Lack of Interactions Between Alteplase/Tenecteplase and the Adenosine A1R/A3R Agonist AST-004

BACKGROUND

AST-004, a small molecule agonist of the adenosine A1 and A3 receptors, is a potential cerebroprotectant for patients with acute stroke and is currently in clinical trials. Drug-drug interactions are critically important to assess in the context of acute stroke care. Lytic therapy with tPA (tissue-type plasminogen activator)-induced plasmin formation (alteplase) is the only available pharmacotherapy for acute stroke. Consequently, it is imperative to evaluate potential interactions between AST-004 and tPAs such as alteplase and tenecteplase.

METHODS

The interactions between AST-004 and tPAs were evaluated in 3 ways in preparation for AST-004 phase II trials. First, the metabolic stability of AST-004 was determined in the presence of alteplase and plasmin. Second, the potential for AST-004 to influence the thrombolytic efficacy of alteplase and tenecteplase was evaluated with an in vitro assay system utilizing a fluorogenic substrate of plasmin. Finally, the potential for AST-004 to influence the thrombolytic efficacy of alteplase was also determined with an in vitro thrombolysis assay of human blood thrombi.

RESULTS

Neither alteplase nor plasmin affected the stability of AST-004 in vitro. In 2 different in vitro systems, AST-004 had no effect on the ability of alteplase or tenecteplase to generate plasmin, and AST-004 had no effect on the thrombolytic efficacy of alteplase to lyse blood clots in human blood.

CONCLUSIONS

These studies indicate that there will be no interactions between AST-004 and tPAs such as alteplase or tenecteplase in patients with stroke undergoing thrombolytic therapy.

Plasminogen activator inhibitor-1 serum levels in frontotemporal lobar degeneration

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aβ) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aβ pathway, the plasmin system may affect cognition through synaptic activity.

Safety and Efficacy of Reteplase Versus Alteplase for Acute Ischemic Stroke: A Phase 2 Randomized Controlled Trial

BACKGROUND

Reteplase is a more affordable new-generation thrombolytic with a prolonged half-life. We aimed to determine the safety dose range of reteplase for patients with acute ischemic stroke within 4.5 hours of onset.

METHODS

This is a multicenter, prospective, randomized controlled, open-label, blinded-end point phase 2 clinical trial. Patients with acute ischemic stroke aged between 18 and 80 years who were eligible for standard intravenous thrombolysis were enrolled from 17 centers in China and randomly assigned (1:1:1) to receive intravenous reteplase 12+12 mg, intravenous reteplase 18+18 mg, or intravenous alteplase 0.9 mg/kg. The primary safety outcome was symptomatic intracranial hemorrhage (SITS definition) within 36 hours. The primary efficacy outcome was the proportion of patients with the National Institutes of Health Stroke Scale score of no more than 1 or a decrease of at least 4 points from the baseline at 14 days after thrombolysis.

RESULTS

Between August 2019 and May 2021, 180 patients were randomly assigned to reteplase 12+12 mg (n=61), reteplase 18+18 mg (n=67), or alteplase (n=52). Four patients did not receive the study agent. Symptomatic intracranial hemorrhage occurred in 3 of 60 (5.0%) in the reteplase 12+12 mg group, 1 of 66 (1.5%) in the reteplase 18+18 mg group, and 1 of 50 (2.0%) in the alteplase group (P=0.53). The primary efficacy outcome in the modified intention-to-treat population occurred in 45 of 60 (75.0%) in the reteplase 12+12 mg group (odds ratio, 0.85 [95% CI, 0.35-2.06]), 48 of 66 (72.7%) in the reteplase 18+18 mg group (odds ratio, 0.75 [95% CI, 0.32-1.78]), and 39 of 50 (78.0%) in alteplase group.

CONCLUSIONS

Reteplase was well tolerated in patients with acute ischemic stroke within 4.5 hours of onset in China with a similar efficacy profile to alteplase. The efficacy and appropriate dosage of reteplase for patients with acute ischemic stroke need prospective validation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04028518.

Characterization and Usefulness of Clot-Fibrinolysis Waveform Analysis in Critical Care Patients with Enhanced or Suppressed Fibrinolysis

INTRODUCTION

 Recently, clot-fibrinolysis waveform analysis (CFWA), which is a coagulation and fibrinolysis global assay based on assessing the activated partial thromboplastin time with tissue-type plasminogen activator, was developed. This study aimed to investigate the characteristics of CFWA using plasma samples from patients in the critical care unit.

MATERIALS AND METHODS

 The fibrinolysis times using CFWA were measured in 298 plasma samples. These samples were divided into three groups based on the reference interval (RI) of fibrinolysis time using CFWA: shortened group, less than RI; within group, within RI; prolonged group, more than RI. The coagulation and fibrinolysis markers, including D-dimer, plasmin-α2 plasmin inhibitor complex (PIC), fibrin monomer complex (FMC), plasmin-α2 plasmin inhibitor (α2-PI), plasminogen (Plg), and fibrinogen (Fbg) were analyzed and compared among the three groups.

RESULTS

 The FMC level decreased in the order of shortened, within, and prolonged groups, and the decrease was statistically significant among all three group pairs. The opposite tendency was observed for Fbg and fibrinolysis-related markers of α2-PI and Plg, and significant differences were recognized in all pair comparisons except for between within and prolonged groups in Plg. The mean values of the fibrinolysis markers D-dimer and PIC in all three groups were higher than the cut-off values, and the PIC value differed significantly between the within and prolonged groups.

CONCLUSION

 The fibrinolysis reaction was detected in all three groups, but the status differed. CFWA has the potential to reflect the fibrinolysis status in one global assay.

Risk factors for the outcome after thrombolysis in acute ischemic stroke - the prominent role of kidney dysfunction: A retrospective cohort observational study

A complex interplay of factors reflecting the general biological, cardiovascular, neurological, renal, and metabolic status of patients influences the outcome of thrombolysis in stroke patients. This is a retrospective cohort observational study aimed to determine the importance of kidney dysfunction among these factors. Data (demographic, lifestyle, physical examination, laboratory, imaging, including metabolic and cardiovascular risk factors and comorbidities, neurological scores, and outcomes) of all stroke patients who underwent thrombolysis have been registered since January 1, 2016, in an online database. A total of 296 patients registered until December 31, 2020, were included in the study. The National Institutes of Health Stroke Scale, modified Rankin scale, Barthel index, percentage of hemorrhagic transformation, and in hospital death were used to evaluate the neurological status and outcomes of the patients. Regression analysis, Mann-Whitney test, Fisher exact test, logistic regression, and multivariate analysis were used for statistical analysis. Kidney dysfunction, as reflected by the estimated glomerular filtration rate, was associated with in hospital death and all but one of the neurological scores. Other risk factors most frequently associated with neurological scores were age, international normalized ratio, and cognitive decline. Multivariate analysis revealed estimated glomerular filtration rate (as determined by chronic kidney disease-EPI equation) as a determinant for all but one of these scores, and as the most important determinant for most of them, except for those reflecting the pre-intervention neurological status of the patient. Kidney dysfunction seems to be the most important determinant of the outcome of thrombolysed stroke patients, a result obtained by no other study.

Neurovascular Inflammation and Complications of Thrombolysis Therapy in Stroke

Intravenous thrombolysis via tPA (tissue-type plasminogen activator) is the only approved pharmacological treatment for acute ischemic stroke, but its benefits are limited by hemorrhagic transformation. Emerging evidence reveals that tPA swiftly mobilizes immune cells which extravasate into the brain parenchyma via the cerebral vasculature, augmenting neurovascular inflammation, and tissue injury. In this review, we summarize the pronounced alterations of immune cells induced by tPA in patients with stroke and experimental stroke models. We argue that neuroinflammation, triggered by ischemia-induced cell death and exacerbated by tPA, compromises neurovascular integrity and the microcirculation, leading to hemorrhagic transformation. Finally, we discuss current and future approaches to attenuate thrombolysis-associated hemorrhagic transformation via uncoupling immune cells from the neurovascular unit.

Socioeconomic Inequalities in Functional Outcome After Reperfusion-Treated Ischemic Stroke

BACKGROUND

We aimed to investigate whether socioeconomic status (SES) was associated with functional outcome in patients with ischemic stroke treated with reperfusion therapy (intravenous thrombolysis and/or thrombectomy).

METHODS

This nationwide cohort study included reperfusion-treated patients with ischemic stroke ≥18 years registered in the Danish Stroke Registry between 2015 and 2018. Functional outcome was determined by the modified Rankin Scale score 90 days after stroke. SES was defined by educational attainment, family income, and employment status before stroke. SES data were available from Statistics Denmark and linked on the individual level with data from the Danish Stroke Registry. Uni- and multivariable ordinal logistic regression was performed for each socioeconomic parameter individually (education, income, and employment) to estimate the common odds ratios (cORs) for lower 90-day modified Rankin Scale scores.

RESULTS

A total of 5666 patients were included. Mean age was 68.7 years (95% CI, 68.3-69.0), and 38.4% were female. Low SES was associated with lower odds for achieving lower 90-day modified Rankin Scale score: Low versus high education, cOR, 0.69 (95% CI, 0.61-0.79), low versus high income, cOR, 0.59 (95% CI, 0.53-0.67), and unemployed versus employed, cOR, 0.70 (95% CI, 0.58-0.83). Inequalities were reduced after adjusting for age, sex, and immigrant status, except for unemployed versus employed patients, adjusted cOR, 0.66 (95% CI, 0.54-0.80). No statistically significant differences remained after adjusting for potentially mediating variables (eg, stroke severity, prestroke modified Rankin Scale, and smoking).

CONCLUSIONS

Socioeconomic inequalities were observed in functional outcome after reperfusion treated ischemic stroke. In particular, prestroke unemployment was negatively associated with good functional outcome. A more adverse prognostic profile among patients with low SES appeared to explain the majority of these inequalities.

Blood Clotting Dissolution in the Presence of a Magnetic Field and Preliminary Study with MG63 Osteoblast-like Cells-Further Developments for Guided Bone Regeneration?

BACKGROUND

The influence of a magnetic field on the activation of bone cells and remodelling of alveolar bone is known to incite bone regeneration. Guided Bone Regeneration (GBR) aims to develop biomimetic scaffolds to allow for the functioning of the barrier and the precise succession of wound healing steps, including haemostasis. The effect of a magnetic field on blood clot dissolution has not been studied yet.

METHODS

We conducted a methodological study on the clot stability in the presence of a static magnetic field (SMF). Preformed whole blood (WB) clots were treated with either a broad proteolytic enzyme (trypsin) or a specific fibrinolytic agent, i.e., tissue-type plasminogen activator (t-PA). MG63 osteoblast-like cells were added to preformed WB clots to assess cell proliferation.

RESULTS

After having experienced a number of clotting and dissolution protocols, we obtained clot stability exerted by SMF when tissue factor (for clotting) and t-PA + plasminogen (for fibrinolysis) were used. WB clots allowed osteoblast-like cells to survive and proliferate, however no obvious effects of the magnetic field were noted.

CONCLUSIONS

Paramagnetic properties of erythrocytes may have influenced the reduction in clot dissolution. Future studies are warranted to fully exploit the combination of magnetic forces, WB clot and cells in GBR applied to orthodontics and prosthodontics.

An antibody that targets cell-surface glucose-regulated protein-78 inhibits expression of inflammatory cytokines and plasminogen activator inhibitors by macrophages

Glucose-regulated protein-78 (Grp78) is an endoplasmic reticulum chaperone, which is secreted by cells and associates with cell surfaces, where it functions as a receptor for activated α2 -macroglobulin (α2 M) and tissue-type plasminogen activator (tPA). In macrophages, α2 M and tPA also bind to the transmembrane receptor, LDL receptor-related protein-1 (LRP1), activating a cell-signaling receptor assembly that includes the NMDA receptor (NMDA-R) to suppress innate immunity. Herein, we demonstrate that an antibody targeting Grp78 (N88) inhibits NFκB activation and expression of proinflammatory cytokines in bone marrow-derived macrophages (BMDMs) treated with the toll-like receptor-4 (TLR4) ligand, lipopolysaccharide, or with agonists that activate TLR2, TLR7, or TLR9. Pharmacologic inhibition of the NMDA-R or deletion of the gene encoding LRP1 (Lrp1) in BMDMs neutralizes the activity of N88. The fibrinolysis protease inhibitor, plasminogen activator inhibitor-1 (PAI1), has been implicated in diverse diseases including metabolic syndrome, cardiovascular disease, and type 2 diabetes. Deletion of Lrp1 independently increased expression of PAI1 and PAI2 in BMDMs, as did treatment of wild-type BMDMs with TLR agonists. tPA, α2 M, and N88 inhibited expression of PAI1 and PAI2 in BMDMs treated with TLR-activating agents. Inhibiting Src family kinases blocked the ability of both N88 and tPA to function as anti-inflammatory agents, suggesting that the cell-signaling pathway activated by tPA and N88, downstream of LRP1 and the NMDA-R, may be equivalent. We conclude that targeting cell-surface Grp78 may be effective in suppressing innate immunity by a mechanism that requires LRP1 and the NMDA-R.

A triple fusion tissue-type plasminogen activator (TriF-ΔtPA) enhanced thrombolysis in carotid embolism-induced stroke model

Recombinant tissue-type plasminogen activator (rtPA) is the first approved thrombolytic agent in acute ischemic stroke, but suffers from a short half-life and poor resistance to plasminogen activator inhibitor (PAI-1), limiting its clinical use. Thus, the development of novel thrombolytic agents with improved benefit/risk balance has always been of great significance. In this study, We identified a serine protease domain of tPA mutant (named ΔtPA^A146V) capable of escaping the inhibition by endogenous PAI-1 with 66-fold increased resistance compared to the wild type. Based on this mutant, we generated a triple fusion ΔtPA (TriF-ΔtPA), including albumin and fibrin binding peptide(FBP). The fusion with albumin effectively prolonged the plasma half-life of ΔtPA in mice to 144 minutes, which is much longer than ΔtPA and did not affect its thrombolytic activity. Furthermore, FBP rendered fibrin specificity of the fusion protein, giving a KD of ∼25 ± 0.9 μM. In a novel murine carotid embolism-induced stroke (CES) model, i.v. administration of TriF-ΔtPA promoted vascular recanalization, reduced infarct volume, and mitigated neurobehavioral deficits more significantly compared to ΔtPA-HSA or Alteplase, showing little bleeding risk. Together, this long-acting PAI-1-resistant thrombolytic agent holds great potential for clinical applications.

Nationally Certified Stroke Centers Outperform Self-Attested Stroke Centers in the Florida Stroke Registry

BACKGROUND

The Florida Stroke Act, signed into law in 2004, set criteria for Comprehensive Stroke Centers (CSC). For a set time period, Florida hospitals were permitted to either receive national certification (NC) or could self-attest (SA) as fulfilling CSC criteria. The aim of this project was to evaluate the quality of ischemic stroke care in NC versus SA stroke centers in Florida, using well-known, guideline-driven ischemic stroke outcome metrics.

METHODS

A total of 37 CSCs (74% of Florida CSCs) in the Florida Stroke Registry from January 2013 through December 2018 were analyzed, including 19 SA CSCs and 18 NC (13 CSCs and 5 Thrombectomy-Capable Stroke Center). Hospital- and patient-level characteristics and stroke metrics were evaluated, adjusting for demographics, medical comorbidities, and stroke severity.

RESULTS

A total of 78 424 acute ischemic stroke cases, 36 089 from SA CSCs and 42 335 from NC CSC/Thrombectomy-Capable Stroke Centers were analyzed. NC centers had older patients (73 [61-83] versus 71 [60-81]; P<0.001) with more severe strokes (median National Institutes of Health Stroke Scale score of 5 versus 4; P<0.001). NC had higher intravenous tissue-type plasminogen activator utilization (15% versus 13%; P<0.001), endovascular treatment (10% versus 7%; P<0.001) and faster median door-to-computed tomography (23 minutes [11-73] versus 31 [12-78]; P<0.001), door-to-needle (37 minutes [26-50] versus 45 [34-58]; P<0.001) and door-to-puncture times (77 minutes [50-113] versus 93 [62-140]; P<0.001). In adjusted analysis, patients arriving to NC hospitals by 3 hours were more likely to get intravenous tissue-type plasminogen activator in the 3- to 4.5-hour window (adjusted odds ratio, 1.87 [95% CI, 1.30-2.68]; P=0.001) and more likely to be treated with intravenous tissue-type plasminogen activator within 45 minutes (adjusted odds ratio, 1.61 [95% CI, 1.04-2.50]; P=0.04) compared with SA CSCs.

CONCLUSIONS

Among Florida-Stroke Registry CSCs, acute ischemic stroke performance and treatment measures at NC centers are superior to SA CSCs. These findings have implications for stroke systems of care in Florida and support legislation updates requiring NC and removal of SA claims.

Improving Large Animal Ischemic Stroke Models for Translational Studies in the Era of Recanalization

Recanalization therapy with endovascular procedures has led to significant advances in the treatment of acute ischemic stroke. Animal models have been the basis for enhancing the development of novel treatments and therapeutic modalities. However, previous translational failures led to an increasing consensus that large animals should be included to bridge the gap between rodent and human studies. In the era of large vessel recanalization, large animal ischemic stroke models should be optimized for preclinical and translational stroke studies. Here we highlight recent progress of reproducing ischemic and reperfusion mechanisms in large animal models of stroke through surgical and endovascular methods. The importance of optimizing large animal stroke modeling is suggested by evaluating new findings from clinical trials and preclinical experiments using large animals, such as adopting advanced imaging analysis and long-term functional evaluation. Furthermore, we also acknowledge the importance of adhering to the Stroke Treatment and Academic Roundtable recommendations and the "3 R" principles to improve the quality and validity of large animal experiments. Large animal models offer many translational benefits; however, more work is still needed to enhance studies using large animal model on acute ischemic stroke in the era of recanalization.

Alteplase for Stroke With Unknown Onset Time in Chronic Kidney Disease: A Pooled Analysis of Individual Participant Data

BACKGROUND

Although chronic kidney disease (CKD) is associated with worse stroke outcomes, data regarding the influence of CKD on intravenous thrombolysis outcomes are scarce. We sought to assess the efficacy and safety of intravenous thrombolysis for acute ischemic stroke with unknown onset time in patients with CKD.

METHODS

Patients with an acute stroke of unknown onset time from the EOS trials (Evaluation of Unknown Onset Stroke Thrombolysis) collaboration were evaluated using an individual patient-level database of randomized controlled trials comparing intravenous thrombolysis with placebo/standard treatment. CKD was defined as baseline estimated glomerular filtration rate of <60 ml/min/1.73m² Mixed-effect logistic-regression analysis was performed to evaluate treatment effects. A favorable outcome was defined as a modified Rankin Scale score of 0 to 1 at 90 days. Safety outcomes were symptomatic intracranial hemorrhage at 22 to 36 hours and 90-day mortality.

RESULTS

Baseline data on renal function were available for 688 of 843 patients. Of these, CKD was present in 146 (21%), including 69 of 351 patients receiving alteplase and 77 of 337 patients receiving placebo/standard treatment. Overall, treatment with alteplase was associated with higher odds of favorable outcome, and CKD did not modify the treatment effect (P_interaction=0.834). A favorable outcome was observed in 31 of 69 (46%) patients with CKD in the alteplase group and in 28 of 77 (36%) patients with CKD in the control group (adjusted odds ratio, 1.19 [95% CI, 0.55-2.58]). Among patients with CKD, symptomatic intracranial hemorrhage occurred in 2 patients (3%) in the alteplase group but in none of the controls (P=0.133). At 90 days, death was reported in 3 patients (4%) in the alteplase group compared with 2 patients (3%) in the controls (P=0.539).

CONCLUSIONS

The present analysis indicates that the benefit of alteplase does not differ between stroke patients with unknown onset time with and without CKD, although the statistical power was lacking to confirm the efficacy in subgroups. This study only applies to mild-to-moderate or predialysis CKD.

Short-Term Efficacy Outcomes of Tenecteplase versus Alteplase for Acute Ischemic Stroke: A Meta-Analysis of 5 Randomized Trials

Tenecteplase (TNK) has been shown to be noninferior to Alteplase (ALT) for long term efficacy and safety outcomes. Whether this also applies to short term efficacy outcomes such as early clinical improvement and recanalization is unknown. To compare TNK and ALT regarding the short term efficacy outcomes: early neurological improvement and recanalization. The PRISMA was used to conduct a meta analysis, adapted to noninferiority analysis. The primary outcome was early (24-72 h) neurological improvement, defined as either NIHSS score 0 or reduction of at least 8 points compared to baseline. Recanalization was a secondary outcome. The noninferiority margin was set at 6.5%. Search strategy yielded 5 randomized clinical trials (1585 patients: 828 TNK, 757 ALT). Mean age was 70.8, 58.8% were men, mean baseline NIHSS was 7, and mean onset to treatment time was 148 min. Patients in intervention group received TNK at doses of 0.1 mg/kg (6.8%), 0.25 mg/kg (24.6%), and 0.4 mg/kg (68.6%), while all ALT patients received 0.9 mg/kg. In random effects meta analysis, TNK was noninferior to ALT for the primary outcome, early major neurological improvement (risk difference 8% in favor of TNK, 95% CI 1%-15%). Recanalization was also noninferior for the TNK compared to the ALT group (risk difference 9% in favor of TNK, 95% CI 6% to 23%). Fixed effects models yielded similarly noninferior results and signaled for a possible TNK superiority for both early neurological improvement and recanalization. TNK is noninferior to ALT at the short term efficacy outcomes: early neurological improvement and recanalization.

Intraventricular Hemorrhage Expansion in the CLEAR III Trial: A Post Hoc Exploratory Analysis

BACKGROUND

The objective of this study was to evaluate factors associated with intraventricular hemorrhage (IVH) expansion and its association with long-term outcomes.

METHODS

We performed a post hoc analysis of the international, multi-center CLEAR III trial (Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage) which enrolled IVH patients between September 1, 2009, and January 31, 2015. The exposure was IVH expansion, defined as >1 mL increase in volume between baseline and stability computed tomography scans, before treatment randomization. We assessed factors associated with IVH expansion and secondarily assessed the relationship of IVH expansion with clinical outcomes: composite of death or major disability (modified Rankin Scale score, >3), and mortality alone at 6 months. The relationship of IVH expansion on ventriculoperitoneal shunt placement was additionally explored. Multivariable logistic regression was used for all analyses.

RESULTS

Of 500 IVH patients analyzed, the mean age was 59 (±11) years old, 44% were female and 135 (27%) had IVH expansion. In multivariable regression models, factors associated with IVH expansion were baseline parenchymal intracerebral hemorrhage (ICH) volume (adjusted odds ratio [OR], 1.04 per 1 mL increase [95% CI, 1.01-1.08]), presence of parenchymal hematoma expansion: >33% (adjusted OR, 6.63 [95% CI, 3.92-11.24]), time to stability head CT (adjusted OR, 0.71 per 1 hour increase [95% CI, 0.54-0.94]), and thalamic hematoma location (adjusted OR, 1.68 [95% CI, 1.01-2.79]) while additionally adjusting for age, sex, and race. In secondary analyses, IVH expansion was associated with higher odds of poor 6-month outcomes (adjusted OR, 1.84 [95% CI, 1.12-3.02]) but not mortality (OR, 1.40 [95% CI, 0.78-2.50]) after adjusting for baseline ICH volume, thalamic ICH location, age, anticoagulant use, Glasgow Coma Scale score, any withdrawal of care order, and treatment randomization arm. However, there were no relationships of IVH expansion on subsequent ventriculoperitoneal shunt placement (adjusted OR, 1.02 [95% CI, 0.58-1.80]) after adjusting for similar covariates.

CONCLUSIONS

In a clinical trial cohort of patients with large IVH, acute hematoma characteristics, specifically larger parenchymal volume, hematoma expansion, and thalamic ICH location were associated with IVH expansion. Given that IVH expansion resulted in poor functional outcomes, exploration of treatment approaches to optimize hemostasis and prevent IVH expansion, particularly in patients with thalamic ICH, require further study.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT00784134.

Fragility Index Meta-Analysis of Randomized Controlled Trials Shows Highly Robust Evidential Strength for Benefit of <3 Hour Intravenous Alteplase

BACKGROUND

Cumulative fragility index (FI) analysis enables quantification of the evidential strength of intravenous alteplase's core indication-treatment of disabling acute ischemic stroke within 3 hours of onset.

METHODS

Meta-analyses were performed (study level) or identified (individual participant level) for freedom-from-disability (modified Rankin Scale [mRS] score 0-1, primary efficacy), functional independence (mRS score 0-2, secondary efficacy), and mortality outcomes. Individual trial and cumulative FI analyses were serially conducted after each successive randomized controlled trial (RCT). FI scores were classified as follows: not robust (FI 0-4), somewhat robust (FI 5-12), robust (FI 13-33), and highly robust (FI >33).

RESULTS

Nine randomized controlled trials were identified from 1995 to 2021 of within-3-hour intravenous alteplase for acute ischemic stroke. In study-level meta-analyses, alteplase increased freedom-from-disability outcome (mRS score 0-1), 31.0% versus 22.3%, relative risk, 1.39 (95% CI, 1.20-1.61); P<0.00001; increased functional independence (mRS score 0-2), 39.7% versus 31.2%, relative risk, 1.29 (95% CI, 1.14-1.45), P<0.000; and did not alter mortality, 24.1% versus 26.1%; P=0.23. Overall FIs for study-level meta-analyses were both highly robust at 42 and 40 for mRS score 0-1 and mRS score 0-2, respectively. Serial FI analyses showed robust evidential strength for intravenous alteplase superiority with publication of the 2 NINDS-tPA trials (National Institute of Neurological Disorders and Stroke-tissue-type plasminogen activator) in 1995, increased to highly robust in 2012, and remains highly robust in 2021.

CONCLUSIONS

Within-3-hour intravenous alteplase for acute ischemic stroke is one of the most robustly proven therapies in medicine. The initial concurrent trials 25 years ago showed robust evidence for benefit and, after additional studies, advanced to highly robust.

Tissue-type plasminogen activator induces TNF-α-mediated preconditioning of the blood-brain barrier

Ischemic tolerance is a phenomenon whereby transient exposure to a non-injurious preconditioning stimulus triggers resistance to a subsequent lethal ischemic insult. Despite the fact that not only neurons but also astrocytes and endothelial cells have a unique response to preconditioning stimuli, current research has been focused mostly on the effect of preconditioning on neuronal death. Thus, it is unclear if the blood-brain barrier (BBB) can be preconditioned independently of an effect on neuronal survival. The release of tissue-type plasminogen activator (tPA) from perivascular astrocytes in response to an ischemic insult increases the permeability of the BBB. In line with these observations, treatment with recombinant tPA increases the permeability of the BBB and genetic deficiency of tPA attenuates the development of post-ischemic edema. Here we show that tPA induces ischemic tolerance in the BBB independently of an effect on neuronal survival. We found that tPA renders the BBB resistant to an ischemic injury by inducing TNF-α-mediated astrocytic activation and increasing the abundance of aquaporin-4-immunoreactive astrocytic end-feet processes in the neurovascular unit. This is a new role for tPA, that does not require plasmin generation, and with potential therapeutic implications for patients with cerebrovascular disease.

Association of Intravenous Alteplase, Early Reperfusion, and Clinical Outcome in Patients With Large Vessel Occlusion Stroke: Post Hoc Analysis of the Randomized DIRECT-MT Trial

BACKGROUND

The added value of intravenous alteplase in reperfusing ischemic brain tissue in patients undergoing endovascular treatment and directly presented to an endovascular treatment-capable hospital is uncertain. We conducted this post hoc analysis of a randomized trial (DIRECT-MT [Direct Intraarterial Thrombectomy in Order to Revascularize Acute Ischemic Stroke Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals: A Multicenter Randomized Clinical Trial]) to explore the association of intravenous alteplase, early (preendovascular treatment) reperfusion, and clinical outcome and to determine factors which may modify alteplase treatment effect on early reperfusion.

METHODS

In this post hoc analysis of the DIRECT-MT randomized trial comparing intravenous alteplase before endovascular treatment versus endovascular treatment only, 623 of 656 randomized patients, with adequate angiographic evaluation for early reperfusion assessment, were included. The association of intravenous alteplase and early reperfusion (defined as expanded Thrombolysis in Cerebral Infarction score ≥2a on angiogram) was assessed using unadjusted comparisons and multivariable logistic regression.

RESULTS

Among 623 patients included (317 received intravenous alteplase and 306 did not), early reperfusion occurred in 91 (15%) patients and was associated with better functional outcome (modified Rankin Scale score, 0-2 of 49/91 [54%] versus 178/531 [34%]; adjusted odds ratio, 1.92 [95% CI, 1.15-3.21]; P<0.001). Intravenous alteplase was independently associated with early reperfusion (59/317 [19%] versus 32/306 [10%]; adjusted odds ratio, 2.06 [95% CI, 1.27-3.33]; P=0.003), and the alteplase effect was modified by time from randomization to groin puncture (dichotomized by median, ≤33 minutes; adjusted odds ratio, 1.06 [95% CI, 0.53-2.10] versus >33 minutes; adjusted odds ratio, 4.07 [95% CI, 1.86-8.86]; P_interaction=0.012).

CONCLUSIONS

For patients with large vessel occlusion directly presenting to an endovascular treatment-capable hospital, intravenous alteplase increases early reperfusion when endovascular treatment gets delayed more than approximately half an hour. Thus, intravenous alteplase should be considered if endovascular treatment delays are anticipated by the treating medical team. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03469206.

Underutilization of Endovascular Therapy in Black Patients With Ischemic Stroke: An Analysis of State and Nationwide Cohorts

BACKGROUND AND PURPOSE

Endovascular therapy (EVT) is a very effective treatment but relies on specialized capabilities that are not available in every hospital where acute ischemic stroke is treated. Here, we assess whether access to and utilization of this therapy has extended uniformly across racial and ethnic groups.

METHODS

We conducted a retrospective, population-based study using the 2019 Texas Inpatient Public Use Data File. Acute ischemic stroke cases and EVT use were identified using the International Classification of Diseases, Tenth Revision (ICD-10) diagnosis and procedure codes. We examined EVT utilization by race/ethnicity and performed patient- and hospital-level analyses. To validate state-specific findings, we conducted patient-level analyses using the 2017 National Inpatient Sample for national estimates. To assess independent associations between race/ethnicity and EVT, multivariable modified Poisson regressions were fitted and adjusted relative risks were estimated accounting for patient risk factors and socioeconomic characteristics.

RESULTS

Among 40 814 acute ischemic stroke cases in Texas in 2019, 54% were White, 17% Black, and 21% Hispanic. Black patients had similar admissions to EVT-performing hospitals and greater admissions to comprehensive stroke centers (CSCs) compared with White patients (EVT 62% versus 62%, P=0.21; CSCs 45% versus 39%, P<0.001) but had lower EVT rates (4.1% versus 5.3%; adjusted relative risk, 0.76 [0.66-0.88]; P<0.001). There were no differences in EVT rates between Hispanic and White patients. Lower rates of EVT among Black patients were consistent in the subgroup of patients who arrived in early time windows and received intravenous recombinant tissue-type plasminogen activator (adjusted relative risk, 0.77 [0.61-0.98]; P=0.032) and the subgroup of those admitted to EVT-performing hospitals in both non-CSC (3.0% versus 5.5, P<0.001) and CSC hospitals (7.9% versus 10.4%, P<0.001) while there were no differences between Whites and Hispanic patients. Nationwide sample data confirmed this finding of lower utilization of EVT among Black patients (adjusted relative risk, 0.87 [0.77-0.98]; P=0.024).

CONCLUSIONS

We found no evidence of disparity in presentation to EVT-performing hospitals or CSCs; however, lower rates of EVT were observed in Black patients.

Review of evidence implicating the plasminogen activator system in blood-brain barrier dysfunction associated with Alzheimer's disease

Elucidating the pathogenic mechanisms of Alzheimer’s disease (AD) to identify therapeutic targets has been the focus of many decades of research. While deposition of extracellular amyloid-beta plaques and intraneuronal neurofibrillary tangles of hyperphosphorylated tau have historically been the two characteristic hallmarks of AD pathology, therapeutic strategies targeting these proteinopathies have not been successful in the clinics. Neuroinflammation has been gaining more attention as a therapeutic target because increasing evidence implicates neuroinflammation as a key factor in the early onset of AD disease progression. The peripheral immune response has emerged as an important contributor to the chronic neuroinflammation associated with AD pathophysiology. In this context, the plasminogen activator system (PAS), also referred to as the vasculature’s fibrinolytic system, is emerging as a potential factor in AD pathogenesis. Evolving evidence suggests that the PAS plays a role in linking chronic peripheral inflammatory conditions to neuroinflammation in the brain. While the PAS is better known for its peripheral functions, components of the PAS are expressed in the brain and have been demonstrated to alter neuroinflammation and blood-brain barrier (BBB) permeation. Here, we review plasmin-dependent and -independent mechanisms by which the PAS modulates the BBB in AD pathogenesis and discuss therapeutic implications of these observations.

Evidence-Based Disparities in Stroke Care Metrics and Outcomes in the United States: A Systematic Review

Stroke disproportionately affects racial minorities, and the level to which stroke treatment practices differ across races is understudied. Here, we performed a systematic review of disparities in stroke treatment between racial minorities and White patients. A systematic literature search was performed on PubMed to identify studies published from January 1, 2010, to April 5, 2021 that investigated disparities in access to stroke treatment between racial minorities and White patients. A total of 30 studies were included in the systematic review. White patients were estimated to use emergency medical services at a greater rate (59.8%) than African American (55.6%), Asian (54.7%), and Hispanic patients (53.2%). A greater proportion of White patients (37.4%) were estimated to arrive within 3 hours from onset of stroke symptoms than African American (26.0%) and Hispanic (28.9%) patients. A greater proportion of White patients (2.8%) were estimated to receive tPA (tissue-type plasminogen activator) as compared with African American (2.3%), Hispanic (2.6%), and Asian (2.3%) patients. Rates of utilization of mechanical thrombectomy were also lower in minorities than in the White population. As shown in this review, racial disparities exist at key points along the continuum of stroke care from onset of stroke symptoms to treatment. Beyond patient level factors, these disparities may be attributed to other provider and system level factors within the health care ecosystem.

Pathomechanisms Underlying Hypoxemia in Two COVID-19-Associated Acute Respiratory Distress Syndrome Phenotypes: Insights From Thrombosis and Hemostasis

BACKGROUND

The pathomechanisms of hypoxemia and treatment strategies for type H and type L acute respiratory distress syndrome (ARDS) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced coronavirus disease 2019 (COVID-19) have not been elucidated.

MAIN TEXT

SARS-CoV-2 mainly targets the lungs and blood, leading to ARDS, and systemic thrombosis or bleeding. Angiotensin II-induced coagulopathy, SARS-CoV-2-induced hyperfibrin(ogen)olysis, and pulmonary and/or disseminated intravascular coagulation due to immunothrombosis contribute to COVID-19-associated coagulopathy. Type H ARDS is associated with hypoxemia due to diffuse alveolar damage-induced high right-to-left shunts. Immunothrombosis occurs at the site of infection due to innate immune inflammatory and coagulofibrinolytic responses to SARS-CoV-2, resulting in microvascular occlusion with hypoperfusion of the lungs. Lung immunothrombosis in type L ARDS results from neutrophil extracellular traps containing platelets and fibrin in the lung microvasculature, leading to hypoxemia due to impaired blood flow and a high ventilation/perfusion (VA/Q) ratio. COVID-19-associated ARDS is more vascular centric than the other types of ARDS. D-dimer levels have been monitored for the progression of microvascular thrombosis in COVID-19 patients. Early anticoagulation therapy in critical patients with high D-dimer levels may improve prognosis, including the prevention and/or alleviation of ARDS.

CONCLUSIONS

Right-to-left shunts and high VA/Q ratios caused by lung microvascular thrombosis contribute to hypoxemia in type H and L ARDS, respectively. D-dimer monitoring-based anticoagulation therapy may prevent the progression to and/or worsening of ARDS in COVID-19 patients.

Two-Chains Tissue Plasminogen Activator Unifies Met and NMDA Receptor Signalling to Control Neuronal Survival

Tissue-type plasminogen activator (tPA) plays roles in the development and the plasticity of the nervous system. Here, we demonstrate in neurons, that by opposition to the single chain form (sc-tPA), the two-chains form of tPA (tc-tPA) activates the MET receptor, leading to the recruitment of N-Methyl-d-Aspartate receptors (NMDARs) and to the endocytosis and proteasome-dependent degradation of NMDARs containing the GluN2B subunit. Accordingly, tc-tPA down-regulated GluN2B-NMDAR-driven signalling, a process prevented by blockers of HGFR/MET and mimicked by its agonists, leading to a modulation of neuronal death. Thus, our present study unmasks a new mechanism of action of tPA, with its two-chains form mediating a crosstalk between MET and the GluN2B subunit of NMDARs to control neuronal survival.

Achieving More Rapid Door-to-Needle Times and Improved Outcomes in Acute Ischemic Stroke in a Nationwide Quality Improvement Intervention

BACKGROUND AND PURPOSE

The benefits of tPA (tissue-type plasminogen activator) in acute ischemic stroke are time-dependent. However, delivery of thrombolytic therapy rapidly after hospital arrival was initially occurring infrequently in hospitals in the United States, discrepant with national guidelines.

METHODS

We evaluated door-to-needle (DTN) times and clinical outcomes among patients with acute ischemic stroke receiving tPA before and after initiation of 2 successive nationwide quality improvement initiatives: Target: Stroke Phase I (2010-2013) and Target: Stroke Phase II (2014-2018) from 913 Get With The Guidelines-Stroke hospitals in the United States between April 2003 and September 2018.

RESULTS

Among 154 221 patients receiving tPA within 3 hours of stroke symptom onset (median age 72 years, 50.1% female), median DTN times decreased from 78 minutes (interquartile range, 60-98) preintervention, to 66 minutes (51-87) during Phase I, and 50 minutes (37-66) during Phase II (P<0.001). Proportions of patients with DTN ≤60 minutes increased from 26.4% to 42.7% to 68.6% (P<0.001). Proportions of patients with DTN ≤45 minutes increased from 10.1% to 17.7% to 41.4% (P<0.001). By the end of the second intervention, 75.4% and 51.7% patients achieved 60-minute and 45-minute DTN goals. Compared with the preintervention period, hospitals during the second intervention period (2014-2018) achieved higher rates of tPA use (11.7% versus 5.6%; adjusted odds ratio, 2.43 [95% CI, 2.31-2.56]), lower in-hospital mortality (6.0% versus 10.0%; adjusted odds ratio, 0.69 [0.64-0.73]), fewer bleeding complication (3.4% versus 5.5%; adjusted odds ratio, 0.68 [0.62-0.74]), and higher rates of discharge to home (49.6% versus 35.7%; adjusted odds ratio, 1.43 [1.38-1.50]). Similar findings were found in sensitivity analyses of 185 501 patients receiving tPA within 4.5 hours of symptom onset.

CONCLUSIONS

A nationwide quality improvement program for acute ischemic stroke was associated with substantial improvement in the timeliness of thrombolytic therapy start, increased thrombolytic treatment, and improved clinical outcomes.