the NINDS rt-PA stroke study

OBJECTIVES

The NINDS rt-PA Stroke Study is frequently cited in support of alteplase for acute ischemic stroke within 3 h of symptom onset. Multiple post-hoc reanalyses of this trial have been published to adjust for a baseline imbalance in stroke severity. We performed a risk of selection bias assessment and reanalyzed trial data to determine if the etiology of this baseline imbalance was more likely due to random chance or randomization errors.

METHODS

A risk of selection bias assessment was conducted using signaling questions from the Cochrane Risk of Bias 2 (ROB 2) tool. Four sensitivity analyses were conducted on the trial data based on the randomization process: assessment of imbalances in allocation in unique strata; adherence to a pre-specified restriction on randomization between time strata at each randomization center; assessment of differences in baseline computed tomography (CT) results in unique strata; and comparison of baseline characteristics between allocation groups within each time strata. A multivariable logistic regression model was used to compare reported treatment effects with revised treatment effects after adjustment of baseline imbalances identified in the sensitivity analyses.

RESULTS

Based on criteria from the ROB 2 tool, the risk of bias arising from the randomization process was high. Sensitivity analyses found 11 of 16 unique strata deviated from the expected 1:1 allocation ratio. Three randomization centers violated an apriori rule regarding a maximum difference in allocation between the time strata. Three unique strata had imbalances in baseline CT results that prognostically favored alteplase. Four imbalances in baseline characteristics were identified in the 91-180-min time stratum that all prognostically favored alteplase and were consistent with a larger alteplase treatment effect size compared to the 0-90-min time stratum. After adjustments for baseline imbalances, all reported treatment effects were reduced. Three out of seven originally positive reported results were revised to non-significant.

CONCLUSION

This risk of selection bias assessment revealed a high risk of selection bias in the NINDS rt-PA Stroke Study. Sensitivity analyses conducted based on the randomization process supported this assessment. Baseline imbalances in the trial were more likely due to randomization errors than random chance. Adjusted analyses accounting for baseline imbalances revealed a reduction in reported treatment effects supporting the presence of selection bias in the trial. Treatment decisions and guideline recommendations based on the original treatment effect reported in the NINDS rt-PA Stroke Study should be done cautiously.

Methodological survey of missing outcome data in an alteplase for ischemic stroke meta-analysis

OBJECTIVE

Recent national guidelines recommend alteplase treatment for ischemic stroke within 4.5 h of symptom-onset based on meta-analyses of randomized controlled clinical trials (RCT). A detailed description of missing outcome data (MOD) due to participant loss to follow-up has never been published. The objective of this study was to perform a methodlogical survey on missing outcome data in an alteplase for ischemic stroke meta-analysis.

MATERIALS AND METHODS

A methodological survey was performed on a chosen meta-analysis of alteplase for ischemic stroke RCTs that most closely aligns with recent national guideline recommendations. Data were collected to assess the number of participants lost to follow-up; differential lost to follow-up between allocation groups; baseline characteristics of those lost to follow-up; and the imputation methods used by individual trials and the chosen meta-analysis. The number of participants lost to follow-up was compared with the fragility index; and repeated for individually positive RCTs in the meta-analysis.

RESULTS

The methodological survey revealed a substantial degree of missing information regarding MOD in the chosen meta-analysis and in individual RCTs. Single imputation was exclusively used in all RCTs and in the meta-analysis. The number of participants lost to follow-up was greater than the fragility index in the chosen meta-analysis and individually positive component RCTs suggesting that MOD may impact the direction of the reported effect or effect size.

CONCLUSION

This methodological survey of an alteplase for ischemic stroke meta-analysis revealed MOD may be an important source of unrecognized bias. This survey highlights the need for sensitivity analyses using more robust methods of imputation.

Investigational drugs for ischemic stroke: what's in the clinical development pipeline for acute phase and prevention?

INTRODUCTION

Stroke is a leading cause of disability and mortality and its burden expected to increase. The only approved drug for acute ischemic stroke is the intravenous thrombolytic alteplase. The risk of bleeding complications is one of the reasons for the undertreatment of eligible patients. Numerous drugs are currently being developed to improve safety-efficacy.

AREAS COVERED

We reviewed literature from January 1^st, 2000, to 15^th January 2022 for the development and testing of novel drugs with the aim of targeting treatment at prevention of ischemic stroke: PubMed, MEDLINE, Google Scholar, and ClinicalTrial.gov.

EXPERT OPINION

The pathophysiology of ischemic stroke involves multiple pathways causing cerebral artery obstruction and brain tissue ischemia. Data suggest that tenecteplase is a more promising fibrinolytic agent with a superior efficacy-safety profile, compared to the currently approved alteplase. Current guidelines consider a short-term cycle of mannitol or hypertonic saline to be advisable in patients with space-occupying hemispheric infarction. Regarding primary and secondary prevention, research is primarily focused on identifying mechanisms to improve the safety-efficacy profile using a "hemostasis-sparing" approach. Further evaluation on those agents that have already shown promise for their risk/benefit profiles, would benefit greatly a neurologist's capacity to successfully prevent and treat ischemic stroke patients.

Controversies in cerebrovascular disease: high or low doses of recombinant tissue plasminogen activator to treat acute stroke? A literature review

INTRODUCTION

The use of low doses of recombinant tissue plasminogen activator (rt-PA) was initially proposed in Asian countries in response to racial peculiarities related to the functionality of fibrinogen and coagulation factors that potentially increased the risk of intracerebral haemorrhage, and with a view to saving costs. In view of the controversy over the use of rt-PA below the standard dose, we conducted a literature review of studies promoting the use of low doses or comparing different doses of rt-PA.

DEVELOPMENT

We reviewed 198 abstracts related to the search terms and the full texts of 52 studies published in the last 30 years. We finally included 13 randomised clinical trials aiming to determine the efficacy and safety of the use of rt-PA at different doses in acute stroke, 14 observational cohort studies, 5 meta-analyses, and 3 systematic reviews.

CONCLUSIONS

There is insufficient evidence to classify low doses of rt-PA as superior or at least not inferior to the standard treatment in the management of acute stroke in western populations. More clinical trials are required to determine whether the use of low doses is beneficial in patients with relative contraindications for thrombolytic therapy or other particular circumstances that may increase the risk of intracerebral haemorrhage.

Controversies in cerebrovascular disease: High or low doses of recombinant tissue plasminogen activator to treat acute stroke? A literature review

INTRODUCTION

The use of low doses of recombinant tissue plasminogen activator (rt-PA) was initially proposed in Asian countries in response to racial peculiarities related to the functionality of fibrinogen and coagulation factors that potentially increased the risk of intracerebral haemorrhage, and with a view to saving costs. In view of the controversy over the use of rt-PA below the standard dose, we conducted a literature review of studies promoting the use of low doses or comparing different doses of rt-PA.

DEVELOPMENT

We reviewed 198 abstracts related to the search terms and the full texts of 52 studies published in the last 30 years. We finally included 13 randomised clinical trials aiming to determine the efficacy and safety of the use of rt-PA at different doses in acute stroke, 14 observational cohort studies, 5 meta-analyses, and 3 systematic reviews.

CONCLUSIONS

There is insufficient evidence to classify low doses of rt-PA as superior or at least not inferior to the standard treatment in the management of acute stroke in western populations. More clinical trials are required to determine whether the use of low doses is beneficial in patients with relative contraindications for thrombolytic therapy or other particular circumstances that may increase the risk of intracerebral haemorrhage.

Dose-Response Relationship and Threshold Drug Dosage Identification for a Novel Hybrid Mechanical-Thrombolytic System with an Ultra-Low Dose Patch

Introduction

Ischemic stroke treatment has advanced in the last two decades and intravenous thrombolysis is now considered the standard of care for selected patients. Recanalization can also be achieved by mechanical endovascular treatment for patients with large vessel occlusions. Complicating treatment-related symptomatic intracerebral hemorrhage and prolonged needle-to-recanalization times have been identified as major determinants of poor three-month functional outcomes. A hybrid mechanical-thrombolytic system with a patch imbued with an ultra-low dose of thrombolytic agents loaded onto a stent-retriever has been developed.

Methods

In this study, the in situ dose-response relationship of the thrombolytic patch imbued with up to 1000 IU of urokinase plasminogen activator (uPA) was quantified using Raman spectroscopy.

Results

Thrombi of up to 400 μm thickness dissolved within 15 min when patches imbued with < 1% of the conventional thrombolysis therapy dosage were applied. The results demonstrated that low-dose thrombolytic patches can dissolve normal clots compressed in the blood vessel in a short time. 500 IU is the threshold uPA dosage in the thrombolytic patch that most effectively dissolves the clots.

Conclusion

This study suggests that a novel endovascular stent-retriever loaded with an ultra-low drug dose fibrinolytic patch may be a suitable treatment for patients who are ineligible for conventional thrombolytic therapy.

Automated Large Artery Occlusion Detection in Stroke: A Single-Center Validation Study of an Artificial Intelligence Algorithm

INTRODUCTION

Expediting notification of lesions in acute ischemic stroke (AIS) is critical. Limited availability of experts to assess such lesions and delays in large vessel occlusion (LVO) recognition can negatively affect outcomes. Artificial intelligence (AI) may aid LVO recognition and treatment. This study aims to evaluate the performance of an AI-based algorithm for LVO detection in AIS.

METHODS

Retrospective analysis of a database of AIS patients admitted in a single center between 2014 and 2019. Vascular neurologists graded computed tomography angiographies (CTAs) for presence and site of LVO. Studies were analyzed by the Viz-LVO Algorithm® version 1.4 - neural network programmed to detect occlusions from the internal carotid artery terminus (ICA-T) to the Sylvian fissure. Comparisons between human versus AI-based readings were done by test characteristic analysis and Cohen's kappa. Primary analysis included ICA-T and/or middle cerebral artery (MCA)-M1 LVOs versus non-LVOs/more distal occlusions. Secondary analysis included MCA-M2 occlusions.

RESULTS

610 CTAs were analyzed. The AI algorithm rejected 2.5% of the CTAs due to poor quality, which were excluded from the analysis. Viz-LVO identified ICA-T and MCA-M1 LVOs with a sensitivity of 87.6%, specificity of 88.5%, and accuracy of 87.9% (AUC 0.88, 95% CI: 0.85-0.92, p < 0.001). Cohen's kappa was 0.74. In the secondary analysis, the algorithm yielded a sensitivity of 80.3%, specificity of 88.5%, and accuracy of 82.7%. The mean run time of the algorithm was 2.78 ± 0.5 min.

CONCLUSION

Automated AI reading allows for fast and accurate identification of LVO strokes with timely notification to emergency teams, enabling quick decision-making for reperfusion therapies or transfer to specialized centers if needed.

"Hesitating and Puzzling": The Experiences and Decision Process of Acute Ischemic Stroke Patients with Prehospital Delay after the Onset of Symptoms

Despite campaigns to increase public awareness of stroke symptoms by advocating FAST (Face-Arms-Speech-Time), some stroke patients still show delays in the recognition of and response to stroke symptoms and miss the golden first 4.5 h to receive rt-PA (recombinant tissue plasminogen activator) treatment. The aim of this study was to explore how acute ischemic stroke patients with prehospital delay seek help and undergo the decision process before arriving at the hospital. A qualitative approach using a grounded theory was applied. There were 24 ischemic stroke patients recruited by purposive sampling. Our main findings were: “Hesitating and puzzling” was the core category to describe and guide the process of acute ischemic stroke patients with prehospital delay. During the process, “Awareness the sudden change of physical sensation and/or function” was the antecedent category. In the prehospital delay experience, the following five interaction categories were identified: (1) “Self-judgment and interpretation according to previous experience,” (2) “Puzzling and doubting—it may only be a minor problem,” (3) “Self-treatment or seeking medical attention nearby,” (4) “Unexpected symptoms getting worse” needing immediate advanced medical help and (5) “Rushing to ER with different transportation—self-alerting that serious disease is coming.” Eventually, the patients “Regret to delay seeking treatment and become a disable person.” The process of prehospital delay provides some hidden cues for patients to increase their knowledge about strokes. The study emphasizes the importance of educating community residents about identifying stroke symptoms, breaking the myth of folk therapy, and seeking medical attention immediately. These results will assist healthcare providers by offering references for designing patient-centric educational strategies for preventing stroke prehospital delay to improve the quality of stroke medical care.

Compliance With Preferred Reporting Items for Systematic Review and Meta-Analysis Individual Participant Data Statement for Meta-Analyses Published for Stroke Studies

[Figure: see text].

Diagnosis and Management of Transient Ischemic Attack and Acute Ischemic Stroke: A Review

IMPORTANCE

Stroke is the fifth leading cause of death and a leading cause of disability in the United States, affecting nearly 800 000 individuals annually.

OBSERVATIONS

Sudden neurologic dysfunction caused by focal brain ischemia with imaging evidence of acute infarction defines acute ischemic stroke (AIS), while an ischemic episode with neurologic deficits but without acute infarction defines transient ischemic attack (TIA). An estimated 7.5% to 17.4% of patients with TIA will have a stroke in the next 3 months. Patients presenting with nondisabling AIS or high-risk TIA (defined as a score ≥4 on the age, blood pressure, clinical symptoms, duration, diabetes [ABCD2] instrument; range, 0-7 [7 indicating worst stroke risk]), who do not have severe carotid stenosis or atrial fibrillation, should receive dual antiplatelet therapy with aspirin and clopidigrel within 24 hours of presentation. Subsequently, combined aspirin and clopidigrel for 3 weeks followed by single antiplatelet therapy reduces stroke risk from 7.8% to 5.2% (hazard ratio, 0.66 [95% CI, 0.56-0.77]). Patients with symptomatic carotid stenosis should receive carotid revascularization and single antiplatelet therapy, and those with atrial fibrillation should receive anticoagulation. In patients presenting with AIS and disabling deficits interfering with activities of daily living, intravenous alteplase improves the likelihood of minimal or no disability by 39% with intravenous recombinant tissue plasminogen activator (IV rtPA) vs 26% with placebo (odds ratio [OR], 1.6 [95% CI, 1.1-2.6]) when administered within 3 hours of presentation and by 35.3% with IV rtPA vs 30.1% with placebo (OR, 1.3 [95% CI, 1.1-1.5]) when administered within 3 to 4.5 hours of presentation. Patients with disabling AIS due to anterior circulation large-vessel occlusions are more likely to be functionally independent when treated with mechanical thrombectomy within 6 hours of presentation vs medical therapy alone (46.0% vs 26.5%; OR, 2.49 [95% CI, 1.76-3.53]) or when treated within 6 to 24 hours after symptom onset if they have a large ratio of ischemic to infarcted tissue on brain magnetic resonance diffusion or computed tomography perfusion imaging (modified Rankin Scale score 0-2: 53% vs 18%; OR, 4.92 [95% CI, 2.87-8.44]).

CONCLUSIONS AND RELEVANCE

Dual antiplatelet therapy initiated within 24 hours of symptom onset and continued for 3 weeks reduces stroke risk in select patients with high-risk TIA and minor stroke. For select patients with disabling AIS, thrombolysis within 4.5 hours and mechanical thrombectomy within 24 hours after symptom onset improves functional outcomes.

European Stroke Organisation (ESO) guidelines on intravenous thrombolysis for acute ischaemic stroke

Intravenous thrombolysis is the only approved systemic reperfusion treatment for patients with acute ischaemic stroke. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist physicians in their clinical decisions with regard to intravenous thrombolysis for acute ischaemic stroke. These guidelines were developed based on the ESO standard operating procedure and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote recommendations. Expert consensus statements were provided if not enough evidence was available to provide recommendations based on the GRADE approach. We found high quality evidence to recommend intravenous thrombolysis with alteplase to improve functional outcome in patients with acute ischemic stroke within 4.5 h after symptom onset. We also found high quality evidence to recommend intravenous thrombolysis with alteplase in patients with acute ischaemic stroke on awakening from sleep, who were last seen well more than 4.5 h earlier, who have MRI DWI-FLAIR mismatch, and for whom mechanical thrombectomy is not planned. These guidelines provide further recommendations regarding patient subgroups, late time windows, imaging selection strategies, relative and absolute contraindications to alteplase, and tenecteplase. Intravenous thrombolysis remains a cornerstone of acute stroke management. Appropriate patient selection and timely treatment are crucial. Further randomized controlled clinical trials are needed to inform clinical decision-making with regard to tenecteplase and the use of intravenous thrombolysis before mechanical thrombectomy in patients with large vessel occlusion.

Examining Outcomes following Thrombolysis in An Increasingly Older and Dependent Stroke Population

Background

Thrombolysis for acute ischaemic stroke (AIS) patients aged ≥80 years is evidence based, although its use in previously dependent patients is controversial.

Methods

Data from 831 thrombolysed AIS patients in our centre from 2009–2017 were used to compare demographic trends and outcomes (haemorrhage, mortality, three-month independence) in patients aged <80 and ≥80 years and with prior dependency. Comparison with UK and world registry data regarding age and pre-stroke dependency was made.

Results

The percentage of treated patients aged ≥80 years increased year-on-year, doubling from 25% to 50% (p<0.01), with increasing average age and pre-stroke dependency in world centres. Patients ≥80 years had higher (p<0.001) stroke severity, symptomatic intracerebral haemorrhage (5% vs. 1.5%), mortality (35% vs. 13%) and lower three month independent survival (24% vs. 60%). Patients with pre-stroke dependency had especially higher three month mortality (57–71%, OR 3.75 [95% CI 1.97–7.15]) in both age groups.

Conclusion

Patients aged ≥80 years and with dependency increasingly receive thrombolysis. Given poorer outcomes thrombolysis trials are needed in pre-stroke dependent patients.

Reperfusion Therapy Frequency and Outcomes in Mild Ischemic Stroke in the United States

BACKGROUND AND PURPOSE

More than half of patients with acute ischemic stroke have minor neurological deficits; however, the frequency and outcomes of reperfusion therapy in regular practice has not been well-delineated.

METHODS

Analysis of US National Inpatient Sample of hospitalizations with acute ischemic stroke and mild deficits (National Institutes of Health Stroke Scale [NIHSS] score 0-5) from October 1, 2016, to December 31, 2017. Patient- and hospital-level characteristics associated with use and outcome of reperfusion therapies were analyzed. Primary outcomes included excellent discharge disposition (discharge to home without assistance); poor discharge disposition (discharge to facility or death); in-hospital mortality; and radiological intracranial hemorrhage.

RESULTS

Among 179 710 acute ischemic stroke admissions with recorded NIHSS during the 15-month study period, 103 765 (57.7%) had mild strokes (47.3% women; median age, 69 [interquartile range, 59-79] years; median NIHSS score of 2 [interquartile range, 1-4]). Considering reperfusion therapies among strokes with documented NIHSS, mild deficit hospitalizations accounted for 40.0% of IVT and 10.7% of mechanical thrombectomy procedures. Characteristics associated with IVT and with mechanical thrombectomy utilization were younger age, absence of diabetes, higher NIHSS score, larger/teaching hospital status, and Western US region. Excellent discharge outcome occurred in 48.2% of all mild strokes, and in multivariable analysis, was associated with younger age, male sex, White race, lower NIHSS score, absence of diabetes, heart failure, and kidney disease, and IVT use. IVT was associated with increased likelihood of excellent outcome (odds ratio, 1.90 [95% CI, 1.71-2.13], P<0.001) despite an increased risk of intracranial hemorrhage (odds ratio, 1.41 [95% CI, 1.09-1.83], P<0.001).

CONCLUSIONS

In national US practice, more than one-half of acute ischemic stroke hospitalizations had mild deficits, accounting for 4 of every 10 IVT and 1 of every 10 mechanical thrombectomy treatments, and IVT use was associated with increased discharge to home despite increased intracranial hemorrhage.

Alteplase for Acute Ischemic Stroke in Patients Aged >80 Years: Pooled Analyses of Individual Patient Data

BACKGROUND/PURPOSE

Expert guidelines specify no upper age limit for alteplase for thrombolysis of acute ischemic stroke (AIS) but, until recently, European regulatory criteria restricted its use to patients aged 18 to 80 years. We performed pooled analyses of randomized controlled trial (RCT) and registry data to evaluate the benefit-risk profile of alteplase for AIS among patients aged >80 years to support a regulatory application to lift the upper age restriction.

METHODS

Individual patient data were evaluated from 7 randomized trials of alteplase (0.9 mg/kg) versus placebo or open control for AIS, and the European SITS-UTMOST registry database. Clinical outcomes, including good functional outcome (score 0-1, modified Rankin Scale day 90 or Oxford Handicap Score day 180), were evaluated in the full RCT and registry populations, and specified age-based subgroups (≤80 or >80 years) who met existing European regulatory criteria for alteplase, excluding upper age restriction.

RESULTS

Regardless of treatment allocation, 90-day mortality was lower among RCT patients aged ≤80 versus >80 years who otherwise met existing European regulatory criteria (246/2405 [10.2%] versus 307/1028 [29.9%], respectively). Among patients aged >80 years, alteplase versus placebo was associated with a higher proportion of good stroke outcome (modified Rankin Scale score 0-1; 99/518 [19.1%] versus 67/510 [13.1%]; P=0.0109) and similar 90-day mortality (153/518 [29.5%] versus 154/510 [30.2%]; P=0.8382). The odds of a good stroke outcome following alteplase allocation in the full RCT population were independent of age (P=0.7383). Good stroke outcome was reported for almost half (4821/11 169 [43.2%]) of the patients who received alteplase in routine practice. Outcomes in routine practice supported those achieved in RCTs.

CONCLUSIONS

Alteplase for AIS has a positive benefit-risk profile among patients aged >80 years when administered according to other regulatory criteria. Alteplase for AIS should be evaluated on an individual benefit-risk basis.

Antagonizing dabigatran by idarucizumab in cases of ischemic stroke or intracranial hemorrhage in Germany-Updated series of 120 cases

BACKGROUND

Idarucizumab is a monoclonal antibody fragment with high affinity for dabigatran reversing its anticoagulant effects within minutes. Thereby, patients with acute ischemic stroke who are on dabigatran treatment may become eligible for thrombolysis with recombinant tissue-type plasminogen activator (rt-PA). In patients on dabigatran with intracerebral hemorrhage idarucizumab could prevent lesion growth.

AIMS

To provide insights into the clinical use of idarucizumab in patients under effective dabigatran anticoagulation presenting with signs of acute ischemic stroke or intracranial hemorrhage.

METHODS

Retrospective data collected from German neurological/neurosurgical departments administering idarucizumab following product launch from January 2016 to August 2018 were used.

RESULTS

One-hundred and twenty stroke patients received idarucizumab in 61 stroke centers. Eighty patients treated with dabigatran presented with ischemic stroke and 40 patients suffered intracranial bleeding (intracerebral hemorrhage (ICH) in n = 27). In patients receiving intravenous thrombolysis with rt-PA following idarucizumab, 78% showed a median improvement of 7 points in National Institutes of Health Stroke Scale. No bleeding complications were reported. Hematoma growth was observed in 3 out of 27 patients with ICH. Outcome was favorable with a median National Institutes of Health Stroke Scale improvement of 4 points and modified Rankin score 0-3 in 61%. Six out of 40 individuals (15%) with intracranial bleeding died during hospital stay.

CONCLUSION

Administration of rt-PA after reversal of dabigatran activity with idarucizumab in case of acute ischemic stroke seems feasible, effective, and safe. In dabigatran-associated intracranial hemorrhage, idarucizumab appears to prevent hematoma growth and to improve outcome.

Validation of a Smartphone Application in the Evaluation and Treatment of Acute Stroke in a Comprehensive Stroke Center

Background and Purpose- The increasing demand and shortage of experts to evaluate and treat acute stroke patients has led to the development of remote communication tools to aid stroke management. We aimed to evaluate the JOIN App smartphone system-a low-cost tool for rapid clinical and neuroimaging data sharing to expedite decision-making in stroke. Methods- Consecutive acute ischemic stroke patients treated at a University Hospital in Brazil from December 2014 to December 2015 were evaluated. The analysis included all patients presenting with acute ischemic stroke who underwent initial evaluation by neurology residents followed by JOIN teleconsultation with a stroke neurologist on call for management decisions. An expert panel of stroke neurologists and neuroradiologists revised all cases using a standard Picture Archiving and Communication System imaging workstation within 24 hours and analyzed the decision made with remote assistance during the emergency setting. Results- A total of 720 stroke codes were evaluated with 442 acute ischemic stroke qualifying. Seventy-eight (18%) patients were treated with intravenous thrombolysis. The main reasons for tPA (tissue-type plasminogen activator) exclusion were symptom onset >4.5 hours (n=295; 67%) and hypodense middle cerebral artery territory area >1/3 (n=31; 7%). The agreement rates between Picture Archiving and Communication System versus JOIN-based thrombolysis decisions were 100% for the stroke (unblinded) and 99.3% for the neuroradiologist (blinded) experts. The use of the application resulted in a significant reduction in the door-to-needle times across the pre- versus postimplementation periods (median, 90 [interquartile range, 75-106] versus 63 [interquartile range, 61-117] minutes; P=0.03). The rates of 90-day excellent outcomes (modified Rankin Scale, 0-1) were 51.3%; 90-day mortality, 2.6%; and symptomatic intracranial hemorrhage, 3.8%. Conclusions- The JOIN smartphone system allows rapid sharing of clinical and imaging data to facilitate decisions for stroke treatment. The remote application-based decisions seem to be as accurate as the physical presence of stroke experts and might lead to faster times to treatment. This system represents an easily implementable low-cost telemedicine solution for centers that cannot afford the full-time presence of stroke specialists.

Thrombolysis in elderly stroke patients in Italy (TESPI) trial and updated meta-analysis of randomized controlled trials

BACKGROUND

Since its approval, the use of alteplase had been limited to patients aged ≤80 years.

AIMS

TESPI trial had been designed to evaluate whether alteplase treatment within 3 h in patients with acute ischemic stroke aged >80 years resulted in favorable benefit/risk ratio compared with standard care. The meta-analysis of randomized controlled trials was updated to put findings in the context of all available evidence.

METHODS

TESPI was a multicenter, open-label with blinded outcome evaluation, randomized, controlled trial. Main clinical endpoints were 90-day favorable functional outcome (mRS score 0-2) and mortality and symptomatic intracerebral hemorrhage. The trial was prematurely terminated for ethical reasons after publication of IST-3 trial which provided evidence of treatment benefit in elderly.

RESULTS

Of the planned 600 patients, 191 (88 assigned to alteplase) were enrolled. Overall, 24/83 (28.9%) alteplase patients had a favorable outcome compared to 22/95 (23.2%) controls (non-significant absolute difference of 5.7% for alteplase; OR 1.35, 95% CI 0.69-2.64, P = 0.381). Rates of death were non-significantly lower in the alteplase patients (18.1% vs. 26.5%); rates of symptomatic intracerebral hemorrhage were similar between the two groups (5.9% vs. 5.1%). The updated meta-analysis showed consistent results with prior estimates and add weights.

CONCLUSIONS

The effects of alteplase observed in this interrupted trial did not reach statistical significance, probably for the small numbers, but are consistent with and add weight to the sum total of the randomized evidence demonstrating that alteplase is beneficial in patients with acute ischemic stroke aged over 80 years, particularly if given within 3 h.

Intravenous Thrombolysis Administration 3-4.5 h After Acute Ischemic Stroke: A Retrospective, Multicenter Study

Background and Objectives: Intravenous recombinant tissue plasminogen activator (rt-PA) has been approved for acute ischemic stroke (AIS) within 3 h after onset and the treatment was then extended to 4.5 h. However, the Food and Drug Administration did not approve the indication in the expanded time window. This retrospective, matched cohort study aims to investigate the effectiveness and safety of rt-PA in AIS at 3-4.5 h after onset. Materials and Methods: The treatment group included AIS patients receiving rt-PA at 3-4.5 h after onset, otherwise complying with the regulation, in the stroke registries in 16 hospitals between 2008 and 2017. The control group included age- and sex-matched patients not receiving intravenous thrombolysis from the same registries, excluding those with contraindications. The primary outcome was modified Rankin Scale (mRS) 0-1 at day 90. The safety outcomes were any intracerebral hemorrhage (ICH), early neurological deterioration and 3-month mortality. Results: Each group had 374 patients. There were 34.0% of patients with 3-month mRS 0-1 in the treatment group vs. 22.7% in the control group with an odds ratio of 1.75 (95% confidence intervals, 1.27 to 2.42, P = 0.001). There was no difference in symptomatic ICH, early neurological deterioration and 3-month mortality rates between two groups. The 3-month mRS and symptomatic ICH did not differ significantly in patients receiving standard dose or low dose of rt-PA. Conclusions: Our results support the prescription of rt-PA in AIS patients 3-4.5 h after onset as an effective and tolerable treatment in their functional recovery.

Intravenous Tissue-Type Plasminogen Activator in Acute Ischemic Stroke Patients With History of Stroke Plus Diabetes Mellitus

Background and Purpose- Acute ischemic stroke patients with history of prior ischemic stroke plus concomitant diabetes mellitus (DM) were excluded from the ECASS III trial (European Cooperative Acute Stroke Study) because of safety concerns. However, there are few data on use of intravenous tissue-type plasminogen activator and symptomatic intracerebral hemorrhage or outcomes in this population. Methods- Using data from the Get With The Guidelines-Stroke Registry between February 2009 and September 2017 (n=1619 hospitals), we examined characteristics and outcomes among patients with acute ischemic stroke treated with tissue-type plasminogen activator within the 3- to 4.5-hour window who had a history of stroke plus diabetes mellitus (HxS+DM) (n=2129) versus those without either history (n=16 690). Results- Compared with patients without either history, those with both prior stroke and DM treated with tissue-type plasminogen activator after an acute ischemic stroke had a higher prevalence of cardiovascular risk factors in addition to history of stroke, DM, and more severe stroke (National Institutes of Health Stroke Scale: median, 8 [interquartile range, 5-15] versus 7 [4-13]). The unadjusted rates of symptomatic intracerebral hemorrhage and in-hospital mortality were 4.3% (HxS+DM) versus 3.8% (without either history; P=0.31) and 6.2% versus 5.5% ( P=0.20), respectively. These differences were not statistically significant after risk adjustment (symptomatic intracerebral hemorrhage: adjusted odds ratio, 0.79 [95% CI, 0.51-1.21]; P=0.28; in-hospital mortality: odds ratio, 0.77 [95% CI, 0.52-1.14]; P=0.19). Unadjusted rate of functional independence (modified Rankin Scale score, 0-2) at discharge was lower in those with HxS+DM (30.9% HxS+DM versus 44.8% without either history; P≤0.0001), and this difference persisted after adjusting for baseline clinical factors (adjusted odds ratio, 0.76 [95% CI, 0.59-0.99]; P=0.04). Conclusions- Among patients with acute ischemic stroke treated with intravenous tissue-type plasminogen activator within the 3- to 4.5-hour window, HxS+DM was not associated with statistically significant increased symptomatic intracerebral hemorrhage or mortality risk.

Tenecteplase for the treatment of acute ischemic stroke: A review of completed and ongoing randomized controlled trials

Alteplase has been the mainstay of thrombolytic treatment since the National Institutes of Neurological Disorders and Stroke trial was published in 1995. Over recent years, several trials have investigated alternative thrombolytic agents. Tenecteplase, a genetically engineered mutant tissue plasminogen activator, has a longer half-life, allowing single intravenous bolus administration without infusion, is more fibrin specific, produces less systemic depletion of circulating fibrinogen, and is more resistant to plasminogen activator inhibitor compared to alteplase. Tenecteplase is established as the first-line intravenous thrombolytic drug for myocardial infarction, where it has been shown to achieve comparable reperfusion with reduced risk of systemic bleeding in comparison to alteplase. We review the literature on tenecteplase for the treatment of acute ischemic stroke, with a focus on the major completed and ongoing trials. Overall, tenecteplase shows promise for treatment of acute ischemic stroke, both in populations currently eligible for alteplase and also in groups not currently treated with thrombolysis.

Canadian Stroke Best Practice Recommendations for Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care, 6th Edition, Update 2018

The 2018 update of the Canadian Stroke Best Practice Recommendations for Acute Stroke Management, 6th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by healthcare providers and system planners caring for persons with very recent symptoms of acute stroke or transient ischemic attack. The recommendations are intended for use by a interdisciplinary team of clinicians across a wide range of settings and highlight key elements involved in prehospital and Emergency Department care, acute treatments for ischemic stroke, and acute inpatient care. The most notable changes included in this 6th edition are the renaming of the module and its integration of the formerly separate modules on prehospital and emergency care and acute inpatient stroke care. The new module, Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care is now a single, comprehensive module addressing the most important aspects of acute stroke care delivery. Other notable changes include the removal of two sections related to the emergency management of intracerebral hemorrhage and subarachnoid hemorrhage. These topics are covered in a new, dedicated module, to be released later this year. The most significant recommendation updates are for neuroimaging; the extension of the time window for endovascular thrombectomy treatment out to 24 h; considerations for treating a highly selected group of people with stroke of unknown time of onset; and recommendations for dual antiplatelet therapy for a limited duration after acute minor ischemic stroke and transient ischemic attack. This module also emphasizes the need for increased public and healthcare provider’s recognition of the signs of stroke and immediate actions to take; the important expanding role of paramedics and all emergency medical services personnel; arriving at a stroke-enabled Emergency Department without delay; and launching local healthcare institution code stroke protocols. Revisions have also been made to the recommendations for the triage and assessment of risk of recurrent stroke after transient ischemic attack/minor stroke and suggested urgency levels for investigations and initiation of management strategies. The goal of this updated guideline is to optimize stroke care across Canada, by reducing practice variations and reducing the gap between current knowledge and clinical practice.

Professional guideline versus product label selection for treatment with IV thrombolysis: An analysis from SITS registry

Introduction

Thrombolysis usage in ischaemic stroke varies across sites. Divergent advice from professional guidelines and product labels may contribute.

Patients and methods

We analysed SITS-International registry patients enrolled January 2010 through June 2016. We grouped sites into organisational tertiles by number of patients arriving ≤2.5 h and treated ≤3 h, percentage arriving ≤2.5 h and treated ≤3 h, and numbers treated ≤3 h. We assigned scores of 1-3 (lower/middle/upper) per variable and 2 for onsite thrombectomy. We classified sites as lower efficiency (summed scores 3-5), medium efficiency (6-8) or higher efficiency (9-11). Sites were also grouped by adherence with European product label and ESO guideline: 'label adherent' (>95% on-label), 'guideline adherent' (≥5% off-label, ≥95% on-guideline) or 'guideline non-adherent' (>5% off-guideline). We cross-tabulated site-efficiency and adherence. We estimated the potential benefit of universally selecting by ESO guidance, using onset-to-treatment time-specific numbers needed to treat for day 90 mRS 0-1.

Results

A total of 56,689 patients at 597 sites were included: 163 sites were higher efficiency, 204 medium efficiency and 230 lower efficiency. Fifty-six sites were 'label adherent', 204 'guideline adherent' and 337 'guideline non-adherent'. There were strong associations between site-efficiency and adherence (P < 0.001). Almost all 'label adherent' sites (55, 98%) were lower efficiency. If all patients were treated by ESO guidelines, an additional 17,031 would receive alteplase, which translates into 1922 more patients with favourable three-month outcomes.

Discussion

Adherence with product labels is highest in lower efficiency sites. Closer alignment with professional guidelines would increase patients treated and favourable outcomes.

Conclusion

Product labels should be revised to allow treatment of patients ≤4.5 h from onset and aged ≥80 years.