Thrombolysis With Alteplase at 0.6 mg/kg for Stroke With Unknown Time of Onset: A Randomized Controlled Trial

Outcomes of wake-up stroke undergoing mechanical thrombectomy: A systematic review and meta-analysis

BACKGROUND

Wake-up stroke represents a significant challenge in acute treatment and care. Thrombolysis has been extensively studied in the wake-up stroke population. However, mechanical thrombectomy in wake-up stroke exclusively has not been well studied. We performed a systematic review and meta-analysis to assess the clinical and functional outcomes of patients undergoing mechanical thrombectomy for wake-up stroke.

METHODS

We performed a systematic review of the literature using publically accessible databases. Data extraction was completed using Nested Knowledge AutoLit software. Outcomes of interest included modified Rankin Scale (mRS) 0-2, mortality, symptomatic intracerebral hemorrhage (sICH), and thrombolysis in cerebral infarction (TICI) score 2b/3. Statistical analysis was performed using R software version 4.1.2.

RESULTS

A total of 12 studies were included in our study with a total of 510 patients included. Patients with wake-up stroke were found to have good functional outcome (mRS 0-2) in 46.2% of patients and successful reperfusion (TICI 2b/3) was seen in 83.5% of patients. Mortality was observed in 20.4% of patients with sICH seen in 8.3%.

CONCLUSION

Mechanical thrombectomy for patients with wake-up stroke was found to have favorable rates of good functional outcomes and relatively low rates of adverse events.

Comprehensive Review of Tenecteplase for Thrombolysis in Acute Ischemic Stroke

Although intravenous thrombolysis with alteplase remains the primary treatment for acute ischemic stroke, tenecteplase has shown potential advantages over alteplase. Animal studies have demonstrated the favorable pharmacokinetics and pharmacodynamics of tenecteplase. Moreover, it is easier to administer. Clinical trials have demonstrated that tenecteplase is not inferior to alteplase and may even be superior in cases of acute ischemic stroke with large vessel occlusion. Current evidence supports the time and cost benefits of tenecteplase, suggesting that it could potentially replace alteplase as the main option for thrombolytic therapy, especially in patients with large vessel occlusion.

Thrombolysis for Wake-Up Stroke Versus Non-Wake-Up Unwitnessed Stroke: EOS Individual Patient Data Meta-Analysis

BACKGROUND

Stroke with unknown time of onset can be categorized into 2 groups; wake-up stroke (WUS) and unwitnessed stroke with an onset time unavailable for reasons other than wake-up (non-wake-up unwitnessed stroke, non-WUS). We aimed to assess potential differences in the efficacy and safety of intravenous thrombolysis (IVT) between these subgroups.

METHODS

Patients with an unknown-onset stroke were evaluated using individual patient-level data of 2 randomized controlled trials (WAKE-UP [Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke], THAWS [Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes With Alteplase at 0.6 mg/kg]) comparing IVT with placebo or standard treatment from the EOS (Evaluation of Unknown-Onset Stroke Thrombolysis trial) data set. A favorable outcome was prespecified as a modified Rankin Scale score of 0 to 1 at 90 days. Safety outcomes included symptomatic intracranial hemorrhage at 22 to 36 hours and 90-day mortality. The IVT effect was compared between the treatment groups in the WUS and non-WUS with multivariable logistic regression analysis.

RESULTS

Six hundred thirty-four patients from 2 trials were analyzed; 542 had WUS (191 women, 272 receiving alteplase), and 92 had non-WUS (42 women, 43 receiving alteplase). Overall, no significant interaction was noted between the mode of onset and treatment effect (P value for interaction=0.796). In patients with WUS, the frequencies of favorable outcomes were 54.8% and 45.5% in the IVT and control groups, respectively (adjusted odds ratio, 1.47 [95% CI, 1.01-2.16]). Death occurred in 4.0% and 1.9%, respectively (P=0.162), and symptomatic intracranial hemorrhage in 1.8% and 0.3%, respectively (P=0.194). In patients with non-WUS, no significant difference was observed in favorable outcomes relative to the control (37.2% versus 29.2%; adjusted odds ratio, 1.76 [0.58-5.37]). One death and one symptomatic intracranial hemorrhage were reported in the IVT group, but none in the control.

CONCLUSIONS

There was no difference in the effect of IVT between patients with WUS and non-WUS. IVT showed a significant benefit in patients with WUS, while there was insufficient statistical power to detect a substantial benefit in the non-WUS subgroup.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: CRD42020166903.

Magnetic Resonance Imaging-Guided Intravenous Thrombolysis in Cardioembolic Stroke Patients With Unknown Time of Onset - Subanalysis of the THAWS Randomized Control Trial

BACKGROUND

We investigated the clinical effect of intravenous thrombolysis using a magnetic resonance imaging (MRI)-guided approach in cardioembolic stroke (CE) patients with unknown time of onset.Methods and Results: This subanalysis of the THAWS trial assessed the efficacy and safety of alteplase 0.6 mg/kg in CE patients with unknown time of onset and showing diffusion-weighted imaging-fluid-attenuated inversion recovery mismatch. Patients were classified as CE and non-CE using the SSS-TOAST classification system during the acute period. The efficacy outcome was a modified Rankin Scale score of 0-1 at 90 days. In all, 126 patients from the THAWS trial were included in this study, of whom 45 (35.7%) were diagnosed with CE. In the CE group, a favorable outcome was numerically more frequent in the alteplase than control group (52% vs. 35%; adjusted odds ratio [aOR] 2.25; 95% confidence interval [CI] 0.50-9.99). However, in the non-CE group, favorable outcomes were comparable between the alteplase and control groups (44% vs. 55%, respectively; aOR 0.39; 95% CI 0.12-1.21). Treatment-by-cohort interaction for a favorable outcome was modestly significant between the CE and non-CE groups (P=0.069). In the CE group, no patients experienced symptomatic intracranial hemorrhage (ICH) or parenchymal hematoma Type II following thrombolysis.

CONCLUSIONS

When an MRI-guided approach is used, CE patients with unknown time of onset appear to be suitable candidates for thrombolysis.

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

Randomized Clinical Trials in Cerebrovascular Neurosurgery From 2018 to 2022

There has been an exponential increase in randomized controlled trials (RCTs) on cerebrovascular disease within neurosurgery. The goal of this study was to review, outline the scope, and summarize all phase 2b and phase 3 RCTs impacting cerebrovascular neurosurgery practice since 2018. We searched PubMed, MEDLINE, Embase, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases for relevant RCTs published between January 1, 2018, and July 1, 2022. We searched for studies related to eight major cerebrovascular disorders relevant to neurosurgery, including acute ischemic stroke, cerebral aneurysms and subarachnoid hemorrhage, intracerebral hemorrhage, subdural hematomas, cerebral venous thrombosis, arteriovenous malformations, Moyamoya disease and extracranial-intracranial bypass, and carotid and intracranial atherosclerosis. We limited our search to phase 2b or 3 RCTs related to cerebrovascular disorders published during the study period. The titles and abstracts of all relevant studies meeting our search criteria were included. Pediatric studies, stroke studies related to rehabilitation or cardiovascular disease, study protocols without published results, prospective cohort studies, registry studies, cluster randomized trials, and nonrandomized pivotal trials were excluded.  From an initial total of 2,797 records retrieved from the database searches, 1,641 records were screened after duplicates and studies outside of our time period were removed. After screening, 511 available reports within our time period of interest were assessed for eligibility. Pediatric studies, stroke studies related to rehabilitation or cardiovascular disease, study protocols without published results, prospective cohort studies, registry studies, cluster randomized trials, and nonrandomized pivotal trials were excluded. We found 80 unique phase 2b or 3 RCTs that fit our criteria, with 165 topic-relevant articles published within the study period.  Numerous RCTs in cerebrovascular neurosurgery have been published since 2018. Ischemic stroke, including mechanical thrombectomy and thrombolysis, accounted for a majority of publications, but there were large trials in intracerebral hemorrhage, subdural hemorrhage, aneurysms, subarachnoid hemorrhage, and cerebral venous thrombosis, among others. This review helps define the scope of the large RCTs published in the last four years to guide future research and clinical care.

Improvement of Functional Outcomes in Patients with Stroke who Received Alteplase for Over 15 Years: Japan Stroke Data Bank

AIM

The nationwide verification of intravenous thrombolysis (IVT) was rarely performed after the extension of the therapeutic time window of alteplase or after the expansion of mechanical thrombectomy (MT). We aimed to examine the long-term change in accurate real-world outcomes of IVT in patients with acute ischemic stroke (AIS) using the Japan Stroke Databank, a representative Japan-wide stroke database.

METHODS

We extracted all patients with AIS who received IVT with alteplase between October 11, 2005, the approval date for alteplase use for AIS in Japan, and December 31, 2020. Patients were categorized into three groups using two critical dates in Japan as cutoffs: the official extension date of the therapeutic time window for IVT to within 4.5 h of symptom onset and the publication date of the revised guideline, where the evidence level of MT was heightened. We assessed the yearly trend of IVT implementation rates and the secular changes and three-group changes in clinical outcomes at discharge.

RESULTS

Of 124,382 patients with AIS, 9,569 (7.7%) received IVT (females, 41%; median age, 75 years). The IVT implementation rate has generally increased over time and plateaued in recent years. The proportion of favorable outcomes (modified Rankin Scale score of 0-2) increased yearly over 15 years. The results of the changes in the outcomes of the three groups were similar to those of the annual changes.

CONCLUSIONS

We revealed that IVT implementation rates in patients with AIS increased, and the functional outcome in these patients improved over 15 years. Therefore, the Japanese IVT dissemination strategy is considered appropriate and effective.

Definition, prediction, prevention and management of patients with severe ischemic stroke and large infarction

ABSTRACT

Severe ischemic stroke carries a high rate of disability and death. The severity of stroke is often assessed by the degree of neurological deficits or the extent of brain infarct, defined as severe stroke and large infarction, respectively. Critically severe stroke is a life-threatening condition that requires neurocritical care or neurosurgical intervention, which includes stroke with malignant brain edema, a leading cause of death during the acute phase, and stroke with severe complications of other vital systems. Early prediction of high-risk patients with critically severe stroke would inform early prevention and treatment to interrupt the malignant course to fatal status. Selected patients with severe stroke could benefit from intravenous thrombolysis and endovascular treatment in improving functional outcome. There is insufficient evidence to inform dual antiplatelet therapy and the timing of anticoagulation initiation after severe stroke. Decompressive hemicraniectomy (DHC) <48 h improves survival in patients aged <60 years with large hemispheric infarction. Studies are ongoing to provide evidence to inform more precise prediction of malignant brain edema, optimal indications for acute reperfusion therapies and neurosurgery, and the individualized management of complications and secondary prevention. We present an evidence-based review for severe ischemic stroke, with the aims of proposing operational definitions, emphasizing the importance of early prediction and prevention of the evolution to critically severe status, summarizing specialized treatment for severe stroke, and proposing directions for future research.

The Value of Applying Machine Learning in Predicting the Time of Symptom Onset in Stroke Patients: Systematic Review and Meta-Analysis

BACKGROUND

Machine learning is a potentially effective method for identifying and predicting the time of the onset of stroke. However, the value of applying machine learning in this field remains controversial and debatable.

OBJECTIVE

We aimed to assess the value of applying machine learning in predicting the time of stroke onset.

METHODS

PubMed, Web of Science, Embase, and Cochrane were comprehensively searched. The C index and sensitivity with 95% CI were used as effect sizes. The risk of bias was evaluated using PROBAST (Prediction Model Risk of Bias Assessment Tool), and meta-analysis was conducted using R (version 4.2.0; R Core Team).

RESULTS

Thirteen eligible studies were included in the meta-analysis involving 55 machine learning models with 41 models in the training set and 14 in the validation set. The overall C index was 0.800 (95% CI 0.773-0.826) in the training set and 0.781 (95% CI 0.709-0.852) in the validation set. The sensitivity and specificity were 0.76 (95% CI 0.73-0.80) and 0.79 (95% CI 0.74-0.82) in the training set and 0.81 (95% CI 0.68-0.90) and 0.83 (95% CI 0.73-0.89) in the validation set, respectively. Subgroup analysis revealed that the accuracy of machine learning in predicting the time of stroke onset within 4.5 hours was optimal (training: 0.80, 95% CI 0.77-0.83; validation: 0.79, 95% CI 0.71-0.86).

CONCLUSIONS

Machine learning has ideal performance in identifying the time of stroke onset. More reasonable image segmentation and texture extraction methods in radiomics should be used to promote the value of applying machine learning in diverse ethnic backgrounds.

TRIAL REGISTRATION

PROSPERO CRD42022358898; https://www.crd.york.ac.uk/Prospero/display_record.php?RecordID=358898.

Intravenous Tenecteplase for Acute Ischemic Stroke Within 4.5-24 Hours of Onset (ROSE-TNK): A Phase 2, Randomized, Multicenter Study

BACKGROUND AND PURPOSE

Intravenous tenecteplase (TNK) efficacy has not been well demonstrated in acute ischemic stroke (AIS) beyond 4.5 hours after onset. This study aimed to determine the effect of intravenous TNK for AIS within 4.5 to 24 hours of onset.

METHODS

In this pilot trial, eligible AIS patients with diffusion-weighted imaging (DWI)-fluid attenuated inversion recovery (FLAIR) mismatch were randomly allocated to intravenous TNK (0.25 mg/kg) or standard care within 4.5-24 hours of onset. The primary endpoint was excellent functional outcome at 90 days (modified Rankin Scale [mRS] score of 0-1). The primary safety endpoint was symptomatic intracranial hemorrhage (sICH).

RESULTS

Of the randomly assigned 80 patients, the primary endpoint occurred in 52.5% (21/40) of TNK group and 50.0% (20/40) of control group, with no significant difference (unadjusted odds ratio, 1.11; 95% confidence interval 0.46-2.66; P=0.82). More early neurological improvement occurred in TNK group than in control group (11 vs. 3, P=0.03), but no significant differences were found in other secondary endpoints, such as mRS 0-2 at 90 days, shift analysis of mRS at 90 days, and change in National Institutes of Health Stroke Scale score at 24 hours and 7 days. There were no cases of sICH in this trial; however, asymptomatic intracranial hemorrhage occurred in 3 of the 40 patients (7.5%) in the TNK group.

CONCLUSION

This phase 2, randomized, multicenter study suggests that intravenous TNK within 4.5-24 hours of onset may be safe and feasible in AIS patients with a DWI-FLAIR mismatch.

Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes with Alteplase at 0.6 mg/kg in Clinical Practice: THAWS2 Study

INTRODUCTION

The aim of this study was to determine the safety and efficacy of intravenous (IV) alteplase at 0.6 mg/kg for patients with acute wake-up or unclear-onset strokes in clinical practice.

METHODS

This multicenter observational study enrolled acute ischemic stroke patients with last-known-well time >4.5 h who had mismatch between DWI and FLAIR and were treated with IV alteplase. The safety outcomes were symptomatic intracranial hemorrhage (sICH) after thrombolysis, all-cause deaths, and all adverse events. The efficacy outcomes were favorable outcome defined as an mRS score of 0-1 or recovery to the same mRS score as the premorbid score, complete independence defined as an mRS score of 0-1 at 90 days, and change in NIHSS at 24 h from baseline.

RESULTS

Sixty-six patients (35 females; mean age, 74 ± 11 years; premorbid complete independence, 54 [82%]; median NIHSS on admission, 11) were enrolled at 15 hospitals. Two patients (3%) had sICH. Median NIHSS changed from 11 (IQR, 6.75-16.25) at baseline to 5 (3-12.25) at 24 h after alteplase initiation (change, -4.8 ± 8.1). At discharge, 31 patients (47%) had favorable outcome and 29 (44%) had complete independence. None died within 90 days. Twenty-three (35%) also underwent mechanical thrombectomy (no sICH, NIHSS change of -8.5 ± 7.3), of whom 11 (48%) were completely independent at discharge.

CONCLUSIONS

In real-world clinical practice, IV alteplase for unclear-onset stroke patients with DWI-FLAIR mismatch provided safe and efficacious outcomes comparable to those in previous trials. Additional mechanical thrombectomy was performed safely in them.

[Intravenous thrombolysis of ischemic stroke-Current status]

Intravenous thrombolysis (IVT) treatment with alteplase (rtPA) is an essential part of the routine treatment of patients with ischemic stroke since its introduction in the late 1990s. Rapid treatment is of essential importance. For patients with an unclear time window, various mismatch concepts have been established to identify salvageable brain tissue prior to IVT. Numerous official contraindications for rtPA are not evidence-based; for example, current data from observational studies show that systemic thrombolytic treatment is possible even in patients receiving direct oral anticoagulant (DOAC) treatment. Tenecteplase (TNK) is an alternative thrombolytic agent with some pharmacologic advantages. The most recent guidelines indicate that TNK is particularly advantageous over rtPA in patients treated in combination with endovascular stroke therapy (EST). The combination of IVT and EST should primarily be performed in the 4.5‑h time window in patients without contraindications; in the later time window EST alone is conceivable if it can be performed without delay.

Cytoskeletal protein breakdown and serum albumin extravasation in MRI DWI-T2WI mismatch area in acute murine cerebral ischemia

MRI diffusion-weighted imaging (DWI)-FLAIR mismatch is known as predictive of symptom onset within 4.5 h. This study assessed the breakdown of cytoskeletal protein and blood-brain barrier (BBB) in DWI-T2 mismatch. We employed occlusion of middle cerebral artery (MCAO) in C57BL/6 mice. We serially measured MRI including DWI and T2WI. After MRI, we prepared brain sections or samples and examined microtubule-associated protein 2 (MAP2) expression, alpha-fodrin degradation, extravasation of albumin and claudin-5 expression. In permanent or transient MCAO for 45 min, DWI hyperintensities was already found at 60 min without change of T2, showing DWI-T2 mismatch. In permanent MCAO, MAP2 expressions were preserved, and no extravasation of albumin was observed. In transient MCAO, MAP2 immunoreaction was already lost in the lateral part of the striatum. In both models, alpha-fodrin degradation was already detected. At 180 min, T2 hyperintensities appeared, where MAP2 signal was lost and albumin extravasation was found. At 24 h, hyperintensities of DWI and T2WI was found in the whole MCA territory, where MAP2 signal was completely lost with marked albumin extravasation and alpha-fodrin degradation. Immunoreaction for claudin-5 was preserved up to 180 min. DWI-T2 mismatch area may not always indicate intactness of cytoskeletal protein but shows preservation of BBB.

Cerebrovascular disease in sickle cell disease

Sickle cell disease (SCD) is the most common type of hereditary anaemia and genetic disorder worldwide. Cerebrovascular disease is one of its most devastating complications, with consequent increased morbidity and mortality. Current guidelines suggest that children and adults with SCD who develop acute ischaemic stroke should be transfused without delay. Those with acute ischaemic stroke aged over 18 years who present within 4.5 hours of symptom onset should be considered for intravenous thrombolysis; older patients with conventional vascular risk factors are the most likely to benefit. Endovascular thrombectomy should be considered carefully in adults with SCD as there are few data to guide how the prevalence of cerebral vasculopathy may confound the expected benefits or risks of intervention. We present a practical approach to cerebrovascular disease in sickle cell patients based on the available evidence and our experience.

Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

BACKGROUND

Current evidence supports the use of intravenous thrombolysis with alteplase in patients with wake-up stroke selected with MRI or perfusion imaging and is recommended in clinical guidelines. However, access to advanced imaging techniques is often scarce. We aimed to determine whether thrombolytic treatment with intravenous tenecteplase given within 4·5 h of awakening improves functional outcome in patients with ischaemic wake-up stroke selected using non-contrast CT.

METHODS

TWIST was an investigator-initiated, multicentre, open-label, randomised controlled trial with blinded endpoint assessment, conducted at 77 hospitals in ten countries. We included patients aged 18 years or older with acute ischaemic stroke symptoms upon awakening, limb weakness, a National Institutes of Health Stroke Scale (NIHSS) score of 3 or higher or aphasia, a non-contrast CT examination of the head, and the ability to receive tenecteplase within 4·5 h of awakening. Patients were randomly assigned (1:1) to either a single intravenous bolus of tenecteplase 0·25 mg per kg of bodyweight (maximum 25 mg) or control (no thrombolysis) using a central, web-based, computer-generated randomisation schedule. Trained research personnel, who conducted telephone interviews at 90 days (follow-up), were masked to treatment allocation. Clinical assessments were performed on day 1 (at baseline) and day 7 of hospital admission (or at discharge, whichever occurred first). The primary outcome was functional outcome assessed by the modified Rankin Scale (mRS) at 90 days and analysed using ordinal logistic regression in the intention-to-treat population. This trial is registered with EudraCT (2014-000096-80), ClinicalTrials.gov (NCT03181360), and ISRCTN (10601890).

FINDINGS

From June 12, 2017, to Sept 30, 2021, 578 of the required 600 patients were enrolled (288 randomly assigned to the tenecteplase group and 290 to the control group [intention-to-treat population]). The median age of participants was 73·7 years (IQR 65·9-81·1). 332 (57%) of 578 participants were male and 246 (43%) were female. Treatment with tenecteplase was not associated with better functional outcome, according to mRS score at 90 days (adjusted OR 1·18, 95% CI 0·88-1·58; p=0·27). Mortality at 90 days did not significantly differ between treatment groups (28 [10%] patients in the tenecteplase group and 23 [8%] in the control group; adjusted HR 1·29, 95% CI 0·74-2·26; p=0·37). Symptomatic intracranial haemorrhage occurred in six (2%) patients in the tenecteplase group versus three (1%) in the control group (adjusted OR 2·17, 95% CI 0·53-8·87; p=0·28), whereas any intracranial haemorrhage occurred in 33 (11%) versus 30 (10%) patients (adjusted OR 1·14, 0·67-1·94; p=0·64).

INTERPRETATION

In patients with wake-up stroke selected with non-contrast CT, treatment with tenecteplase was not associated with better functional outcome at 90 days. The number of symptomatic haemorrhages and any intracranial haemorrhages in both treatment groups was similar to findings from previous trials of wake-up stroke patients selected using advanced imaging. Current evidence does not support treatment with tenecteplase in patients selected with non-contrast CT.

FUNDING

Norwegian Clinical Research Therapy in the Specialist Health Services Programme, the Swiss Heart Foundation, the British Heart Foundation, and the Norwegian National Association for Public Health.

Low-dose vs. standard-dose intravenous alteplase for acute ischemic stroke with unknown time of onset

Background

Standard-dose intravenous alteplase for acute ischemic stroke (AIS) in the unknown or extended time window beyond 4.5 h after symptom onset is both effective and safe for certain patients who were selected based on multimodal neuroimaging. However, uncertainty exists regarding the potential benefit of using low-dose alteplase among the Asian population outside the 4.5-h time window.

Methods

Consecutive AIS patients who received intravenous alteplase between 4.5 and 9 h after symptom onset or with an unknown time of onset guided by multimodal computed tomography (CT) imaging were identified from our prospectively maintained database. The primary outcome was excellent functional recovery, defined as having a modified Rankin scale (mRS) score of 0-1 at 90 days. Secondary outcomes included functional independence (an mRS score of 0-2 at 90 days), early major neurologic improvement (ENI), early neurologic deterioration (END), any intracranial hemorrhage (ICH), symptomatic ICH (sICH), and 90-day mortality. Propensity score matching (PSM) and multivariable logistic regression models were used to adjust for confounding factors and compare the clinical outcomes between the low- and standard-dose groups.

Results

From June 2019 to June 2022, a total of 206 patients were included in the final analysis, of which 143 were treated with low-dose alteplase and 63 were treated with standard-dose alteplase. After accounting for confounding factors, we observed that there were no statistically significant differences between the standard- and low-dose groups with respect to excellent functional recovery [adjusted odds ratio = 1.22 (aOR), 95% confidence interval (CI): 0.62-2.39; adjusted rate difference (aRD) = 4.6%, and 95% CI: -11.2 to 20.3%]. Patients of both groups had similar rates of functional independence, ENI, END, any ICH, sICH, and 90-day mortality. In the subgroup analysis, patients aged ≥70 years were more likely to achieve excellent functional recovery when receiving standard-dose rather than low-dose alteplase.

Conclusion

The effectiveness of low-dose alteplase might be comparable to that of standard-dose alteplase in AIS patients aged <70 years with favorable perfusion-imaging profiles in the unknown or extended time window but not in those aged ≥70 years. Furthermore, low-dose alteplase did not significantly reduce the risk of sICH compared to standard-dose alteplase.

Intravenous Alteplase at 0.6 mg/kg for Unknown Onset Stroke with Prior Antithrombotic Medication: THAWS Randomized Clinical Trial

AIM

This study aimed to assess the potential effect of prior antithrombotic medication for thrombolysis in an unknown onset stroke.

METHODS

This was a predefined sub-analysis of the THAWS trial. Stroke patients with a time last known well ＞4.5 h who had a DWI-fluid-attenuated inversion recovery mismatch were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg (alteplase group) or standard medical treatment (control group). Patients were dichotomized by prior antithrombotic medication.

RESULTS

Of 126 patients (intention-to-treat population), 40 took antithrombotic medication (24 with antiplatelets alone, 13 with anticoagulants alone, and 3 with both), and the remaining 86 did not before stroke onset. Of these, 17 and 52 patients, respectively, received alteplase, and 23 and 34, respectively, had standard medical treatment. Antithrombotic therapy was initiated within 24 h after randomization less frequently in the alteplase group (12% vs. 86%, p＜0.01). Both any intracranial hemorrhage within 22-36 h (26% vs. 14%) and a modified Rankin Scale score of 0-1 at 90 days (good outcome) (47% vs. 48%) were comparable between the two groups. A good outcome was more common in the alteplase group than in the control group in patients with prior antithrombotic medication [relative risk (RR) 2.25, 95% confidence interval (CI) 1.02-4.99], but it tended to be less common in the alteplase group in those without (RR 0.69, 95% CI 0.46-1.03) (p＜0.01 for interaction). The frequency of any intracranial hemorrhage did not significantly differ between the two groups in any patients dichotomized by prior antithrombotic medication.

CONCLUSION

Alteplase appears more beneficial in patients with prior antithrombotic medication.

The efficacy and safety of alteplase treatment in patients with acute ischemic stroke with unknown time of onset: -Real world data

INTRODUCTION

Treatment with alteplase for acute ischemic stroke patients with an unknown time of onset is safe and effective. However, clinical trials have some selection bias. The purpose of this study was to clarify the efficacy and safety of alteplase treatment in patients with unknown time of onset in a real-world clinical setting.

METHODS

We included consecutive patients with acute ischemic stroke visited within 4.5 h of onset or symptom recognition. We divided patients into two groups: onset clear group (C-group) and unknown time of onset group (U-group). We treated patients with an unknown time of onset if the DWI-FLAIR mismatch was positive. We calculated the prevalence of alteplase treatment in each group and compared prognosis between the two groups.

RESULTS

Six hundred thirty-two patients arrived within 4.5 h of onset or symptom recognition. Of these, 446 patients (71 %) were in the C-group and 186 (29 %) in the U group. Alteplase treatment was performed in 35 % of patients in the C group and in 18 % in the U group (p < 0.001). Favorable outcomes at 90 days in patients treated with alteplase were comparable between the C group (52 %) and the U group (53 %) (p = 0.887). All hemorrhagic complications, including non-symptomatic hemorrhagic transformation, occurred in 11 of 157 patients (7 %) in the C-group and one of 34 patients (3 %) in the U-group (p = 0.696).

CONCLUSION

In a real-world clinical setting, alteplase treatment was performed safe in 18% of patients with an unknown time of stroke onset based on patient selection using the DWI-FLAIR mismatch.

Ischemic stroke with unknown onset of symptoms: current scenario and perspectives for the future

BACKGROUND

Stroke is a major cause of disability worldwide and a neurological emergency. Intravenous thrombolysis and mechanical thrombectomy are effective in the reperfusion of the parenchyma in distress, but the impossibility to determine the exact time of onset was an important cause of exclusion from treatment until a few years ago.

OBJECTIVES

To review the clinical and radiological profile of patients with unknown-onset stroke, the imaging methods to guide the reperfusion treatment, and suggest a protocol for the therapeutic approach.

METHODS

The different imaging methods were grouped according to current evidence-based treatments.

RESULTS

Most studies found no difference between the clinical and imaging characteristics of patients with wake-up stroke and known-onset stroke, suggesting that the ictus, in the first group, occurs just prior to awakening. Regarding the treatment of patients with unknown-onset stroke, four main phase-three trials stand out: WAKE-UP and EXTEND for intravenous thrombolysis, and DAWN and DEFUSE-3 for mechanical thrombectomy. The length of the therapeutic window is based on the diffusion weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch, core-penumbra mismatch, and clinical core mismatch paradigms. The challenges to approach unknown-onset stroke involve extending the length of the time window, the reproducibility of real-world imaging modalities, and the discovery of new methods and therapies for this condition.

CONCLUSION

The advance in the possibilities for the treatment of ischemic stroke, while guided by imaging concepts, has become evident. New studies in this field are essential and needed to structure the health care services for this new scenario.

Detection of acute ischemic stroke and backtracking stroke onset time via machine learning analysis of metabolomics

The time window from stroke onset is critical for the treatment decision. However, in unknown onset stroke, it is often difficult to determine the exact onset time because of the lack of assessment methods, which can result in controversial and random treatment decisions. Previous studies have shown that serum biomarkers, in addition to imaging assessment, are useful for determining the stroke onset time. However, as yet there are no specific biomarkers or corresponding methodologies that are accurate and effective for determining the onset time of unknown onset stroke. Herein, we describe our novel advanced metabolites-based machine learning method (termed extreme gradient boost [XGBoost]) combined with recursive feature elimination, which accurately screened five metabolites from 1124 metabolites detected in serum. These metabolites were capable of both detecting acute ischemic stroke and backtracking the acute ischemic stroke onset time. To further investigate the pathological mechanisms of acute ischemic stroke, we also examined characteristic metabolites in different brain regions, and found two metabolites that could distinguish the core infarct area from the ischemic penumbra. Although this study is based on animal experiments, our machine learning framework and selected metabolites may provide a basis for clinical stroke evaluation and treatment.

Retinal and optic nerve magnetic resonance diffusion-weighted imaging in acute non-arteritic central retinal artery occlusion

OBJECTIVES

Diffusion weighted imaging hyperintensity (DWI-H) has been described in the retina and optic nerve during acute central retinal artery occlusion (CRAO). We aimed to determine whether DWI-H can be accurately identified on standard brain magnetic resonance imaging (MRI) in non-arteritic CRAO patients at two tertiary academic centers.

MATERIALS AND METHODS

Retrospective cross-sectional study that included all consecutive adult patients with confirmed acute non-arteritic CRAO and brain MRI performed within 14 days of CRAO. At each center, two neuroradiologists masked to patient clinical data reviewed each MRI for DWI-H in the retina and optic nerve, first independently then together. Statistical analysis for inter-rater reliability and correlation with clinical data was performed.

RESULTS

We included 204 patients [mean age 67.9±14.6 years; 47.5% females; median time from CRAO to MRI 1 day (IQR 1-4.3); 1.5 T in 127/204 (62.3%) and 3.0 T in 77/204 (37.7%)]. Inter-rater reliability varied between centers (κ = 0.27 vs. κ = 0.65) and was better for retinal DWI-H. Miss and error rates significantly differed between neuroradiologists at each center. After consensus review, DWI-H was identified in 87/204 (42.6%) patients [miss rate 117/204 (57.4%) and error rate 11/87 (12.6%)]. Significantly more patients without DWI-H had good visual acuity at follow-up (p = 0.038).

CONCLUSIONS

In this real-world case series, differences in agreement and interpretation accuracy among neuroradiologists limited the role of DWI-H in diagnosing acute CRAO on standard MRI. DWI-H was identified in 42.6% of patients and was more accurately detected in the retina than in the optic nerve. Further studies are needed with standardized novel MRI protocols.

Systematic Review of Existing Stroke Guidelines: Case for a Change

Methods

We systematically searched for guideline recommendation on the day-to-day use of peripheral inflammatory markers such as NLR published in the English language between January 1, 2005, and October 2020. Any other evidence of system biology-based approach or recommendation was explored within the selected guidelines for this scoping review. Only the latest guideline per writing group was selected. Each guideline was analyzed independently by 2 to 4 authors to determine clinical scenarios explained/given, scientific evidence used, and recommendations presented in the context of system biology.

Results

The scoping review found 2,911 titles at the beginning of the search. Final review included with 15 guidelines. Stroke-related organizations wrote sixty-five percent of the guidelines while national ministries wrote a fewer number of guidelines. We were primarily interested in recommendations for acute management in AIS published in the English language. Fifteen eligible guidelines were identified from 15 different countries/regions. None of the guidelines recommended the routine use of peripheral markers of inflammation, such as NLR, among their acute assessment and management recommendations. None of the existing guidelines explored the system biology approach to one of the most complex diseases affecting the human brain, stroke.

Conclusions

This systematic review has identified a significant evidence-practice gap in all existing national stroke guidelines published in English medium as of October 2020. These guidelines included the only current “living stroke guidelines,” stroke guidelines from Australia with a real opportunity to modernize the living stroke guidelines with systems biology approach, and provide 2020 vision towards better stroke care globally. Investigation of complex disease such as stroke is best served through a systems biology approach. One of the easiest places to start is simple blood tests such as total white cell count and NLR. Systems biology approach point us towards simple tools such immune-inflammatory index (SII) and serial systemic immune inflammatory indices (SSIIi) which should pave the way for the stroke physician community address the challenges in systems biology approach in stroke care. These challenges include translating bench research to the bedside, managing big data (continuous pulse, blood pressure, sleep, oxygen saturation, progressive changes in NLR, SII, SSIIi, etc.). Working with an interdisciplinary team also provides a distinct advantage. Recent adoption of historic WHO-IGAP calls for immediate action. The 2022 World Brain Day campaign on Brain Health for All is the perfect opportunity to raise awareness and start the process.

The End of Tissue-Type Plasminogen Activator's Reign?

Mechanical thrombectomy is a highly effective treatment for acute ischemic stroke caused by large-vessel occlusion in the anterior cerebral circulation, significantly increasing the likelihood of recovery to functional independence. Until recently, whether intravenous thrombolysis before mechanical thrombectomy provided additional benefits to patients with acute ischemic stroke-large-vessel occlusion remained unclear. Given that reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke-large-vessel occlusion and the efficacy of both intravenous thrombolysis and mechanical thrombectomy is time-dependent, achieving complete reperfusion with a single pass should be the primary angiographic goal. However, it remains undetermined whether extending the procedure with additional endovascular attempts or local lytics administration safely leads to higher reperfusion grades and whether there are significant public health and cost implications. Here, we outline the current state of knowledge and research avenues that remain to be explored regarding the consistent therapeutic benefit of intravenous thrombolysis in anterior circulation strokes and the potential place of adjunctive intra-arterial lytics administration, including alternative thrombolytic agent place.

Advances in Acute Ischemic Stroke Therapy

The treatment of acute ischemic stroke continues to advance. The mainstay of treatment remains intravenous thrombolysis with alteplase. Recent studies demonstrated that later treatment with alteplase is beneficial in patients selected with advanced imaging techniques. Tenecteplase has been evaluated as an alternative thrombolytic drug and evidence suggests that it is as least as effective as alteplase and may lyse large vessel clots more effectively. Endovascular therapy with mechanical thrombectomy has now been shown to be beneficial up to 24 hours after stroke onset in carefully selected patients with proximal, large vessel occlusions. Ongoing studies are evaluating the effectiveness of thrombectomy in patients with more distal vessel occlusions and patients with proximal large vessel occlusions with larger ischemic core volumes and also in patients with milder neurological deficits. Cytoprotection is another potential acute stroke therapy that has not demonstrated efficacy in prior clinical trials. It should be reconsidered as an adjunct to reperfusion and a variety of new clinical trials can be envisioned to evaluate the potential benefits of cytoprotection in patients before and after reperfusion.

European Stroke Organisation (ESO)-European Society for Minimally Invasive Neurological Therapy (ESMINT) expedited recommendation on indication for intravenous thrombolysis before mechanical thrombectomy in patients with acute ischemic stroke and anterior circulation large vessel occlusion

Six randomized controlled clinical trials have assessed whether mechanical thrombectomy (MT) alone is non-inferior to intravenous thrombolysis (IVT) plus MT within 4.5 hours of symptom onset in patients with anterior circulation large vessel occlusion (LVO) ischemic stroke and no contraindication to IVT. An expedited recommendation process was initiated by the European Stroke Organisation (ESO) and conducted with the European Society of Minimally Invasive Neurological Therapy (ESMINT) according to ESO standard operating procedure based on the GRADE system. We identified two relevant Population, Intervention, Comparator, Outcome (PICO) questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote evidence-based recommendations. Expert opinion was provided if insufficient evidence was available to provide recommendations based on the GRADE approach.For stroke patients with anterior circulation LVO directly admitted to a MT-capable center ('mothership') within 4.5 hours of symptom onset and eligible for both treatments, we recommend IVT plus MT over MT alone (moderate evidence, strong recommendation). MT should not prevent the initiation of IVT, nor should IVT delay MT. In stroke patients with anterior circulation LVO admitted to a center without MT facilities and eligible for IVT ≤4.5 hours and MT, we recommend IVT followed by rapid transfer to a MT capable-center ('drip-and-ship') in preference to omitting IVT (low evidence, strong recommendation). Expert consensus statements on ischemic stroke on awakening from sleep are also provided. Patients with anterior circulation LVO stroke should receive IVT in addition to MT if they have no contraindications to either treatment.

Point-of-care ultrasound for stroke patients in the emergency room

Stroke requires rapid determination of the cause to provide timely and appropriate initial management. Various ultrasonographic techniques have been evaluated as ways to determine the cause of stroke; among them, carotid artery ultrasonography is particularly useful since it provides considerable information within a short time period when used to evaluate a specific site. In the emergency room, carotid artery ultrasonography can be used to diagnose internal carotid artery stenosis, predict an occluded vessel, and infer the cause of ischemic stroke. Additionally, carotid artery ultrasonography can diagnose different conditions including subclavian artery steal syndrome, bow hunter's stroke, Takayasu's arteritis, moyamoya disease, and dural arteriovenous fistula. Furthermore, patients with ischemic stroke with a pulse deficit or hypotension must be differentiated from acute type A aortic dissection, which requires emergency surgery; carotid artery ultrasonography can immediately differentiate between the two conditions by identifying the intimal flap of the common carotid artery. The following article provides an overview of carotid artery ultrasonography performed as point-of-care ultrasound in the emergency room in patients with suspected stroke.

EXPRESS: European Stroke Organisation (ESO) – European Society for Minimally Invasive Neurological Therapy (ESMINT) expedited recommendation on indication for intravenous thrombolysis before mechanical thrombectomy in patients with acute ischaemic stroke and anterior circulation large vessel occlusion

Six randomized controlled clinical trials have assessed whether mechanical thrombectomy (MT) alone is non-inferior to intravenous thrombolysis (IVT) plus MT within 4.5 hours of symptom onset in patients with anterior circulation large vessel occlusion (LVO) ischaemic stroke and no contraindication to IVT. An expedited recommendation process was initiated by the European Stroke Organisation (ESO) and conducted with the European Society of Minimally Invasive Neurological Therapy (ESMINT) according to ESO standard operating procedure based on the GRADE system. We identified two relevant Population, Intervention, Comparator, Outcome (PICO) questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote evidence-based recommendations. Expert opinion was provided if insufficient evidence was available to provide recommendations based on the GRADE approach. For stroke patients with anterior circulation LVO directly admitted to a MT-capable centre (“mothership”) within 4.5 hours of symptom onset and eligible for both treatments, we recommend IVT plus MT over MT alone (moderate evidence, strong recommendation). MT should not prevent the initiation of IVT, nor should IVT delay MT. In stroke patients with anterior circulation LVO admitted to a centre without MT facilities and eligible for IVT ≤4.5 hrs and MT, we recommend IVT followed by rapid transfer to a MT capable-centre (“drip-and-ship”) in preference to omitting IVT (low evidence, strong recommendation). Expert consensus statements on ischaemic stroke on awakening from sleep are also provided. Patients with anterior circulation LVO stroke should receive IVT in addition to MT if they have no contraindications to either treatment.

Intravenous thrombolysis for acute ischemic stroke: why not?

PURPOSE OF REVIEW

The aim of this study was to summarize available evidence regarding the safety and efficacy of intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA) in acute ischemic stroke (AIS) patients with specific comorbidities and potential contraindications to systemic reperfusion therapy. Recent advances in IVT implementation in wake-up stroke and in extended time window using advanced neuroimaging will also be highlighted.

RECENT FINDINGS

Despite theoretical concerns of a higher bleeding risk with IVT, there are no data showing increased risk of symptomatic intracerebral haemorrhage (sICH) in patients with stroke mimics, including seizures, increasing age and dual antiplatelet pretreatment. In addition, recent randomized evidence allows us to expand the time window of IVT for AIS using advanced neuroimaging both in wake-up stroke patients and in patients presenting within 4.5-9 h from symptom onset fulfilling certain neuroimaging criteria (based on DWI/FLAIR mismatch or perfusion mismatch).

SUMMARY

IVT is a highly effective systemic reperfusion therapy that counts 25 years of everyday clinical experience but still presents several challenges in its application. Appropriate patient selection and adherence to rt-PA protocol is paramount in terms of safety. The effort to simplify the indications, expand the therapeutic time window and eliminate specific initial contraindications is continuously evolving.

MRI radiomic features-based machine learning approach to classify ischemic stroke onset time

PURPOSE

We aimed to investigate the ability of MRI radiomics features-based machine learning (ML) models to classify the time since stroke onset (TSS), which could aid in stroke assessment and treatment options.

METHODS

This study involved 84 patients with acute ischemic stroke due to anterior circulation artery occlusion (51 in the training cohort and 33 in the independent test cohort). Region of infarct segmentation was manually outlined by 3D-slicer software. Image processing including registration, normalization and radiomics features calculation were done in R (version 3.6.1). A total of 4312 radiomic features from each image sequence were captured and used in six ML models to estimate stroke onset time for binary classification (≤ 4.5 h). Receiver-operating characteristic curve (ROC) and other parameters were calculated to evaluate the performance of the models in both training and test cohorts.

RESULTS

Twelve radiomics and six clinic features were selected to construct the ML models for TSS classification. The deep learning model-based DWI/ADC radiomic features performed the best for binary TSS classification in the independent test cohort, with an AUC of 0.754, accuracy of 0.788, sensitivity of 0.952, specificity of 0.500, positive predictive value of 0.769, and negative predictive value of 0.857, respectively. Furthermore, adding clinical information did not improve the performance of the DWI/ADC-based deep learning model. The TSS prediction models can be visited at: http://123.57.65.199:3838/deeptss/ .

CONCLUSIONS

A unique deep learning model based on DWI/ADC radiomic features was constructed for TSS classification, which could aid in decision making for thrombolysis in patients with unknown stroke onset.

Intravenous thrombolytic treatment and endovascular thrombectomy for ischaemic wake-up stroke

BACKGROUND

About one in five strokes occur during sleep (wake-up stroke). People with wake-up strokes have previously been considered to be ineligible for thrombolytic treatment because the time of stroke onset is unknown. However, recent studies suggest benefit from recanalisation therapies in selected patients.

OBJECTIVES

To assess the effects of intravenous thrombolysis and endovascular thrombectomy versus control in people with acute ischaemic stroke presenting on awakening from sleep.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last search 24 of May 2021). In addition, we searched the following electronic databases in May 2021: Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 4 of 12, April 2021) in the Cochrane Library, MEDLINE, Embase, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We searched the Stroke Trials Registry (last search 7 December 2017, as the site is currently inactive). We also screened references lists of relevant trials, contacted trialists, and undertook forward tracking of relevant references.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of intravenous thrombolytic drugs or endovascular thrombectomy treatments in people with acute ischaemic stroke presenting upon awakening.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria, extracted data, and assessed risk of bias and the certainty of the evidence using the GRADE approach. We obtained both published and unpublished data for participants with wake-up strokes. We excluded participants with strokes of unknown onset if the symptoms did not begin upon awakening.

MAIN RESULTS

We included seven trials with a total of 980 participants, of which five trials with 775 participants investigated intravenous thrombolytic treatment and two trials with 205 participants investigated endovascular thrombectomy in large vessel occlusion in the anterior intracranial circulation. All trials used advanced imaging for selecting patients to treat. For intravenous thrombolytic treatment, good functional outcome (defined as modified Rankin Scale score 0 to 2) at 90 days follow-up was observed in 66% of participants randomised to thrombolytic treatment and 58% of participants randomised to control (risk ratio (RR) 1.13, 95% confidence interval (CI) 1.01 to 1.26; P = 0.03; 763 participants, 5 RCTs; high-certainty evidence). Seven per cent of participants randomised to intravenous thrombolytic treatment and 10% of participants randomised to control had died at 90 days follow-up (RR 0.68, 95% CI 0.43 to 1.07; P = 0.09; 763 participants, 5 RCTs; high-certainty evidence). Symptomatic intracranial haemorrhage occurred in 3% of participants randomised to intravenous thrombolytic treatment and 1% of participants randomised to control (RR 3.47, 95% CI 0.98 to 12.26; P = 0.05; 754 participants, 4 RCTs; high-certainty evidence). For endovascular thrombectomy of large vessel occlusion, good functional outcome at 90 days follow-up was observed in 46% of participants randomised to endovascular thrombectomy and 9% of participants randomised to control (RR 5.12, 95% CI 2.57 to 10.17; P < 0.001; 205 participants, 2 RCTs; high-certainty evidence). Twenty-two per cent of participants randomised to endovascular thrombectomy and 33% of participants randomised to control had died at 90 days follow-up (RR 0.68, 95% CI 0.43 to 1.07; P = 0.10; 205 participants, 2 RCTs; high-certainty evidence).

AUTHORS' CONCLUSIONS

In selected patients with acute ischaemic wake-up stroke, both intravenous thrombolytic treatment and endovascular thrombectomy of large vessel occlusion improved functional outcome without increasing the risk of death. However, a possible increased risk of symptomatic intracranial haemorrhage associated with thrombolytic treatment cannot be ruled out. The criteria used for selecting patients to treatment differed between the trials. All studies were relatively small, and six of the seven studies were terminated early. More studies are warranted in order to determine the optimal criteria for selecting patients for treatment.

Imaging selection for reperfusion therapy in acute ischemic stroke beyond the conventional time window

Originally, the efficacy of acute ischemic stroke treatment with thrombolysis or thrombectomy was only proven in narrow time windows of, respectively, 4.5 and 6 h after onset. Introducing imaging-based selection beyond non-contrast enhanced computed tomography has expanded the treatment window, focusing on presumed tissue status rather than solely on time after stroke onset. Different mismatch concepts have been adopted in clinical practice to select patients in the extended and unknown time window based on findings from randomized controlled trials. Since various concepts exist that can identify patients likely to benefit from reperfusion strategies, clinicians may wonder which imaging modality may be preferred in the emergency setting. In this review, we will discuss the different mismatch concepts and their practical implementation for patient selection for thrombolysis or thrombectomy, beyond the conventional time window.

Cerebral microbleeds development after stroke thrombolysis: A secondary analysis of the THAWS randomized clinical trial

BACKGROUND AND AIM

We determined to investigate the incidence and clinical impact of new cerebral microbleeds after intravenous thrombolysis in patients with acute stroke.

METHODS

The THAWS was a multicenter, randomized trial to study the efficacy and safety of intravenous thrombolysis with alteplase in patients with wake-up stroke or unknown onset stroke. Prescheduled T2*-weighted imaging assessed cerebral microbleeds at three time points: baseline, 22-36 h, and 7-14 days. Outcomes included new cerebral microbleeds development, modified Rankin Scale (mRS) ≥3 at 90 days, and change in the National Institutes of Health Stroke Scale (NIHSS) score from 24 h to 7 days.

RESULTS

Of all 131 patients randomized in the THAWS trial, 113 patients (mean 74.3 ± 12.6 years, 50 female, 62 allocated to intravenous thrombolysis) were available for analysis. Overall, 46 (41%) had baseline cerebral microbleeds (15 strictly lobar cerebral microbleeds, 14 mixed cerebral microbleeds, and 17 deep cerebral microbleeds). New cerebral microbleeds only emerged in the intravenous thrombolysis group (seven patients, 11%) within a median of 28.3 h, and did not additionally increase within a median of 7.35 days. In adjusted models, number of cerebral microbleeds (relative risk (RR) 1.30, 95% confidence interval (CI): 1.17-1.44), mixed distribution (RR 19.2, 95% CI: 3.94-93.7), and cerebral microbleeds burden ≥5 (RR 44.9, 95% CI: 5.78-349.8) were associated with new cerebral microbleeds. New cerebral microbleeds were associated with an increase in NIHSS score (p = 0.023). Treatment with alteplase in patients with baseline ≥5 cerebral microbleeds resulted in a numerical shift toward worse outcomes on ordinal mRS (median [IQR]; 4 [3-4] vs. 0 [0-3]), compared with those with <5 cerebral microbleeds (common odds ratio 17.1, 95% CI: 0.76-382.8). The association of baseline ≥5 cerebral microbleeds with ordinal mRS score differed according to the treatment group (p interaction = 0.042).

CONCLUSION

New cerebral microbleeds developed within 36 h in 11% of the patients after intravenous thrombolysis, and they were significantly associated with mixed-distribution and ≥5 cerebral microbleeds. New cerebral microbleeds development might impede neurological improvement. Furthermore, cerebral microbleeds burden might affect the effect of alteplase.

Staying InformED: Top emergency Medicine pharmacotherapy articles of 2020

The year 2020 was not easy for Emergency Medicine (EM) clinicians with the burden of tackling a pandemic. A large focus, rightfully so, was placed on the evolving diagnosis and management of patients with COVID-19 and, as such, the ability of clinicians to remain up to date on key EM pharmacotherapy literature may have been compromised. This article reviews the most important EM pharmacotherapy publications indexed in 2020. A modified Delphi approach was utilized for selected journals to identify the most impactful EM pharmacotherapy studies. A total of fifteen articles, eleven trials and four meta-analyses, were identified. This review provides a summary of each study, along with a commentary on the impact to the EM literature and EM clinician.

Acute reperfusion therapies for acute ischemic stroke patients with unknown time of symptom onset or in extended time windows: an individualized approach

Recent randomized controlled clinical trials (RCTs) have revolutionized acute ischemic stroke care by extending the use of intravenous thrombolysis and endovascular reperfusion therapies in time windows that have been originally considered futile or even unsafe. Both systemic and endovascular reperfusion therapies have been shown to improve outcome in patients with wake-up strokes or symptom onset beyond 4.5 h for intravenous thrombolysis and beyond 6 h for endovascular treatment; however, they require advanced neuroimaging to select stroke patients safely. Experts have proposed simpler imaging algorithms but high-quality data on safety and efficacy are currently missing. RCTs used diverse imaging and clinical inclusion criteria for patient selection during the dawn of this novel stroke treatment paradigm. After taking into consideration the dismal prognosis of nonrecanalized ischemic stroke patients and the substantial clinical benefit of reperfusion therapies in selected late presenters, we propose rescue reperfusion therapies for acute ischemic stroke patients not fulfilling all clinical and imaging inclusion criteria as an option in a subgroup of patients with clinical and radiological profiles suggesting low risk for complications, notably hemorrhagic transformation as well as local or remote parenchymal hemorrhage. Incorporating new data to treatment algorithms may seem perplexing to stroke physicians, since treatment and imaging capabilities of each stroke center may dictate diverse treatment pathways. This narrative review will summarize current data that will assist clinicians in the selection of those late presenters that will most likely benefit from acute reperfusion therapies. Different treatment algorithms are provided according to available neuroimaging and endovascular treatment capabilities.

Sex Disparities in Enrollment in Recent Randomized Clinical Trials of Acute Stroke: A Meta-analysis

Importance

The underenrollment of women in randomized clinical trials represents a threat to the validity of the evidence supporting clinical guidelines and potential disparities in access to novel treatments.

Objective

To determine whether women were underenrolled in contemporary randomized clinical trials of acute stroke therapies published in 9 major journals after accounting for their representation in underlying stroke populations.

Data Sources

MEDLINE was searched for acute stroke therapeutic trials published between January 1, 2010, and June 11, 2020.

Study Selection

Eligible articles reported the results of a phase 2 or 3 randomized clinical trial that enrolled patients with stroke and/or transient ischemic attack and examined a therapeutic intervention initiated within 1 month of onset.

Data Extraction

Data extraction was performed by 2 independent authors in duplicate. Individual trials were matched to estimates of the proportion of women in underlying stroke populations using the Global Burden of Disease database.

Main Outcomes and Measures

The primary outcome was the enrollment disparity difference (EDD), the absolute difference between the proportion of trial participants who were women and the proportion of strokes in the underlying disease populations that occurred in women. Random-effects meta-analyses of the EDD were performed, and multivariable metaregression was used to explore the associations of trial eligibility criteria with disparity estimates.

Results

The search returned 1529 results, and 115 trials (7.5%) met inclusion criteria. Of 121 105 randomized patients for whom sex was reported, 52 522 (43.4%) were women. The random-effects summary EDD was -0.053 (95% CI, -0.065 to -0.040), indicating that women were underenrolled by 5.3 percentage points. This disparity persisted across virtually all geographic regions, intervention types, and stroke types, apart from subarachnoid hemorrhage (0.117 [95% CI, 0.084 to 0.150]). When subarachnoid hemorrhage trials were excluded, the summary EDD was -0.067 (95% CI, -0.078 to -0.057). In the multivariable metaregression analysis, an upper age limit of 80 years as an eligibility criterion was associated with a 6-percentage point decrease in the enrollment of women.

Conclusions and Relevance

Further research is needed to understand the causes of the underenrollment of women in acute stroke trials. However, to maximize representation, investigators should avoid imposing age limits on enrollment.

Safety of intravenous thrombolysis in stroke of unknown time of onset: A systematic review and meta-analysis

The safety of intravenous tissue plasminogen activator (IV-tPA) in patients with stroke of unknown time of onset (SUTO) was unclear and mostly concerned. We sought to investigate the safety in terms of symptomatic intracranial hemorrhage (sICH) and death in SUTO patients treated with IV-tPA. We searched PubMed and EMBASE from inception to 2 December 2020 for eligible studies reporting IV-tPA in SUTO patients compared to conservative medical therapy, or to stroke of known onset time (SKOT) treated with IV-tPA within standard time window. We pooled relative risk (RR) with 95% confidence interval (95%CI) with random-effects model. Twenty-four studies were included, enrolling 77,398 patients. SUTO patients with IV-tPA had higher incidence of sICH than that in SUTO patients without IV-tPA (3.8% versus 0.96%; RR = 3.75, 95%CI: 2.69-5.22) but comparable to that in SKOT patients with IV-tPA (3.8% versus 4.1%; RR = 1.16, 95%CI: 0.94-1.44). There was no significant difference in death risk in SUTO patients with IV-tPA versus SUTO patients without IV-tPA (RR = 1.34, 95%CI: 0.60-3.01) and versus SKOT patients with IV-tPA (RR = 1.19, 95%CI: 0.95-1.50). Compared with SUTO patients without IV-tPA, SUTO patients with IV-tPA had higher likelihood of favorable functional outcome (adjusted RR = 1.28, 95%CI: 1.03-1.60) and functional independence (adjusted RR = 1.95, 95%CI: 1.24-3.06), comparable to that in SKOT patients with IV-tPA in favorable functional outcome (adjusted RR = 0.67, 95%CI: 0.38-1.20) and functional independence (adjusted RR = 0.84, 95%CI: 0.59-1.18). SUTO patients could be treated safely and effectively with IV-tPA under the guidance of imaging evaluation.

Fluid-Attenuated Inversion Recovery May Serve As a Tissue Clock in Patients Treated With Endovascular Thrombectomy

[Figure: see text].

Thrombolytic therapy for wake-up stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

According to evidence-based clinical practice guidelines, patients presenting with disabling stroke symptoms should be treated with intravenous tissue plasminogen activator (IV tPA) within 4.5 h of time last known well. However, 25% of strokes are detected upon awakening (i.e., wake-up stroke [WUS]), which renders patients ineligible for IV tPA administered via time-based treatment algorithms, because it is impossible to establish a reliable time of symptom onset. We performed a systematic review and meta-analysis of the efficacy and safety of IV tPA compared with normal saline, placebo, or no treatment in patients with WUS using imaging-based treatment algorithms.

METHODS

We searched MEDLINE, Web of Science, and Scopus between January 1, 2006 and April 30, 2020. We included controlled trials (randomized or nonrandomized), observational cohort studies (prospective or retrospective), and single-arm studies in which adults with WUS were administered IV tPA after magnetic resonance imaging (MRI)- or computed tomography (CT)-based imaging. Our primary outcome was recovery at 90 days (defined as a modified Rankin Scale [mRS] score of 0-2), and our secondary outcomes were symptomatic intracranial hemorrhage (sICH) within 36 h, mortality, and other adverse effects.

RESULTS

We included 16 studies that enrolled a total of 14,017 patients. Most studies were conducted in Europe (37.5%) or North America (37.5%), and 1757 patients (12.5%) received IV tPA. All studies used MRI-based (five studies) or CT-based (10 studies) imaging selection, and one study used a combination of modalities. Sixty-one percent of patients receiving IV tPA achieved an mRS score of 0 to 2 at 90 days (95% confidence interval [CI]: 51%-70%, 12 studies), with a relative risk (RR) of 1.21 compared with patients not receiving IV tPA (95% CI: 1.01-1.46, four studies). Three percent of patients receiving IV tPA experienced sICH within 36 h (95% CI: 2.5%-4.1%; 16 studies), which is an RR of 4.00 compared with patients not receiving IV tPA (95% CI: 2.85-5.61, seven studies).

CONCLUSIONS

This systematic review and meta-analysis suggests that IV tPA is associated with a better functional outcome at 90 days despite the increased but acceptable risk of sICH. Based on these results, IV tPA should be offered as a treatment for WUS patients with favorable neuroimaging findings.

Off-label use of intravenous thrombolysis for acute ischemic stroke: a critical appraisal of randomized and real-world evidence

Intravenous thrombolysis (IVT) represents the only systemic reperfusion therapy able to reverse neurological deficit in patients with acute ischemic stroke (AIS). Despite its effectiveness in patients with or without large vessel occlusion, it can be offered only to a minority of them, because of the short therapeutic window and additional contraindications derived from stringent but arbitrary inclusion and exclusion criteria used in landmark randomized controlled clinical trials. Many absolute or relative contraindications lead to disparities between the official drug label and guidelines or expert recommendations. Based on recent advances in neuroimaging and evidence from cohort studies, off-label use of IVT is increasingly incorporated into the daily practice of many stroke centers. They relate to extension of therapeutic time windows, and expansion of indications in co-existing conditions originally listed in exclusion criteria, such as use of alternative thrombolytic agents, pre-treatment with antiplatelets, anticoagulants or low molecular weight heparins. In this narrative review, we summarize recent randomized and real-world data on the safety and efficacy of off-label use of IVT for AIS. We also make some practical recommendations to stroke physicians regarding the off-label use of thrombolytic agents in complex and uncommon presentations of AIS or other conditions mimicking acute cerebral ischemia. Finally, we provide guidance on the risks and benefits of IVT in numerous AIS subgroups, where equipoise exists and guidelines and treatment practices vary.

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.

Rare cause of cardioembolic stroke and central retinal artery occlusion

Primary cardiac valve tumours are rare. This is a case report of a 32-year-old non-smoker man with a history of stroke 1 year prior and no other cardiovascular risk factors. The patient was admitted to our acute stroke ward for recurrent left hemiparesis, slurring of speech, facial asymmetry and central retinal artery occlusion. Initial laboratory investigations and ECG were normal. An urgent CT brain showed a large hypodense area at the right frontal, parietal, temporal, occipital region with effaced sulci and right lateral ventricle with midline shift and cerebral oedema in keeping with acute infarction. We proceeded with CT angiography of the cerebral and carotid on the following day, which revealed no evidence of thrombosis, aneurysm or arteriovenous malformation. There were no abnormal beaded vessels to suggest vasculitis. Transthoracic echocardiography revealed a large mobile mass in the left atrium. Meanwhile, MRI cardiac confirmed a large ill-defined mobile solid mass attached to the mitral valve's inferoseptal component suggestive of mitral valve myxoma. This case report highlights the significance of considering a cardiogenic source of emboli in patients with large cerebral infarcts and other cardiac embolic phenomena. Imaging modalities such as echocardiography and cardiac MRI will help detect treatable conditions, such as valvular myxoma and prevent further complications.

Which Imaging Approach Should Be Used for Stroke of Unknown Time of Onset?

Reperfusion therapy with intravenous thrombolysis or mechanical thrombectomy is effective in improving outcome for ischemic stroke but remains underused. Patients presenting with stroke of unknown onset are a common clinical scenario and a common reason for not offering reperfusion therapy. Recent studies have demonstrated the efficacy of reperfusion therapy in stroke of unknown time of onset, when guided by advanced brain imaging. However, translation into clinical practice is challenged by variability in the available data. Comparison between studies is difficult because of use of different imaging modalities (magnetic resonance imaging or computed tomography), different imaging paradigms (imaging biomarkers of lesion age versus imaging biomarkers of tissue viability), and different populations studied (ie, both patients with large vessel occlusion or those with less severe strokes). Physicians involved in acute stroke care are faced with the key question of which imaging approach they should use to guide reperfusion treatment for stroke with unknown time of onset. In this review, we provide an overview of the available evidence for selecting and treating patients with strokes of unknown onset, based on the underlying imaging concepts. The perspective provided is from the viewpoint of the clinician seeing these patients acutely, to provide pragmatic recommendations for clinical practice.

Magnetic Resonance Imaging-Guided Thrombolysis (0.6 mg/kg) Was Beneficial for Unknown Onset Stroke Above a Certain Core Size: THAWS RCT Substudy

BACKGROUND AND PURPOSE

We determined to identify patients with unknown onset stroke who could have favorable 90-day outcomes after low-dose thrombolysis from the THAWS (Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes With Alteplase at 0.6 mg/kg) database.

METHODS

This was a subanalysis of an investigator-initiated, multicenter, randomized, open-label, blinded-end point trial. Patients with stroke with a time last-known-well >4.5 hours who showed a mismatch between diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg intravenously or standard medical treatment. The patients were dichotomized by ischemic core size or National Institutes of Health Stroke Scale score, and the effects of assigned treatments were compared in each group. The efficacy outcome was favorable outcome at 90 days, defined as a modified Rankin Scale score of 0 to 1.

RESULTS

The median DWI-Alberta Stroke Program Early CT Score (ASPECTS) was 9, and the median ischemic core volume was 2.5 mL. Both favorable outcome (47.1% versus 48.3%) and any intracranial hemorrhage (26% versus 14%) at 22 to 36 hours were comparable between the 68 thrombolyzed patients and the 58 control patients. There was a significant treatment-by-cohort interaction for favorable outcome between dichotomized patients by ASPECTS on DWI (P=0.026) and core volume (P=0.035). Favorable outcome was more common in the alteplase group than in the control group in patients with DWI-ASPECTS 5 to 8 (RR, 4.75 [95% CI, 1.33-30.2]), although not in patients with DWI-ASPECTS 9 to 10. Favorable outcome tended to be more common in the alteplase group than in the control group in patients with core volume >6.4 mL (RR, 6.15 [95% CI, 0.87-43.64]), although not in patients with volume ≤6.4 mL. The frequency of any intracranial hemorrhage did not differ significantly between the 2 treatment groups in any dichotomized patients.

CONCLUSIONS

Patients developing unknown onset stroke with DWI-ASPECTS 5 to 8 showed favorable outcomes more commonly after low-dose thrombolysis than after standard treatment. Registration: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02002325. URL: https://www.umin.ac.jp/ctr; Unique Identifier: UMIN000011630.

[To guide and train young neurologists as stroke specialists: proceedings of the third annual workshop for stroke education]

The Japanese Society of Neurology has held an annual workshop for stroke education since September 2018 for young members of the society and medical students to take an interest in stroke medicine and stroke research and to contribute to conquest of stroke, a national disease. The third annual workshop will be held in the National Cerebral and Cardiovascular Center, Osaka in September 2020 also with the support of the Japan Stroke Society. Designated lecturers are preparing for presentation of their own devising. Here, brief abstracts of educational lectures and special statements on career formation of vascular neurologists are introduced.

Intravenous alteplase for stroke with unknown time of onset guided by advanced imaging: systematic review and meta-analysis of individual patient data

BACKGROUND

Patients who have had a stroke with unknown time of onset have been previously excluded from thrombolysis. We aimed to establish whether intravenous alteplase is safe and effective in such patients when salvageable tissue has been identified with imaging biomarkers.

METHODS

We did a systematic review and meta-analysis of individual patient data for trials published before Sept 21, 2020. Randomised trials of intravenous alteplase versus standard of care or placebo in adults with stroke with unknown time of onset with perfusion-diffusion MRI, perfusion CT, or MRI with diffusion weighted imaging-fluid attenuated inversion recovery (DWI-FLAIR) mismatch were eligible. The primary outcome was favourable functional outcome (score of 0-1 on the modified Rankin Scale [mRS]) at 90 days indicating no disability using an unconditional mixed-effect logistic-regression model fitted to estimate the treatment effect. Secondary outcomes were mRS shift towards a better functional outcome and independent outcome (mRS 0-2) at 90 days. Safety outcomes included death, severe disability or death (mRS score 4-6), and symptomatic intracranial haemorrhage. This study is registered with PROSPERO, CRD42020166903.

FINDINGS

Of 249 identified abstracts, four trials met our eligibility criteria for inclusion: WAKE-UP, EXTEND, THAWS, and ECASS-4. The four trials provided individual patient data for 843 individuals, of whom 429 (51%) were assigned to alteplase and 414 (49%) to placebo or standard care. A favourable outcome occurred in 199 (47%) of 420 patients with alteplase and in 160 (39%) of 409 patients among controls (adjusted odds ratio [OR] 1·49 [95% CI 1·10-2·03]; p=0·011), with low heterogeneity across studies (I²=27%). Alteplase was associated with a significant shift towards better functional outcome (adjusted common OR 1·38 [95% CI 1·05-1·80]; p=0·019), and a higher odds of independent outcome (adjusted OR 1·50 [1·06-2·12]; p=0·022). In the alteplase group, 90 (21%) patients were severely disabled or died (mRS score 4-6), compared with 102 (25%) patients in the control group (adjusted OR 0·76 [0·52-1·11]; p=0·15). 27 (6%) patients died in the alteplase group and 14 (3%) patients died among controls (adjusted OR 2·06 [1·03-4·09]; p=0·040). The prevalence of symptomatic intracranial haemorrhage was higher in the alteplase group than among controls (11 [3%] vs two [<1%], adjusted OR 5·58 [1·22-25·50]; p=0·024).

INTERPRETATION

In patients who have had a stroke with unknown time of onset with a DWI-FLAIR or perfusion mismatch, intravenous alteplase resulted in better functional outcome at 90 days than placebo or standard care. A net benefit was observed for all functional outcomes despite an increased risk of symptomatic intracranial haemorrhage. Although there were more deaths with alteplase than placebo, there were fewer cases of severe disability or death.

FUNDING

None.

[MRI and intravenous thrombolysis for unclear-onset stroke during the COVID-19 pandemic: a case report]

During the COVID-19 pandemic in 2020, an 81-year-old afebrile woman was transported to our institute at 44 minutes after she was found to have global aphasia and weakness of the right extremities. The onset time was unclear. CT showed an occlusion of the left middle cerebral artery without early ischemic changes. MRI revealed a negative fluid-attenuated inversion recovery (FLAIR) pattern, in which several small acute infarcts were seen in diffusion-weighted images with no corresponding hyperintensity lesions on FLAIR. Accordingly, intravenous thrombolysis with alteplase (0.6 mg/kg, the dose approved in Japan) was administered at 1,660 minutes after the last known well and 116 minutes after the symptom recognition. An immediate internal carotid angiogram showed severe stenosis at the distal end of the horizontal portion of the left middle cerebral artery. In the follow-up angiogram at 164 minutes after the symptom recognition, the stenotic lesion almost resolved with the restoration of quick and nearly complete antegrade flow. Her symptoms also resolved promptly. Although the use of MRI is recommended to be minimized in the emergency stroke management during the COVID-19 pandemic, MRI is occasionally mandatory for patient selection, such as cases with unclear onset to perform intravenous thrombolysis. The individualized protected code stroke is essential and must be well considered by each institute for diagnosing patients by selecting appropriate modalities.