Bypassing primary stroke centre reduces delay and improves outcomes for patients with large vessel occlusion

Diagnostic accuracy of 3-item stroke scale for detection of cerebral large vessel occlusion: A systematic review and meta-analysis

BACKGROUND

Prompt identification of large vessel occlusion (LVO) in acute ischemic stroke (AIS) is crucial for expedited endovascular therapy (EVT) and improved patient outcomes. Prehospital stroke scales, such as the 3-Item Stroke Scale (3I-SS), could be beneficial in detecting LVO in suspected patients. This meta-analysis evaluates the diagnostic accuracy of 3I-SS for LVO detection in AIS.

METHODS

A systematic search was conducted in Medline, Embase, Scopus, and Web of Science databases until February 2024 with no time and language restrictions. Prehospital and in-hospital studies reporting diagnostic accuracy were included. Review articles, studies without reported 3I-SS cut-offs, and studies lacking the required data were excluded. Pooled effect sizes, including area under the curve (AUC), sensitivity, specificity, diagnostic odds ratio (DOR), positive and negative likelihood ratios (PLR and NLR) with 95% confidence intervals (CI) were calculated.

RESULTS

Twenty-two studies were included in the present meta-analysis. A 3I-SS score of 2 or higher demonstrated sensitivity of 76% (95% CI: 52%-90%) and specificity of 74% (95% CI: 57%-86%) as the optimal cut-off, with an AUC of 0.81 (95% CI: 0.78-0.84). DOR, PLR, and NLR, were 9 (95% CI: 5-15), 2.9 (95% CI: 2.0-4.3) and 0.32 (95% CI: 0.17-0.61), respectively. Sensitivity analysis confirmed the analyses' robustness in suspected to stroke patients, anterior circulation LVO, assessment by paramedics, and pre-hospital settings. Meta-regression analyses pinpointed LVO definition (anterior circulation, posterior circulation) and patient setting (suspected stroke, confirmed stroke) as potential sources of heterogeneity.

CONCLUSION

3I-SS demonstrates good diagnostic accuracy in identifying LVO stroke and may be valuable in the prompt identification of patients for direct transfer to comprehensive stroke centers.

Network analysis of stroke systems of care in Korea

Background

The landscape of stroke care has shifted from stand-alone hospitals to cooperative networks among hospitals. Despite the importance of these networks, limited information exists on their characteristics and functional attributes.

Methods

We extracted patient-level data on acute stroke care and hospital connectivity by integrating national stroke audit data with reimbursement claims data. We then used this information to transform interhospital transfers into a network framework, where hospitals were designated as nodes and transfers as edges. Using the Louvain algorithm, we grouped densely connected hospitals into distinct stroke care communities. The quality and characteristics in given stroke communities were analysed, and their distinct types were derived using network parameters. The clinical implications of this network model were also explored.

Results

Over 6 months, 19 113 patients with acute ischaemic stroke initially presented to 1009 hospitals, with 3114 (16.3%) transferred to 246 stroke care hospitals. These connected hospitals formed 93 communities, with a median of 9 hospitals treating a median of 201 patients. Derived communities demonstrated a modularity of 0.904 , indicating a strong community structure, highly centralised around one or two hubs. Three distinct types of structures were identified: single-hub (n=60), double-hub (n=22) and hubless systems (n=11). The endovascular treatment rate was highest in double-hub systems, followed by single-hub systems, and was almost zero in hubless systems. The hubless communities were characterised by lower patient volumes, fewer hospitals, no hub hospital and no stroke unit.

Conclusions

This network analysis could quantify the national stroke care system and point out areas where the organisation and functionality of acute stroke care could be improved.

Cincinnati Prehospital Stroke Scale (CPSS) as a Screening Tool for Early Identification of Cerebral Large Vessel Occlusions; a Systematic Review and Meta-analysis

Introduction

Large vessel occlusion (LVO) strokes are associated with worse functional outcomes and higher mortality rates. In the present systematic review and meta-analysis, we evaluated the diagnostic yield of the Cincinnati Prehospital Stroke Scale (CPSS) in detecting LVO.

Methods

We performed an extensive systematic search among online databases including Medline, Embase, Web of Science, and Scopus, until July 31st, 2023. We also conducted a manual search on Google and Google scholar, along with citation tracking to supplement the systematic search in retrieving all studies that evaluated the diagnostic accuracy of the CPSS in detecting LVO among patients suspected to stroke.

Results

Fourteen studies were included in the present meta-analysis. CPSS showed the sensitivity of 97% (95% CI: 87%-99%) and the specificity of 17% (95% CI: 4%-54%) at the cut-off point of ≥1. The optimal threshold was determined to be ≥2, with a sensitivity of 82% (95% CI: 74%-88%) and specificity of 62% (95% CI: 48%-74%) in detecting LVO. At the highest cut-off point of ≥3, the CPSS had the lowest sensitivity of 60% (95% CI: 51%-69%) and the highest specificity of 81% (95% CI: 71%-88%). Sensitivity analyses showed the robustness of the results regardless of study population, inclusion of hemorrhagic stroke patients, pre-hospital or in-hospital settings, and the definition of LVO.

Conclusion

A very low level of evidence demonstrated that CPSS, with a threshold set at ≥2, is a useful tool for identifying LVO stroke and directing patients to CSCs, both in prehospital and in-hospital settings.

Transport Strategy in Patients With Suspected Acute Large Vessel Occlusion Stroke: TRIAGE-STROKE, a Randomized Clinical Trial

BACKGROUND

When patients with acute ischemic stroke present with suspected large vessel occlusion in the catchment area of a primary stroke center (PSC), the benefit of direct transport to a comprehensive stroke center (CSC) has been suggested. Equipoise remains between transport strategies and the best transport strategy is not well established.

METHODS

We conducted a national investigator-driven, multicenter, randomized, assessor-blinded clinical trial. Patients eligible for intravenous thrombolysis (IVT) who were suspected for large vessel occlusion were randomized 1:1 to admission to the nearest PSC (prioritizing IVT) or direct CSC admission (prioritizing endovascular therapy). The primary outcome was functional improvement at day 90 for all patients with acute ischemic stroke, measured as shift towards a lower score on the modified Rankin Scale score.

RESULTS

From September 2018 to May 2022, we enrolled 171 patients of whom 104 had acute ischemic stroke. The trial was halted before full recruitment. Baseline characteristics were well balanced. Primary analysis of shift in modified Rankin Scale (ordinal logistic regression) revealed an odds ratio for functional improvement at day 90 of 1.42 (95% CI, 0.72-2.82, P=0.31). Onset to groin time for patients with large vessel occlusion was 35 minutes (P=0.007) shorter when patients were transported to a CSC first, whereas onset to needle (IVT) was 30 minutes (P=0.012) shorter when patients were transported to PSC first. IVT was administered in 67% of patients in the PSC group versus 78% in the CSC group and EVT was performed in 53% versus 63% of the patients, respectively.

CONCLUSIONS

This trial investigated the benefit of bypassing PSC. We included only IVT-eligible patients presenting <4 hours from onset and with suspected large vessel occlusion. Lack of power prevented the results from showing effect on functional outcome for patients going directly to CSC.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03542188.

Associations between emergency call stroke triage and pre-hospital delay, primary hospital admission, and acute reperfusion treatment among early comers with acute ischemic stroke

To investigate the association between the Emergency Medical Service dispatcher's initial stroke triage and prehospital stroke management, primary admission to hospitals offering revascularization treatment, prehospital time delay, and rate of acute revascularization. In an observational cohort study, patients with acute ischemic stroke (AIS) in Denmark (2017-2018) were included if the emergency call to the Emergency Medical Dispatch Center (EMDC) was made within three hours after symptom onset. Among 3546 included AIS patients, the EMS dispatcher identified 74.6% (95% confidence interval (CI) 73.1-76.0) correctly as stroke. EMS dispatcher stroke recognition was associated with a higher rate of primary admission to a hospital offering revascularization treatment (85.8 versus 74.5%); producing an adjusted risk difference (RD) of 11.1% (95% CI 7.8; 14.3) and a higher rate of revascularization treatment (49.6 versus 41.6%) with an adjusted RD of 8.4% (95% CI 4.6; 12.2). We adjusted for sex, age, previous stroke or transient ischemic attack, and stroke severity. EMDC stroke recognition was associated with shorter prehospital delay. For all AIS patients, the adjusted difference was - 33.2 min (95% CI - 44.4; - 22.0). Among patients receiving acute revascularization treatment (n = 1687), the adjusted difference was -12.6 min (95% CI - 18.9; - 6.3). Stroke recognition by the EMS dispatcher was associated with a higher probability of primary admission to a hospital offering acute stroke treatment, and subsequently with a higher rate of acute revascularization treatment, and with an overall reduction in prehospital delay.

Long-term effect of field triage on times to endovascular treatment for emergent large vessel occlusion

BACKGROUND

Delays to endovascular therapy (EVT) for stroke may be mitigated with direct field triage to EVT centers. We sought to compare times to treatment over a 5.5 year span between two adjacent states, one with field triage and one without, served by a single comprehensive stroke center (CSC).

METHODS

During the study period, one of the two states implemented severity-based triage for suspected emergent large vessel occlusion, while in the other state, patients were transported to the closest hospital regardless of severity. We compared times to treatment and clinical outcomes between these two states. We also performed a matched pairs analysis, matching on date treated and distance from field to CSC.

RESULTS

639 patients met the inclusion criteria, 407 in State 1 (with field triage) and 232 in State 2 (without field triage). In State 1, scene to EVT decreased 6% (or 8.13 min, p=0.0004) every year but no decrease was observed for State 2 (<1%, p=0.94). Cumulatively over 5.5 years, there was a reduction of 43 min in time to EVT in State 1, but no change in State 2. Lower rates of disability were seen in State 1, both for the entire cohort (all OR 1.22, 95% CI 1.07 to 1.40, p=0.0032) and for those independent at baseline (1.36, 95% CI 1.15 to 1.59, p=0.0003).

CONCLUSIONS

Comparing adjacent states over time, the implementation of severity-based field triage significantly reduced time to EVT.

Simulation modelling to study the impact of adding comprehensive stroke centres. Can we deliver endovascular thrombectomy sooner?

OBJECTIVES

Regional accessibility and distribution of endovascular thrombectomy (EVT) capable facilities, that is, comprehensive stroke centres (CSCs), may significantly influence time to treatment. We analysed the impact of adding CSCs in the north of the Netherlands, a region with roughly 1.7 million inhabitants currently served by one CSC and eight primary stroke centres (PSCs).

DESIGN

Monte Carlo simulation modelling was used to establish new CSCs in our region by hypothetically upgrading existing PSCs to CSCs and ensuing adjustments in health services set-up.

SETTING

One CSC and eight PSCs in the north of the Netherlands.

PARTICIPANTS

165 patients with acute stroke treated with EVT and underwent interhospital transfer between PSC and CSC (drip and ship patients).

PRIMARY AND SECONDARY OUTCOMES

Time from onset to groin (OTG) puncture and predicted probability of favourable outcome (modified Rankin Scale 0-2) after 90 days. Sensitivity analyses were performed to assess uncertainty in workflow efficiency of CSCs.

RESULTS

Adding one or two CSCs would reduce the OTG time up to approximately 17 min and increases the predicted probability of favourable outcome by approximately 2%. Sensitivity analyses revealed that 'slow-acting' CSCs may reduce OTG by 3-5 min compared with 24-32 min for 'fast-acting' CSCs.

CONCLUSIONS

This study suggests that adding one or two CSCs in the north of the Netherlands would have modest impact. Improving workflow efficiencies seems to be more potent when aiming to improve existing acute stroke care systems.

Assessing the Relationship between LAMS and CT Perfusion Parameters in Acute Ischemic Stroke Secondary to Large Vessel Occlusion

BACKGROUND

The Los Angeles Motor Scale (LAMS) is a rapid pre-hospital scale used to predict stroke severity which has also been shown to accurately predict large vessel occlusions (LVOs). However, to date there is no study exploring whether LAMS correlates with the computed tomography perfusion (CTP) parameters in LVOs.

METHODS

Patients with LVO between September 2019 and October 2021 were retrospectively reviewed and included if the CTP data and admission neurologic exams were available. The LAMS was documented based on emergency personnel exams or scored retrospectively using an admission neurologic exam. The CTP data was processed by RAPID (IschemaView, Menlo Park, CA, USA) with an ischemic core volume (relative cerebral blood flow [rCBF] < 30%), time-to-maximum (Tmax) volume (Tmax > 6 s delay), hypoperfusion index (HI), and cerebral blood volume (CBV) index. Spearman's correlations were performed between the LAMS and CTP parameters.

RESULTS

A total of 85 patients were included, of which there were 9 intracranial internal carotid artery (ICA), 53 proximal M1 branch middle cerebral artery M1, and 23 proximal M2 branch occlusions. Overall, 26 patients had LAMS 0-3, and 59 had LAMS 4-5. In total, LAMS positively correlated with CBF < 30% (Correlation Coefficient (CC): 0.32, p < 0.01), Tmax > 6 s (CC:0.23, p < 0.04), HI (CC:0.27, p < 0.01), and negatively correlated with the CBV index (CC:-0.24, p < 0.05). The relationships between LAMS and CBF were < 30% and the HI was more pronounced in M1 occlusions (CC:0.42, p < 0.01; 0.34, p < 0.01 respectively) and proximal M2 occlusions (CC:0.53, p < 0.01; 0.48, p < 0.03 respectively). The LAMS also correlated with a Tmax > 6 s in M1 occlusions (CC:0.42, p < 0.01), and negatively correlated with the CBV index in M2 occlusions (CC:-0.69, p < 0.01). There were no significant correlations between the LAMS and intracranial ICA occlusions.

CONCLUSIONS

The results of our preliminary study indicate that the LAMS is positively correlated with the estimated ischemic core, perfusion deficit, and HI, and negatively correlated with the CBV index in patients with anterior circulation LVO, with stronger relationships in the M1 and M2 occlusions. This is the first study showing that the LAMS may be correlated with the collateral status and estimated ischemic core in patients with LVO.

Prehospital Stroke Care Part 1: Emergency Medical Services and the Stroke Systems of Care

Acute stroke care begins before hospital arrival, and several prehospital factors are critical in influencing overall patient care and poststroke outcomes. This topical review provides an overview of the state of the science on prehospital components of stroke systems of care and how emergency medical services systems may interact in the system to support acute stroke care. Topics include layperson recognition of stroke, prehospital transport strategies, networked stroke care, systems for data integration and real-time feedback, and inequities that exist within and among systems.

Validation of a cloud-based tele-stroke system reliability in determining national institutes of health stroke scale scores for acute ischemic stroke screening in the emergency department

Background and purpose

The National Institutes of Health Stroke Scale (NIHSS) is the most recommended tool for objectively quantifying the impairment caused by a suspected stroke. Nevertheless, it is mainly used by trained neurologists in the emergency department (ED). To bring forward the NIHSS to the pre-hospital setting, a smartphone-based Telestroke system was developed. It captures the full NIHSS by video, transmits it off-line, and enables assessment by a distant stroke physician. We aimed to compare the reliability of an NIHSS score determined by a neurologist from afar, using the platform with a standard NIHSS assessment performed in the emergency departments.

Methods

A multi-center prospective study was conducted in two centers (Vall d'Hebron, Barcelona, and Rambam, Israel). Patients admitted to the ED with suspected stroke had a neurological exam based on the NIHSS, while being recorded by the system. A skilled neurologist rated the NIHSS according to the videos offline. The results were compared with the NIHSS score given by a neurologist at the bedside.

Results

A total of 95 patients with suspected stroke were included. The overall intraclass correlation coefficient was 0.936 (0.99 in VdH and 0.84 in Rambam), indicating excellent and good reliability, respectively.

Conclusion

Remote stroke assessment based on the NIHSS, using videos segments collected by a dedicated platform, installed on a standard smartphone, is a reliable measurement as compared with the bedside evaluation.

How do interventions to improve the efficiency of acute stroke care affect prehospital times? A systematic review and narrative synthesis

Background

Emergency medical services (EMS) are the first point of contact for most acute stroke patients. EMS call to hospital times have increased in recent years for stroke patients in the UK which is undesirable due to the relationship between time and effectiveness of reperfusion treatment. This review aimed to identify and describe interventions devised to improve the efficiency of acute stroke care which reported an impact on ground-based EMS call to hospital times.

Methods

A systematic review of published literature identified from five databases (Medline, EMBASE, CINAHL, the Cochrane library and the Database of Research in Stroke (DORIS)) from January 2000 to December 2020 with narrative synthesis was conducted. Inclusion criteria were primary studies of ground-based EMS, focused on stroke and aiming to improve EMS times. Papers published before 2000, focussing on mobile stroke units or in languages other than English were excluded. Two reviewers independently screened prospective titles. Cochrane ROB2 and ROBINS-I tools were used to assess for risk of bias. This review was funded by a Stroke Association fellowship.

Results

From 3767 initial records, 11 studies were included in the review. Included studies were categorised into three groups: studies targeting EMS dispatch and EMS clinicians (n = 4); studies targeting EMS clinicians only (n = 4); and studies targeting whole system change (n = 3). Suspected stroke patients were the primary population studied and most (n = 10) interventions involved clinician education. Only one study (9%) reported a significant decrease in call to hospital time in one subgroup whereas two studies (18%) reported a significant increase in call to hospital time and all other studies (73%) reported no significant change.

Conclusions

Based on the included studies, interventions intended to improve the efficiency of the acute stroke pathway rarely improved EMS call to hospital times. Included studies were heterogenous and rarely focussed on the review topic which limits the usability of the findings. Further research is needed to explore the trade-off between changes to EMS stroke care and call to hospital times and subsequent impacts on in-hospital care and patient outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00713-6.

Analysis and modelling of mistriage in the Stockholm stroke triage system

INTRODUCTION

The Stockholm Stroke Triage System (SSTS) is a prehospital triage system for detection of patients eligible for endovascular thrombectomy (EVT). Assessment of hemiparesis combined with ambulance-hospital teleconsultation is used to route patients directly to the thrombectomy centre. Some patients are not identified and require secondary transport for EVT (undertriage) while others taken to the thrombectomy centre do not undergo EVT (overtriage). The aims of this study were to characterize mistriaged patients, model for and evaluate alternative triage algorithms.

PATIENTS AND METHODS

Patients with suspected stroke transported by priority 1 ground ambulance between October 2017 and October 2018 (n = 2905) were included. Three triage algorithms were modelled using prehospital data. Decision curve analysis was performed to calculate net benefit (correctly routing patients for EVT without increasing mistriage) of alternative models vs SSTS.

RESULTS

Undertriage for EVT occurred in n = 35/2582 (1.4%) and overtriage in n = 239/323 (74.0%). Compared to correct thrombectomy triages, undertriaged patients were younger and had lower median NIHSS (10 vs 18), despite 62.9% with an M1 occlusion. In overtriaged patients, 77.0% had a stroke diagnosis (29.7% haemorrhagic). Hemiparesis and FAST items face and speech were included in all models. Decision curve analysis showed highest net benefit for SSTS for EVT, but lower for large artery occlusion (LAO) stroke.

DISCUSSION

Undertriaged patients had lower NIHSS, likely due to better compensated proximal occlusions. SSTS was superior to other models for identifying EVT candidates, but lacked information allowing comparison to other prehospital scales.

CONCLUSION

Using prehospital data, alternative models did not outperform the SSTS in finding EVT candidates.

Can Helicopters Solve the Transport Dilemma for Patients With Symptoms of Large-Vessel Occlusion Stroke in Intermediate Density Areas? A Simulation Model Based on Real Life Data

Background

This modeling study aimed to determine if helicopters may optimize the transportation of patients with symptoms of large vessel stroke in “intermediate density” areas, such as Denmark, by bringing them directly to the comprehensive stroke center.

Methods

We estimated the time for the treatment of patients requiring endovascular therapy or intravenous thrombolysis under four configurations: “drip and ship” with and without helicopter and “bypass” with and without helicopter. Time delays, stroke numbers per municipality, and helicopter dispatches for four helicopter bases from 2019 were obtained from the Danish Stroke and Helicopter Registries. Discrete event simulation (DES) was used to estimate the capacity of the helicopter fleet to meet patient transport requests, given the number of stroke codes per municipality.

Results

The median onset-to-needle time at the comprehensive stroke center (CSC) for the bypass model with the helicopter was 115 min [interquartile range (IQR): 108, 124]; the median onset-to-groin time was 157 min (IQR: 150, 166). The median onset-to-needle time at the primary stroke center (PSC) by ground transport was 112 min (IQR: 101, 125) and the median onset-to-groin time when primary transport to the PSC was prioritized was 234 min (IQR: 209, 261).

A linear correlation between travel time by ground and the number of patients transported by helicopter (rho = 0.69, p < 0.001) indicated that helicopters are being used to transport more remote patients. DES demonstrated that an increase in helicopter capture zone by 20 min increased the number of rejected patients by only 5%.

Conclusions

Our model calculations suggest that using helicopters to transport patients with stroke directly to the CSC in intermediate density areas markedly reduce onset-to-groin time without affecting time to thrombolysis. In this setting, helicopter capacity is not challenged by increasing the capture zone.

Comparison of large vessel occlusion scales using prehospital patient reports

BACKGROUND

Prehospital identification of large vessel occlusion (LVO) holds significant potential to decrease the onset-to-treatment time. Several prehospital scales have been developed to identify LVO but data on their comparison has been limited. The aim of this study was to review the currently available prehospital LVO scales and compare their performance using prehospital data.

METHODS

All patients transported by ambulance using stroke code on a six-month period were enrolled into the study. The prehospital patient reports were retrospectively evaluated by two investigators using sixteen LVO scales identified by literature search and expert opinion. After the evaluation, the computed tomography angiography results were reviewed by a neuroradiologist to confirm or exclude LVO.

RESULTS

Sixteen different LVO scales met the predetermined study criteria and were selected for further comparison. Using them, a total of 610 evaluations were registered. The sensitivity of the scales varied between 8%-73%, specificity between 71%-97% and overall accuracy between 71%-87%. The areas under curve (AUC) varied between 0.61-0.80 for the whole scale range and 0.53%-0.74 for the scales' binary cut-offs. The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) was the only scale with AUC > 0.8. Regarding scales' binary cut-offs, The FAST-ED (0.70), Gaze - Face Arm Speech Time (G-FAST) (0.74) and Emergency Medical Stroke Assessment (EMSA) (0.72) were the only scales with AUC > 0.7.

CONCLUSIONS

In a comparison of 16 different LVO scales, the FAST-ED, G-FAST and EMSA achieved the highest overall performance.

A regional strategy to decrease the time to thrombectomy in patients with low probability of treatment by thrombolysis

BACKGROUND AND PURPOSE

The best transportation strategy for patients with suspected large vessel occlusion (LVO) is unknown. Here, we evaluated a new regional strategy of direct transportation to a Comprehensive Stroke Center (CSC) for patients with suspected LVO and low probability of receiving intravenous thrombolysis (IVT) at the nearest Primary Stroke Center (PSC).

METHODS

Patients could be directly transported to the CSC (bypass group) if they met our pre-hospital bypass criteria: high LVO probability (i.e., severe hemiplegia) with low IVT probability (contraindications) and/or travel time difference between CSC and PSC<15 minutes. The other patients were transported to the PSC according to a "drip-and-ship" strategy. Treatment time metrics were compared in patients with pre-hospital bypass criteria and confirmed LVO in the bypass and drip-and-ship groups.

RESULTS

In the bypass group (n=79), 54/79 (68.3%) patients met the bypass criteria and 29 (36.7%) had confirmed LVO. The positive predictive value of the hemiplegia criterion for LVO detection was 0.49. In the drip-and-ship group (n=457), 92/457 (20.1%) patients with confirmed LVO met our bypass criteria. Among the 121 patients with bypass criteria and confirmed LVO, direct routing decreased the time between symptom discovery and groin puncture by 55 minutes compared with the drip-and-ship strategy (325 vs. 229 minutes, P<0.001), without significantly increasing the time to IVT (P=0.19).

CONCLUSIONS

Our regional strategy led to the correct identification of LVO and a significant decrease of the time to mechanical thrombectomy, without increasing the time to IVT, and could be easily implemented in other territories.

Effect of pre-hospital notification on delays and neurological outcomes in acute ischemic stroke

BACKGROUND

Since timely thrombolytic therapy is a crucial variable in acute ischemic stroke recovery, health care systems are trying to find new interventions to reduce treatment delay in order to improve neurological function. In Iran, SAMA code as a pre-hospital notification plan has been developed to help emergent stroke treatment. This study aimed to compare delay to thrombolysis therapy and neurological outcomes between SAMA-transported and self-transported patients in ischemic stroke.

METHODS

In this retrospective cohort study, the data of 185 stroke patients treated with intravenous thrombolysis from Mar 2016 to May 2020 were collected. P-value < 0.05 was considered as significant.

RESULTS

The results showed that delays reduced in SAMA-transported patient compared to that in self-transported patients. There was a significant difference in Onset to Needle time, Door to Needle Time, and Door to CT Time but not Onset to Door time between SAMA-transported and self-transported patients (P values: 0.001, 0.000, 0.001, and 0.22 respectively). However, there was no significant difference between two groups in terms of neurologic deficit severity.

CONCLUSIONS

Although pre-hospital notification could partially reduce treatment delays in stroke, that reduction was not enough to impact on neurologic deficit recovery. It seems more reduction in delay is needed to significantly improve neurological dysfunctions.

Prehospital Stroke Triage

PURPOSE OF THE REVIEW

This article reviews prehospital organization in the treatment of acute stroke. Rapid access to an endovascular therapy (EVT) capable center and prehospital assessment of large vessel occlusion (LVO) are 2 important challenges in acute stroke therapy. This article emphasizes the use of transfer protocols to assure the prompt access of patients with an LVO to a comprehensive stroke center where EVT can be offered. Available prehospital clinical tools and novel technologies to identify LVO are also discussed. Moreover, different routing paradigms like first attention at a local stroke center ("drip and ship"), direct transfer of the patient to an endovascular center ("mothership"), transfer of the neurointerventional team to a local primary center ("drip and drive"), mobile stroke units, and prehospital management communication tools all aimed to improve connection and coordination between care levels are reviewed.

RECENT FINDINGS

Local observational data and mathematical models suggest that implementing triage tools and bypass protocols may be an efficient solution. Ongoing randomized clinical trials comparing drip and ship vs mothership will elucidate which is the more effective routing protocol.

SUMMARY

Prehospital organization is critical in realizing maximum benefit from available therapies in acute stroke. The optimal transfer protocols directed to accelerate EVT are under study, and more accurate prehospital triage tools are needed. To improve care in the prehospital setting, efficient tools based on patient factors, local geography, and hospital capability are needed. These tools would optimally lead to individualized real-time decision-making.

Prehospital identification of large vessel occlusion using the FAST-ED score

OBJECTIVES

The prehospital identification of stroke patients with large vessel occlusion (LVO) enables appropriate hospital selection and reduces the onset-to-treatment time. The aim of this study was to investigate whether the Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale could be reconstructed from existing prehospital patient reports and to compare its performance with neurologist's clinical judgement using the same prehospital data.

MATERIALS & METHODS

All patients transported by ambulance using stroke code on a six-month period were registered for the study. The prehospital patient reports were retrospectively evaluated using the FAST-ED scale by two investigators. The performance of FAST-ED score (≥4 points) in LVO identification was compared to neurologist's clinical judgement ('LVO or not'). The presence of LVO was verified using computed tomography angiography imaging.

RESULTS

A total of 610 FAST-ED scores were obtained. The FAST-ED had a sensitivity of 57.8%, specificity of 87.2%, positive predictive value (PPV) of 37.3%, negative predictive value (NPV) of 93.4% and area under curve (AUC) of 0.724. Interclass correlation coefficient for both raters over the entire range of FAST-ED was 0.92 (0.88-0.94). The neurologist's clinical judgement raised sensitivity to 79.4%, NPV to 97.1% and PPV to 45.0% with an AUC of 0.837 (p < .05).

CONCLUSIONS

The existing patient report data could be feasibly used to reconstruct FAST-ED scores to identify LVO. The binary FAST-ED score had a moderate sensitivity and good specificity for prehospital LVO identification. However, the FAST-ED was surpassed by neurologist's clinical judgement which further increased the sensitivity of identification.

The Stockholm Stroke Triage Project: Outcomes of Endovascular Thrombectomy Before and After Triage Implementation

BACKGROUND AND PURPOSE

The Stockholm Stroke Triage System (SSTS) is a prehospital algorithm for detection of endovascular thrombectomy (EVT)-eligible patients, combining symptom severity assessment and ambulance-to-hospital teleconsultation, leading to a decision on primary stroke center bypass. In the Stockholm Region (6 primary stroke centers, 1 EVT center), SSTS implementation in October 2017 reduced onset-to-EVT time by 69 minutes. We compared clinical outcomes before and after implementation of SSTS in an observational study.

METHODS

We prospectively recruited patients transported by Code Stroke ambulance within the Stockholm region under the SSTS, treated with EVT during October 2017 to October 2019, and compared to EVT patients from 2 previous years.

OUTCOMES

shift in modified Rankin Scale (mRS) scores, mRS score 0 to 1, mRS score 0 to 2, and death (all 3 months), National Institutes of Health Stroke Scale (NIHSS) score change 24-hour post-EVT, recanalization (Thrombolysis in Cerebral Infarction 2b-3), and symptomatic intracranial hemorrhage. mRS outcomes were adjusted for age and baseline NIHSS.

RESULTS

Patients with EVT in the SSTS group (n=244) were older and had higher baseline NIHSS versus historical controls (n=187): median age 74 (interquartile range, 63-81) versus 71 (61-78); NIHSS score 17 (11.5-21) versus 15 (10-20). During SSTS, median onset-to-puncture time was 136 versus 205 minutes (P<0.001). Adjusted common odds ratio for lower mRS in SSTS patients was 1.7 (95% CI, 1.2-2.3) versus controls. During SSTS, 83/240 (34.6%) versus 44/186 (23.7%) reached 3-month mRS score 0 to 1 (P=0.014), adjusted common odds ratio 2.3 (95% CI, 1.4-3.6). Median NIHSS change 24-hour post-EVT was 6 versus 4 (P=0.005). Differences in Thrombolysis in Cerebral Infarction, symptomatic intracranial hemorrhage, and death were nonsignificant.

CONCLUSIONS

With an onset to arterial puncture time reduction by 69 minutes, outcomes in thrombectomy-treated patients improved significantly after region-wide large artery occlusion triage system implementation. These results warrant replication studies in other geographic and organizational circumstances.

High-resolution CT with arch/neck/head CT angiography on a mobile stroke unit

BACKGROUND

Mobile stroke units (MSUs) performance dependability and diagnostic yield of 16-slice, ultra-fast CT with auto-injection angiography (CTA) of the aortic arch/neck/circle of Willis has not been previously reported.

METHODS

We performed a prospective observational study of the first-of-its kind MSU equipped with high resolution, 16-slice CT with multiphasic CTA. Field CT/CTA was performed on all suspected stroke patients regardless of symptom severity or resolution. Performance dependability, efficiency and diagnostic yield over 365 days was quantified.

RESULTS

1031 MSU emergency activations occurred; of these, 629 (61%) were disregarded with unrelated diagnoses, and 402 patients transported: 245 (61%) ischemic or hemorrhagic stroke, 17 (4%) transient ischemic attack, 140 (35%) other neurologic emergencies. Total time from non-contrast CT/CTA start to images ready for viewing was 4.0 (IQR 3.5-4.5) min. Hemorrhagic stroke totaled 24 (10%): aneurysmal subarachnoid hemorrhage 3, hemorrhagic infarct 1, and 20 intraparenchymal hemorrhages (median intracerebral hemorrhage score was 2 (IQR 1-3), 4 (20%) spot sign positive). In 221 patients with ischemic stroke, 73 (33%) received alteplase with 31.5% treated within 60 min of onset. CTA revealed large vessel occlusion in 66 patients (30%) of which 9 (14%) were extracranial; 27 (41%) underwent thrombectomy with onset to puncture time averaging 141±90 min (median 112 (IQR 90-139) min) with full emergency department (ED) bypass. No imaging needed to be repeated for image quality; all patients were triaged correctly with no inter-hospital transfer required.

CONCLUSIONS

MSU use of advanced imaging including multiphasic head/neck CTA is feasible, offers high LVO yield and enables full ED bypass.

Validation of field assessment stroke triage for emergency destination for prehospital use in a rural EMS system

BACKGROUND

Field Assessment Stroke Triage for Emergency Destination (FAST-ED) is a simple and accurate prehospital stroke severity scale that has been shown to have comparable accuracy to the gold standard National Institutes of Health Stroke Scale (NIHSS) but requires further field validation for use by emergency medical services (EMS), particularly in rural systems. FAST-ED scores ≥4 are considered high probability for large vessel occlusion (LVO) strokes, while scores <4 are low to moderate probability for LVO. The objective of this study was to assess inter-rater reliability of the EMS FAST-ED (EMS) score to the emergency department FAST-ED (ED-MD) scores.

METHODS

EMS calculated FAST-ED scores prior to transport to the emergency department (ED) on patients with a positive prehospital stroke screen. EDMD calculated FAST-ED scores for the same patients upon arrival to the ED. Interrater reliability and test characteristics were calculated.

RESULTS

A total of 95 patients were included in this study and 14 were subsequently diagnosed with an LVO. EMS assigned 34 patients (35.8%) a FAST-ED score of ≥4. EDMD assigned 25 patients (26.3%) a FAST-ED score of ≥4. Using the clinical cut-points of FAST-ED scores <4 and ≥ 4, a linearly weighted Cohen's kappa coefficient showed moderate interrater reliability when comparing EMS and EDMD scores (k_w 0.44, 95% CI 0.25-0.63). At ≥4, EMS FAST-ED scores had a sensitivity 0.48, specificity 0.75, PPV 0.62, NPV 0.62 for predicting an LVO, while EDMD FAST-ED scores had a sensitivity 0.36, specificity 0.82, PPV 0.64, NPV 0.60. Comparable receiver operator curve area under the curve values were obtained.

CONCLUSIONS

EMS and EDMD FAST-ED scores were moderately comparable in a rural EMS system. Similar NPVs compared to EDMD suggest the use of FAST-ED as an appropriate screening tool for EMS to predict the probability of LVO in the prehospital setting and make destination determinations regarding primary transport to a thrombectomy-capable stroke center.

Is concurrent intravenous alteplase in patients undergoing endovascular treatment for large vessel occlusion stroke cost-effective even if the cost of alteplase is only US$1?

BACKGROUND

The added value of intravenous (IV) alteplase in large vessel occlusion (LVO) stroke over and beyond endovascular treatment (EVT) is controversial. We compared the long-term costs and cost-effectiveness of a direct-to-EVT paradigm in LVO stroke patients presenting directly to the mothership hospital to concurrent EVT and IV alteplase.

METHODS

We used a decision model consisting of a short-run model to analyze costs and functional outcomes within 90 days after the index stroke and a long-run Markov state transition model (cycle length of 12 months) to estimate expected lifetime costs and outcomes. Outcome data were from the DIRECT-MT trial (NCT03469206). Incremental cost-effectiveness ratios and net monetary benefits were calculated and probabilistic sensitivity analysis was performed. Analysis was performed from a healthcare perspective and a societal perspective using both a minimal assumed alteplase cost of US$1 and true alteplase cost.

RESULTS

When assuming a minimal cost of alteplase of $1, EVT with concurrent IV alteplase resulted in incremental lifetime cost of $5664 (healthcare perspective)/$4804 (societal perspective) and a decrement of 0.25 quality-adjusted life years (QALYs) compared with EVT only, indicating dominance of the EVT only approach. Net monetary benefits were consistently higher for EVT only compared with EVT with concurrent alteplase. Probabilistic sensitivity analysis showed increased costs without an increase in QALYs for EVT and concurrent IV alteplase compared with EVT only. Results were even more in favor of EVT when the true cost of alteplase was used for analysis.

CONCLUSION

EVT without concurrent alteplase is the preferred strategy from a health economic standpoint.

Swiss guidelines for the prehospital phase in suspected acute stroke

Acute stroke treatment has advanced substantially over the last years. Important milestones constitute intravenous thrombolysis, endovascular therapy (EVT), and treatment of stroke patients in dedicated units (stroke units). At present in Switzerland there are 13 certified stroke units and 10 certified EVT-capable stroke centers. Emerging challenges for the prehospital pathways are that (i) acute stroke treatment remains very time sensitive, (ii) the time window for acute stroke treatment has opened up to 24 h in selected cases, and (iii) EVT is only available in stroke centers. The goal of the current guideline is to standardize the prehospital phase of patients with acute stroke for them to receive the optimal treatment without unnecessary delays. Different prehospital models exist. For patients with large vessel occlusion (LVO), the Drip and Ship model is the most commonly used in Switzerland. This model is challenged by the Mothership model where stroke patients with suspected LVO are directly transferred to the stroke center. This latter model is only effective if there is an accurate triage by paramedics, hence the patient may benefit from the right treatment in the right place, without loss of time. Although the Cincinnati Prehospital Stroke Scale is a well-established scale to detect acute stroke in the prehospital setting, it neglects nonmotor symptoms like visual impairment or severe vertigo. Therefore we suggest “acute occurrence of a focal neurological deficit” as the trigger to enter the acute stroke pathway. For the triage whether a patient has a LVO (yes/no), there are a number of scores published. Accuracy of these scores is borderline. Nevertheless, applying the Rapid Arterial Occlusion Evaluation score or a comparable score to recognize patients with LVO may help to speed up and triage prehospital pathways. Ultimately, the decision of which model to use in which stroke network will depend on local (e.g. geographical) characteristics.

Prospective Evaluation of a Two-Scale Protocol for Prehospital Large Vessel Occlusion Detection

Background and purposes: Stroke severity scales may expedite prehospital large vessel occlusion (LVO) stroke detection, but few are validated for paramedic use. We evaluated the feasibility of introducing the Cincinnati Stroke Triage Assessment Tool (C-STAT) in the field and its capacity to detect LVO stroke.Methods: We performed a prospective paramedic-based study assessing C-STAT in the field on patients currently redirected to two comprehensive stroke centers (CSC), based on a Cincinnati Prehospital Stroke Scale (CPSS) score of 3/3. C-STAT was administered by on-site paramedics with telephone guidance from trained centralized clinical support paramedics.Results: Between October 2018 and November 2019, C-STAT scores were obtained in 188/218 (86.2%) patients, among which 118/188 (62.8%) were positive. Paramedics reported performing the C-STAT in less than 5 minutes on 170/188 (90.4%) patients and noted no difficulties administering the scale in 151/188 (80.3%). A positive C-STAT identified 51/68 (75%) LVO strokes in the cohort, demonstrating a 43% (95% CI: 38%-48%) positive and 76% (95% CI: 66%-83%) negative predictive value for LVO stroke diagnosis. In a cohort of 100 patients with CPSS 3/3, requiring a positive C-STAT for redirection would decrease CSC patient volume by 37 but miss 9 of 36 LVO strokes.Conclusion: Prehospital administration of the C-STAT was feasible, using a model of minimal paramedic training and real-time telephone guidance. A protocol based on both a CPSS 3/3 and a positive C-STAT would decrease CSC redirected patient volume by one-third but would miss one-quarter of LVO strokes when compared to a CPSS-based protocol.

Prehospital Triage Accuracy in Patients With Stroke Symptoms Assessed Within 6 to 24 Hours or With an Unknown Time of Onset

BACKGROUND AND PURPOSE

The Stockholm Stroke Triage System, implemented in 2017, identifies patients with high likelihood of large vessel occlusion (LVO) stroke. A previous report has shown Stockholm Stroke Triage System notably reduced time to endovascular thrombectomy (EVT). As the indication for EVT now includes patients up to 24 hours, we aimed to assess Stockholm Stroke Triage System triage accuracy for LVO stroke and EVT treatment for patients presenting late (within 6-24 hours or with an unknown onset), put in contrast to triage accuracy within 0 to 6 hours.

METHODS

Between October 2017 and October 2018, we included 2905 patients with suspected stroke, transported by priority 1 ground ambulance to a Stockholm Region hospital. Patients assessed 6 to 24 hours from last known well or with unknown onset were defined as late-presenting; those within <6 hours as early-presenting. Triage positivity was defined as transport to comprehensive stroke center because of suspected stroke, hemiparesis and high likelihood of EVT-eligible LVO per teleconsultation.

RESULTS

Overall triage accuracy was high in late-presenting patients (90.9% for LVO, 93.9% for EVT), with high specificity (95.7% for LVO, 94.5% for EVT), and low to moderate sensitivity (34.3% for LVO, 64.7% for EVT), with similar findings in the early-presenting group.

CONCLUSIONS

Our results may support using the Stockholm Stroke Triage System for primary stroke center bypass in patients assessed by ambulance up to 24 hours from time of last known well.

In-hospital acute stroke workflow in acute stroke - Systems-based approaches

Clinical outcomes of acute ischaemic stroke patients have significantly improved with the advent of reperfusion therapy. However, time continues to be a critical factor. Reducing treatment delays by improving workflows can improve the efficacy of acute reperfusion therapy. Systems-based approaches have improved in-hospital temporal parameters, maximizing the utility of reperfusion therapies and improving clinical benefit to patients. However, studies aimed at optimizing and hence reducing treatment delays in emergency department (ED) settings are limited. The aim of this article is to discuss existing systems-based approaches to optimize ED acute stroke workflows and its value in reducing treatment delays and identify gaps in existing workflows that need optimization. Identifying gaps in acute stroke workflow, variations in processes and challenges in implementation, in the in-hospital settings, is essential for systems-based interventions to be effective in delivering improved outcomes for patients with acute ischaemic stroke.

Early Thrombectomy Outcomes in Transfer Patients

OBJECTIVE

The optimal patient transportation destination of acute ischemic stroke (AIS) patients remains uncertain. The purpose of this study was to evaluate the predictive variables that determine stroke outcomes depending on the patient transportation destination.

METHODS

We performed a retrospective study using an AIS database consisting of patients who underwent thrombectomy admitted to our institution from November 1, 2011, through October 1, 2018.

RESULTS

A total of 171 patients were included in the statistical analysis; 42.1% (72/171) of patients were in the mothership group (directly admitted) and 57.9% (99/171) in the drip-and-ship group (transferred). Multivariable logistic regression revealed the predictive factors for favorable outcomes were driving distance (expressed in miles) between the patient's home and a comprehensive stroke center (CSC) (odds ratio [OR] = 0.95; 95% confidence interval [CI], 0.90-0.99; P = .035), absence of diabetes mellitus (OR = 3.60; 95% CI, 1.20-10.82; P = .022), lower National Institutes of Health Stroke Scale score at admission (OR = 0.91; 95% CI, 0.85-0.97; P = .003), and shorter symptom onset to CSC arrival time (expressed in hours) (OR = 0.84; 95% CI, 0.72-0.99; P = .038).

CONCLUSIONS

Our study revealed that a shorter driving distance between the patient's home and CSC, absence of diabetes, lower National Institutes of Health Stroke Scale score, and shorter onset to hospital arrival time positively impacted the outcomes of endovascularly treated AIS patients.

Gaze Deviation and Paresis Score (GPS) Sufficiently Predicts Emergent Large Vessel Occluding Strokes

OBJECTIVES

The prognosis of patients with acute ischemic stroke (AIS) essentially depends on both prompt diagnosis and appropriate treatment. Endovascular stroke therapy (EST) proved to be highly efficient in the treatment of emergent large vessel occluding (ELVO) strokes in the anterior circulation. To achieve a timely diagnosis, a robust combination of few and simple signs to identify ELVOs in AIS patients applicable by paramedics in the prehospital triage is worthwhile.

MATERIALS AND METHODS

This retrospective single-center study included 904 AIS patients (324 ELVO, 580 non-ELVO) admitted between 2010 and 2015 in a tertiary stroke center. We re-evaluated two symptoms based on NIHSS items, gaze deviation and hemiparesis of the limbs ("Gaze deviation and Paresis Score, GPS") for the pre-hospital prediction of ELVO.

RESULTS

A positive GPS AIS in patients predicted ELVO with a sensitivity of 0.89, specificity = 0.97, positive predictive value (PPV) = 0.95, negative predictive value (NPV) = 0.94 and diagnostic odds ratio (DOR) = 34.25 (CI: 20.75-56.53). The positive Likelihood-ratio (LR⁺) was 29.67, the negative Likelihood ratio (LR^-) 0.11. NIHSS of patients with positive GPS (gaze palsy NIHSS ≥ 0, Motor arm NIHSS ≥2 and Motor leg NIHSS ≥2) was markedly higher compared to negative GPS patients (p < 0.001).

CONCLUSIONS

The GPS proved to be similarly accurate in detecting ELVO in the anterior circulation of AIS patients and even more specific than other published clinical scores. Its simplicity and clarity might enable non-neurological medical staff to identify ELVO AIS patients with high certainty in a preclinical setting.

Routing to Endovascular Treatment of Ischemic Stroke in Korea: Recognition of Need for Process Improvement

BACKGROUND

To track triage, routing, and treatment status regarding access to endovascular treatment (EVT) after acute ischemic stroke (AIS) at a national level.

METHODS

From national stroke audit data, potential candidates for EVT arriving within 6 hours with National Institute of Health Stroke Scale score of ≥ 7 were identified. Acute care hospitals were classified as thrombectomy-capable hospitals (TCHs, ≥ 15 EVT cases/year) or primary stroke hospital (PSH, < 15 cases/year), and patients' initial routes and subsequent inter-hospital transfer were described. Impact of initial routing to TCHs vs. PSHs on EVT and clinical outcomes were analyzed using multilevel generalized mixed effect models.

RESULTS

Out of 14,902 AIS patients, 2,180 (14.6%) were EVT candidates. Eighty-one percent of EVT candidates were transported by ambulance, but only one-third were taken initially to TCHs. Initial routing to TCHs was associated with greater chances of receiving EVT compared to initial routing to PSHs (33.3% vs 12.1%, P < 0.001; adjusted odds ratio [aOR], 2.21; 95% confidence interval [CI], 1.59-2.92) and favorable outcome (38.5% vs. 28.2%, P < 0.001; aOR, 1.52; 95% CI, 1.16-2.00). Inter-hospital transfers to TCHs occurred in 17.4% of those initially routed to a PSH and was associated with the greater chance of EVT compared to remaining at PSHs (34.8% vs. 7.5%, P < 0.001), but not with better outcomes.

CONCLUSION

Two-thirds of EVT candidates were initially routed to PSHs despite greater chance of receiving EVT and having favorable outcomes if routed to a TCH in Korea. Process improvement is needed to direct appropriate patients to TCHs.

The first seven years of nationally organized helicopter emergency medical services in Finland - the data from quality registry

Background

Helicopter Emergency Medical Services (HEMS) play an important role in prehospital care of the critically ill. Differences in funding, crew composition, dispatch criteria and mission profile make comparison between systems challenging. Several systems incorporate databases for quality control, performance evaluation and scientific purposes. FinnHEMS database was incorporated for such purposes following the national organization of HEMS in Finland 2012. The aims of this study are to describe information recorded in the database, data collection, and operational characteristics of Finnish HEMS during 2012–2018.

Methods

All dispatches of the six Finnish HEMS units recorded in the national database from 2012 to 2018 were included in this observational registry study. Five of the units are physician staffed, and all are on call 24/7. The database follows a template for uniform reporting in physician staffed pre-hospital services, exceeding the recommended variables of relevant guidelines.

Results

The study included 100,482 dispatches, resulting in 33,844 (34%) patient contacts. Variables were recorded with little or no missing data. A total of 16,045 patients (16%) were escorted by HEMS to hospital, of which 2239 (2%) by helicopter. Of encountered patients 4195 (4%) were declared deceased on scene. The number of denied or cancelled dispatches was 66,638 (66%). The majority of patients were male (21,185, 63%), and the median age was 57.7 years. The median American Society of Anesthesiologists Physical Scale classification was 2 and Eastern Cooperative Oncology Group performance class 0. The most common reason for response was trauma representing 26% (8897) of the patients, followed by out-of-hospital cardiac arrest 20% (6900), acute neurological reason excluding stroke 13% (4366) and intoxication and related psychiatric conditions 10% (3318). Blunt trauma (86%, 7653) predominated in the trauma classification.

Conclusions

Gathering detailed and comprehensive data nationally on all HEMS missions is feasible. A national database provides valuable insights into where the operation of HEMS could be improved. We observed a high number of cancelled or denied missions and a low percentage of patients transported by helicopter. The medical problem of encountered patients also differs from comparable systems.

Optimizing Stroke Care for Patients with Large Vessel Occlusions: Current State of the Art and Future Directions

Acute ischemic stroke (AIS) is a severely disabling disease. Endovascular therapy is a powerful and highly effective treatment option for these patients and has recently become standard of care. The benefits of endovascular treatment (EVT) are tremendous both from a patient and from an economic perspective, since it dramatically improves individual patient outcomes while reducing long-term healthcare costs at the same time. The effect of EVT is highly time-dependent. Thus, the overarching goal in AIS is to quickly transport and diagnose the patient to minimize treatment delays. In this review, we provide an overview about the current state of stroke care, propose a fast and simplified imaging protocol and management approach for AIS patients. We also highlight the challenges we are currently facing in endovascular stroke treatment and suggest possible solutions to overcome these.

Bypassing the Closest Stroke Center for Thrombectomy Candidates

Background and Purpose—

Patients with acute ischemic stroke who have large vessel occlusion benefit from direct transport to a comprehensive stroke center (CSC) capable of endovascular therapy. To avoid harm for patients without large vessel occlusion from delayed access to intravenous thrombolysis (IVT), it has been suggested to only redirect patients with high likelihood of large vessel occlusion for whom the additional delay to intravenous thrombolysis (IVT) caused by transport to the CSC is below a certain threshold. However, which threshold achieves the greatest clinical benefit is unknown.

Methods—

We used mathematical modeling to calculate additional-delay-to-IVT thresholds associated with the greatest reduction in disability-adjusted life years in abstracted 2-stroke center and multiple-stroke center scenarios. Model parameters were extracted from recent meta-analyses or large prospective cohort studies. Uncertainty was quantified in probabilistic and 2-way univariate sensitivity analyses.

Results—

Assuming ideal treatment time performance metrics, transport to the nearest CSC was the preferred strategy irrespective of additional delay-to-IVT when the transfer time between primary stroke center and CSC was <40 minutes (95% credible interval: 25–66 minutes); otherwise, the optimal additional delay-to-IVT-threshold ranged from 28 to 139 minutes. In multiple-stroke center scenarios, optimal additional-delay-to-IVT thresholds were 30 to 54 minutes in urban and 49 to 141 minutes in rural settings; use of optimal thresholds as compared with a 15 minute-threshold saved 0 to 0.11 and 0 to 0.37 disability-adjusted life years per triage case, respectively. Assuming slower treatment times at primary stroke centers and CSCs yielded longer permissible additional delays.

Conclusions—

Our results suggest that patients with acute ischemic stroke with suspected large vessel occlusion should be redirected to a CSC if the additional delay to IVT is <30 minutes in urban and 50 minutes in rural settings.

Asymmetrical Bioimpedance in the Anterior Circulation for Urgent Stratification of suspected Stroke (ABACUS Stroke): study protocol for a diagnostic accuracy study

BACKGROUND

Early identification and treatment of stroke improve outcome. Ischaemic stroke due to large vessel occlusion (LVO) benefits from time-critical thrombectomy but this is only available in highly specialised healthcare services. Cerebral Bioimpedance Asymmetry (CBA) measurement obtained with the portable and rapid Cerebrotech Visor™ System device may be able to identify certain types of stroke including LVO. This test could be deployed pre-hospital and used to immediately direct patients to the most appropriate healthcare service for treatment. This study is evaluating the diagnostic accuracy of CBA measurements obtained from a real-world population of suspected stroke.

METHODS

Study design: Prospective observational cohort study.Setting: A hyperacute stroke unit and neuroscience centre in North East England.Participants: Adults with a paramedic assigned diagnosis of suspected stroke arriving at hospital within 6 hours of symptom onset.Index Test: Cerebral Bioimpedance Asymmetry measurement performed using the Cerebrotech Visor™ System. Measurement values produce continuous data (range 0 -100); pre-defined threshold for positive state ≥ 10.Reference Standard Tests: Standard CT brain +/- CT/MR angiography, and expert clinician opinion will establish the following clinical outcomes which constitute the suspected stroke population: ischaemic stroke +/- large vessel occlusion; symptomatic severe anterior vessel stenosis; large (≥60ml) and small (<60mls) vessel intracerebral haemorrhage; transient ischaemic attack; stroke mimic conditions; prior territorial stroke.Analyses: Sensitivity, specificity, negative and positive predictive values, area under the Receiver Operating Characteristic curve for identification of i) "complex stroke" (ischaemic stroke with large vessel occlusion or symptomatic severe anterior vessel stenosis or intracerebral haemorrhage ≥60ml or prior territorial stroke) and ii) ischaemic stroke with large vessel occlusion in isolation.Sample size: 124 participants.

DISCUSSION

The results from this study will determine how accurately CBA measurement using the Cerebrotech Visor™ System can identify key stroke types within the suspected stroke population. Acceptable diagnostic performance would be an important step forwards for access to time-critical treatments.

TRIAL REGISTRATION

Registered with ISRCTN (identifier: ISRCTN79169844) on 06/08/2018.

How Do Physicians Approach Intravenous Alteplase Treatment in Patients with Acute Ischemic Stroke Who Are Eligible for Intravenous Alteplase and Endovascular Therapy? Insights from UNMASK-EVT

BACKGROUND AND PURPOSE

With increasing use of endovascular therapy, physicians' attitudes toward intravenous alteplase in endovascular therapy-eligible patients may be changing. We explored current intravenous alteplase treatment practices of physicians in endovascular therapy- and alteplase-eligible patients with acute stroke using prespecified case scenarios and compared how their current local treatment practices differ compared with an assumed ideal environment.

MATERIALS AND METHODS

In an international multidisciplinary survey, 607 physicians involved in acute stroke care were randomly assigned 10 of 22 case scenarios, among them 14 with guideline-based alteplase recommendations (9 with level 1A and 5 with level 2B recommendation) and were asked how they would treat the patient: A) under their current local resources, and B) under assumed ideal conditions. Answer options were the following: 1) anticoagulation/antiplatelet therapy, 2) endovascular therapy, 3) endovascular therapy plus intravenous alteplase, and 4) intravenous alteplase. Decision rates were calculated, and multivariable regression analysis was performed to determine variables associated with the decision to abandon intravenous alteplase.

RESULTS

In cases with guideline recommendations for alteplase, physicians favored alteplase in 82.0% under current local resources and in 79.3% under assumed ideal conditions (P < .001). Under assumed ideal conditions, interventional neuroradiologists would refrain from intravenous alteplase most often (6.28%, OR = 2.40; 95% CI, 1.01-5.71). When physicians' current and ideal decisions differed, most would like to add endovascular therapy to intravenous alteplase in an ideal setting (196/3861 responses, 5.1%).

CONCLUSIONS

In patients eligible for endovascular therapy and intravenous alteplase, we observed a slightly lower decision rate in favor of intravenous alteplase under assumed ideal conditions compared with the decision rate under current local resources.

TRIAGE-STROKE: Treatment strategy In Acute larGE vessel occlusion: Prioritize IV or endovascular treatment-A randomized trial

RATIONALE

For patients with acute ischemic stroke and large vessel occlusions, intravenous thrombolysis and endovascular therapy are standard of care, but the effect of endovascular therapy is superior to intravenous thrombolysis. If a severe stroke with symptoms indicating large vessel occlusions occurs in the catchment area of a primary stroke center, there is equipoise regarding optimal transport strategy.

AIM

For patients presenting with suspected large vessel occlusions (PASS ≥ 2) and a final diagnosis of acute ischemic stroke, we hypothesize that bypassing the primary stroke center will result in an improved 90-day functional outcome.

SAMPLE SIZE

We aim to randomize 600 patients, 1:1.

DESIGN

A national investigator-driven, multi-center, randomized assessor-blinded clinical trial. The Prehospital Acute Stroke Severity Scale has been developed. It identifies most patients with large vessel occlusions in the pre-hospital setting. Patients without a contraindication for intravenous thrombolysis are randomized to either transport directly to a comprehensive stroke centers for intravenous thrombolysis and of endovascular therapy or to a primary stroke center for intravenous thrombolysis and subsequent transport to a comprehensive stroke centers for of endovascular therapy, if needed.

OUTCOMES

The primary outcome will be the 90-day modified Rankin Scale score (mRS) for all patients with acute ischemic stroke. Secondary outcomes include 90-day mRS for all randomized patients, all patients with ischemic stroke but without large vessel occlusions, and patients with hemorrhagic stroke. The safety outcomes include severe dependency or death and time to intravenous thrombolysis for ischemic stroke patients.

DISCUSSION

Study results will influence decision making regarding transport strategy for patients with suspected large vessel occlusions.

Modeling Stroke Patient Transport for All Patients With Suspected Large-Vessel Occlusion

Importance

Ischemic stroke with large-vessel occlusion can be treated with alteplase and/or endovascular therapy; however, the administration of each treatment is time sensitive.

Objective

To identify the optimal triage and transport strategy: direct to the endovascular center (mothership) or immediate alteplase treatment followed by transfer to the endovascular center (drip and ship), for all patients with suspected large-vessel occlusion stroke.

Design Setting, and Participants

This was a theoretical, conditional probability modeling study. Existing data from clinical trials of stroke treatment were used for model generation. The study was conducted from February 1, 2017, to March 1, 2018.

Main Outcomes and Measures

The time-dependent efficacy of alteplase and endovascular therapy and the accuracy of large-vessel occlusion screening tools were modeled to estimate the probability of positive outcome (modified Rankin Scale score, 0-1 at 90 days) for both the drip-and-ship and mothership transport strategies. Based from onset to treatment, the strategy that estimates the greatest probability of excellent outcome is determined in several different scenarios.

Results

The patient's travel time from both thrombolysis and endovascular therapy centers, speed of treatment, and positive predictive value of the screening tool affect whether the drip-and-ship or mothership strategy estimates best outcomes. With optimal treatment times (door-to-needle time: 30 minutes; door-in-door-out time: 50 minutes; door-to-groin-puncture time: 60 minutes [mothership], 30 minutes [drip and ship]), both options estimate similar outcomes when the centers are 60 minutes or less apart. However, with increasing travel time between the 2 centers (90 or 120 minutes), drip and ship is favored if the patient would have to travel past the thrombolysis center to reach the endovascular therapy center or if the patient would arrive outside the alteplase treatment time window in the mothership scenario. Holding other variables constant, if treatment times are slow at the thrombolysis center (door-to-needle time: 60 minutes; door-in-door-out time: 120 minutes), the area where mothership estimates the best outcomes expands, especially when the 2 centers are close together (60 minutes apart or less). The area where mothership estimates the best outcome also expands as the positive predictive value of the screening tool increases.

Conclusions and Relevance

This study suggests that decision making for prehospital transport can be modeled using existing clinical trial data and that these models can be dynamically adapted to changing realities. Based on current median treatment times to realize the full benefit of endovascular therapy on a population level, the study findings suggest that delivery of the treatment should be regionally centralized. The study modeling suggests that transport decision making is context specific and the radius of superiority of the transport strategy changes based on treatment times at both centers, transport times, and the triaging tool used.

Field triage for endovascular stroke therapy: a population-based comparison

Background

Endovascular therapy (EVT) for stroke improves outcomes but is time sensitive.

Objective

To compare times to treatment and outcomes between patients taken to the closest primary stroke center (PSC) with those triaged in the field to a more distant comprehensive stroke center (CSC).

Methods

During the study, a portion of our region allowed field triage of patients who met severity criteria to a more distant CSC than the closest PSC. The remaining patients were transported to the closest PSC. We compared times to treatment and clinical outcomes between those two groups. Additionally, we performed a matched-pairs analysis of patients from both groups on stroke severity and distance to CSC.

Results

Over 2 years, 232 patients met inclusion criteria and were closest from the field to a PSC; 144 were taken to the closest PSC and 88 to the more distant CSC. The median additional transport time to the CSC was 7 min. Times from scene departure to alteplase and arterial puncture were faster in the direct group (50 vs 62 min; 93 vs 152 min; p<0.001 for both). Among patients who were independent before the stroke, the OR for less disability in the direct group was 1.47 (95% CI 1.13 to 1.93, p=0.003), and 2.06 (95% CI 1.10 to 3.89, p=0.01) for the matched pairs.

Conclusions

In a densely populated setting, for patients with stroke who are EVT candidates and closest to a PSC from the field, triage to a slightly more distant CSC is associated with faster time to EVT, no delay to alteplase, and less disability at 90 days.

Cincinnati Prehospital Stroke Scale for EMS Redirection of Large Vessel Occlusion Stroke

Introduction:

Prehospital identification of large vessel occlusion (LVO) stroke may expedite treatment by direct transport to comprehensive stroke centers (CSCs) with endovascular capabilities. The Cincinnati Prehospital Stroke Scale (CPSS) is commonly used for prehospital stroke detection. We aimed to assess whether (1) a high CPSS score can identify LVO and (2) an Emergency Medical Service (EMS) redirection protocol based on high CPSS accelerated endovascular treatment (EVT).

Methods:

A retrospective comparison of patients transported by EMSs for suspected stroke to a high-volume CSC over a 16-month period, before and after implementation of an EMS redirection protocol based on high CPSS score (3/3). Charts were reviewed to determine the presence of LVO. Time to EVT and 3-month outcomes were compared before and after implementation.

Results:

A prehospital CPSS 3/3 score was found in 223 (59%) patients, demonstrating positive and negative predictive values for LVO of 29% and 94%, respectively. CPSS-based EMS redirection increased the proportion of EVT performed after direct transport to CSC [before: 21 (36%), after: 45 (63%), p < 0.01] and decreased median first door-to-groin puncture time by 28 minutes [109 (interquartile range (IQR) 64–116) versus 81 (IQR 56–130), p = 0.03]. At 3 months, the proportion of patients achieving functional independence (modified Rankin score 0–2) went from 20/57 (35%) to 29/68 (43%) (p = 0.39) following implementation.

Conclusions:

CPSS-based EMS redirection accelerated identification of LVO strokes in the out-of-hospital setting and decreased time to EVT. Nevertheless, this protocol was also associated with high rates of non-LVO stroke. Impact on clinical outcomes should be evaluated in a larger cohort.

Real-World Treatment Trends in Endovascular Stroke Therapy

Background and Purpose- Recent landmark trials provided overwhelming evidence for effectiveness of endovascular stroke therapy (EST). Yet, the impact of these trials on clinical practice and effectiveness of EST among lower volume centers remains poorly characterized. Here, we determine population-level patterns in EST performance in US hospitals and compare EST outcomes from higher versus lower volume centers. Methods- Using validated diagnosis codes from data on all discharges from hospitals and Emergency Rooms in Florida (2006-2016) and the National Inpatient Sample (2012-2016) we identified patients with acute ischemic stroke treated with EST. The primary end point was good discharge outcome defined as discharge to home or acute rehabilitation facility. Multivariate regressions adjusted for medical comorbidities, intravenous tPA (tissue-type plasminogen activator) usage and annual hospital stroke volume were used to evaluate the likelihood of good outcome over time and by annual hospital EST volume. Results- A total of 3890 patients (median age, 73 [61-82] years, 51% female) with EST were identified in the Florida cohort and 42 505 (median age, 69 [58-79], 50% female) in the National Inpatient Sample. In both Florida and the National Inpatient Sample, the number of hospitals performing EST increased continuously. Increasing numbers of EST procedures were performed at lower annual EST volume hospitals over the studied time period. In adjusted multivariate regression, there was a continuous increase in the likelihood of good outcomes among patients treated in hospitals with increasing annual EST procedures per year (odds ratio, 1.1; 95% CI, 1.1-1.2 in Florida and odds ratio, 1.3; 95% CI, 1.2-1.4 in National Inpatient Sample). Conclusions- Analysis of population-level datasets of patients treated with EST from 2006 to 2016 demonstrated an increase in the number of centers performing EST, resulting in a greater number of procedures performed at lower volume centers. There was a positive association between EST volume and favorable discharge outcomes in EST-performing hospitals.

A review of acute ischemic stroke triage protocol evidence: a context for discussion

Endovascular thrombectomy (EVT) is now the standard of care for eligible patients with acute ischemic stroke (AIS) secondary to emergent large vessel occlusion (ELVO). However, there remains uncertainty in how hospital systems can most efficiently route patients with suspected ELVO for EVT treatment. Given the relative geographic distribution of centers with and without endovascular capabilities, the value of prehospital triage directly to centers with the ability to provide EVT remains debated. While there are no randomized trial data available to date, there is substantial evidence in the literature that may offer guidance on the subject. In this review we examine the available data in the context of improving the existing AIS triage systems and discuss how prehospital triage directly to endovascular-capable centers may confer clinical benefits for patients with suspected ELVO.

Drip and ship versus direct to endovascular thrombectomy: The impact of treatment times on transport decision-making

INTRODUCTION

In ischaemic stroke care, fast reperfusion is essential for disability free survival. It is unknown if bypassing thrombolysis centres in favour of endovascular thrombectomy (mothership) outweighs transport to the nearest thrombolysis centre for alteplase and then transfer for endovascular thrombectomy (drip-and-ship). We use conditional probability modelling to determine the impact of treatment times on transport decision-making for acute ischaemic stroke.

MATERIALS AND METHODS

Probability of good outcome was modelled using a previously published framework, data from the Irish National Stroke Register, and an endovascular thrombectomy registry at a tertiary referral centre in Ireland. Ireland was divided into 139 regions, transport times between each region and hospital were estimated using Google's Distance Matrix Application Program Interface. Results were mapped using ArcGIS 10.3.

RESULTS

Using current treatment times, drip-and-ship rarely predicts best outcomes. However, if door to needle times are reduced to 30 min, drip-and-ship becomes more favourable; even more so if turnaround time (time from thrombolysis to departure for the endovascular thrombectomy centre) is also reduced. Reducing door to groin puncture times predicts better outcomes with the mothership model.

DISCUSSION

This is the first case study modelling pre-hospital transport for ischaemic stroke utilising real treatment times in a defined geographic area. A moderate improvement in treatment times results in significant predicted changes to the optimisation of a national acute stroke patient transport strategy.

CONCLUSIONS

Modelling patient transport for system-level planning is sensitive to treatment times at both thrombolysis and thrombectomy centres and has important implications for the future planning of thrombectomy services.

Cincinnati Prehospital Stroke Scale Can Identify Large Vessel Occlusion Stroke

OBJECTIVE

Accurate prehospital identification of patients with acute ischemic stroke (AIS) from large vessel occlusion (LVO) facilitates direct transport to hospitals that perform endovascular thrombectomy. We hypothesize that a cut-off score of the Cincinnati Prehospital Stroke Scale (CPSS), a simple assessment tool currently used by emergency medical services (EMS) providers, can be used to identify LVO.

METHODS

Consecutively enrolled, confirmed AIS patients arriving via EMS between August 2012 and April 2014 at a high-volume stroke center in a large city with a single municipal EMS provider agency were identified in a prospective, single-center registry. Head and neck vessel imaging confirmed LVO. CPSS scores were abstracted from prehospital EMS records. Spearman's rank correlation, Wilcoxon rank-sum test, and Student's t-test were performed. Cohen's kappa was calculated between CPSS abstractors. The Youden index identified the optimal CPSS cut-off. Multivariate logistic regression controlling for age, sex, and race determined the odds ratio (OR) for LVO.

RESULTS

Of 144 eligible patients, 138 (95.8%) had CPSS scores in the EMS record and were included for analysis. The median age was 69 (IQR 58-81) years. Vessel imaging was performed in 97.9% of patients at a median of 5.9 (IQR 3.6-10.2) hours from hospital arrival, and 43.7% had an LVO. Intravenous tissue plasminogen activator was administered to 29 patients, in whom 12 had no LVO on subsequent vessel imaging. The optimal CPSS cut-off predicting LVO was 3, with a Youden index of 0.29, sensitivity of 0.41, and specificity of 0.88. The adjusted OR for LVO with CPSS = 3 was 5.7 (95% CI 2.3-14.1). Among patients with CPSS = 3, 72.7% had an LVO, compared with 34.3% of patients with CPSS ≤ 2 (p < 0.0001).

CONCLUSIONS

A CPSS score of 3 reliably identifies LVO in AIS patients. EMS providers may be able to use the CPSS, a simple, widely adopted prehospital stroke assessment tool, with a cut-off score to screen for patients with suspected LVO.