Tranexamic acid versus placebo in individuals with intracerebral haemorrhage treated within 2 h of symptom onset (STOP-MSU): an international, double-blind, randomised, phase 2 trial.

BACKGROUND: Tranexamic acid, an antifibrinolytic agent, might attenuate haematoma growth after an intracerebral haemorrhage. We aimed to determine whether treatment with intravenous tranexamic acid within 2 h of an intracerebral haemorrhage would reduce haematoma growth compared with placebo. METHODS: STOP-MSU was an investigator-led, double-blind, randomised, phase 2 trial conducted at 24 hospitals and one mobile stroke unit in Australia, Finland, New Zealand, Taiwan, and Viet Nam. Eligible participants had acute spontaneous intracerebral haemorrhage confirmed on non-contrast CT, were aged 18 years or older, and could be treated with the investigational product within 2 h of stroke onset. Using randomly permuted blocks (block size of 4) and a concealed pre-randomised assignment procedure, participants were randomly assigned (1:1) to receive intravenous tranexamic acid (1 g over 10 min followed by 1 g over 8 h) or placebo (saline; matched dosing regimen) commencing within 2 h of symptom onset. Participants, investigators, and treating teams were masked to group assignment. The primary outcome was haematoma growth, defined as either at least 33% relative growth or at least 6 mL absolute growth on CT at 24 h (target range 18-30 h) from the baseline CT. The analysis was conducted within the estimand framework with primary analyses adhering to the intention-to-treat principle. The primary endpoint and secondary safety endpoints (mortality at days 7 and 90 and major thromboembolic events at day 90) were assessed in all participants randomly assigned to treatment groups who did not withdraw consent to use any data. This study was registered with ClinicalTrials.gov, NCT03385928, and the trial is now complete. FINDINGS: Between March 19, 2018, and Feb 27, 2023, 202 participants were recruited, of whom one withdrew consent for any data use. The remaining 201 participants were randomly assigned to either placebo (n=98) or tranexamic acid (n=103; intention-to-treat population). Median age was 66 years (IQR 55-77), and 82 (41%) were female and 119 (59%) were male; no data on race or ethnicity were collected. CT scans at baseline or follow-up were missing or of inadequate quality in three participants (one in the placebo group and two in the tranexamic acid group), and were considered missing at random. Haematoma growth occurred in 37 (38%) of 97 assessable participants in the placebo group and 43 (43%) of 101 assessable participants in the tranexamic acid group (adjusted odds ratio [aOR] 1·31 [95% CI 0·72 to 2·40], p=0·37). Major thromboembolic events occurred in one (1%) of 98 participants in the placebo group and three (3%) of 103 in the tranexamic acid group (risk difference 0·02 [95% CI -0·02 to 0·06]). By 7 days, eight (8%) participants in the placebo group and eight (8%) in the tranexamic acid group had died (aOR 1·08 [95% CI 0·35 to 3·35]) and by 90 days, 15 (15%) participants in the placebo group and 19 (18%) in the tranexamic acid group had died (aOR 1·61 [95% CI 0·65 to 3·98]). INTERPRETATION: Intravenous tranexamic acid did not reduce haematoma growth when administered within 2 h of intracerebral haemorrhage symptom onset. There were no observed effects on other imaging endpoints, functional outcome, or safety. Based on our results, tranexamic acid should not be used routinely in primary intracerebral haemorrhage, although results of ongoing phase 3 trials will add further context to these findings. FUNDING: Australian Government Medical Research Future Fund.

Large vessel occlusive stroke with milder baseline severity shows better collaterals and reduced harm from thrombectomy transfer delays.

BACKGROUND: Patients with large vessel occlusion (LVO) stroke presenting with milder baseline clinical severity are common and require endovascular thrombectomy. However, such patients are difficult to recognize using pre-hospital severity-based triage tools and therefore are likely to require a secondary inter-hospital transfer if transported to a non-thrombectomy center. Given the potential for milder severity to represent better underlying cerebrovascular collateral circulation, it is unknown whether transfer delays are still associated with poorer post-stroke outcomes in this patient group. AIMS: We primarily aimed to examine whether the harmful effect of inter-hospital transfer delay for thrombectomy was different for LVO patients with mild or severe deficits. Secondarily, we also investigated whether imaging markers of collateral circulation were different between severity groups. METHODS: Registry data from two large Australian thrombectomy centers were used to identify all directly presenting and secondarily transferred LVO patients undergoing thrombectomy, divided into those with lower (NIHSS < 10) and higher (NIHSS ⩾ 10) baseline deficits. The primary outcome was the functional independence or return to baseline defined as modified Rankin Scale 0-2 or baseline at 90 days. Patients with complete baseline CT-perfusion data were analyzed for imaging markers of collateral circulation by baseline severity group. RESULTS: A total of 1210 LVO patients undergoing thrombectomy were included, of which 273 (22.6%) had lower baseline severity. Despite similar thrombolysis and recanalization rates, transferred patients had lower odds of achieving the primary outcome compared to the primary presentation to a thrombectomy center, where baseline severity was higher (adjusted odds ratio (aOR) 0.759 (95% CI 0.576-0.999)), but not when severity was lower (aOR 1.357 (95% CI 0.764-2.409), p-interaction = 0.122). In the imaging analysis of 436 patients, those with milder severity showed smaller median ischemic core volumes (12.6 (IQR 0.0-17.9) vs 27.5 (IQR 6.5-37.1) mL, p < 0.001)), higher median perfusion mismatch ratio (10.8 (IQR 4.8-54.5) vs 6.6 (IQR 3.5-16.5), p < 0.001), and lower median hypoperfusion intensity ratio (0.25 (IQR 0.18-0.38) vs 0.40 (IQR 0.22-0.57), p < 0.001). DISCUSSION: Patients receiving secondary inter-hospital transfer for thrombectomy had poorer outcomes compared to those presenting directly to a thrombectomy center if baseline deficits were severe, but this difference was not observed when baseline deficits were milder. This result may potentially be due to our secondary findings of significantly improved collateral circulation markers in lower-severity LVO patients. As such, failure of pre-hospital screening tools to detect lower-severity LVO patients for pre-hospital bypass to a thrombectomy center may not necessarily deleteriously affect outcome. DATA ACCESS STATEMENT: Anonymized data not published within this article will be made available on request from any qualified investigator.

Diagnostic Accuracy of Posterior Circulation Stroke by Paramedics: A Systematic Review.

OBJECTIVE: This systematic review aims to identify the diagnostic accuracy of posterior circulation stroke (PCS) by paramedics and the causes and duration of delay in its recognition. METHODS: A systematic search using CINAHL Plus, MEDLINE, Scopus, and PubMed was performed. All databases were searched up to May 25, 2022. Studies were included where patients were adults, assessed by paramedics, and PCS was the primary diagnosis. Bias was assessed using the Newcastle-Ottawa Scale and the Effective Practice and Organization of Care tool. Results have been described by proportions, and both sensitivity calculations and subgroup analysis were performed utilizing MedCalc. RESULTS: A total of 797 titles/abstracts and a subsequent 87 full texts were screened, of which 15 were included. There were 5395 patients who were assessed by paramedics and had a confirmed diagnosis of PCS. Among five studies containing both true positive and false negative data, there were 98 (45.8%) true positives. PCS patients lost an average of 27 min (p < 0.001) compared to anterior stroke patients in the prehospital setting. One study revealed that educational intervention, including implementing the finger-to-nose test, increased the sensitivity for diagnosis from 45.8 to 74.1% (p = 0.039) and decreased the time from door to computed tomography from 62 to 41 min (p = 0.037). CONCLUSION: There is a substantial lack of evidence regarding the diagnosis of PCS by paramedics. Despite the low quality of evidence available, overall, the sensitivity for paramedic PCS diagnosis appears to be poor. Further investigation is required into paramedics' diagnosis of PCS and the use of educational interventions.Prospective Register of Systematic Reviews Registration Number: CRD42022324675.

Sustaining a New Model of Acute Stroke Care: A Mixed-Method Process Evaluation of the Melbourne Mobile Stroke Unit.

BACKGROUND: Internationally, Mobile Stroke Unit (MSU) ambulances have changed pre-hospital acute stroke care delivery. MSU clinical and cost-effectiveness studies are emerging, but little is known about important factors for achieving sustainability of this innovative model of care. METHODS: Mixed-methods study from the Melbourne MSU (operational since November 2017) process evaluation. Participant purposive sampling included clinical, operational and executive/management representatives from Ambulance Victoria (AV) (emergency medical service provider), the MSU clinical team, and receiving hospitals. Sustainability was defined as ongoing MSU operations, including MSU workforce and future model considerations. Theoretically-based on-line survey with Unified Theory of Acceptance and Use of Technology (UTAUT), Self Determination Theory (SDT, Intrinsic Motivation), and open-text questions targeting barriers and benefits was administered (June-September 2019). Individual/group interviews were conducted, eliciting improvement suggestions and requirements for ongoing use. Descriptive and regression analyses (quantitative data) and directed content and thematic analysis (open text and interview data) were conducted. RESULTS: There were 135 surveys completed. Identifying that the MSU was beneficial to daily work (ß=0.61), not experiencing pressure/tension about working on the MSU (ß=0.17) and thinking they did well working within the team model (ß=0.17) were significantly associated with wanting to continue working within the MSU model [R2=0.76; F(15, 60)=12.76, P<.001]. Experiences varied between those on the MSU team and those working with the MSU. Advantages were identified for patients (better, faster care) and clinicians (interdisciplinary learning). Disadvantages included challenges integrating into established systems, and establishing working relationships. Themes identified from 35 interviews were MSU team composition, MSU vehicle design and layout, personnel recruitment and rostering, communication improvements between organisations, telemedicine options, MSU operations and dispatch specificity. CONCLUSION: Important factors affecting the sustainability of the MSU model of stroke care emerged. A cohesive team approach, with identifiable benefits and good communication between participating organisations is important for clinical and operational sustainability.

Cost-effectiveness of tenecteplase versus alteplase for stroke thrombolysis evaluation trial in the ambulance.

BACKGROUND: Tenecteplase administered to patients with ischaemic stroke in a mobile stroke unit (MSU) has been shown to reduce the perfusion lesion volumes and result in ultra-early recovery. We now seek to assess the cost-effectiveness of tenecteplase in the MSU. METHODS: A within-trial (TASTE-A) economic analysis and a model-based long-term cost-effectiveness analysis were performed. This post hoc within-trial economic analysis utilised the patient-level data (intention to treat, ITT) prospectively collected over the trial to calculate the difference in both healthcare costs and quality-adjusted life years (QALYs, estimated from modified Rankin scale score). A Markov microsimulation model was developed to simulate the long-term costs and benefits. RESULTS: In total, there were 104 patients with ischaemic stroke randomised to tenecteplase (n = 55) or alteplase (n = 49) treatment groups, respectively in the TASTE-A trial. The ITT-based analysis showed that treatment with tenecteplase was associated with non-signficantly lower costs (A$28,903 vs A$40,150 (p = 0.056)) and greater benefits (0.171 vs 0.158 (p = 0.457)) than that for the alteplase group over the first 90 days post the index stroke. The long-term model showed that tenecteplase led to greater savings in costs (-A$18,610) and more health benefits (0.47 QALY or 0.31 LY gains). Tenecteplase-treated patients had reduced costs for rehospitalisation (-A$1464), nursing home care (-A$16,767) and nonmedical care (-A$620) per patient. CONCLUSIONS: Treatment of ischaemic stroke patients with tenecteplase appeared to be cost-effective and improve QALYs in the MSU setting based on Phase II data. The reduced total cost from tenecteplase was driven by savings from acute hospitalisation and reduce need for nursing home care.

Interdisciplinary interactions, social systems and technical infrastructure required for successful implementation of mobile stroke units: A qualitative process evaluation.

RATIONALE: Mobile stroke units (MSUs) are increasingly being implemented to provide acute stroke care in the prehospital environment, but a comprehensive implementation evaluation has not been undertaken. AIM: To identify successes and challenges in the pre- and initial operations of the first Australian MSU service from an interdisciplinary perspective. METHODS: Process evaluation of the Melbourne MSU with a mixed-methods design. Purposive sampling targeted key stakeholder groups. Online surveys (administered June-September 2019) and semistructured interviews (October-November 2019) explored experiences. Directed content analysis (raters' agreement 85%) and thematic analysis results are presented using the Interactive Sociotechnical Analysis framework. RESULTS: Participants representing executive/program operations, MSU clinicians and hospital-based clinicians completed 135 surveys and 38 interviews. Results converged, with major themes addressing successes and challenges: stakeholders, vehicle, knowledge, training/education, communication, work processes and working relationships. CONCLUSIONS: Successes and challenges of establishing a new MSU service extend beyond technical, to include operational and social aspects across prehospital and hospital environments.

Long-Term Cost-Effectiveness of Severity-Based Triaging for Large Vessel Occlusion Stroke.

Background and Purpose: Pre-hospital severity-based triaging using the Ambulance Clinical Triage For Acute Stroke Treatment (ACT-FAST) algorithm has been demonstrated to substantially reduce time to endovascular thrombectomy in Melbourne, Australia. We aimed to model the cost-effectiveness of an ACT-FAST bypass system from the healthcare system perspective. Methods: A simulation model was developed to estimate the long-term costs and health benefits associated with diagnostic accuracy of the ACT-FAST algorithm. Three-month post stroke functional outcome was projected to the lifetime horizon to estimate the long-term cost-effectiveness between two strategies (ACT-FAST vs. standard care pathways). For ACT-FAST screened true positives (i.e., screened positive and eligible for EVT), a 52 mins time saving was applied unanimously to the onset to arterial time for EVT, while 10 mins delay in thrombolysis was applied for false-positive (i.e., screened positive but was ineligible for EVT) thrombolysis-eligible infarction. Quality-adjusted life year (QALY) was employed as the outcome measure to calculate the incremental cost-effectiveness ratio (ICER) between the ACT-FAST algorithm and the current standard care pathway. Results: Over the lifetime, ACT-FAST was associated with lower costs (-$45) and greater QALY gains (0.006) compared to the current standard care pathway, resulting in it being the dominant strategy (less costly but more health benefits). Implementing ACT-FAST triaging led to higher proportion of patients received EVT procedure (30 more additional EVT performed per 10,000 patients). The total Net Monetary Benefit from ACT-FAST care estimated at A$0.76 million based on its implementation for a single year. Conclusions: An ACT-FAST severity-triaging strategy is associated with cost-saving and increased benefits when compared to standard care pathways. Implementing ACT-FAST triaging increased the proportion of patients who received EVT procedure due to more patients arriving at EVT-capable hospitals within the 6-h time window (when imaging selection is less rigorous).

A magnetoimpedance biosensor microfluidic platform for detection of glial fibrillary acidic protein in blood for acute stroke classification.

Acute stroke is the third leading cause of mortality and disability worldwide. Administration of appropriate therapy for acute stroke is critically dependent on timely classification into either ischemic or hemorrhagic subtypes, which have divergent treatment pathways. The current classification method is based on neuroimaging, which generally requires the transport of the patient to a hospital-based facility unless a mobile stroke unit is available. Plasma glial fibrillary acidic protein (GFAP) level has been identified as a useful blood-based biomarker to differentiate stroke subtypes. However, its conventional immunoassay methods are laboratory-based and time-consuming. Novel approaches for rapid stroke classification near the patients are urgently needed. Here, we report the development and testing of a microfluidic-based magnetoimpedance biosensor platform for measuring GFAP levels. The platform consists of a microfluidic chip for GFAP extraction from a blood sample and a magnetoimpedance (MI) biosensor that employs Dynabeads as a magnetic label to capture the GFAP molecules. We demonstrated the detection of recombinant GFAP protein in phosphate-buffered saline (PBS) and in mouse blood samples (detection limit 0.01 ng/mL) and of physiological GFAP in blood and plasma samples (detection limit 1.0 ng/mL) obtained from acute stroke patients. This detection level is within the range of cut-off levels required for clinical stroke subtype differentiation. This platform has the potential to be incorporated into a small device with further development to assist in the classification of acute stroke patients and clinical decision-making at the point-of-care.

Comparison of tenecteplase with alteplase for the early treatment of ischaemic stroke in the Melbourne Mobile Stroke Unit (TASTE-A): a phase 2, randomised, open-label trial.

BACKGROUND: Mobile stroke units (MSUs) equipped with a CT scanner reduce time to thrombolytic treatment and improve patient outcomes. We tested the hypothesis that tenecteplase administered in an MSU would result in superior reperfusion at hospital arrival, when compared with alteplase. METHODS: The TASTE-A trial is a phase 2, randomised, open-label trial at the Melbourne MSU and five tertiary hospitals in Melbourne, VIC, Australia. Patients (aged ≥18 years) with ischaemic stroke who were eligible for thrombolytic treatment were randomly allocated in the MSU to receive, within 4·5 h of symptom onset, either standard-of-care alteplase (0·9 mg/kg [maximum 90 mg], administered intravenously with 10% as a bolus over 1 min and 90% as an infusion over 1 h), or the investigational product tenecteplase (0·25 mg/kg [maximum 25 mg], administered as an intravenous bolus over 10 s), before being transported to hospital for ongoing care. The primary outcome was the volume of the perfusion lesion on arrival at hospital, assessed by CT-perfusion imaging. Secondary safety outcomes were modified Rankin Scale (mRS) score of 5 or 6 at 90 days, symptomatic intracerebral haemorrhage and any haemorrhage within 36 h, and death at 90 days. Assessors were masked to treatment allocation. Analysis was by intention-to-treat. The trial was registered with ClinicalTrials.gov, NCT04071613, and is completed. FINDINGS: Between June 20, 2019, and Nov 16, 2021, 104 patients were enrolled and randomly allocated to receive either tenecteplase (n=55) or alteplase (n=49). The median age of patients was 73 years (IQR 61-83), and the median NIHSS at baseline was 8 (5-14). On arrival at the hospital, the perfusion lesion volume was significantly smaller with tenecteplase (median 12 mL [IQR 3-28]) than with alteplase (35 mL [18-76]; adjusted incidence rate ratio 0·55, 95% CI 0·37-0·81; p=0·0030). At 90 days, an mRS of 5 or 6 was reported in eight (15%) patients allocated to tenecteplase and ten (20%) patients allocated to alteplase (adjusted odds ratio [aOR] 0·70, 95% CI 0·23-2·16; p=0·54). Five (9%) patients allocated to tenecteplase and five (10%) patients allocated to alteplase died from any cause at 90 days (aOR 1·12, 95% CI 0·26-4·90; p=0·88). No cases of symptomatic intracerebral haemorrhage were reported within 36 h with either treatment. Up to day 90, 13 serious adverse events were noted: five (5%) in patients treated with tenecteplase, and eight (8%) in patients treated with alteplase. INTERPRETATION: Treatment with tenecteplase on the MSU in Melbourne resulted in a superior rate of early reperfusion compared with alteplase, and no safety concerns were noted. This trial provides evidence to support the use of tenecteplase and MSUs in an optimal model of stroke care. FUNDING: Melbourne Academic Centre for Health.

Tenecteplase versus Alteplase for Stroke Thrombolysis Evaluation Trial in the Ambulance (Mobile Stroke Unit-TASTE-A): protocol for a prospective randomised, open-label, blinded endpoint, phase II superiority trial of tenecteplase versus alteplase for ischaemic stroke patients presenting within 4.5 hours of symptom onset to the mobile stroke unit.

INTRODUCTION: Mobile stroke units (MSUs) equipped with a CT scanner are increasingly being used to assess and treat stroke patients' prehospital with thrombolysis and transfer them to the most appropriate hospital for ongoing stroke care and thrombectomy when indicated. The effect of MSUs in both reducing the time to reperfusion treatment and improving patient outcomes is now established. There is now an opportunity to improve the efficacy of treatment provided by the MSU. Tenecteplase is a potent plasminogen activator, which may have benefits over the standard of care stroke lytic alteplase. Specifically, in the MSU environment tenecteplase presents practical benefits since it is given as a single bolus and does not require an infusion over an hour like alteplase. OBJECTIVE: In this trial, we seek to investigate if tenecteplase, given to patients with acute ischaemic stroke as diagnosed on the MSU, improves the rate of early reperfusion. METHODS AND ANALYSIS: TASTE-A is a prospective, randomised, open-label, blinded endpoint (PROBE) phase II trial of patients who had an ischaemic stroke assessed in an MSU within 4.5 hours of symptom onset. The primary endpoint is early reperfusion measured by the post-lysis volume of the CT perfusion lesion performed immediately after hospital arrival. ETHICS AND DISSEMINATION: The study was approved by the Royal Melbourne Hospital Human Ethics committee. The findings will be published in peer-reviewed journals, presented at academic conferences and disseminated among consumer and healthcare professional audiences. TRIAL REGISTRATION NUMBER: NCT04071613.

Does tranexamic acid affect intraventricular hemorrhage growth in acute ICH? An analysis of the STOP-AUST trial.

Background: Trials of tranexamic acid (TXA) in acute intracerebral hemorrhage (ICH) have focused on the imaging outcomes of intraparenchymal hematoma growth. However, intraventricular hemorrhage (IVH) growth is also strongly associated with outcome after ICH. Revised definitions of hematoma expansion incorporating IVH growth have been proposed. Aims: We sought to evaluate the effect of TXA on IVH growth. Methods: We analyzed data from the STOP-AUST trial, a prospective randomized trial comparing TXA to placebo in ICH patients presenting ≤ 4.5 h from symptom onset with a CT-angiography spot sign. New IVH development at follow-up, any interval IVH growth, and IVH growth ≥ 1 mL were compared between the treatment groups using logistic regression. The treatment effect of TXA against placebo using conventional (> 6 mL or 33%), and revised definitions of hematoma expansion (> 6 mL or 33% or IVH expansion ≥ 1 mL, > 6 mL or 33%, or any IVH expansion, and > 6 mL or 33% or new IVH development) were also assessed. Treatment effects were adjusted for baseline ICH volume. Results: The analysis population consisted of 99 patients (50 placebo, 49 TXA). New IVH development at follow-up was observed in 6/49 (12%) who received TXA and 13/50 (26%) who received placebo (aOR: 0.38 [95% CI: 0.13-1.13]). Any interval IVH growth was observed in 12/49 (25%) who received TXA versus 26/50 (32%) receiving placebo (aOR: 0.69 [95% CI: 0.28-1.66]). IVH growth ≥ 1 mL did not differ between the two groups. Using revised definitions of hematoma expansion, no significant difference in treatment effect was observed between TXA and placebo. Conclusions: IVH may be attenuated by TXA following ICH; however, studies with larger cohorts are required to investigate this further. Registration: http://www.clinicaltrials.gov; Unique identifier: NCT01702636.

The Mobile Stroke Unit Nurse: An International Exploration of Their Scope of Practice, Education, and Training.

ABSTRACT: BACKGROUND: Mobile stroke units (MSUs) are ambulance-based prehospital stroke care services. Through immediate roadside assessment and onboard brain imaging, MSUs provide faster stroke management with improved patient outcomes. Mobile stroke units have enabled the development of expanded scope of practice for stroke nurses; however, there is limited published evidence about these evolving prehospital acute nursing roles. AIMS: The aim of this study was to explore the expanded scope of practice of nurses working on MSUs by identifying MSUs with onboard nurses; describing the roles and responsibilities, training, and experience of MSU nurses, through a search of the literature; and describing 2 international MSU services incorporating nurses from Memphis, Tennessee, and Melbourne, Australia. METHODS: We searched PubMed, CINAHL, and the Joanna Briggs Institute Evidence-Based Practice database using the terms "mobile stroke unit" and "nurse." Existing MSUs were identified through the PRE-hospital Stroke Treatment Organization to determine models that involved nurses. We describe 2 MSUs involving nurses: one in Memphis and one in Melbourne, led by 2 of our authors. RESULTS: Ninety articles were found describing 15 MSUs; however, staffing details were lacking, and it is unknown how many employ nurses. Nine articles described the role of the nurse, but role specifics, training, and expertise were largely undocumented. The MSU in Memphis, the only unit to be staffed exclusively by onboard nurse practitioners, is supported by a neurologist who consults via telephone. The Melbourne MSU plans to trial a nurse-led telemedicine model in the near future. CONCLUSION: We lack information on how many MSUs employ nurses, and the nurses' scope of practice, training, and expertise. Expert stroke nurse practitioners can safely perform many of the tasks undertaken by the onboard neurologist, making a nurse-led telemedicine model an effective and potentially cost-effective model that should be considered for all MSUs.

Comparison of Mobile Stroke Unit With Usual Care for Acute Ischemic Stroke Management: A Systematic Review and Meta-analysis.

IMPORTANCE: So far, uncertainty remains as to whether there is sufficient cumulative evidence that mobile stroke unit (MSU; specialized ambulance equipped with computed tomography scanner, point-of-care laboratory, and neurological expertise) use leads to better functional outcomes compared with usual care. OBJECTIVE: To determine with a systematic review and meta-analysis of the literature whether MSU use is associated with better functional outcomes in patients with acute ischemic stroke (AIS). DATA SOURCES: MEDLINE, Cochrane Library, and Embase from 1960 to 2021. STUDY SELECTION: Studies comparing MSU deployment and usual care for patients with suspected stroke were eligible for analysis, excluding case series and case-control studies. DATA EXTRACTION AND SYNTHESIS: Independent data extraction by 2 observers, following the PRISMA and MOOSE reporting guidelines. The risk of bias in each study was determined using the ROBINS-I and RoB2 tools. In the case of articles with partially overlapping study populations, unpublished disentangled results were obtained. Data were pooled in random-effects meta-analyses. MAIN OUTCOMES AND MEASURES: The primary outcome was excellent outcome as measured with the modified Rankin Scale (mRS; score of 0 to 1 at 90 days). RESULTS: Compared with usual care, MSU use was associated with excellent outcome (adjusted odds ratio [OR], 1.64; 95% CI, 1.27-2.13; P < .001; 5 studies; n = 3228), reduced disability over the full range of the mRS (adjusted common OR, 1.39; 95% CI, 1.14-1.70; P = .001; 3 studies; n = 1563), good outcome (mRS score of 0 to 2: crude OR, 1.25; 95% CI, 1.09-1.44; P = .001; 6 studies; n = 3266), shorter onset-to-intravenous thrombolysis (IVT) times (median reduction, 31 minutes [95% CI, 23-39]; P < .001; 13 studies; n = 3322), delivery of IVT (crude OR, 1.83; 95% CI, 1.58-2.12; P < .001; 7 studies; n = 4790), and IVT within 60 minutes of symptom onset (crude OR, 7.71; 95% CI, 4.17-14.25; P < .001; 8 studies; n = 3351). MSU use was not associated with an increased risk of all-cause mortality at 7 days or at 90 days or with higher proportions of symptomatic intracranial hemorrhage after IVT. CONCLUSIONS AND RELEVANCE: Compared with usual care, MSU use was associated with an approximately 65% increase in the odds of excellent outcome and a 30-minute reduction in onset-to-IVT times, without safety concerns. These results should help guideline writing committees and policy makers.

Does variability in automated perfusion software outputs for acute ischemic stroke matter? Reanalysis of EXTEND perfusion imaging.

AIMS: We reprocessed the Extending the time for Thrombolysis in Emergency Neurological Deficits (EXTEND) perfusion imaging with a different automated software with the aim of comparing mismatch eligibility and outcomes. METHODS: EXTEND baseline perfusion imaging data were reprocessed using autoMIStar software to identify patients who were eligible based on the same target mismatch criteria as per the original trial. RESULTS: From the 225 patients fulfilling RAPID-based mismatch criteria randomized in the EXTEND study, 196 (87%) patients met the revised mismatch criteria. Most common reasons for not meeting revised criteria were core >70 ml (n = 9), and no perfusion lesion/lack of penumbral tissue (n = 20). The revised perfusion lesion volumes were significantly smaller compared to the original RAPID volumes (median 68 ml IQR 34-102 ml vs. 42 ml 16-92 ml, p = 0.036). Of the patients who met the revised mismatch criteria, 40% receiving alteplase had modified Rankin Scale (mRS) 0-1 at 3-month compared to 28% with placebo (Adjusted Odds Ratio (OR) = 2.23, CI 1.08-4.58, p = 0.028). In contrast, in the original mismatch cohort, 35% receiving alteplase had mRS 0-1 at 3-month compared to 30% with placebo (adjusted OR = 1.88, p = 0.056). CONCLUSIONS: These data reinforce the benefit of alteplase in the later time window, and suggest that differences in automated perfusion imaging software outputs may be clinically relevant.

Posterior National Institutes of Health Stroke Scale Improves Prognostic Accuracy in Posterior Circulation Stroke.

BACKGROUND AND PURPOSE: The National Institutes of Health Stroke Scale (NIHSS) underestimates clinical severity in posterior circulation stroke and patients presenting with low NIHSS may be considered ineligible for reperfusion therapies. This study aimed to develop a modified version of the NIHSS, the Posterior NIHSS (POST-NIHSS), to improve NIHSS prognostic accuracy for posterior circulation stroke patients with mild-moderate symptoms. METHODS: Clinical data of consecutive posterior circulation stroke patients with mild-moderate symptoms (NIHSS <10), who were conservatively managed, were retrospectively analyzed from the Basilar Artery Treatment and Management registry. Clinical features were assessed within 24 hours of symptom onset; dysphagia was assessed by a speech therapist within 48 hours of symptom onset. Random forest classification algorithm and constrained optimization were used to develop the POST-NIHSS in the derivation cohort. The POST-NIHSS was then validated in a prospective cohort. Poor outcome was defined as modified Rankin Scale score ≥3 at 3 months. RESULTS: We included 202 patients (mean [SD] age 63 [14] years, median NIHSS 3 [interquartile range, 1-5]) in the derivation cohort and 65 patients (mean [SD] age 63 [16] years, median NIHSS 2 [interquartile range, 1-4]) in the validation cohort. In the derivation cohort, age, NIHSS, abnormal cough, dysphagia and gait/truncal ataxia were ranked as the most important predictors of functional outcome. POST-NIHSS was calculated by adding 5 points for abnormal cough, 4 points for dysphagia, and 3 points for gait/truncal ataxia to the baseline NIHSS. In receiver operating characteristic analysis adjusted for age, POST-NIHSS area under receiver operating characteristic curve was 0.80 (95% CI, 0.73-0.87) versus NIHSS area under receiver operating characteristic curve, 0.73 (95% CI, 0.64-0.83), P=0.03. In the validation cohort, POST-NIHSS area under receiver operating characteristic curve was 0.82 (95% CI, 0.69-0.94) versus NIHSS area under receiver operating characteristic curve 0.73 (95% CI, 0.58-0.87), P=0.04. CONCLUSIONS: POST-NIHSS showed higher prognostic accuracy than NIHSS and may be useful to identify posterior circulation stroke patients with NIHSS <10 at higher risk of poor outcome.

Tranexamic acid for intracerebral haemorrhage within 2 hours of onset: protocol of a phase II randomised placebo-controlled double-blind multicentre trial.

RATIONALE: Haematoma growth is common early after intracerebral haemorrhage (ICH), and is a key determinant of outcome. Tranexamic acid, a widely available antifibrinolytic agent with an excellent safety profile, may reduce haematoma growth. METHODS AND DESIGN: Stopping intracerebral haemorrhage with tranexamic acid for hyperacute onset presentation including mobile stroke units (STOP-MSU) is a phase II double-blind, randomised, placebo-controlled, multicentre, international investigator-led clinical trial, conducted within the estimand statistical framework. HYPOTHESIS: In patients with spontaneous ICH, treatment with tranexamic acid within 2 hours of onset will reduce haematoma expansion compared with placebo. SAMPLE SIZE ESTIMATES: A sample size of 180 patients (90 in each arm) would be required to detect an absolute difference in the primary outcome of 20% (placebo 39% vs treatment 19%) under a two-tailed significance level of 0.05. An adaptive sample size re-estimation based on the outcomes of 144 patients will allow a possible increase to a prespecified maximum of 326 patients. INTERVENTION: Participants will receive 1 g intravenous tranexamic acid over 10 min, followed by 1 g intravenous tranexamic acid over 8 hours; or matching placebo. PRIMARY EFFICACY MEASURE: The primary efficacy measure is the proportion of patients with haematoma growth by 24±6 hours, defined as either ≥33% relative increase or ≥6 mL absolute increase in haematoma volume between baseline and follow-up CT scan. DISCUSSION: We describe the rationale and protocol of STOP-MSU, a phase II trial of tranexamic acid in patients with ICH within 2 hours from onset, based in participating mobile stroke units and emergency departments.

Mobile Stroke Units Facilitate Prehospital Management of Intracerebral Hemorrhage.

Background and Purpose: Mobile stroke units (MSUs) improve reperfusion therapy times in acute ischemic stroke (AIS). However, prehospital management options for intracerebral hemorrhage (ICH) are less established. We describe the initial Melbourne MSU experience in ICH. Methods: Consecutive patients with ICH and AIS treated by the Melbourne MSU were included. We describe demographics, proportions of patients receiving specific therapies, and bypass to comprehensive/neurosurgical centers. We also compare operational time metrics between patients with MSU-ICH and MSU-AIS. Results: During a 2-year period, the Melbourne MSU managed 49 patients with ICH, mean (SD) age 74 (12) years, median (interquartile range) National Institutes of Health Stroke Scale 17 (12­20). Intravenous antihypertensives were the commonest treatment provided (46.9%). Bypass of a primary center to a comprehensive center with neurosurgical expertise occurred in 32.7% of patients with MSU-ICH compared with 20.5% of patients with MSU-AIS. Compared with patients with MSU-AIS, patients with MSU-ICH had faster onset-to-emergency-call, and onset-to-scene-arrival times at the median and 75th percentiles. Conclusions: MSUs can facilitate ultra-early ICH diagnosis, management, and triage.

The Kynurenine/Tryptophan Ratio Is a Sensitive Biomarker for the Diagnosis of Pediatric Tuberculosis Among Indian Children.

Objectives: Pediatric tuberculosis (TB) remains difficult to diagnose. The plasma kynurenine to tryptophan ratio (K/T ratio) is a potential biomarker for TB diagnosis and treatment response but has not been assessed in children. Methods: We performed a targeted diagnostic accuracy analysis of four biomarkers: kynurenine abundance, tryptophan abundance, the K/T ratio, and IDO-1 gene expression. Data were obtained from transcriptome and metabolome profiling of children with confirmed tuberculosis and age- and sex-matched uninfected household contacts of pulmonary tuberculosis patients. Each biomarker was assessed as a baseline diagnostic and in response to successful TB treatment. Results: Despite non-significant between-group differences in unbiased analysis, the K/T ratio achieved an area under the receiver operator characteristic curve (AUC) of 0.667 and 81.5% sensitivity for TB diagnosis. Kynurenine, tryptophan, and IDO-1 demonstrated diagnostic AUCs of 0.667, 0.602, and 0.463, respectively. None of these biomarkers demonstrated high AUCs for treatment response. The AUC of the K/T ratio was lower than biomarkers identified in unbiased analysis, but improved sensitivity over existing commercial assays for pediatric TB diagnosis. Conclusions: Plasma kynurenine and the K/T ratio may be useful biomarkers for pediatric TB. Ongoing studies in geographically diverse populations will determine optimal use of these biomarkers worldwide.

Economic evaluation of the Melbourne Mobile Stroke Unit.

BACKGROUND: The Melbourne Mobile Stroke Unit (MSU) is the first Australian service to provide prehospital acute stroke treatment, including thrombolysis and facilitated triage for endovascular thrombectomy. AIMS: To estimate the cost-effectiveness of the MSU during the first full year of operation compared with standard ambulance and hospital stroke care pathways (standard care). METHODS: The costs and benefits of the Melbourne MSU were estimated using an economic simulation model. Operational costs and service utilization data were obtained from the MSU financial and patient tracking reports. The health benefits were estimated as disability-adjusted life years (DALYs) avoided using local data on reperfusion therapy and estimates from the published literature on their effectiveness. Costs were presented in Australian dollars. The robustness of results was assessed using multivariable (model inputs varied simultaneously: 10,000 Monte Carlo iterations) and various one-way sensitivity analyses. RESULTS: In 2018, the MSU was dispatched to 1244 patients during 200 days of operation. Overall, 167 patients were diagnosed with acute ischemic stroke, and 58 received thrombolysis, endovascular thrombectomy, or both. We estimated 27.94 DALYs avoided with earlier access to endovascular thrombectomy (95% confidence interval (CI) 15.30 to 35.93) and 16.90 DALYs avoided with improvements in access to thrombolysis (95% CI 9.05 to 24.68). The MSU was estimated to cost an additional $30,982 per DALY avoided (95% CI $21,142 to $47,517) compared to standard care. CONCLUSIONS: There is evidence that the introduction of MSU is cost-effective when compared with standard care due to earlier provision of reperfusion therapies.

Utility of Severity-Based Prehospital Triage for Endovascular Thrombectomy: ACT-FAST Validation Study.

BACKGROUND AND PURPOSE: Severity-based assessment tools may assist in prehospital triage of patients to comprehensive stroke centers (CSCs) for endovascular thrombectomy (EVT), but criticisms regarding diagnostic inaccuracy have not been adequately addressed. This study aimed to quantify the benefits and disadvantages of severity-based triage in a large real-world paramedic validation of the Ambulance Clinical Triage for Acute Stroke Treatment (ACT-FAST) algorithm. METHODS: Ambulance Victoria paramedics assessed the prehospital ACT-FAST algorithm in patients with suspected stroke from November 2017 to July 2019 following an 8-minute training video. All patients were transported to the nearest stroke center as per current guidelines. ACT-FAST diagnostic accuracy was compared with hospital imaging for the presence of large vessel occlusion (LVO) and need for CSC-level care (LVO, intracranial hemorrhage, and tumor). Patient-level time saving to EVT was modeled using a validated Google Maps algorithm. Disadvantages of CSC bypass examined potential thrombolysis delays in non-LVO infarcts, proportion of patients with false-negative EVT, and CSC overburdening. RESULTS: Of 517 prehospital assessments, 168/517 (32.5%) were ACT-FAST positive and 132/517 (25.5%) had LVO. ACT-FAST sensitivity and specificity for LVO was 75.8% and 81.8%, respectively. Positive predictive value was 58.8% for LVO and 80.0% when intracranial hemorrhage and tumor (CSC-level care) were included. Within the metropolitan region, 29/55 (52.7%) of ACT-FAST-positive patients requiring EVT underwent a secondary interhospital transfer. Prehospital bypass with avoidance of secondary transfers was modeled to save 52 minutes (95% CI, 40.0-61.5) to EVT commencement. ACT-FAST was false-positive in 8 patients receiving thrombolysis (8.1% of 99 non-LVO infarcts) and false-negative in 4 patients with EVT requiring secondary transfer (5.4% of 74 EVT cases). CSC bypass was estimated to over-triage 1.1 patients-per-CSC-per-week in our region. CONCLUSIONS: The overall benefits of an ACT-FAST algorithm bypass strategy in expediting EVT and avoiding secondary transfers are estimated to substantially outweigh the disadvantages of potentially delayed thrombolysis and over-triage, with only a small proportion of EVT patients missed.