Suspected Large Vessel Occlusion: Should Emergency Medical Services Transport to the Nearest Primary Stroke Center or Bypass to a Comprehensive Stroke Center With Endovascular Capabilities?

Outcome of stroke patients eligible to mechanical thrombectomy managed by spoke center, primary stroke center or comprehensive stroke center in the East of France

BACKGROUND AND PURPOSE

Patients with suspected stroke are referred to the nearest hospital and are managed either in a spoke center (SC), a primary stroke center (PSC), or a comprehensive stroke center (CSC) in order to benefit from early intravenous thrombolysis (IVT). In case of large vessel occlusion (LVO), mechanical thrombectomy (MT) is only performed in the CSC, whereas the effectiveness of MT is highly time-dependent. There is a debate about the best management model of patients with suspected LVO. Therefore, we aimed to compare functional and safety outcomes of LVO patients eligible for MT managed through our regional telestroke system.

METHOD

We performed a retrospective analysis of our observational prospective clinical registry in all consecutive subjects with LVO within six hours of onset who were admitted to the SC, PSC, or CSC in the east of France between October 2017 and November 2022. The primary endpoint was the functional independence defined as modified Rankin scale (mRS) score 0 to 2 at 90 days. Secondary endpoints were functional outcome, early neurological improvement, symptomatic intracranial hemorrhage and 90-day mortality.

RESULTS

Among the 794 included patients with LVO who underwent MT, 122 (15.4%) were managed by a SC, 403 (50.8%) were first admitted to a PSC, and 269 (33.9%) were first admitted to the CSC. The overall median NIHSS and ASPECTS score were 16 and 8, respectively. Multivariate analysis did not find any significant difference for the primary endpoint between patients managed by PSC versus CSC (OR 1.06 [95% CI 0.64;1.76], P=0.82) and between patient managed by SC versus CSC (OR 0.69 [0.34;1.40], P=0.30). No difference between the three groups was found except for the parenchymal hematoma rate between PSC and CSC (15.7 versus 7.4%, OR 2.25 [1.07;4.74], P=0.032).

CONCLUSIONS

Compared with a first admission to a CSC, the clinical outcomes of stroke patients with LVO eligible for MT first admitted to a SC or a PSC are similar.

An optimization model for reducing thrombectomy center rotations while maintaining medical accessibility

BACKGROUND/PURPOSE

This study addresses the delicate balance between healthcare personnel burnout and medical accessibility in the context of endovascular thrombectomy (EVT) services in urban areas. We aimed to determine the minimum number of hospitals providing EVT on rotation each day without compromising patient access.

METHODS

Employing an optimization model, we developed shift schedules based on patient coverage rates and volumes during the pre-pandemic (2016-2018) and pandemic (2019-2021) periods. Starting with a minimum of two hospitals on duty per day, we gradually increased to a maximum of eight. Patient coverage rates, defined as the proportion of patients meeting bypass criteria and transported to rotating hospitals capable of EVT, were the primary outcomes. Sensitivity analyses explored the impact of varying patient transport intervals and accumulating patients over multiple years.

RESULTS

Results from 7024 patient records revealed patient coverage rates of 92.5% (standard deviation [SD] 2.8%) during the pre-pandemic and 91.4% (SD 2.8%) during the pandemic, with at least two rotating hospitals daily. No significant differences were observed between schedules based on the highest patient volume and coverage rate months. A patient coverage rate of 98.99% was achieved with four rotating hospitals per day during the pre-pandemic period, with limited improvement beyond this threshold. Changing patient transport intervals and accumulating patients over six years (p = 0.83) had no significant impact on coverage rates.

CONCLUSION

Our optimization model supports reducing the number of daily rotating hospitals by half while preserving a balance between patient accessibility and alleviating strain on medical teams.

Rapid Arterial Occlusion Evaluation (RACE) Tool in Detecting Large Cerebral Vessel Occlusions; a Systematic Review and Meta-Analysis

Introduction

Large vessel occlusion (LVO) strokes are linked to higher mortality rates and a greater risk of long-term disability. This study aimed to evaluate the diagnostic performance of the Rapid Arterial Occlusion Evaluation (RACE) tool in detecting LVO through a systematic review and meta-analysis.

Methods

A comprehensive search was conducted across online databases including PubMed, Embase, Scopus, and Web of Science, up to June 25th, 2023. Additionally, a manual search on Google and Google Scholar was performed to identify studies that assessed the diagnostic accuracy of the RACE scale in detecting LVO among patients with stroke symptoms.

Results

Data extracted from 43 studies were analyzed. The optimal cut-off points were determined to be 3 and 4, with a sensitivity of 0.86 (95% confidence interval (CI): 0.78, 0.91) and specificity of 0.57 (95% CI: 0.49, 0.67) for cut-off ≥3, and a sensitivity of 0.78 (95% CI: 0.70, 0.84) and specificity of 0.68 (95% CI: 0.59, 0.75) for cut-off ≥4. Subgroup meta-regression analysis revealed significant variations in sensitivity and specificity. RACE scale's sensitivity was significantly higher in LVO detection in suspected stroke cases, in pre-hospital settings, prospective design studies, and when considering both anterior and posterior occlusions for LVO definition. RACE scale's specificity was significantly higher when evaluating confirmed stroke cases, in-hospital settings, and considering only anterior occlusions for LVO definition and retrospective design studies. Notably, RACE exhibited higher sensitivity and specificity when utilized by neurologists and physicians compared to other emergency staff. Despite these variations, our study found comparable diagnostic accuracy across different conditions.

Conclusion

A high level of evidence indicates that the RACE scale lacks promising diagnostic value for detection of LVOs. A sensitivity range of 0.69 to 0.86 is insufficient for a screening tool intended to aid in the diagnosis of strokes, considering the substantial morbidity and mortality associated with this condition.

Futility in Clinical Trials

This JAMA Guide to Statistics and Methods discusses the early stopping of clinical trials for futility due to lack of evidence supporting the desired benefit, evidence of harm, or practical issues that make successful completion unlikely.

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

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

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

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

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.

Optimizing Emergency Stroke Transport Strategies Using Physiological Models

Supplemental Digital Content is available in the text.

The criteria for choosing between drip and ship and mothership transport strategies in emergency stroke care is widely debated. Although existing data-driven probability models can inform transport decision-making at an epidemiological level, we propose a novel mathematical, physiologically derived framework that provides insight into how patient characteristics underlying infarct core growth influence these decisions.

Potential accuracy of prehospital NIHSS-based triage for selection of candidates for acute endovascular stroke therapy

OBJECTIVE

Whether patients with acute stroke and large vessel occlusion (LVO) benefit from prehospital identification and diversion by emergency medical services (EMS) to an endovascular stroke therapy (EST)-capable center is controversial. We sought to estimate the accuracy of field-based identification of potential EST candidates in a hypothetical best-of-all-worlds situation.

METHODS

In Kaiser Permanente Northern California, all acute stroke patients arriving at its 21 stroke centers between 7:00 am and midnight from January 2016 to December 2019 were evaluated by teleneurologists on arrival. Initial National Institutes of Health Stroke Scale (NIHSS) score, presence of LVO, and referral for EST were obtained from standardized teleneurology notes. Factors associated with LVO were evaluated using generalized estimating equations accounting for clustering by facility.

RESULTS

Among 13,377 patients brought in by EMS with potential stroke, 7168 (53.6%) were not candidates for acute stroke interventions. Of the remaining 6089 cases, 2,573 (42.3%) had an NIHSS score >10, the cutoff with a higher association for LVO. Only 703 patients (27.3% with NIHSS score >10) were ultimately diagnosed with LVO and referred for EST. Across all NIHSS scores, only 884 (6.6%) suspected acute stroke patients had LVO and EST referral.

CONCLUSIONS

Even if field-based tools were as accurate as NIHSS scoring and predictions by stroke neurologists, only about 1 in 4 acute stroke patients diverted to EST-capable centers would benefit by receiving EST. Depending on geography and stroke center performance on door-to-needle time, many systems may be better served by focusing on expediting evaluation, treatment with intravenous thrombolysis, and transfer to EST-capable centers.

CTA Protocols in a Telestroke Network Improve Efficiency for Both Spoke and Hub Hospitals

BACKGROUND AND PURPOSE

Telestroke networks support screening for patients with emergent large-vessel occlusions who are eligible for endovascular thrombectomy. Ideal triage processes within telestroke networks remain uncertain. We characterize the impact of implementing a routine spoke hospital CTA protocol in our integrated telestroke network on transfer and thrombectomy patterns.

MATERIALS AND METHODS

A protocol-driven CTA process was introduced at 22 spoke hospitals in November 2017. We retrospectively identified prospectively collected patients who presented to a spoke hospital with National Institutes of Health Stroke Scale scores ≥6 between March 1, 2016 and March 1, 2017 (pre-CTA), and March 1, 2018 and March 1, 2019 (post-CTA). We describe the demographics, CTA utilization, spoke hospital retention rates, emergent large-vessel occlusion identification, and rates of endovascular thrombectomy.

RESULTS

There were 167 patients pre-CTA and 207 post-CTA. The rate of CTA at spoke hospitals increased from 15% to 70% (P < .001). Despite increased endovascular thrombectomy screening in the extended window, the overall rates of transfer out of spoke hospitals remained similar (56% versus 54%; P = .83). There was a nonsignificant increase in transfers to our hub hospital for endovascular thrombectomy (26% versus 35%; P = .12), but patients transferred >4.5 hours from last known well increased nearly 5-fold (7% versus 34%; P < .001). The rate of endovascular thrombectomy performed on patients transferred for possible endovascular thrombectomy more than doubled (22% versus 47%; P = .011).

CONCLUSIONS

Implementation of CTA at spoke hospitals in our telestroke network was feasible and improved the efficiency of stroke triage. Rates of patients retained at spoke hospitals remained stable despite higher numbers of patients screened. Emergent large-vessel occlusion confirmation at the spoke hospital lead to a more than 2-fold increase in thrombectomy rates among transferred patients at the hub.

Duration of symptomatic stroke and successful reperfusion with endovascular thrombectomy for anterior circulation large vessel occlusive stroke

BACKGROUND

It has been reported that longer time intervals from stroke onset to endovascular therapy are associated with lower rates of successful reperfusion in acute ischemic stroke patients with large vessel occlusion. However, procedural variables and potential mechanisms of this association have not been fully elucidated.

METHODS

We performed a secondary analysis of individual patient data from the North American Solitaire Stent Retriever Acute Stroke (NASA) and Trevo Stent-Retriever Acute Stroke (TRACK) registries. We included patients with occlusion of the internal carotid artery or middle cerebral artery (M1 and M2 segments) who were treated by mechanical thrombectomy within 24 hours of last known normal. The primary outcome was reperfusion, defined as a Thrombolysis In Cerebral Infarction (TICI) score ≥2b. The secondary outcome was reperfusion on the first pass. The primary predictor was duration of symptomatic stroke, defined as time from last known normal to time of final pass. Adjusted logistic regression models were utilized to determine associations between variables and outcome.

RESULTS

We included 506 patients, of which 401 (79.3%) achieved successful reperfusion (TICI 2b/3). The mean (SD) duration of symptomatic stroke was 6.8 (3.5) hours and in the adjusted logistic regression model the duration of symptomatic stroke was associated with reperfusion (OR 0.90, 95% CI 0.84 to 0.96) and reperfusion on the first pass (OR 0.89, 95% CI 0.83 to 0.95). In that model, the predicted probability of reperfusion was 88% (95% CI 0.83 to 0.92) at 1 hour, 81% (95% CI 0.78 to 0.84) at 6 hours, 70% (95% CI 0.63 to 0.77) at 12 hours, and 42% (95% CI 0.17 to 0.67) at 24 hours (p_trend=0.001). Reperfused patients were significantly younger, more likely to be male, and to have had a balloon guide catheter used during the procedure.

CONCLUSION

In a real-world cohort of acute ischemic stroke patients with anterior circulation occlusion treated with endovascular therapy, longer duration of symptomatic stroke is associated with lower rates of successful reperfusion and reperfusion on the first pass.

Recanalization Therapy for Acute Ischemic Stroke with Large Vessel Occlusion: Where We Are and What Comes Next?

In the past 5 years, the success of multiple randomized controlled trials of recanalization therapy with endovascular thrombectomy has transformed the treatment of acute ischemic stroke with large vessel occlusion. The evidence from these trials has now established endovascular thrombectomy as standard of care. This review will discuss the chronological evolution of large vessel occlusion treatment from early medical therapy with tissue plasminogen activator to the latest mechanical thrombectomy. Additionally, it will highlight the potential areas in endovascular thrombectomy for acute ischemic stroke open to exploration and further progress in the next decade.

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.

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.

Endovascular Thrombectomy in Acute Ischemic Stroke

Despite several effective strategies of stroke prevention, the stroke epidemic still constitutes the leading cause of permanent disability. The recent series of well-designed, convincingly-positive randomized controlled trials of endovascular thrombectomy in stroke patients with large vessel occlusion launched a paradigm shift and a new era in acute stroke management. The present review provides an overview of the technical aspects of the procedure, discusses patient selection criteria, summarizes the current evidence from randomized trials about its efficacy and safety, and explores its implications in the organization of acute stroke care.

Using G-FAST to recognize emergent large vessel occlusion: a training program for a prehospital bypass strategy

INTRODUCTION

The shorter the time between the onset of symptoms and reperfusion using endovascular thrombectomy, the better the functional outcome of patients. A training program was designed for emergency medical technicians (EMTs) to learn the gaze-face-arm-speech-time test (G-FAST) score for initiating a prehospital bypass strategy in an urban city. This study aimed to evaluate the effect of the training program on EMTs.

METHODS

All EMTs in the city were invited to join the training program. The program consisted of a 30 min lecture and a 20 min video which demonstrated the G-FAST evaluation. The participants underwent tests before and after the program. The tests included (1) a questionnaire of knowledge, attitudes, confidence, and behaviors towards stroke care; and (2) watching 10 different scenarios in a video and answering questions, including eight sub-questions of G-FAST parameters, and choosing a suitable receiving hospital.

RESULTS

In total, 1058 EMTs completed the training program. After the program, significant improvement was noted in knowledge, attitudes, and confidence, as well as scenario judgement. The performance of the EMTs in evaluating G-FAST criteria in comatose patients was relatively poor in the pre-test and improved significantly after the training course. Although the participants answered the G-FAST items correctly, they tended to overtriage the patients and refer them to higher-level hospitals.

CONCLUSIONS

A short training program can improve the ability to identify stroke patients and choose a suitable receiving hospital. A future training program could put further emphasis on how to evaluate comatose patients and choose a suitable receiving hospital.

Neighborhood-level stroke hot spots within major United States cities

OBJECTIVE

Identifying communities at high risk of stroke is an important step in improving systems of stroke care. Stroke is known to show spatial clustering at the state and county levels, but it is not known if clusters are present within city boundaries.

METHODS

We performed a geospatial analysis of the prevalence of stroke within 500 major cities in the United States using the Centers for Disease Control and Prevention 500 Cities Project. For each city, we calculated the Moran's I statistic, which looks for evidence of spatial clustering, and used Monte Carlo simulation to assess for clustering significance.

RESULTS

The mean overall crude prevalence of self-reported history of stroke at the city level was 2.8% (IQR 2.4-3.2%). Monte Carlo simulations of spatial patterns of stroke were successfully performed for 497 cities, of which 136 (27.3%) showed significant spatial clustering at the neighborhood level. All nine cities with more than one million inhabitants in 2010 showed significant spatial clustering.

CONCLUSIONS

This is the first study to demonstrate that stroke shows clustering at the neighborhood level within many major cities in the United States and within all of the largest cities. Understanding where stroke clusters exist within cities can form the basis of optimizing emergency medical services deployment and improving systems of stroke care.

Redistributing medical resources for a bypass strategy for large vessel occlusion: a community-based study

BACKGROUND

A bypass strategy for large vessel occlusion (LVO) benefits patients receiving endovascular thrombectomy (EVT), but may delay some patients from receiving IV thrombolysis. However, patient centralization has been shown to improve outcomes.

OBJECTIVE

To understand the current coverage of medical services for patients with stroke, and to identify the best coverage under different medical resource redistribution to help balance medical equality and patient centralization.

METHODS

This 6-year geographic study of 7679 on-scene patients with suspected stroke with a positive Cincinnati Prehospital Stroke Scale (CPSS) score identified 4037 patients with all three CPSS items who were suspected as having an LVO. Geographic, population, and patient coverage rates for hospitals providing IV thrombolysis and those providing EVT were identified according to hospital service areas, defined as geographic districts with access to a hospital within a ≤15 min off-peak driving time estimated using Google Maps. Moreover, we estimated the effects on resource redistribution when implementing a bypass strategy.

RESULTS

Geographic coverage rates for hospitals providing IV thrombolysis and those providing EVT were 64.75% and 56.62%, respectively, and population coverage rates were 97.30% and 92.72%, respectively. The service areas of hospitals providing IV thrombolysis covered 93.77% of patients with suspected stroke, and those of hospitals providing EVT covered 87.89% of patients with suspected LVO. The number of hospitals providing IV thrombolysis and those providing EVT could be reduced to six and two hospitals, respectively, without affecting hospital arrival time when implementing a bypass strategy.

CONCLUSION

Hospitals providing IV thrombolysis and EVT could be reduced without reducing medical equality.

Availability of Hospital Resources and Specialty Services for Stroke Care in North Carolina

OBJECTIVES

Effective regionalization of acute stroke care requires assessment and coordination of limited hospital resources. We described the availability of stroke-specific hospital resources (neurology specialty physicians and neuro-intensive care unit [neuro-ICU] bed capacity) for North Carolina overall and by region and population density. We also assessed daily trends in hospital bed availability.

METHODS

This statewide descriptive study was conducted with data from the State Medical Asset Resource Tracking Tool (SMARTT), a Web-based system used by North Carolina to track available medical resources within the state. The SMARTT system was queried for stroke-specific physician and bed resources at each North Carolina hospital during a 1-year period (June 2015-May 2016), including daily availability of neuro-ICU beds. We compared hospital resources by geographic region and population density (metropolitan, urban, and rural).

RESULTS

Data from 108 acute care hospitals located in 75 of 100 counties in North Carolina were included in the analysis. Fifty-seven percent of hospitals had no neurology specialty physicians. Western and eastern North Carolina had the lowest prevalence of these physicians. Most hospitals (88%) had general ICUs, whereas only 17 hospitals (16%) had neuro-ICUs. Neuro-ICUs were concentrated in metropolitan areas and in central North Carolina. On average, there were 276 general ICU and 27 neuro-ICU beds available statewide each day. Daily neuro-ICU bed availability was lowest in eastern and southeastern regions and during the week compared with weekends.

CONCLUSIONS

In North Carolina, stroke-specific hospital subspecialists and resources are not distributed evenly across the state. Daily bed availability, particularly in neuro-ICUs, is lacking in rural areas and noncentral regions and appears to decrease on weekdays. Regionalization of stroke care needs to consider the geographic distribution and daily variability of hospital resources.

Impact of pretreatment with intravenous thrombolysis on reperfusion status in acute strokes treated with mechanical thrombectomy

Introduction

We sought to evaluate the impact of pretreatment with intravenous thrombolysis (IVT) on the rate and speed of successful reperfusion (SR) in patients with emergent large vessel occlusion (ELVO) treated with mechanical thrombectomy (MT) in a high-volume tertiary care stroke center.

Methods

Consecutive patients with ELVO treated with MT were evaluated. Outcomes were compared between patients who underwent combined IVT and MT (IVT+MT) and those treated with direct MT (dMT). The elapsed time between groin puncture to beginning of reperfusion (GPTBRT) and the numbers of device passes required to achieve SR were also documented.

Results

A total of 287 and 132 patients were treated with IVT+MT and dMT, respectively. The IVT+MT group had higher SR (73.8% vs 62.9%; p=0.023) and 3-month functional independence (modified Rankin Scale score 0–2;51.6% vs 38.2%; p=0.008) rates. The median GPTBRT was shorter in the IVT+MT group (48 (IQR 33–70) vs 70 (IQR 44–98) min; p<0.001). Among patients who achieved SR (n=292), the median number of required device passes was lower in the IVT+MT subgroup (1 (IQR 1–1) vs 2 (IQR 1–2); p<0.001), while the rate of patients requiring ≤2 device passes was higher (98% vs 77%; p<0.001). IVT+MT was independently related to higher odds of SR (OR 1.64; 95% CI 1.03 to 2.61; p=0.036) and shorter GPTBRT (unstandardized linear regression coefficient −20.39; 95% CI −27.56 to –13.22; p<0.001) on multivariable analyses adjusting for potential confounders. Among patients with SR, IVT+MT was independently associated with a higher likelihood of ≤2 device passes (OR 14.63; 95% CI 4.46 to 48.00; p<0.001).

Conclusions

IVT pretreatment appears to increase the rates of SR and shortens the duration of the endovascular procedure by requiring fewer device passes in patients with ELVO treated with MT.

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.

Effect of routing paradigm on patient centered outcomes in acute ischemic stroke

Background

To compare performance of routing paradigms for patients with acute ischemic stroke using clinical outcomes.

Methods

We simulated different routing paradigms in a system comprising one primary stroke center (PSC) and one comprehensive stroke center (CSC), separated by distances representative of urban, suburban, and rural environments. In the nearest center paradigm, patients are initially sent to the nearest center, while in CSC first, patients are sent to the CSC. In the Rhode Island and distributive paradigms, patients with a FAST-ED (Facial palsy, Arm weakness, Speech changes, Time, Eye deviation, and Denial/neglect) score ≥4 are sent to the CSC, while others are sent to the nearest center or PSC, respectively. Performance and efficiency were compared using rates of good clinical outcome, determined by type and timing of treatment using clinical trial data, and number needed to bypass (NNB).

Results

Good clinical outcome was achieved in 43.76% of patients in nearest center, 44.48% in CSC first, and 44.44% in Rhode Island and distributive in an urban setting; 43.38% in nearest center, 44.19% in CSC first, and 44.17% in Rhode Island in a suburban setting; and 41.10% in nearest center, 43.20% in CSC first, and 42.73% in Rhode Island in a rural setting. In all settings, NNB was generally higher for CSC first compared with Rhode Island or distributive.

Conclusion

Routing paradigms that allow bypass of nearer hospitals for thrombectomy capable centers improve population level patient outcomes. Differences are more pronounced with increasing distance between hospitals; therefore, paradigm choice may be most impactful in rural settings. Selective bypass, as implemented in the Rhode Island and distributive paradigms, improves system efficiency with minimal impact on outcomes.

Emergency medical services for acute ischemic stroke: Hub-and-spoke model versus exclusive care in comprehensive centers

BACKGROUND

The emergent disposition of acute stroke patients remains an issue of debate. We investigated whether a hub-and-spoke model was associated with worse stroke outcomes when compared to care exclusively in comprehensive centers.

METHODS

We performed a cohort study of all acute ischemic stroke patients who were hospitalized in endovascular-capable facilities, and were registered in the New York Statewide Planning and Research Cooperative System (SPARCS) database from 2009 to 2015. We examined the association of transfer status (transfer to endovascular capable hospitals versus initial treatment in these facilities) with inpatient case-fatality, discharge to a facility, and length of stay (LOS). An instrumental variable analysis was used to control for unmeasured confounding and simulate a randomized trial.

RESULTS

During the study period, 128,122 acute stroke patients met inclusion criteria. Instrumental variable analysis demonstrated that patients transferred to endovascular-capable hospitals did not have higher case-fatality (Adjusted difference, 4.4%; 95% CI, -0.1% to 9.0%), rate discharge to a facility (Adjusted difference, -2.3%; 95% CI, -5.2% to 0.6%), or longer LOS (Adjusted difference, 4.2; 95% CI, -2.2 to 10.1) in comparison to patients presenting for initial treatment in these facilities. The same associations were present when restricting the cohort to patients receiving intravenous tissue plasminogen (IV-tPA) and to patients receiving mechanical thrombectomy.

CONCLUSIONS

Using a comprehensive all-payer cohort of acute ischemic stroke patients in New York State we demonstrated that patients treated in a hub-and-spoke model were not associated with worse outcomes than patients receiving care exclusively in comprehensive institutions. This needs to be taken into consideration when considering acute emergency services in this setting.

Mothership versus drip and ship for thrombectomy in patients who had an acute stroke: a systematic review and meta-analysis

Background

The effectiveness of mechanical thrombectomy (MT) in acute ischemic stroke due to large vessel occlusion is time-dependent. While only stroke centers with endovascular capabilities perform MT, many patients who had a stroke initially present to the closest primary stroke centers capable of administering earlier intravenous thrombolysis, and then require to be transferred to a comprehensive stroke center for MT.

Purpose

To compare the outcomes of this care pathway (drip and ship (DS)) with that whereby patients are directly transferred to a comprehensive stroke center (mothership (MS)).

Methods

We performed a systematic review and meta-analysis of published studies using several electronic databases to determine whether successful reperfusion (modified Thrombolysis In Cerebral Infarction ≥2b), functional independence at 90 days (modified Rankin Scale score ≤2), symptomatic intracranial hemorrhage, and 90-day mortality differed between those who underwent MT with the DS or the MS treatment pathway. Outcomes were meta-analyzed and the results expressed as adjusted relative risk (aRR) for the primary analysis and unadjusted relative risk (uRR) for secondary analysis.

Results

Eight studies including 2068 patients were selected, including one study reporting results fully adjusted for baseline characteristics. Patients undergoing MS had better functional independence than those undergoing DS (uRR=0.87, 95% CI 0.81 to 0.93; aRR=0.87, 95% CI 0.77 to 0.98). No difference was found between the treatment pathways in successful reperfusion (uRR=1.05, 95% CI 0.95 to 1.15; aRR=1.00, 95% CI 0.92 to 1.10), symptomatic intracranial hemorrhage (uRR=1.37, 95% CI 0.91 to 2.06; aRR, 1.53, 95% CI 0.79 to 2.98), and 90-day mortality (uRR=1.00, 95% CI 0.84 to 1.19; aRR=1.21, 95% CI 0.89 to 1.64).

Conclusions

Patients who had an acute ischemic stroke admitted directly to a comprehensive stroke center (MS patients) with endovascular capacities may have better 90-day outcomes than those receiving DS treatment. However, major limitations of current evidence (ie, retrospective studies and selection bias) suggest a need for adequately powered studies. Multicenter randomized controlled trials are expected to answer this question.

Stationary Computed Tomography for Space and other Resource-constrained Environments

Computed tomography (CT) is used to diagnose many emergent medical conditions, including stroke and traumatic brain injuries. Unfortunately, the size, weight, and expense of CT systems make them largely inaccessible for patients outside of major hospitals. We have designed a module containing multiple miniature x-ray sources that could allow for CT systems to be significantly lighter, smaller, and cheaper, and to operate without any moving parts. We have developed a novel photocathode-based x-ray source, created by depositing a thin film of magnesium on an electron multiplier. When illuminated by a UV LED, this photocathode emits a beam of electrons, with a beam current of up to 1 mA. The produced electrons are accelerated through a high voltage to a tungsten target. These sources are individually addressable and can be pulsed rapidly, through electronic control of the LEDs. Seven of these sources are housed together in a 17.5 degree arc within a custom vacuum manifold. A full ring of these modules could be used for CT imaging. By pulsing the sources in series, we are able to demonstrate x-ray tomosynthesis without any moving parts. With a clinical flat-panel detector, we demonstrate 3D acquisition and reconstructions of a cadaver swine lung.

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.

Effect of routing paradigm on patient-centered outcomes in acute ischemic stroke

OBJECTIVE

To compare performance of routing paradigms for patients with acute ischemic stroke using clinical outcomes.

METHODS

We simulated different routing paradigms in a system comprising one primary stroke center (PSC) and onecomprehensive stroke center (CSC), separated by distances representative of urban, suburban, and rural environments. In the Nearest Center paradigm, patients are initially sent to the nearest center, while in CSC First, patients are sent to the CSC. In Rhode Island and Distributive paradigms, patients with Field Assessment Stroke Triage for Emergency Destination (FAST-ED) score ≥4 are sent to the CSC, while others are sent to the nearest center or PSC, respectively. Performance and efficiency were compared using rates of good clinical outcome determined by type and timing of treatment using clinical trial data and number needed to bypass (NNB).

RESULTS

Good clinical outcome was achieved in 43.67% of patients in Nearest Center and 44.62% in CSC First, Rhode Island, and Distributive in an urban setting; 42.79% in Nearest Center and 43.97% in CSC First and Rhode Island in a suburban setting; and 39.76% in Nearest Center, 41.73% in CSC First, and 41.59% in Rhode Island in a rural setting. In all settings, the NNB was considerably higher for CSC First than for Rhode Island or Distributive.

CONCLUSION

Routing paradigms that allow bypass of nearer hospitals for thrombectomy-capable centers improve population-level patient outcomes. Differences are more pronounced with increasing distance between hospitals; therefore, the choice of model may have greater effect in rural settings. Selective bypass, as implemented in Rhode Island and Distributive paradigms, improves system efficiency with minimal effect on outcomes.

Intravenous thrombolysis for acute ischemic stroke: a bridge between two centuries

INTRODUCTION

Intravenous tissue-plasminogen activator (tPA) remains the only approved systemic reperfusion therapy suitable for most patients presenting timely with acute ischemic stroke. Accumulating real-word experience for over 20 years regarding tPA safety and effectiveness led to re-appraisal of original contraindications for intravenous thrombolysis (IVT). Areas covered: This narrative review focuses on fast yet appropriate selection of patients for safe administration of tPA per recently expanded indications. Novel strategies for rapid patient assessment will be discussed. The potential for mobile stroke units (MSU) that shorten onset-to-needle time and increase tPA treatment rates is addressed. The use of IVT in the era of non-vitamin K antagonist oral anticoagulants (NOACs) is highlighted. The continuing role of IVT in large vessel occlusion (LVO) patients eligible for mechanical thrombectomy (MT) is discussed with regards to 'drip and ship' vs. 'mothership' treatment paradigms. Promising studies of penumbral imaging to extend IVT beyond the 4.5-hour window and in wake-up strokes are summarized. Expert commentary: This review provides an update on the role of IVT in specific conditions originally considered tPA contraindications. Novel practice challenges including NOAC's, MSU proliferation and bridging therapy (IVT&MT) for LVO patients, and the potential extension of IVT time-window using penumbral imaging are emerging as safe and potentially effective IVT applications.

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.

Support of New Triage Protocol among Acute Stroke Care Providers

Objective

We conducted an online survey to gauge the acceptance of sending acute stroke patients with suspected large vessel occlusion (LVO) directly to an endovascular-capable hospital (ECH) even if that means bypassing a closer alteplase-capable hospital (ACH) without endovascular capability.

Methods

The survey was composed of two cases of acute stroke, one with cortical symptoms suggestive of LVO and the other without. In each case, responders were asked to choose between triaging to a closer ACH or an ECH that is further away and to provide an opinion regarding the maximum extra travel time they would tolerate if they chose the ECH. The survey was sent electronically to national groups of neurologists, emergency department (ED) physicians, emergency medical service (EMS) directors, and stroke coordinators.

Results

There were 320 responders from 44 states, most of them with 10 years or more of experience. Most of the responders, 72.5%, chose ECH for the LVO case, while 56% chose ACH for the non-LVO case. There were marked differences in responses by specialty: neurology strongly supported ECH for LVO and strongly supported ACH for non-LVO, most ED and EMS chose ECH for both cases, and stroke coordinators were the least supportive of bypassing ACH. Almost all groups agreed on 30 min as the acceptable extra transfer time to ECH.

Conclusion

Among the survey responders, there is a broad acceptance of the idea of bypassing ACH and going straight to ECH when LVO is suspected; however, there is less agreement on triaging patients with non-LVO stroke.

Mechanical Thrombectomy-A Brief Review of a Revolutionary new Treatment for Thromboembolic Stroke

The recent success of endovascular stroke treatment has heralded a new era in the management of acute ischemic stroke (AIS) with significantly improved outcome for patients. A large number of patients may be amenable to this new treatment and as the evidence expands the number of patients eligible for mechanical thrombectomy continues to increase. Recent evidence suggests that the time window for treatment can be extended up to 24 h after symptom onset for patients with anterior circulation strokes; however, many clinicians and medical professionals may not be aware of these recent changes and it is important that they are kept up-to-date with this rapidly evolving treatment. This review provides an overview of the recent successful trials and highlights important steps that should be instituted in order to achieve rapid reperfusion and optimize the outcome for ischemic stroke patients. It also looks at the remaining controversies facing the field of thrombectomy. A short summary of each of these contentious areas is provided and the current state of the art.

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.

Evolution of a US County System for Acute Comprehensive Stroke Care

BACKGROUND AND PURPOSE

In Orange County, California, patients with suspected acute stroke are taken to stroke neurology receiving centers that are designated by County Emergency Medical Services authorities as either hubs or spokes based on endovascular treatment capability. We examined relationships between stroke details, reperfusion therapies, hospital transfers, and their change over time.

METHODS

All patients from January 1, 2013, to December 31, 2015, for whom 911 was called within 7 hours of onset in whom Emergency Medical Services personnel suspected acute stroke were evaluated.

RESULTS

Among 6132 patients, 3924 (64%) had confirmed diagnosis of stroke (74% ischemic/26% hemorrhagic), yielding diagnostic precision of 64% in the field. Of the 2892 patients with acute ischemic stroke, acute reperfusion therapy was given to 29.2% (21.7% intravenous tPA [tissue-type plasminogen activator] only and 7.5% endovascular treatment). Rates of endovascular treatment of patients with ischemic stroke increased over time, more than doubling from 5.6% in 2013 to 12.5% (odds ratio per 3-month quarter=1.09; 95% confidence interval, 1.04-1.14; P<0.0001). Only 3.4% of patients with acute ischemic stroke were transferred from a spoke to a hub hospital; transfer rates were inversely related to age (P<0.0001), and reperfusion therapy rates did not vary according to transfer status.

CONCLUSIONS

Favorable features of this acute stroke care system include reperfusion therapy in 29.2% of patients with ischemic stroke and substantial increases in endovascular treatment rates over time. Continued efforts to optimize acute stroke systems of care can be directed toward improving access to best acute stroke therapies.

Interfacility transfers for US ischemic stroke and TIA, 2006-2014

OBJECTIVE

To investigate changes in emergency department (ED) transfers for ischemic stroke (IS) and TIA.

METHODS

We performed a retrospective observational study using the US Nationwide Emergency Department Sample to identify changes in interfacility ED transfers for IS and TIA from the perspective of the transferring ED (2006-2014). We calculated nationwide transfer rates and individual ED transfer rates for IS/TIA by diagnosis and hospital characteristics. Hospital-level fractional logistic regression examined changes in transfer rates over time.

RESULTS

The population-estimated number of transfers for IS/TIA increased from 22,576 patient visits in 2006 to 54,485 patient visits in 2014 (p trend < 0.001). The rate of IS/TIA transfer increased from 3.4 (95% confidence interval [CI] 3.0-3.8) in 2006 to 7.6 (95% CI 7.2-7.9) in 2014 per 100 ED visits. Among individual EDs, mean transfer rates for IS/TIA increased from 8.2 per 100 ED visits (median 2.0, interquartile range [IQR] 0-10.2) to 19.4 per 100 ED visits (median 8.1, IQR 1.1-33.3) (2006-2014) (p trend < 0.001). Transfers were more common among IS. Transfer rates were greatest among rural (adjusted odds ratio [AOR] 3.05, 95% CI 2.56-3.64) vs urban/teaching and low-volume EDs (AOR 7.49, 95% CI 6.58-8.53, 1st vs 4th quartile). The adjusted odds of transfer for IS/TIA increased threefold (2006-2014).

CONCLUSIONS

Interfacility ED transfers for IS/TIA more than doubled from 2006 to 2014. Further work should determine the necessity of IS/TIA transfers and seek to optimize the US stroke care system.

Primary to comprehensive stroke center transfers: Appropriateness, not futility

Background and purpose

Ischemic stroke patients must be transferred to comprehensive stroke centers for endovascular treatment, but this transfer can be interpreted post hoc as “futile” if patients do not ultimately undergo the procedure or have a poor outcome. We posit that transfer decisions must instead be evaluated in terms of appropriateness at the time of decision-making.

Methods

We propose a classification schema for Appropriateness of Transfer for Endovascular Thrombectomy based on patient, logistic, and center characteristics.

Results

The classification outline characteristics of patients that are 1. Appropriate for transfer for endovascular treatment; 2. Inappropriate for transfer; and 3. Appropriate for transfer for higher level of care.

Conclusions

Appropriate transfer decisions for endovascular treatment are significant for patient outcomes. A more nuanced understanding of transfer decision-making and a classification for such transfers can help minimize inappropriate transfers in acute stroke.

Leukoaraiosis Attenuates Diagnostic Accuracy of Large-Vessel Occlusion Scales

BACKGROUND AND PURPOSE

Prehospital stroke scales may help identify patients likely to have large-vessel occlusion to facilitate rapid triage to thrombectomy-capable stroke centers. Scale misclassification may result in inaccurate decisions and possible harm. Pre-existing leukoaraiosis has been shown to attenuate the association between deficit type and stroke severity. We sought to determine whether leukoaraiosis affects the predictive ability of 5 commonly used large-vessel occlusion scales.

MATERIALS AND METHODS

We retrospectively analyzed 274 consecutive patients with stroke with available brain MR imaging and vessel imaging. We used the following large-vessel occlusion scales: the 3-Item Stroke Scale; Field Assessment Stroke Triage for Emergency Destination; Rapid Arterial Occlusion Evaluation; Vision, Aphasia, Neglect score; and Cincinnati Prehospital Stroke Severity Scale. For diagnostic scale accuracy, we assessed sensitivity, specificity, positive predictive value, negative predictive value, and κ. Multivariable logistic regression was used to determine the predictive ability of the scales after adjustment for leukoaraiosis and potential confounders.

RESULTS

In unadjusted analyses, all scales predicted the presence of large-vessel occlusion (n = 46, P < .01 each), though diagnostic accuracy was attenuated among patients with moderate-to-severe leukoaraiosis. After adjustment, the Field Assessment Stroke Triage for Emergency Destination (OR = 3.2; 95% CI, 1.1-9.5; P = .033) and Rapid Arterial Occlusion Evaluation (OR = 3.7; 95% CI, 1.3-10.8; P = .015), but not the 3-Item Stroke Scale (OR = 5.4; 95% CI, 0.86-33.9; P = .073), Vision, Aphasia, Neglect score (OR = 2.5; 95% CI, 0.8-7.2), and Cincinnati Prehospital Stroke Severity Scale (OR = 2.8; 95% CI, 1.0-8.0), predicted large-vessel occlusion.

CONCLUSIONS

The diagnostic accuracy of the tested large-vessel occlusion scales was attenuated in the presence of moderate-to-severe leukoaraiosis. This information that may aid the design of future studies that require large-vessel occlusion scale screening of patients who are likely to have concomitant leukoaraiosis.

Impact of Prehospital Triage Scales to Detect Large Vessel Occlusion on Resource Utilization and Time to Treatment

BACKGROUND AND PURPOSE

Prehospital stroke severity scales may help to triage acute ischemic stroke patients with large vessel occlusion (LVO) for direct transportation to a comprehensive stroke center. The impact on resource use and time to reperfusion treatment for patients with and without LVO is unknown.

METHODS

Based on empirical distributions of stroke symptom severity, prehospital delay times, and stroke symptom severity-dependent likelihood of LVO, we simulate prehospital incidents of stroke-like symptoms in abstract geographical environments to estimate the impact of prehospital triage strategies based on different cutoffs of the rapid arterial occlusion evaluation scale.

RESULTS

Compared with transporting each patient to the nearest stroke center, implementation of a prehospital triage strategy based on a rapid arterial occlusion evaluation scale cutoff score ≥5 is associated with more patients with suspected acute stroke at comprehensive stroke centers and less patients at primary stroke centers (+11.7% [95% confidence interval: +8.1% to +15.3%] and -18.4% [-19.1% to -17.7%], respectively). Mean time to groin puncture is reduced by 29.6 minutes (-35.2 to -24.7 minutes) while mean time to thrombolysis does not change significantly (±0.0 minutes [-0.3 to +0.3 minutes]). The total number of secondary transfers is reduced by 60.9% (-62.8% to -59.0%); mean time of ambulance use per patient is unchanged. Results are robust with regards to variation in model parameters.

CONCLUSIONS

Implementation of prehospital triage based on stroke severity scales would have strong impact on patient flow and distribution. The benefit of earlier thrombectomy for patients with LVO may outweigh the harm associated with delayed access to thrombolysis for some patients without LVO. Randomized trials using clinical stroke severity scales as a triage tool are needed to confirm our findings.

Drip ‘n Ship Versus Mothership for Endovascular Treatment

Background and Purpose—

There is uncertainty regarding the best way for patients outside of endovascular-capable or Comprehensive Stroke Centers (CSC) to access endovascular treatment for acute ischemic stroke. The role of the nonendovascular-capable Primary Stroke Centers (PSC) that can offer thrombolysis with alteplase but not endovascular treatment is unclear. A key question is whether average benefit is greater with early thrombolysis at the closest PSC before transportation to the CSC (Drip ‘n Ship) or with PSC bypass and direct transport to the CSC (Mothership). Ideal transportation options were mapped based on the location of their endovascular-capable CSCs and nonendovascular-capable PSCs.

Methods—

Probability models for endovascular treatment were developed from the ESCAPE trial’s (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) decay curves and for alteplase treatment were extracted from the Get With The Guidelines decay curve. The time on-scene, needle-to-door-out time at the PSC, door-to-needle time at the CSC, and door-to-reperfusion time were assumed constant at 25, 20, 30, and 115 minutes, respectively. Emergency medical services transportation times were calculated using Google’s Distance Matrix Application Programming Interface interfaced with MATLAB’s Mapping Toolbox to create map visualizations.

Results—

Maps were generated for multiple onset-to-first medical response times and door-to-needle times at the PSCs of 30, 60, and 90. These figures demonstrate the transportation option that yields the better modeled outcome in specific regions. The probability of good outcome is shown.

Conclusions—

Drip ‘n Ship demonstrates that a PSC that is in close proximity to a CSC remains significant only when the PSC is able to achieve a door-to-needle time of ≤30 minutes when the CSC is also efficient.

Acute Ischemic Stroke Therapy Overview

The treatment of acute ischemic stroke has undergone dramatic changes recently subsequent to the demonstrated efficacy of intra-arterial (IA) device-based therapy in multiple trials. The selection of patients for both intravenous and IA therapy is based on timely imaging with either computed tomography or magnetic resonance imaging, and if IA therapy is considered noninvasive, angiography with one of these modalities is necessary to document a large-vessel occlusion amenable for intervention. More advanced computed tomography and magnetic resonance imaging studies are available that can be used to identify a small ischemic core and ischemic penumbra, and this information will contribute increasingly in treatment decisions as the therapeutic time window is lengthened. Intravenous thrombolysis with tissue-type plasminogen activator remains the mainstay of acute stroke therapy within the initial 4.5 hours after stroke onset, despite the lack of Food and Drug Administration approval in the 3- to 4.5-hour time window. In patients with proximal, large-vessel occlusions, IA device-based treatment should be initiated in patients with small/moderate-sized ischemic cores who can be treated within 6 hours of stroke onset. The organization and implementation of regional stroke care systems will be needed to treat as many eligible patients as expeditiously as possible. Novel treatment paradigms can be envisioned combining neuroprotection with IA device treatment to potentially increase the number of patients who can be treated despite long transport times and to ameliorate the consequences of reperfusion injury. Acute stroke treatment has entered a golden age, and many additional advances can be anticipated.