Establishing the First Mobile Stroke Unit in the United States

Mobile stroke units: Beyond thrombolysis

In the last decade, mobile stroke units (MSUs) have shown the potential to transform prehospital stroke care, marking a paradigm shift in delivering ultra-rapid thrombolysis and streamlining triage processes. These units bring acute stroke care directly to patients, significantly shortening treatment times. This review outlines the rationale for MSU care and discusses the potential applications beyond the original purpose of delivering thrombolysis, including large vessel occlusion detection, intracerebral hemorrhage management, and innovative forms of prehospital research.

Comparing 5G mobile stroke unit and emergency medical service in patients acute ischemic stroke eligible for t-PA treatment: A prospective, single-center clinical trial in Ya'an, China

BACKGROUND

This study aims to assess and compare the functional outcomes of patients with acute ischemic stroke (AIS) eligible for tissue plasminogen activator (t-PA) treatment who received care from either a fifth-generation(5G) mobile stroke unit (MSU) or traditional emergency medical service (EMS).

METHOD

The study recruited patients between February 2020 and January 2022, with the final 90-day follow-up concluded in April 2022. Prior to enrollment, patients were assigned to either EMS or MSU care based on predetermined rules. The primary outcome measure was the Modified Rankin Scale (mRS) score at 90 days, with secondary outcome measures including time metrics, mRS and National Institutes of Health Stroke Scale scores at 7-day follow-up, and hospitalization costs.

RESULTS

Of the 2281 enrolled patients, 207 were eligible for t-PA treatment, with 101 allocated to MSU care and 106 to EMS care. The percentage of patients achieving a favorable mRS score (0-2) at 90 days was 82.2% in the MSU group compared to 72.6% in the EMS group (p < .05). Median times from symptom onset to thrombolysis were 146 min in the MSU group and 204 min in the EMS group, while median times from ambulance alert to computed tomography (CT) completion were 53 and 128 min, respectively. Hospitalization charges averaged approximately $3592 in the MSU group and $4800 in the EMS group.

CONCLUSIONS

Our findings indicate that 5G MSU care significantly reduces the time from symptom onset to stroke diagnosis and intravenous thrombolysis in patients with AIS, resulting in improved functional outcomes compared to EMS care. As China continues its deployment of 5G technology and other digital infrastructures, the adoption of 5G MSU care on a broader scale may eventually supplant traditional stroke treatment approaches.

Current role of portable MRI in diagnosis of acute neurological conditions

Neuroimaging is an inevitable component of the assessment of neurological emergencies. Magnetic resonance imaging (MRI) is the preferred imaging modality for detecting neurological pathologies and provides higher sensitivity than other modalities. However, difficulties such as intra-hospital transport, long exam times, and availability in strict access-controlled suites limit its utility in emergency departments and intensive care units (ICUs). The evolution of novel imaging technologies over the past decades has led to the development of portable MRI (pMRI) machines that can be deployed at point-of-care. This article reviews pMRI technologies and their clinical implications in acute neurological conditions. Benefits of pMRI include timely and accurate detection of major acute neurological pathologies such as stroke and intracranial hemorrhage. Additionally, pMRI can be potentially used to monitor the progression of neurological complications by facilitating serial measurements at the bedside.

Brain imaging with portable low-field MRI

The advent of portable, low-field MRI (LF-MRI) heralds new opportunities in neuroimaging. Low power requirements and transportability have enabled scanning outside the controlled environment of a conventional MRI suite, enhancing access to neuroimaging for indications that are not well suited to existing technologies. Maximizing the information extracted from the reduced signal-to-noise ratio of LF-MRI is crucial to developing clinically useful diagnostic images. Progress in electromagnetic noise cancellation and machine learning reconstruction algorithms from sparse k-space data as well as new approaches to image enhancement have now enabled these advancements. Coupling technological innovation with bedside imaging creates new prospects in visualizing the healthy brain and detecting acute and chronic pathological changes. Ongoing development of hardware, improvements in pulse sequences and image reconstruction, and validation of clinical utility will continue to accelerate this field. As further innovation occurs, portable LF-MRI will facilitate the democratization of MRI and create new applications not previously feasible with conventional systems.

Prehospital Stroke Care Part 2: On-Scene Evaluation and Management by Emergency Medical Services Practitioners

The prehospital phase is a critical component of delivering high-quality acute stroke care. This topical review discusses the current state of prehospital acute stroke screening and transport, as well as new and emerging advances in prehospital diagnosis and treatment of acute stroke. Topics include prehospital stroke screening, stroke severity screening, emerging technologies to aid in the identification and diagnosis of acute stroke in the prehospital setting, prenotification of receiving emergency departments, decision support for destination determination, and the capabilities and opportunities for prehospital stroke treatment in mobile stroke units. Further evidence-based guideline development and implementation of new technologies are critical for ongoing improvements in prehospital stroke care.

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 (β=0.61), not experiencing pressure/tension about working on the MSU (β=0.17) and thinking they did well working within the team model (β=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.

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.

Disparities in spatial access to neurological care in Appalachia: a cross-sectional health services analysis

Background

Appalachia is rural and socioeconomically deprived with a heavy burden of neurological disorders and poor access to healthcare providers. Rates of neurological disorders are increasing over time without equal increases in providers, indicating that Appalachian disparities are likely to worsen. Spatial access to neurological care has not been robustly explored for U.S. areas, so we aimed to examine disparities in the vulnerable Appalachian region.

Methods

Using 2022 CMS Care Compare physician data, we conducted a cross-sectional health services analysis, where we computed spatial accessibility of neurologists for all census tracts in the 13 states with Appalachian counties. We stratified access ratios by state, area deprivation, and rural-urban commuting area (RUCA) codes then utilized Welch two-sample t-tests to compare Appalachian tracts with non-Appalachian tracts. Using stratified results, we identified Appalachian areas where interventions would have the largest impact.

Findings

Appalachian tracts (n = 6169) had neurologist spatial access ratios between 25% and 35% lower than non-Appalachian tracts (n = 18,441; p < 0.001). When stratified by rurality and deprivation, three-step floating catchment area spatial access ratios for Appalachian tracts remained significantly lower in the most urban (RUCA = 1 [p < 0.0001) and most rural tracts (RUCA = 9 [p = 0.0093]; RUCA = 10 [p = 0.0227]). We identified 937 Appalachian census tracts where interventions can be targeted.

Interpretation

After stratifying by rural status and deprivation, significant disparities in spatial access to neurologists remained for Appalachian areas, indicating both poorer access in Appalachia and that neurologist accessibility cannot be determined solely by remoteness and socioeconomic status. These findings and our identified disparity areas have broad implications for policymaking and intervention targeting in Appalachia.

Funding

R.B.B. was supported by NIH Award Number T32CA094186. M.P.M. was supported by NIH-NCATS Award Number KL2TR002547.

Low-field MRI: Clinical promise and challenges

Modern MRI scanners have trended toward higher field strengths to maximize signal and resolution while minimizing scan time. However, high-field devices remain expensive to install and operate, making them scarce outside of high-income countries and major population centers. Low-field strength scanners have drawn renewed academic, industry, and philanthropic interest due to advantages that could dramatically increase imaging access, including lower cost and portability. Nevertheless, low-field MRI still faces inherent limitations in image quality that come with decreased signal. In this article, we review advantages and disadvantages of low-field MRI scanners, describe hardware and software innovations that accentuate advantages and mitigate disadvantages, and consider clinical applications for a new generation of low-field devices. In our review, we explore how these devices are being or could be used for high acuity brain imaging, outpatient neuroimaging, MRI-guided procedures, pediatric imaging, and musculoskeletal imaging. Challenges for their successful clinical translation include selecting and validating appropriate use cases, integrating with standards of care in high resource settings, expanding options with actionable information in low resource settings, and facilitating health care providers and clinical practice in new ways. By embracing both the promise and challenges of low-field MRI, clinicians and researchers have an opportunity to transform medical care for patients around the world. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 6.

Portable, low-field magnetic resonance imaging enables highly accessible and dynamic bedside evaluation of ischemic stroke

Brain imaging is essential to the clinical management of patients with ischemic stroke. Timely and accessible neuroimaging, however, can be limited in clinical stroke pathways. Here, portable magnetic resonance imaging (pMRI) acquired at very low magnetic field strength (0.064 T) is used to obtain actionable bedside neuroimaging for 50 confirmed patients with ischemic stroke. Low-field pMRI detected infarcts in 45 (90%) patients across cortical, subcortical, and cerebellar structures. Lesions as small as 4 mm were captured. Infarcts appeared as hyperintense regions on T2-weighted, fluid-attenuated inversion recovery and diffusion-weighted imaging sequences. Stroke volume measurements were consistent across pMRI sequences and between low-field pMRI and conventional high-field MRI studies. Low-field pMRI stroke volumes significantly correlated with stroke severity and functional outcome at discharge. These results validate the use of low-field pMRI to obtain clinically useful imaging of stroke, setting the stage for use in resource-limited environments.

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.

A Systematic Review of Mobile Stroke Unit Among Acute Stroke Patients: Time Metrics, Adverse Events, Functional Result and Cost-Effectiveness

Background

Mobile stroke unit (MSU) is deployed to shorten the duration of ischemic stroke recognition to thrombolysis treatment, thus reducing disability, mortality after an acute stroke attack, and related economic burden. Therefore, we conducted a comprehensive systematic review of the clinical trial and economic literature focusing on various outcomes of MSU compared with conventional emergency medical services (EMS).

Methods

An electronic search was conducted in four databases (PubMed, OVID Medline, Embase, and the Cochrane Controlled Register of Trials) from 1990 to 2021. In these trials, patients with acute stroke were assigned to receive either MSU or EMS, with clinical and economic outcomes. First, we extracted interested data in the pooled population and conducted a subgroup analysis to examine related heterogeneity. We then implemented a descriptive analysis of economic outcomes. All analyses were performed with R 4.0.1 software.

Results

A total of 22,766 patients from 16 publications were included. In total 7,682 (n = 33.8%) were treated in the MSU and 15,084 (n = 66.2%) in the conventional EMS. Economic analysis were available in four studies, of which two were based on trial data and the others on model simulations. The pooled analysis of time metrics indicated a mean reduction of 32.64 min (95% confidence interval: 23.38–41.89, p &lt; 0.01) and 28.26 minutes (95% CI: 16.11–40.41, p &lt; 0.01) in the time-to-therapy and time-to-CT completion, respectively in the MSU. However, there was no significant difference on stroke-related neurological events (OR = 0.94, 95% CI: 0.70–1.27, p = 0.69) and in-hospital mortality (OR = 1.11, 95% CI: 0.83–1.50, p = 0.48) between the MSU and EMS. The proportion of patients with modified Ranking scale (mRS) of 0–2 at 90 days from onset was higher in the MSU than EMS (p &lt; 0.05). MSU displayed favorable benefit-cost ratios (2.16–6.85) and incremental cost-effectiveness ratio ($31,911 /QALY and $38,731 per DALY) comparing to EMS in multiple economic publications. Total cost data based on 2014 USD showed that the MSU has the highest cost in Australia ($1,410,708) and the lowest cost in the USA ($783,463).

Conclusion

A comprehensive analysis of current research suggests that MUS, compared with conventional EMS, has a better performance in terms of time metrics, safety, long-term medical benefits, and cost-effectiveness.

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.

Mobile Stroke Units: Current Evidence and Impact

PURPOSE OF REVIEW

Several approaches have been developed to optimize prehospital systems for acute stroke given poor access and significant delays to timely treatment. Specially equipped ambulances that directly initiate treatment, known as Mobile Stroke Units (MSUs), have rapidly proliferated across the world. This review provides a comprehensive summary on the efficacy of MSUs in acute stroke, its various applications beyond thrombolysis, as well as the establishment, optimal setting and cost-effectiveness of incorporating an MSU into healthcare systems.

RECENT FINDINGS

MSUs speed stroke treatment into the first "golden hour" when better outcomes from thrombolysis are achieved. While evidence for the positive impact of MSUs on outcomes was previously unavailable, two recent landmark controlled trials, B_PROUD and BEST-MSU, show that MSUs result in significantly lesser disability compared to conventional ambulance care. Emerging literature prove the significant impact of MSUs. Adaptability however remains limited by significant upfront financial investment, challenges with reimbursements and pending evidence on their cost-effectiveness.

Fifty Years of Acute Ischemic Stroke Treatment: A Personal History

BACKGROUND

It has been 50 years since the first explorations of the physiology of cerebral ischemia by measuring cerebral blood flow (CBF), and 25 years since the approval of tissue plasminogen activator for treating acute ischemic stroke. My personal career began and matured during those eras. Here, I provide my perspective on the evolution of acute stroke research and treatment from 1971 to the present, with some in-depth discussion of the National Institutes of Neurologic Disease and Stroke (NINDS) tissue-type plasminogen activator (tPA) stroke trial and development of mobile stroke units.

SUMMARY

Studies of CBF and metabolism in acute stroke patients revealed graded tissue injury that was dependent on the duration of ischemia. Subsequent animal research unraveled the biochemical cascade of events occurring at the cellular level after cerebral ischemia. After a decade of failed translation, the development of a relatively safe thrombolytic allowed us to achieve reperfusion and apply the lessons from earlier research to achieve positive clinical results. The successful conduct of the NINDS tPA stroke study coupled with positive outcomes from companion tPA studies around the world created the specialty of vascular neurology. This was followed by an avalanche of research in imaging, a focus on enhancing reperfusion through thrombectomy, and improving delivery of faster treatment culminating in mobile stroke units. Key Messages: The last half century has seen the birth and evolution of successful acute stroke treatment. More research is needed in developing new drugs and catheters to build on the advances we have already made with reperfusion and also in evolving our systems of care to get more patients treated more quickly in the prehospital setting. The history of stroke treatment over the last 50 years exemplifies that medical "science" is an evolving discipline worth an entire career's dedication. What was impossible 50 years ago is today's standard of care, what we claim as dogma today will be laughed at a decade from now, and what appears currently impossible will be tomorrow's realities.

Telemedicine-enabled ambulances and mobile stroke units for prehospital stroke management

The recognition and management of stroke in the prehospital setting has become increasingly important to improve patient outcomes. Several strategies to advance prehospital stroke care have been developed, including the mobile stroke unit and the telemedicine-enabled ambulance-or "mini-MSU." These strategies both incorporate ambulance-based audio-visual telemedicine evaluation with a vascular neurologist to facilitate faster treatment but differ in several areas including upfront and recurring costs, scalability or growth potential, ability to integrate into existing emergency medical services systems, and interoperability across multiple specialties or conditions. While both the mobile stroke unit and mini-mobile stroke unit model are valid approaches to improve stroke care, the authors aim to compare these models based on costs, scalability, integration, and interoperability in order to guide our prehospital leaders to find the best solutions for their communities.

Prospective, Multicenter, Controlled Trial of Mobile Stroke Units

BACKGROUND

Mobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard management by emergency medical services (EMS). Whether and how much MSUs alter outcomes has not been extensively studied.

METHODS

In an observational, prospective, multicenter, alternating-week trial, we assessed outcomes from MSU or EMS management within 4.5 hours after onset of acute stroke symptoms. The primary outcome was the score on the utility-weighted modified Rankin scale (range, 0 to 1, with higher scores indicating better outcomes according to a patient value system, derived from scores on the modified Rankin scale of 0 to 6, with higher scores indicating more disability). The main analysis involved dichotomized scores on the utility-weighted modified Rankin scale (≥0.91 or <0.91, approximating scores on the modified Rankin scale of ≤1 or >1) at 90 days in patients eligible for t-PA. Analyses were also performed in all enrolled patients.

RESULTS

We enrolled 1515 patients, of whom 1047 were eligible to receive t-PA; 617 received care by MSU and 430 by EMS. The median time from onset of stroke to administration of t-PA was 72 minutes in the MSU group and 108 minutes in the EMS group. Of patients eligible for t-PA, 97.1% in the MSU group received t-PA, as compared with 79.5% in the EMS group. The mean score on the utility-weighted modified Rankin scale at 90 days in patients eligible for t-PA was 0.72 in the MSU group and 0.66 in the EMS group (adjusted odds ratio for a score of ≥0.91, 2.43; 95% confidence interval [CI], 1.75 to 3.36; P<0.001). Among the patients eligible for t-PA, 55.0% in the MSU group and 44.4% in the EMS group had a score of 0 or 1 on the modified Rankin scale at 90 days. Among all enrolled patients, the mean score on the utility-weighted modified Rankin scale at discharge was 0.57 in the MSU group and 0.51 in the EMS group (adjusted odds ratio for a score of ≥0.91, 1.82; 95% CI, 1.39 to 2.37; P<0.001). Secondary clinical outcomes generally favored MSUs. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group.

CONCLUSIONS

In patients with acute stroke who were eligible for t-PA, utility-weighted disability outcomes at 90 days were better with MSUs than with EMS. (Funded by the Patient-Centered Outcomes Research Institute; BEST-MSU ClinicalTrials.gov number, NCT02190500.).

Direct to Angiography vs Repeated Imaging Approaches in Transferred Patients Undergoing Endovascular Thrombectomy

Importance

A direct to angiography (DTA) treatment paradigm without repeated imaging for transferred patients with large vessel occlusion (LVO) may reduce time to endovascular thrombectomy (EVT). Whether DTA is safe and associated with better outcomes in the late (>6 hours) window is unknown. Also, DTA feasibility and effectiveness in reducing time to EVT during on-call vs regular-work hours and the association of interfacility transfer times with DTA outcomes have not been established.

Objective

To evaluate the functional and safety outcomes of DTA vs repeated imaging in the different treatment windows and on-call hours vs regular hours.

Design, Setting, and Participants

This pooled retrospective cohort study at 6 US and European comprehensive stroke centers enrolled adults (aged ≥18 years) with anterior circulation LVO (internal cerebral artery or middle cerebral artery subdivisions M1/M2) and transferred for EVT within 24 hours of the last-known-well time from January 1, 2014, to February 29, 2020.

Exposures

Repeated imaging (computed tomography with or without computed tomographic angiography or computed tomography perfusion) before EVT vs DTA.

Main Outcomes and Measures

Functional independence (90-day modified Rankin Scale score, 0-2) was the primary outcome. Symptomatic intracerebral hemorrhage, mortality, and time metrics were also compared between the DTA and repeated imaging groups.

Results

A total of 1140 patients with LVO received EVT after transfer, including 327 (28.7%) in the DTA group and 813 (71.3%) in the repeated imaging group. The median age was 69 (interquartile range [IQR], 59-78) years; 529 were female (46.4%) and 609 (53.4%) were male. Patients undergoing DTA had greater use of intravenous alteplase (200 of 327 [61.2%] vs 412 of 808 [51.0%]; P = .002), but otherwise groups were similar. Median time from EVT center arrival to groin puncture was faster with DTA (34 [IQR, 20-62] vs 60 [IQR, 37-95] minutes; P < .001), overall and in both regular and on-call hours. Three-month functional independence was higher with DTA overall (164 of 312 [52.6%] vs 282 of 763 [37.0%]; adjusted odds ratio [aOR], 1.85 [95% CI, 1.33-2.57]; P < .001) and during regular (77 of 143 [53.8%] vs 118 of 292 [40.4%]; P = .008) and on-call (87 of 169 [51.5%] vs 164 of 471 [34.8%]; P < .001) hours. The results did not vary by time window (0-6 vs >6 to 24 hours; P = .88 for interaction). Three-month mortality was lower with DTA (53 of 312 [17.0%] vs 186 of 763 [24.4%]; P = .008). A 10-minute increase in EVT-center arrival to groin puncture in the repeated imaging group correlated with 5% reduction in the functional independence odds (aOR, 0.95 [95% CI, 0.91-0.99]; P = .01). The rates of modified Rankin Scale score of 0 to 2 decreased with interfacility transfer times of greater than 3 hours in the DTA group (96 of 161 [59.6%] vs 15 of 42 [35.7%]; P = .006), but not in the repeated imaging group (75 of 208 [36.1%] vs 71 of 192 [37.0%]; P = .85).

Conclusions and Relevance

The DTA approach may be associated with faster treatment and better functional outcomes during all hours and treatment windows, and repeated imaging may be reasonable with prolonged transfer times. Optimal EVT workflow in transfers may be associated with faster, safe reperfusion with improved outcomes.

Application of Mobile Stroke Unit in Prehospital Thrombolysis of Acute Stroke: Experience from China

BACKGROUND AND PURPOSE

Most patients cannot receive intravenous thrombolytic therapy in the early stage of stroke onset, and the application of mobile stroke unit (MSU) in prehospital intravenous thrombolytic therapy of acute stroke may change this situation. The first MSU in China was put into use in 2017. Herein, we aimed to explore the preliminary experience of MSU in prehospital thrombolysis of acute stroke.

METHODS

Patients who received prehospital intravenous thrombolytic therapy using MSU were classified to the MSU thrombolysis group, and the control group consisted of stroke patients admitted by regular ambulances, who were transferred to hospital for intravenous thrombolytic therapy. The feasibility, safety, and duration of procedures were compared.

RESULTS

There were 14 patients received prehospital intravenous thrombolysis on the MSU, and 24 patients underwent intravenous thrombolysis in the emergency center, who were transferred by the ordinary ambulance during the same period. The median call-to-needle time was 59.5 min in the MSU thrombolysis group, while it was 89 min in the control group; the difference between the 2 groups was statistically significant (p = 0.001). The median time from onset to thrombolysis was 70 and 102.5 min, respectively, in the 2 groups (p = 0.002). The percentages of good clinical outcome (modified Rankin Scale score ≤ 2) at 90-day follow-up were 79 and 67%, respectively (p = 0.488). The rate of symptomatic intracranial hemorrhage and mortality during the perioperative period did not differ significantly between 2 groups.

CONCLUSION

Despite the small sample size, our preliminary experience of the application of MSU in the prehospital thrombosis therapy seems to indicate a significant reduction in time from call to needle, the efficacy of MSU in the treatment of acute stroke needs further experiment and larger sample size to confirm.

Prehospital Stroke Management Optimized by Use of Clinical Scoring vs Mobile Stroke Unit for Triage of Patients With Stroke: A Randomized Clinical Trial

Importance

Transferring patients with large-vessel occlusion (LVO) or intracranial hemorrhage (ICH) to hospitals not providing interventional treatment options is an unresolved medical problem.

Objective

To determine how optimized prehospital management (OPM) based on use of the Los Angeles Motor Scale (LAMS) compares with management in a Mobile Stroke Unit (MSU) in accurately triaging patients to the appropriate hospital with (comprehensive stroke center [CSC]) or without (primary stroke center [PSC]) interventional treatment.

Design, Setting, and Participants

In this randomized multicenter trial with 3-month follow-up, patients were assigned week-wise to one of the pathways between June 15, 2015, and November 15, 2017, in 2 regions of Saarland, Germany; 708 of 824 suspected stroke patients did not meet inclusion criteria, resulting in a study population of 116 adult patients.

Interventions

Patients received either OPM based on a standard operating procedure that included the use of the LAMS (cut point ≥4) or management in an MSU (an ambulance with vascular imaging, point-of-care laboratory, and telecommunication capabilities).

Main Outcomes and Measures

The primary end point was the proportion of patients accurately triaged to either CSCs (LVO, ICH) or PSCs (others).

Results

A predefined interim analysis was performed after 116 patients of the planned 232 patients had been enrolled. Of these, 53 were included in the OPM group (67.9% women; mean [SD] age, 74 [11] years) and 63 in the MSU group (57.1% women; mean [SD] age, 75 [11] years). The primary end point, an accurate triage decision, was reached for 37 of 53 patients (69.8%) in the OPM group and for 63 of 63 patients (100%) in the MSU group (difference, 30.2%; 95% CI, 17.8%-42.5%; P < .001). Whereas 7 of 17 OPM patients (41.2%) with LVO or ICH required secondary transfers from a PSC to a CSC, none of the 11 MSU patients (0%) required such transfers (difference, 41.2%; 95% CI, 17.8%-64.6%; P = .02). The LAMS at a cut point of 4 or higher led to an accurate diagnosis of LVO or ICH for 13 of 17 patients (76.5%; 6 triaged to a CSC) and of LVO selectively for 7 of 9 patients (77.8%; 2 triaged to a CSC). Stroke management metrics were better in the MSU group, although patient outcomes were not significantly different.

Conclusions and Relevance

Whereas prehospital management optimized by LAMS allows accurate triage decisions for approximately 70% of patients, MSU-based management enables accurate triage decisions for 100%. Depending on the specific health care environment considered, both approaches are potentially valuable in triaging stroke patients.

Trial Registration

ClinicalTrials.gov identifier: NCT02465346.

The role of stroke nurses in thrombolysis administration in Australia and the United Kingdom: A cross-sectional survey of current practice

BACKGROUND

The role of stroke nurses in patient selection and administration of recombinant tissue plasminogen activator (rt-PA) for acute ischaemic stroke is evolving.

OBJECTIVES

To compare differences in stroke nurses' practices related to rt-PA administration in Australia and the United Kingdom (UK) and to examine whether these differences influence rt-PA treatment rates.

METHODS

A cross-sectional, self-administered questionnaire administered to a lead stroke clinician from hospitals known to provide rt-PA for acute ischaemic stroke. Chi-square tests were used to analyse between-country differences in ten pre-specified rt-PA practices. Non-parametric equality of medians test was used to assess within-country differences for likelihood of undertaking practices and association with rt-PA treatment rates. Reporting followed STROBE checklist.

RESULTS

Response rate 68%; (Australia: 74% [n = 63/85]; UK: 65% [n = 93/144]). There were significant differences between countries for 7/10 practices. UK nurses were more likely to: request CT scan; screen patient for rt-PA suitability; gain informed consent; use telemedicine to assess, diagnose or treat; assist in the decision for rt-PA with Emergency Department physician or neurologist; and undergo training in rt-PA administration. Reported median hospital rt-PA treatment rates were 12% in the UK and 7.8% in Australia: (7.8%). In Australia, there was an association between higher treatment rates and nurses involvement in 5/10 practices; read and interpret CT scans; screen patient for rt-PA suitability; gain informed consent; assess suitability for rt-PA with neurologist/stroke physician; undergo training in rt-PA administration. There was no relationship between UK treatment rates and likelihood of a stroke nurse to undertake any of the ten rt-PA practices.

CONCLUSION

Stroke nurses' active role in rt-PA administration can improve rt-PA treatment rates. Models of care that broaden stroke nurses' scope of practice to maximise rt-PA treatment rates for ischaemic stroke patients are needed.

RELEVANCE TO CLINICAL PRACTICE

This study demonstrates that UK and Australian nurses play an important role in thrombolysis practices; however, they are underused. Formalising and extending the role of stroke nurses in rt-PA administration could potentially increase thrombolysis rates with clinical benefits for patients.

Time Is Brain: Prehospital Emergency Medical Services Response Times for Suspected Stroke and Effects of Prehospital Interventions

OBJECTIVES

To compare prehospital time for patients with suspected stroke in Florida with the American Stroke Association (ASA) time benchmarks, and to investigate the effects of dispatch notification and stroke assessment scales on prehospital time.

PATIENTS AND METHODS

A retrospective analysis was performed using data from Florida's Emergency Medical Services Tracking and Reporting System database. All patients with suspected stroke transported to a treatment center from January 1, 2018, through December 31, 2018, were analyzed. Time intervals from 911 call to hospital arrival were evaluated and compared with ASA benchmarks.

RESULTS

In 2018, 11,577 patients with suspected stroke were transported to a hospital (mean age, 71.5±15.7 years; 51.5% women). The median alarm-to-hospital time was 33.98 minutes (27.8 to 41.4), with a total emergency medical services (EMS) time of 32.30 minutes (26.5 to 39.478). The on-scene time was the largest time interval with a median of 13.28 minutes (10.0 to 17.4). Emergency medical services encounters met the ASA benchmarks for time in 58% to 62% of the EMS encounters in Florida (recommended 90%; P<.001). The total EMS time was reduced when a stroke notification was reported by the dispatch center (32.00 minutes vs 32.62 minutes; P=.006) or when a stroke assessment scale was used by the EMS personnel (31.88 minutes vs 32.96 minutes; P=.005).

CONCLUSION

This study reveals a substantial opportunity for improvement in stroke care in Florida. Two prehospital EMS stroke interventions seem to reduce prehospital time for patients with suspected stroke. Adoption of these interventions might improve the stroke systems of care.

Impact of mobile stroke units

Since its first introduction in clinical practice in 2008, the concept of mobile stroke unit enabling prehospital stroke treatment has rapidly expanded worldwide. This review summarises current knowledge in this young field of stroke research, discussing topics such as benefits in reduction of delay before treatment, vascular imaging-based triage of patients with large-vessel occlusion in the field, differential blood pressure management or prehospital antagonisation of anticoagulants. However, before mobile stroke units can become routine, several questions remain to be answered. Current research, therefore, focuses on safety, long-term medical benefit, best setting and cost-efficiency as crucial determinants for the sustainability of this novel strategy of acute stroke management.

A Comparison of Time to Treatment between an Emergency Department Focused Stroke Protocol and Mobile Stroke Units

BACKGROUND

San Francisco (California USA) is a relatively compact city with a population of 884,000 and nine stroke centers within a 47 square mile area. Emergency Medical Services (EMS) transport distances and times are short and there are currently no Mobile Stroke Units (MSUs).

METHODS

This study evaluated EMS activation to computed tomography (CT [EMS-CT]) and EMS activation to thrombolysis (EMS-TPA) times for acute stroke in the first two years after implementation of an emergency department (ED) focused, direct EMS-to-CT protocol entitled "Mission Protocol" (MP) at a safety net hospital in San Francisco and compared performance to published reports from MSUs. The EMS times were abstracted from ambulance records. Geometric means were calculated for MP data and pooled means were similarly calculated from published MSU data.

RESULTS

From July 2017 through June 2019, a total of 423 patients with suspected stroke were evaluated under the MP, and 166 of these patients were either ultimately diagnosed with ischemic stroke or were treated as a stroke but later diagnosed as a stroke mimic. The EMS and treatment time data were available for 134 of these patients with 61 patients (45.5%) receiving thrombolysis, with mean EMS-CT and EMS-TPA times of 41 minutes (95% CI, 39-43) and 63 minutes (95% CI, 57-70), respectively. The pooled estimates for MSUs suggested a mean EMS-CT time of 35 minutes (95% CI, 27-45) and a mean EMS-TPA time of 48 minutes (95% CI, 39-60). The MSUs achieved faster EMS-CT and EMS-TPA times (P <.0001 for each).

CONCLUSIONS

In a moderate-sized, urban setting with high population density, MP was able to achieve EMS activation to treatment times for stroke thrombolysis that were approximately 15 minutes slower than the published performance of MSUs.

The Story of Intracerebral Hemorrhage: From Recalcitrant to Treatable Disease

This invited special report is based on an award presentation at the World Stroke Organization/European Stroke Organization Conference in November of 2020 outlining progress in the acute management of intracerebral hemorrhage (ICH) over the past 35 years. ICH is the second most common and the deadliest type of stroke for which there is no scientifically proven medical or surgical treatment. Prospective studies from the 1990s onward have demonstrated that most growth of spontaneous ICH occurs within the first 2 to 3 hours and that growth of ICH and resulting volumes of ICH and intraventricular hemorrhage are modifiable factors that can improve outcome. Trials focusing on early treatment of elevated blood pressure have suggested a target systolic blood pressure of 140 mm Hg, but none of the trials were positive by their primary end point. Hemostatic agents to decrease bleeding in spontaneous ICH have included desmopressin, tranexamic acid, and rFVIIa (recombinant factor VIIa) without clear benefit, and platelet infusions which were associated with harm. Hemostatic agents delivered within the first several hours have the greatest impact on growth of ICH and potentially on outcome. No large Phase III surgical ICH trial has been positive by primary end point, but pooled analyses suggest that earlier ICH removal is more likely to be beneficial. Recent trials emphasize maximization of clot removal and minimizing brain injury from the surgical approach. The future of ICH therapy must focus on delivery of medical and surgical therapies as soon as possible if we are to improve outcomes.

Stroke-unit care for stroke patients in China: the results from Bigdata Observatory platform for Stroke of China

BACKGROUND

To assess whether stroke patients admitted to stroke units (SU) have a better short-term outcome than those treated in conventional wards (CW).

METHODS

A total of 20 hospitals from 16 provinces in China were initially selected in this study. Finally, 24,090 consecutive admissions in 2013-2015 treated in CW and 21,332 consecutive entries in 2017-2019 treated in SU were included. The primary endpoint of this study was the all-cause death or dependency condition three months after admission.

RESULTS

Patients in the SU group were more likely receiving thrombolytic therapy (3.9 vs 2.1%) and intravascular treatment (1.2 and 0.7%). In-hospital death were lower in the SU group than the CW group (SU vs CW: 2.93 vs 4.58% [absolute difference, - 2.28% {95% CI, - 3.32% to - 0.93%}, odd ratio {OR}, 0.72{95% CI, 0.61 to 0.82}]. Death after discharge was also lower in the SU group than the CW (SU vs CW: 5.07 vs 6.72% [absolute difference, - 2.33% {95% CI, - 3.39% to - 0.90%}, odd ratio {OR}, 0.75{95% CI, 0.68 to 0.84}]. In addition, patients who received SU care were less likely to be dead or disabled than those patients who received CW care after adjusting for other variability (SU vs CW: 36.20 vs 44.33% [absolute difference, - 11.33% {95% CI, - 15.32% to - 7.14%}, odd ratio {OR}, 0.78{95% CI, 0.80 to 0.85}].

CONCLUSIONS

Among patients with stroke, admission to a designated SU was associated with modestly lower mortality at discharge, reduced probability of death, or being disabled at the end of follow-up.

Pre-hospital triage of suspected acute stroke patients in a mobile stroke unit in the rural Alberta

Mobile Stroke Unit (MSU) expedites the delivery of intravenous thrombolysis in acute stroke patients. We further evaluated the functional outcome of patients shipped to a tertiary care centre or repatriated to local hospitals after triage by MSU in acute stroke syndrome in rural northern Alberta. Consecutive patients with suspected acute stroke syndrome were included. On the basis of neurology consultation and, Computed Tomography findings, patients, who were thrombolysed or needed advanced care were transported to the Comprehensive stroke center (CSC) (Triage to CSC group). Other patients were repatriated to local hospital care (Triage to LHC group). A total of 156 patients were assessed in MSU, 73 (46.8%) were female and the mean age was 66.6 ± 15 years. One hundred and eight (69.2%) patients, including 41 (26.3%) treated with thrombolysis were transported to the CSC (Triage to CSC group) and 48 (30.8%) were repatriated to local hospital care. The diagnosis made in MSU and final diagnosis were matching in 88% (95) and 91.7% (44, p = 0.39) in Triage to CSC and Triage to LHC groups respectively. Prehospital triage by MSU of acute stroke syndrome can reliably repatriate patients to the home hospital. The proposed model has the potential to triage patients according to their medical needs by enabling treatment in home hospitals whenever reasonable.

Mobile Stroke Units: Current and Future Impact on Stroke Care

Ischemic stroke is a leading cause of death and major disability that impacts societies across the world. Earlier thrombolysis of blocked arteries with intravenous tissue plasminogen activator (tPA) and/or endovascular clot extraction is associated with better clinical outcomes. Mobile stroke units (MSU) can deliver faster tPA treatment and rapidly transport stroke patients to centers with endovascular capabilities. Initial MSU trials in Germany indicated more rapid tPA treatment times using MSUs compared with standard emergency room treatment, a higher proportion of patients treated within 60 minutes of stroke onset, and a trend toward better 3-month clinical outcomes with MSU care. In the United States, the first multicenter, randomized clinical trial comparing standard versus MSU treatment began in 2014 in Houston, TX, and has demonstrated feasibility and safety of MSU operations, reliability of telemedicine technology to assess patients for tPA eligibility without additional time delays, and faster door-to-groin puncture times of MSU patients needing endovascular thrombectomy in interim analysis. Scheduled for completion in 2021, this trial will determine the cost-effectiveness and benefit of MSU treatment on clinical outcomes compared with standard ambulance and hospital treatment. Beyond ischemic stroke, MSUs have additional clinical and research applications that can profoundly impact other cohorts of patients who require time-sensitive neurological care.

Probability assessment of intracerebral hemorrhage in prehospital emergency patients

BACKGROUND

Routing of patients with intracerebral hemorrhage (ICH) and acute ischemic stroke (AIS) to the most appropriate hospital is challenging for emergency medical services particularly when specific treatment options are only provided by specialized hospitals and determination of the exact diagnosis is difficult. We aimed to develop a prehospital score - called prehospital-intracerebral hemorrhage score (ph-ICH score) - to assist in discriminating between both conditions.

METHODS

The ph-ICH score was developed with data from patients treated aboard a mobile stroke unit in Berlin, Germany, between 2011 and 2013 (derivation cohort) and in 2018 (validation cohort). Diagnosis of ICH or AIS was established using clinical data and neuroradiological cerebral imaging. Diagnostic accuracy was measured with significance testing, Cohen's d and receiver-operating-characteristics.

RESULTS

We analyzed 416 patients (32 ICH, 224 AIS, 41 transient ischemic attack, 119 stroke mimic) in the derivation cohort and 285 patients (33 ICH and 252 AIS) in the validation cohort. Systolic blood pressure, level of consciousness and severity of neurological deficits (i. e. certain items of the National Institutes of Health Stroke Scale) were used to calculate the ph-ICH score that showed higher values in the ICH compared to the AIS group (derivation cohort: 1.8 ± 1.2 vs. 1.0 ± 0.9 points; validation cohort: 1.8 ± 0.9 vs. 0.8 ± 0.7 points; d = 0.9 and 1.4, both p < 0.01). Receiver-operating-characteristics showed fair and good accuracy with an area under the curve of 0.71 for the derivation and 0.81 for the validation cohort.

CONCLUSIONS

The ph-ICH score can assist medical personnel in the field to assess the likelihood of ICH and AIS in emergency patients.

Triage and systems of care in stroke

There has been increasing adoption of endovascular stroke treatment in the United States following multiple clinical trials demonstrating superior efficacy. Next steps in enhancing this treatment include an analysis and development of stroke systems of care geared toward efficient delivery of endovascular and comprehensive stroke care. The chapter presents epidemiological data and an overview of the current state of stroke delivery and potential improvements for the future in the light of clinical data.

Impact of Initial Imaging Protocol on Likelihood of Endovascular Stroke Therapy

Background and Purpose:

Noncontrast head CT and CT perfusion (CTP) are both used to screen for endovascular stroke therapy (EST), but the impact of imaging strategy on likelihood of EST is undetermined. Here, we examine the influence of CTP utilization on likelihood of EST in patients with large vessel occlusion (LVO).

Methods:

We identified patients with acute ischemic stroke at 4 comprehensive stroke centers. All 4 hospitals had 24/7 CTP and EST capability and were covered by a single physician group (Neurology, NeuroIntervention, NeuroICU). All centers performed noncontrast head CT and CT angiography in the initial evaluation. One center also performed CTP routinely with high CTP utilization (CTP-H), and the others performed CTP optionally with lower utilization (CTP-L). Primary outcome was likelihood of EST. Multivariable logistic regression was used to determine whether facility type (CTP-H versus CTP-L) was associated with EST adjusting for age, prestroke mRS, National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, LVO location, time window, and intravenous tPA (tissue-type plasminogen activator).

Results:

Among 3107 patients with acute ischemic stroke, 715 had LVO, of which 403 (56%) presented to CTP-H and 312 (44%) presented to CTP-L. CTP utilization among LVO patients was greater at CTP-H centers (72% versus 18%, CTP-H versus CTP-L, P <0.01). In univariable analysis, EST rates for patients with LVO were similar between CTP-H versus CTP-L (46% versus 49%). In multivariable analysis, patients with LVO were less likely to undergo EST at CTP-H (odds ratio, 0.59 [0.41–0.85]). This finding was maintained in multiple patient subsets including late time window, anterior circulation LVO, and direct presentation patients. Ninety-day functional independence (odds ratio, 1.04 [0.70–1.54]) was not different, nor were rates of post-EST PH-2 hemorrhage (1% versus 1%).

Conclusions:

We identified an increased likelihood for undergoing EST in centers with lower CTP utilization, which was not associated with worse clinical outcomes or increased hemorrhage. These findings suggest under-treatment bias with routine CTP.

Mobile Stroke Unit in the UK Healthcare System: Avoidance of Unnecessary Accident and Emergency Admissions

BACKGROUND

Acute stroke patients are usually transported to the nearest hospital regardless of their required level of care. This can lead to increased pressure on emergency departments and treatment delay.

OBJECTIVE

The aim of the study was to explore the benefit of a mobile stroke unit (MSU) in the UK National Health Service (NHS) for reduction of hospital admissions.

METHODS

Prospective cohort audit observation with dispatch of the MSU in the East of England Ambulance Service area in Southend-on-Sea was conducted. Emergency patients categorized as code stroke and headache were included from June 5, 2018, to December 18, 2018. Rate of avoided admission to the accident and emergency (A&amp;E) department, rate of admission directly to target ward, and stroke management metrics were assessed.

RESULTS

In 116 MSU-treated patients, the following diagnoses were made: acute stroke, n = 33 (28.4%); transient ischaemic attacks, n = 13 (11.2%); stroke mimics, n = 32 (27.6%); and other conditions, n = 38 (32.8%). Pre-hospital thrombolysis was administered to 8 of 28 (28.6%) ischaemic stroke patients. Pre-hospital diagnosis avoided hospital admission for 29 (25.0%) patients. As hospital treatment was indicated, 35 (30.2%) patients were directly triaged to the stroke unit, 1 patient (0.9%) even directly to the catheter laboratory. Thus, only 50 (43.1%) patients required transfer to the A&amp;E department. Moreover, the MSU enabled thrombolysis with a median dispatch-to-needle time of 42 min (interquartile range, 40-60).

CONCLUSION

This first deployment of an MSU in the UK NHS demonstrated improved triage decision-making for or against hospital admission and admission to the appropriate target ward, thereby reducing pressure on strained A&amp;E departments.

Telemedicine in Prehospital Acute Stroke Care

Background

Mobile stroke units (MSUs), equipped with an integrated computed tomography scanner, can shorten time to thrombolytic treatment and may improve outcome in patients with acute ischemic stroke. Original (German) MSUs are staffed by neurologists trained as emergency physicians, but patient assessment and treatment decisions by a remote neurologist may offer an alternative to neurologists aboard MSU.

Methods and Results

Remote neurologists examined and assessed emergency patients treated aboard the MSU in Berlin, Germany. Audiovisual quality was rated by the remote neurologist from 1 (excellent) to 6 (insufficient), and duration of video examinations was assessed. We analyzed interrater reliability of diagnoses, scores on the National Institutes of Health Stroke Scale and treatment decisions (intravenous thrombolysis) between the MSU neurologist and the remote neurologist. We included 90 of 103 emergency assessments (13 patients were excluded because of either failed connection, technical problems, clinical worsening during teleconsultation, or missing data in documentation) in this study. The remote neurologist rated audiovisual quality with a median grade for audio quality of 3 (satisfactory) and for video quality of 2 (good). Mean time for completion of teleconsultations was about 19±5 minutes. The interrater reliabilities between the onboard and remote neurologist were high for diagnoses (Cohen's κ=0.86), National Institutes of Health Stroke Scale sum scores (intraclass correlation coefficient, 0.87) and treatment decisions (16 treatment decisions agreed versus 2 disagreed; Cohen's κ=0.93).

Conclusions

Remote assessment and treatment decisions of emergency patients are technically feasible with satisfactory audiovisual quality. Agreement on diagnoses, neurological examinations, and treatment decisions between onboard and remote neurologists was high.

See Editorial by Derry et al

Mobile stroke unit versus standard medical care in the management of patients with acute stroke: A systematic review and meta-analysis

INTRODUCTION

Mobile stroke units have recently been introduced in the care of patients suspected of having an acute stroke, leading to shortening in the time to thrombolytics. We aimed to compare the clinical effectiveness in terms of functional outcome and survival among patients treated in mobile stroke unit and/or conventional care.

METHODS

A systematic search of electronic databases, comparing the clinical outcomes among patients with acute stroke in the same study was conducted from 1990 to 2019. Pooled and subgroup analysis were performed using the random- and fixed-effect model based upon the I² heterogeneity.

RESULTS

A total of 21,297 patients from 11 publications (seven randomized controlled trials and four non-randomized controlled trials including prospective cohort studies) were retrieved. This included 6065 (n = 28.4%) of the patients treated in the mobile stroke unit and 71.6% (n = 15,232) of the patients managed in the conventional care. The mean age at clinical presentation (70.1 ± 14.5 vs. 71.05 ± 15.8) and National Institute Health Stroke Scale (9.8 ± 1.7 vs. 8.4 ± 1.5) was comparable (p > 0.05) in patients treated with mobile stroke unit and conventional care, respectively. The mean time-to-treatment window was significantly shorter among the patients treated in mobile stroke unit compared to conventional care (62.0 min vs. 75.0 min; p = 0.03, respectively). The pooled analysis of clinical outcome at day 7 indicated that patients treated in mobile stroke unit had 1.46-folds higher likelihood of better clinical outcome (modified Rankin scale 0-2) than those in the hospital (odds ratio: 1.46, 95% confidence interval: 1.306-2.03, p = 0.02). However, there was no significant difference in terms of mortality (odds ratio: 0.98, 95% confidence interval: 0.81-1.18, p = 0.80), stroke-related neurological deficits (odds ratio: 1.37, 95% confidence interval: 0.81-2.32, p = 0.24), and other serious adverse events (odds ratio: 0.69, 95% confidence interval: 0.39-1.20, p = 0.19) among patients treated in mobile stroke unit versus conventional care.

CONCLUSION

Our results corroborate that patients treated in mobile stroke unit lead to short-term recovery following acute stroke without influencing the mortality rate. Further prospective studies are needed to validate our results.

Enhanced dispatch and rendezvous doubles the catchment area and number of patients treated on a mobile stroke unit

INTRODUCTION

Mobile Stroke Units (MSUs) deliver acute stroke treatment on-scene in coordination with Emergency Medical Services (EMS). One criticism of the MSU approach is the limited range of a single MSU. The Houston MSU is evaluating MSU implementation, and we developed a rendezvous approach as an innovative solution to expand the range and number of patients treated.

METHODS

In addition to direct 911 dispatch of our MSU to the scene within our 7-mile catchment area, we empowered more distant EMS units to activate the MSU. We also monitored EMS radio communications to identify possible patients. For these distant patients, the MSU met the EMS unit en route to the stroke center and treated the patient at that intermediate location. The distribution of the distance from MSU base station to site of stroke and time from 911 alert to tissue plasminogen activator (tPA) bolus were compared between patients treated on-scene and by rendezvous using Wilcoxon rank sum test.

RESULTS

Over 4 years, 338 acute ischemic stroke patients were treated with tPA on our MSU. Of these, 169 (50%) were treated on-scene after MSU dispatch at a median of 6.4 miles (IQR 6.4 miles) from MSU base station. 169 (50%) were treated by 'rendezvous' pathway with assessment and treatment of stroke a median of 12.4 miles from base (IQR 5.5 miles) (p< 0.0001). Time (min) from MSU alert to tPA bolus did not differ: 36.0 ± 10.0 for on-scene vs 37.0 ± 10.0 with rendezvous (p=0.65). 13% of patients alerted via direct 911 dispatch were treated vs 44% of rendezvous patients.

CONCLUSION

Adding a rendezvous approach to an MSU dispatch pathway doubles the range of operations and the number of patients treated by an MSU in an urban area, without incurring delay.

A review of mobile stroke units

PURPOSE OF REVIEW

Mobile stroke units (MSUs) for prehospital treatment and management of patients with acute stroke have been developed more than a decade ago and is currently spreading worldwide. This review discusses the history of MSU and current operations and research.

RECENT FINDINGS

Multiple studies have shown that MSU can significantly reduce treatment time with a tenfold increase of patients treated within the first 60 min of symptom onset. Recent preliminary results from the Berlin Prehospital or Usual Delivery of Acute Stroke Care trial (B-PROUD) showed a positive shift in modified Rankin Scale (mRS) scores at 3 months for patients treated in MSUs. Two German studies indicate that the MSU model is cost effective by reducing disability and improving adjusted quality-life years after stroke. The MSU model for prehospital management of acute stroke is spreading worldwide. More research is needed, however, to establish cost-effectiveness, efficacy and best setting for prehospital stroke management.

Emerging Technologies in Optimizing Pre-Intervention Workflow for Acute Stroke

Over the last several years, thrombectomy for large vessel occlusions (LVOs) has emerged as a standard of care for acute stroke patients. Furthermore, the time to reperfusion has been identified as a predictor of overall patient outcomes, and much effort has been made to identify potential areas to target in enhancing preintervention workflow. As medical technology and stroke devices improve, nearly all time points can be affected, from field stroke triage to automated imaging interpretation to mass mobile stroke code communications. In this article, we review the preintervention stroke workflow with specific regard to emerging technologies in improving time to reperfusion and overall patient outcomes.

Cost-Consequence Analysis of Mobile Stroke Units vs. Standard Prehospital Care and Transport

Background: Mobile stroke units (MSUs) are the latest approach to improving time-sensitive stroke care delivery. Currently, there are no published studies looking at the expanded value of the MSU to diagnose and transport patients to the closest most appropriate facility. The purpose of this paper is to perform a cost consequence analysis of standard transport (ST) vs. MSU.

Methods and Results: A cost consequence analysis was undertaken within a decision framework to compare the incremental cost of care for patients with confirmed stroke that were served by the MSU vs. their simulated care had they been served by standard emergency medical services between July 2014 and October 2015. At baseline values, the incremental cost between MSU and ST was $70,613 ($856,482 vs. $785,869) for 355 patient transports. The MSU avoided 76 secondary interhospital transfers and 76 emergency department (ED) encounters. Sensitivity analysis identified six variables that had measurable impact on the model's variability and a threshold value at which MSU becomes the optimal strategy: number of stroke patients (>391), probability of requiring transfer to a comprehensive stroke center (CSC, >0.52), annual cost of MSU operations (<$696,053), cost of air transfer (>$8,841), probability initial receiving hospital is a CSC (<0.32), and probability of ischemic stroke with ST (<0.76).

Conclusions: MSUs can avert significant costs in the administration of stroke care once optimal thresholds are achieved. A comprehensive cost-effectiveness analysis is required to determine not just the operational value of an MSU but also its clinical value to patients and the society.

Endovascular Thrombectomy for Acute Ischemic Strokes: Current US Access Paradigms and Optimization Methodology

Background and Purpose- Timely access to endovascular thrombectomy (EVT) centers is vital for best acute ischemic stroke outcomes. Methods- US stroke-treating centers were mapped utilizing geo-mapping and stratified into non-EVT or EVT if they reported ≥1 acute ischemic stroke thrombectomy code in 2017 to Center for Medicare and Medicaid Services. Direct EVT-access, defined as the population with the closest facility being an EVT-center, was calculated from validated trauma-models adapted for stroke. Current 15- and 30-minute access were described nationwide and at state-level with emphasis on 4 states (TX, NY, CA, IL). Two optimization models were utilized. Model-A used a greedy algorithm to capture the largest population with direct access when flipping 10% and 20% non-EVT to EVT-centers to maximize access. Model-B used bypassing methodology to directly transport patients to the nearest EVT centers if the drive-time difference from the geo-centroid to hospital was within 15 minutes from the geo-centroid to the closest non-EVT center. Results- Of 1941 stroke-centers, 713 (37%) were EVT. Approximately 61 million (19.8%) Americans have direct EVT access within 15 minutes while 95 million (30.9%) within 30 minutes. There were 65 (43%) EVT centers in TX with 22% of the population currently within 15-minute access. Flipping 10% hospitals with top population density improved access to 30.8%, while bypassing resulted in 45.5% having direct access to EVT centers. Similar results were found in NY (current, 20.9%; flipping, 34.7%; bypassing, 50.4%), CA (current, 25.5%; flipping, 37.3%; bypassing, 53.9%), and IL (current, 15.3%; flipping, 21.9%; bypassing, 34.6%). Nationwide, the current direct access within 15 minutes of 19.8% increased by 7.5% by flipping the top 10% non-EVT to EVT-capable in all states. Bypassing non-EVT centers by 15 minutes resulted in a 16.7% gain in coverage. Conclusions- EVT-access within 15 minutes is limited to less than one-fifth of the US population. Optimization methodologies that increase EVT centers or bypass non-EVT to the closest EVT center both showed enhanced access. Results varied by states based on the population size and density. However, bypass showed more potential for maximizing direct EVT-access. National and state efforts should focus on identifying gaps and tailoring solutions to improve EVT-access.

Mobile Stroke Units: Bringing Treatment to the Patient

PURPOSE OF REVIEW

Mobile stroke units (MSUs) have revolutionized emergency stroke care by delivering pre-hospital thrombolysis faster than conventional ambulance transport and in-hospital treatment. This review discusses the history of MSUs technological development, current operations and research, cost-effectiveness, and future directions.

RECENT FINDINGS

Multiple prospective and retrospective studies have shown that MSUs deliver acute ischemic stroke treatment with intravenous recombinant tissue plasminogen activator (IV r-tPA) approximately 30 min faster than conventional care. The 90-day modified Rankin Scores for patients who received IV r-tPA on the MSU compared to conventional care were not statistically different in the PHANTOM-S study. Two German studies suggest that the MSU model is cost-effective by reducing disability and improving adjusted quality-life years post-stroke. The ongoing BEST-MSU trial will be the first multicenter, randomized controlled study that will shed light on MSUs' impact on long-term neurologic outcomes and cost-effectiveness. MSUs are effective in reducing treatment times in acute ischemic stroke without increasing adverse events. MSUs could potentially improve treatment times in large vessel occlusion and intracranial hemorrhage. Further studies are needed to assess functional outcomes and cost-effectiveness. Clinical trials are ongoing internationally.

Acute ischaemic stroke interventions: large vessel occlusion and beyond

Care for acute ischaemic stroke is one of the most rapidly evolving fields due to the robust outcomes achieved by mechanical thrombectomy. Large vessel occlusion (LVO) accounts for up to 38% of acute ischaemic stroke and comes with devastating outcomes for patients, families and society in the pre-intervention era. A paradigm shift and a breakthrough brought mechanical thrombectomy back into the spotlight for acute ischaemic stroke; this was because five randomised controlled trials from several countries concluded that mechanical thrombectomy for acute stroke offered overwhelming benefits. This review article will present a comprehensive overview of LVO management, techniques and devices used, and the future of stroke therapy. In addition, we review our institution experience of mechanical thrombectomy for posterior and distal circulation occlusion.

Mobile stroke unit use for prehospital stroke treatment-an update

BACKGROUND

Acute ischemic stroke is a treatable disease. Moreover, there is increasing evidence supporting mechanical recanalization for large-vessel occlusion, even beyond a strict time window. However, only small numbers of patients receive causal treatment.

METHODS

One of the main reasons that patients do not receive causal therapy is their late arrival at the correct target hospital, which, depending on the type of stroke, is either a regional stroke unit or a comprehensive stroke center for interventional treatment. In order to triage patients correctly, a fast and complex diagnostic work-up is necessary, allowing a stroke specialist to decide on the best therapy option. As treatment possibilities become more comprehensive with the need for individualized decisions, the gap between treatment options and practical implementation is increasing.

RESULTS

The "mobile stroke unit" concept encompasses the administration of prehospital acute stroke diagnostic work-up, therapy initiation, and triage to the correct hospital using a specially equipped ambulance, staffed with a team specialized in stroke. The concept, which was conceived and first put into practice in Homburg/Saar, Germany, in 2008, is currently spreading with more than 20 active mobile stroke unit centers worldwide. The use of mobile stroke units can reduce the time until stroke treatment by 50% with a tenfold increase of patients treated within the first 60 min of symptom onset.

CONCLUSION

The mobile stroke unit concept for acute stroke prehospital management is spreading worldwide. Intensive research is still needed to analyze the best setting for prehospital stroke management.

Emergency Department Door-to-Puncture Time Since 2014

Background and Purpose- The impact of a mobile stroke unit (MSU) on access to intraarterial thrombectomy (IAT) is a prespecified BEST-MSU substudy (Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services). On the MSU, IAT decision-making steps, such as computed tomography, neurological exam, and tPA (tissue-type plasminogen activator) treatment are completed before emergency department arrival. We hypothesized that such pre-ED assessment of potential IAT patients on an MSU improves the time from ED arrival to skin puncture time (door-to-puncture-time, DTPT). Methods- BEST-MSU is a prospective comparative effectiveness study of MSU versus standard management by emergency medical services (EMS). We compared ED DTPT among the following groups of MSU and EMS patients: all IAT patients, IAT patients post-tPA, and IAT patients post-tPA meeting thrombolytic adjudication criteria over the first 4 years of the study. Results- From August 2014 to July 2018, a total of 161 patients underwent IAT. Ninety-four patients presented to the ED via the MSU and 67 by EMS. One hundred forty patients received tPA before IAT, 85 in the MSU arm, and 55 in the EMS arm. One hundred twenty-six patients received tPA within thrombolytic adjudication criteria: 76 MSU and 50 EMS. DTPT in minutes was shorter for MSU patients (all IAT MSU versus EMS 89 versus 99, P=0.01; IAT post-tPA MSU versus EMS 93 versus 100, P=0.03; and IAT post-tPA within adjudicated criteria MSU versus EMS 93 versus 99.5, P=0.03). From 2014 to 2018, DTPT decreased at a faster rate for EMS compared with MSU-managed patients, improving by about an hour. Conclusions- Pre-ED IAT evaluation on an MSU results in faster DTPT compared with arrival by EMS. Since 2014, dramatic improvement in ED IAT metrics has attenuated this difference. However, DTPT in all groups indicates substantial room for improvement.

Improving Prehospital Stroke Services in Rural and Underserved Settings With Mobile Stroke Units

In acute stroke management, time is brain, as narrow therapeutic windows for both intravenous thrombolysis and mechanical thrombectomy depend on expedient and specialized treatment. In rural settings, patients are often far from specialized treatment centers. Concurrently, financial constraints, cutting of services and understaffing of specialists for many rural hospitals have resulted in many patients being underserved. Mobile Stroke Units (MSU) provide a valuable prehospital resource to rural and remote settings where patients may not have easy access to in-hospital stroke care. In addition to standard ambulance equipment, the MSU is equipped with the necessary tools for diagnosis and treatment of acute stroke or similar emergencies at the emergency site. The MSU strategy has proven to be effective at facilitating time-saving stroke triage decisions. The additional on-board imaging helps to determine whether a patient should be taken to a primary stroke center (PSC) for standard treatment or to a comprehensive stroke center (CSC) for advanced stroke treatment (such as intra-arterial therapy) instead. Diagnosis at the emergency site may prevent additional in-hospital delays in workup, handover and secondary (inter-hospital) transport. MSUs may be adapted to local needs-especially in rural and remote settings-with adjustments in staffing, ambulance configuration, and transport models. Further, with advanced imaging and further diagnostic capabilities, MSUs provide a valuable platform for telemedicine (teleradiology and telestroke) in these underserved areas. As MSU programmes continue to be implemented across the world, optimal and adaptable configurations could be explored.

A History of Mobile Stroke Units and Review of Literature

Using intravenous tissue plasminogen activator (IV tPA), improved functional outcomes are seen with earlier initiation of treatment. Recent studies have shown endovascular revascularization to be a revolutionary and effective treatment. There have been many initiatives focused on improving public education and awareness of stroke symptoms. The concept of a mobile stroke unit (MSU) was created as a way of bringing treatment to patients. Earlier CT scans, delivery of tPA, proper triage and on-scene goal-directed care were the primary goals with these units. It was thought that rapid implementation would shorten hospital stay and improve outcomes. The University of Saarland found a decrease of 41 minutes from stroke alarm to therapeutic decision when an MSU was used. A second trial found a decrease of 25 minutes in time to treatment, an increase in the rate of thrombolysis utilization, and no change in the rates of intracranial hemorrhage or 7-day mortality when an MSU was employed. In 2016, a Lancet article showed that 3 month modified Rankin Scale (mRS) and 3-month mortality were improved in MSU patients. Finally, starting thrombolytic therapy in the MSU was associated with higher probability of mRS of 0-3 but not an improved 3-month survival rate. Long-term results are thus far not available precluding an effective cost-benefit analysis. Many study results are not generalizable as they compare a single hospital system and specialized MSU team to conventional care delivered by a multiple healthcare systems. Future studies will target these limitations.