Optimization modeling to maximize population access to comprehensive stroke centers

Differential thrombectomy utilization across hospital classifications in the United States

OBJECTIVES

To determine hospital-level factors associated with thrombectomy uptake.

MATERIALS AND METHODS

The Nationwide Emergency Department Sample was retrospectively queried to determine the total number of thrombectomies performed based on different hospital characteristics. Joint point analysis was used to determine which years were associated with significant increases in the number of high-volume thrombectomy centers (ostensibly defined as >50 thrombectomies/year), thrombectomy-capable centers (>15 thrombectomies/year), and total number of thrombectomies performed. Multivariable logistic regression was used to determine hospital factors associated with having an increased odds of performing thrombectomies, and of being classified as a high-volume thrombectomy or a thrombectomy-capable center.

RESULTS

Between 2007-2020 there was a stepwise increase in the number of thrombectomy-capable and high-volume thrombectomy centers in the United States. In 2020, there were a total of 15,705 thrombectomies performed, with 89 high-volume thrombectomy centers, and 359 thrombectomy-capable centers. The number of thrombectomy-capable centers significantly increased after 2011. After 2013 and 2016 there was a significant change in the growth rate of high-volume thrombectomy centers. There was also a significant increase in the total number of thrombectomies performed after 2016. Hospital characteristics that were associated with an increased likelihood of being classified as thrombectomy-capable or high-volume included trauma level 1 and 2 hospitals.

CONCLUSIONS

Between 2007 and 2020, there was a marked growth in thrombectomy utilization for acute ischemic stroke. This growth outpaced new diagnoses of ischemic stroke, and was driven largely by certain hospital types, with the greatest rises following seminal publications of positive randomized thrombectomy trials.

Geographical Requirements for the Applicability of the Results of the RACECAT Study to Other Stroke Networks

Background The RACECAT (Transfer to the Closest Local Stroke Center vs Direct Transfer to Endovascular Stroke Center of Acute Stroke Patients With Suspected Large Vessel Occlusion in the Catalan Territory) trial was the first randomized trial addressing the prehospital triage of acute stroke patients based on the distribution of thrombolysis centers and intervention centers in Catalonia, Spain. The study compared the drip-and-ship with the mothership paradigm in regions where a local thrombolysis center can be reached faster than the nearest intervention center (equipoise region). The present study aims to determine the population-based applicability of the results of the RACECAT study to 4 stroke networks with a different degree of clustering of the intervention centers (clustered, dispersed). Methods and Results Stroke networks were compared with regard to transport time saved for thrombolysis (under the drip-and-ship approach) and transport time saved for endovascular therapy (under the mothership approach). Population-based transport times were modeled with a local instance of an openrouteservice server using open data from OpenStreetMap.The fraction of the population in the equipoise region differed substantially between clustered networks (Catalonia, 63.4%; France North, 87.7%) and dispersed networks (Southwest Bavaria, 40.1%; Switzerland, 40.0%). Transport time savings for thrombolysis under the drip-and-ship approach were more marked in clustered networks (Catalonia, 29 minutes; France North, 27 minutes) than in dispersed networks (Southwest Bavaria and Switzerland, both 18 minutes). Conclusions Infrastructure differences between stroke networks may hamper the applicability of the results of the RACECAT study to other stroke networks with a different distribution of intervention centers. Stroke networks should assess the population densities and hospital type/distribution in the temporal domain before applying prehospital triage algorithms to their specific setting.

Evolving Stroke Systems of Care: Stroke Diagnosis and Treatment in the Post-Thrombectomy Era

Thrombectomy became the gold-standard treatment of acute ischemic stroke caused by large-vessel occlusions (LVO) in 2015 after five clinical trials published that year demonstrated significantly improved patient outcomes. In subsequent years, advances in stroke systems of care have centered around improving access to and expanding patient eligibility for thrombectomy. The prehospital and acute stroke treatment settings have had the greatest emphasis. Numerous prehospital stroke scales now provide emergency medical services with focused physical exams to identify LVOs, and many devices to non-invasively detect LVO are undergoing clinical testing. Mobile stroke units deployed throughout Western Europe and the USA also show promising results by bringing elements of acute stroke care directly to the patient. Numerous clinical trials since 2015 have aimed to increase candidates for thrombectomy by expanding indications and the eligibility time window. Further optimizations of thrombectomy treatment have focused on the role of thrombolytics and other adjunctive therapies that may promote neuroprotection and neurorecovery. While many of these approaches require further clinical investigation, the next decade shows significant potential for further advances in stroke care.

Geographic Disparities in Re-triage Destinations Among Seriously Injured Californians

Objective

To quantify geographic disparities in sub-optimal re-triage of seriously injured patients in California.

Summary of Background Data

Re-triage is the emergent transfer of seriously injured patients from the emergency departments of non-trauma and low-level trauma centers to, ideally, high-level trauma centers. Some patients are re-triaged to a second non-trauma or low-level trauma center (sub-optimal) instead of a high-level trauma center (optimal).

Methods

This was a retrospective observational cohort study of seriously injured patients, defined by an Injury Severity Score > 15, re-triaged in California (2009-2018). Re-triages within one day of presentation to the sending center were considered. The sub-optimal re-triage rate was quantified at the state, regional trauma coordinating committees (RTCC), local emergency medical service agencies, and sending center level. A generalized linear mixed-effects regression quantified the association of sub-optimality with the RTCC of the sending center. Geospatial analyses demonstrated geographic variations in sub-optimal re-triage rates and calculated alternative re-triage destinations.

Results

There were 8,882 re-triages of seriously injured patients and 2,680 (30.2 %) were sub-optimal. Sub-optimally re-triaged patients had 1.5 higher odds of transfer to a third short-term acute care hospital and 1.25 increased odds of re-admission within 60 days from discharge. The sub-optimal re-triage rates increased from 29.3 % in 2009 to 38.6 % in 2018. 56.0 % of non-trauma and low-level trauma centers had at least one sub-optimal re-triage. The Southwest RTCC accounted for the largest proportion (39.8 %) of all sub-optimal re-triages in California.

Conclusion

High population density geographic areas experienced higher sub-optimal re-triage rates.

Artificial Intelligence-Assisted Software Significantly Decreases All Workflow Metrics for Large Vessel Occlusion Transfer Patients, within a Large Spoke and Hub System

INTRODUCTION

Artificial intelligence (AI) software is increasingly applied in stroke diagnostics. Viz LVO (large vessel occlusion) is an AI-based software that is FDA-approved for LVO detection in CT angiography (CTA) scans. We sought to investigate differences in transfer times (from peripheral [spoke] to central [hub] hospitals) for LVO patients between spoke hospitals that utilize Viz LVO and those that do not.

METHODS

In this retrospective cohort study, we used our institutional database to identify all suspected/confirmed LVO-transferred patients from spokes (peripheral hospitals) within and outside of our healthcare system, from January 2020 to December 2021. The "Viz-transfers" group includes all LVO transfers from spokes within our system where Viz LVO is readily available, while the "Non-Viz-transfers" group (control group) is comprised of all LVO transfers from spokes outside our system, without Viz LVO. Primary outcome included all available time metrics from peripheral CTA commencement.

RESULTS

In total, 78 patients required a transfer. Despite comparable peripheral hospital door to peripheral hospital CTA times (20.5 [24.3] vs. 32 [45] min, p = 0.28) and transfer (spoke to hub) time (23 [18] vs. 26 [13.5], p = 0.763), all workflow metrics were statistically significantly shorter in the Viz-transfers group. Peripheral CTA to interventional neuroradiology team notification was 12 (16.8) versus 58 (59.5), p < 0.001, and peripheral CTA to peripheral departure was 91.5 (37) versus 122.5 (68.5), p < 0.001. Peripheral arrival to peripheral departure was 116.5 (75.5) versus 169 (126.8), p = 0.002, and peripheral arrival to central arrival was 145 (62.5) versus 207 (97.8), p < 0.001. In addition, peripheral CTA to angiosuite arrival was 121 (41) versus 207 (92.5), p < 0.001, peripheral CTA to arterial puncture was 146 (53) versus 234 (99.8), p < 0.001, and peripheral CTA to recanalization was 198 (25) versus 253.5 (86), p < 0.001.

CONCLUSION

Within our spoke and hub system, Viz LVO significantly decreased all workflow metrics for patients who were transferred from spokes with versus without Viz.

AI software detection of large vessel occlusion stroke on CT angiography: a real-world prospective diagnostic test accuracy study

BACKGROUND

Artificial intelligence (AI) software is increasingly applied in stroke diagnostics. However, the actual performance of AI tools for identifying large vessel occlusion (LVO) stroke in real time in a real-world setting has not been fully studied.

OBJECTIVE

To determine the accuracy of AI software in a real-world, three-tiered multihospital stroke network.

METHODS

All consecutive head and neck CT angiography (CTA) scans performed during stroke codes and run through an AI software engine (Viz LVO) between May 2019 and October 2020 were prospectively collected. CTA readings by radiologists served as the clinical reference standard test and Viz LVO output served as the index test. Accuracy metrics were calculated.

RESULTS

Of a total of 1822 CTAs performed, 190 occlusions were identified; 142 of which were internal carotid artery terminus (ICA-T), middle cerebral artery M1, or M2 locations. Accuracy metrics were analyzed for two different groups: ICA-T and M1 ±M2. For the ICA-T/M1 versus the ICA-T/M1/M2 group, sensitivity was 93.8% vs 74.6%, specificity was 91.1% vs 91.1%, negative predictive value was 99.7% vs 97.6%, accuracy was 91.2% vs 89.8%, and area under the curve was 0.95 vs 0.86, respectively. Detection rates for ICA-T, M1, and M2 occlusions were 100%, 93%, and 49%, respectively. As expected, the algorithm offered better detection rates for proximal occlusions than for mid/distal M2 occlusions (58% vs 28%, p=0.03).

CONCLUSIONS

These accuracy metrics support Viz LVO as a useful adjunct tool in stroke diagnostics. Fast and accurate diagnosis with high negative predictive value mitigates missing potentially salvageable patients.

Comparison of Factors Associated With Direct Versus Transferred-in Admission to Government-Designated Regional Centers Between Acute Ischemic Stroke and Myocardial Infarction in Korea

BACKGROUND

There has been no comparison of the determinants of admission route between acute ischemic stroke (AIS) and acute myocardial infarction (AMI). We examined whether factors associated with direct versus transferred-in admission to regional cardiocerebrovascular centers (RCVCs) differed between AIS and AMI.

METHODS

Using a nationwide RCVC registry, we identified consecutive patients presenting with AMI and AIS between July 2016 and December 2018. We explored factors associated with direct admission to RCVCs in patients with AIS and AMI and examined whether those associations differed between AIS and AMI, including interaction terms between each factor and disease type in multivariable models. To explore the influence of emergency medical service (EMS) paramedics on hospital selection, stratified analyses according to use of EMS were also performed.

RESULTS

Among the 17,897 and 8,927 AIS and AMI patients, 66.6% and 48.2% were directly admitted to RCVCs, respectively. Multivariable analysis showed that previous coronary heart disease, prehospital awareness, higher education level, and EMS use increased the odds of direct admission to RCVCs, but the odds ratio (OR) was different between AIS and AMI (for the first 3 factors, AMI > AIS; for EMS use, AMI < AIS). EMS use was the single most important factor for both AIS and AMI (OR, 4.72 vs. 3.90). Hypertension and hyperlipidemia increased, while living alone decreased the odds of direct admission only in AMI; additionally, age (65-74 years), previous stroke, and presentation during non-working hours increased the odds only in AIS. EMS use weakened the associations between direct admission and most factors in both AIS and AMI.

CONCLUSIONS

Various patient factors were differentially associated with direct admission to RCVCs between AIS and AMI. Public education for symptom awareness and use of EMS is essential in optimizing the transportation and hospitalization of patients with AMI and AIS.

Structural Inequities for Historically Underserved Communities in the Adoption of Stroke Certification in the United States

Importance

Stroke centers are associated with better outcomes. There is substantial literature surrounding disparities in stroke outcomes for underserved populations. However, the existing literature has focused primarily on discrimination at the individual or institutional level, and studies of structural discrimination in stroke care are scant.

Objective

To examine differences in hospitals' likelihood of adopting stroke care certification between historically underserved and general communities.

Design, Setting, and Participants

This study combined a data set of hospital stroke certification from all general acute nonfederal hospitals in the continental US from January 1, 2009, to December 31, 2019, with national, hospital, and census data to define historically underserved communities by racial and ethnic composition, income distribution, and rurality. For all categories except rurality, communities were categorized by the composition and degree of segregation of each characteristic. Cox proportional hazard models were then estimated to compare the hazard of adopting stroke care certification between historically underserved and general communities, adjusting for population size and hospital bed capacity. Data were analyzed from June 2021 to April 2022.

Main Outcomes and Measures

Hospitals' likelihood of adopting stroke care certification.

Results

A total of 4984 hospitals were included. From 2009 to 2019, the total number of hospitals with stroke certification grew from 961 to 1763. Hospitals serving Black, racially segregated communities had the highest hazard of adopting stroke care certification (hazard ratio [HR], 1.67; 95% CI, 1.41-1.97) in models not accounting for population size, but their hazard was 26% lower than among those serving non-Black, racially segregated communities (HR, 0.74; 95% CI, 0.62-0.89) in models controlling for population and hospital size. Adoption hazard was lower in low-income communities compared with high-income communities, regardless of their level of economic segregation, and rural hospitals were much less likely to adopt any level of stroke care certification relative to urban hospitals (HR, 0.43; 95% CI, 0.35-0.51).

Conclusions and Relevance

In this analysis of stroke certification adoption across acute care hospitals in the US from 2009 to 2019, hospitals in low-income and rural communities had a lower likelihood of receiving stroke certification than hospitals in general communities. Hospitals operating in Black, racially segregated communities had the highest likelihood of adopting stroke care, but because these communities had the largest population, patients in these communities had the lowest likelihood of access to stroke-certified hospitals when the model controlled for population size. These findings provide empirical evidence that the provision of acute neurological services is structurally inequitable across historically underserved communities.

Influence of Hospital Characteristics on Hospital Transfer Destinations for Patients With Stroke

BACKGROUND

Patients with stroke are frequently transferred between hospitals. This may have implications on the quality of care received by patients; however, it is not well understood how the characteristics of sending and receiving hospitals affect the likelihood of a transfer event. Our objective was to identify hospital characteristics associated with sending and receiving patients with stroke.

METHODS

Using a comprehensive statewide administrative dataset, including all 78 Massachusetts hospitals, we identified all transfers of patients with ischemic stroke between October 2007 and September 2015 for this observational study. Hospital variables included reputation (US News and World Report ranking), capability (stroke center status, annual stroke volume, and trauma center designation), and institutional affiliation. We included network variables to control for the structure of hospital-to-hospital transfers. We used relational event modeling to account for complex temporal and relational dependencies associated with transfers. This method decomposes a series of patient transfers into a sequence of decisions characterized by transfer initiations and destinations, modeling them using a discrete-choice framework.

RESULTS

Among 73 114 ischemic stroke admissions there were 7189 (9.8%) transfers during the study period. After accounting for travel time between hospitals and structural network characteristics, factors associated with increased likelihood of being a receiving hospital (in descending order of relative effect size) included shared hospital affiliation (5.8× higher), teaching hospital status (4.2× higher), stroke center status (4.3× and 3.8× higher when of the same or higher status), and hospitals of the same or higher reputational ranking (1.5× higher).

CONCLUSIONS

After accounting for distance and structural network characteristics, in descending order of importance, shared hospital affiliation, hospital capabilities, and hospital reputation were important factor in determining transfer destination of patients with stroke. This study provides a starting point for future research exploring how relational coordination between hospitals may ensure optimized allocation of patients with stroke for maximal patient benefit.

The relationship between stroke system organization and disparities in access to stroke center care in California

Background

There are significant racial and ethnic disparities in receipt of reperfusion interventions for acute ischemic stroke. Our objective was to determine whether there are disparities in access to stroke center care by race or ethnicity that help explain differences in reperfusion therapy and to understand whether interhospital patient transfer plays a role in improving access.

Methods

Using statewide administrating data including all emergency department and hospital discharges in California from 2010 to 2017, we identified all acute ischemic stroke patients. Primary outcomes of interest included presentation to primary or comprehensive stroke center (PSC or CSC), interhospital transfer, discharge from PSC or CSC, and discharge from CSC alone. We used hierarchical logistic regression modeling to identify the relationship between patient‐ and hospital‐level characteristics and outcomes of interest.

Results

Of 336,247 ischemic stroke patients, 55.4% were non‐Hispanic White, 19.6% Hispanic, 10.6% non‐Hispanic Asian/Pacific Islander, and 10.3% non‐Hispanic Black. There was no difference in initial presentation to stroke center hospitals between groups. However, adjusted odds of reperfusion intervention, interhospital transfer and discharge from CSC did vary by race and ethnicity. Adjusted odds of interhospital transfer were lower among Hispanic (odds ratio [OR] 0.94, 95% confidence interval [CI] 0.89 to 0.98) and non‐Hispanic Asian/Pacific Islander patients (OR 0.84, 95% CI 0.79 to 0.90) and odds of discharge from a CSC were lower for Hispanic (OR 0.91, 95% CI 0.85 to 0.97) and non‐Hispanic Black patients (OR 0.74, 95% CI 0.67 to 0.81).

Conclusions

There are racial and ethnic disparities in reperfusion intervention receipt among stroke patients in California. Stroke system of care design, hospital resources, and transfer patterns may contribute to this disparity.

Regional Disparity of Reperfusion Therapy for Acute Ischemic Stroke in Japan: A Retrospective Analysis of Nationwide Claims Data from 2010 to 2015

Background

We aimed to determine whether a regional disparity exists in usage of reperfusion therapy (intravenous recombinant tissue plasminogen activator [IV rt‐PA] and endovascular thrombectomy [EVT]) and post‐reperfusion 30‐day mortality in patients with acute ischemic stroke, and which regional factors are associated with their usage.

Methods and Results

We retrospectively investigated 69 948 patients (mean age±SD, 74.9±12.0 years; women, 41.4%) with acute ischemic stroke treated with reperfusion therapy between April 2010 and March 2016 in Japan using nationwide claims data. Regional disparity was evaluated using Gini coefficients for age‐ and sex‐adjusted usage of reperfusion therapy and 30‐day post‐reperfusion in‐hospital death ratio in 47 administrative regions. The association between regional factors and reperfusion therapy usage was evaluated with fixed‐effects regression models. During the study period, Gini coefficients showed low inequality (0.11–0.15) for use of IV rt‐PA monotherapy and IV rt‐PA and/or EVT and extreme inequality (0.49) for EVT usage in 2010, which became moderate inequality (0.25) by 2015. The densities of stroke centers and endovascular specialists, as well as market concentration, were associated with increased usage of reperfusion therapy whereas the proportion of rural residents and delayed ambulance transport were negatively associated with usage. Inequality in the standardized death ratio after EVT was extreme (0.86) in 2010 but became moderate (0.29) by 2015; inequality was low to moderate (0.17–0.23) for IV rt‐PA monotherapy and IV rt‐PA and/or EVT.

Conclusions

Scrutinizing existing data sources revealed regional disparity in reperfusion therapy for acute ischemic stroke and its associated regional factors in Japan.

Expanding resources of endovascular thrombectomy: An optimization model

BACKGROUND/PURPOSE

Recently optimized models for selecting the locations of hospitals capable of providing endovascular thrombectomy (EVT) did not consider the accuracy of the prehospital stroke scale assessment and possibility of secondary transport. Our study aimed to propose a new model for selecting existing hospitals with intravenous thrombolysis capability to become EVT-capable hospitals.

METHODS

A sequential order was provided to upgrade hospitals providing intravenous thrombolysis, using a mixed integer programming model based on current medical resource allocation. In addition, we drafted a centralized plan to redistribute existing EVT resources by redetermining locations of EVT-capable hospitals. Using historical data of 7679 on-scene patients with suspected stroke, the model was implemented to determine the hospital that maximizes the number of patients receiving EVT treatment within call-to-definitive-treatment time.

RESULTS

All suspected stroke patients were sent to EVT-capable hospitals directly under the current medical resource allocation model. After upgrading one additional hospital to become an EVT-capable hospital, the percentage of patients receiving definitive treatment within the standard call-to-definitive-treatment time was elevated from 68.82% to 72.97%. In the model, assuming that there is no hospital providing EVT, all patients suspected of stroke will be sent to EVT-capable hospitals directly after upgrading three or more hospitals to be able to provide treatment.

CONCLUSION

All patients eligible for acute stroke treatment are sent to EVT-capable hospitals in the simulation under the current medical resource allocation model. This model can be utilized to provide insights for capacity redistribution in other regions.

Geographic Access to Stroke Care Services in Rural Communities in Ontario, Canada

BACKGROUND

Optimal stroke care requires access to resources such as neuroimaging, acute revascularization, rehabilitation, and stroke prevention services, which may not be available in rural areas. We aimed to determine geographic access to stroke care for residents of rural communities in the province of Ontario, Canada.

METHODS

We used the Ontario Road Network File database linked with the 2016 Ontario Acute Stroke Care Resource Inventory to estimate the proportion of people in rural communities, defined as those with a population size <10,000, who were within 30, 60, and 240 minutes of travel time by car from stroke care services, including brain imaging, thrombolysis treatment centers, stroke units, stroke prevention clinics, inpatient rehabilitation facilities, and endovascular treatment centers.

RESULTS

Of the 1,496,262 people residing in rural communities, the majority resided within 60 minutes of driving time to a center with computed tomography (85%), thrombolysis (81%), a stroke unit (68%), a stroke prevention clinic (74%), or inpatient rehabilitation (77.0%), but a much lower proportion (32%) were within 60 minutes of driving time to a center capable of providing endovascular thrombectomy (EVT).

CONCLUSIONS

Most rural Ontario residents have appropriate geographic access to stroke services, with the exception of EVT. This information may be useful for jurisdictions seeking to optimize the regional organization of stroke care services.

Access to Mechanical Thrombectomy for Ischemic Stroke in the United States

[Figure: see text].

Changes in Patient Volumes and Outcomes After Adding Thrombectomy Capability

BACKGROUND AND PURPOSE

With the rising demand for endovascular thrombectomy (EVT) and introduction of thrombectomy-capable stroke centers (TSC), there is interest among existing stroke hospitals to add EVT capability to attract and retain stroke patient referrals. In this work, we quantify changes in patient volumes and outcomes when adding EVT capability to an existing stroke center.

METHODS

In MATLAB 2017a Simulink, we simulate a 3-center system comprising an EVT-capable comprehensive stroke center, an EVT-incapable primary stroke center, and an EVT-incapable primary stroke center that gains EVT capability (TSC). We model these changes in 2 geographic settings (urban and rural) using 2 routing paradigms (Nearest Center and Bypass). In Nearest Center, patients are sent to the nearest center regardless of EVT capability. In Bypass, patients with severe strokes are sent to the nearest EVT-capable center, and all others are sent to the nearest center. Probability of good clinical outcome is determined by type and timing of treatment using outcomes reported in clinical trials.

RESULTS

Adding EVT capability in the Bypass model produced an absolute increase of 40.1% in total volume of patients with stroke and 31.2% to 31.9% in total volume of acute stroke treatments at the TSC. In the Nearest Center model, the total volume of patients with stroke did not change, but total volume of acute stroke treatment at the TSC had an absolute increase of 9.3% to 9.5%. Good clinical outcomes saw an absolute increase of 0.2% to 0.6% in the whole population and 0.3% to 1.8% in the TSC population.

CONCLUSIONS

Adding EVT capability shifts patient and treatment volume to the TSC. However, these changes produce modest improvement in overall population health. Health systems should weigh relative hospital and patient benefits when considering adding EVT capability.

Effect of Transport Time on the Use of Reperfusion Therapy for Patients with Acute Ischemic Stroke in Korea

BACKGROUND

We investigated the association between geographic proximity to hospitals and the administration rate of reperfusion therapy for acute ischemic stroke.

METHODS

We identified patients with acute ischemic stroke who visited the hospital within 12 hours of symptom onset from a prospective nationwide multicenter stroke registry. Reperfusion therapy was classified as intravenous thrombolysis (IVT), endovascular therapy (EVT), or combined therapy. The association between the proportion of patients who were treated with reperfusion therapy and the ground transport time was evaluated using a spline regression analysis adjusted for patient-level characteristics. We also estimated the proportion of Korean population that lived within each 30-minute incremental service area from 67 stroke centers accredited by the Korean Stroke Society.

RESULTS

Of 12,172 patients (mean age, 68 ± 13 years; men, 59.7%) who met the eligibility criteria, 96.5% lived within 90 minutes of ground transport time from the admitting hospital. The proportion of patients treated with IVT decreased significantly when stroke patients lived beyond 90 minutes of the transport time (P = 0.006). The proportion treated with EVT also showed a similar trend with the transport time. Based on the residential area, 98.4% of Korean population was accessible to 67 stroke centers within 90 minutes.

CONCLUSION

The use of reperfusion therapy for acute stroke decreased when patients lived beyond 90 minutes of the ground transport time from the hospital. More than 95% of the South Korean population was accessible to 67 stroke centers within 90 minutes of the ground transport time.

Mapping access to endovascular stroke care in the USA and implications for transport models

BACKGROUND

The purpose of this cross-sectional study was to determine the percentage of the US population with 60 min ground or air access to accredited or state-designated endovascular-capable stroke centers (ECCs) and non-endovascular capable stroke centers (NECCs) and the percentage of NECCs with an ECC within a 30 min drive.

METHODS

Stroke centers were identified and classified broadly as ECCs or NECCs. Geographic mapping of stroke centers was performed. The population was divided into census blocks, and their centroids were calculated. Fastest air and ground travel times from centroid to nearest ECC and NECC were estimated.

RESULTS

Overall, 49.6% of US residents had 60 min ground access to ECCs. Approximately 37.7% (113 million) lack 60 min ground or air access to ECCs. Approximately 84.4% have 60 min access to NECCs. Ground-only access was available to 77.9%. Approximately 738 NECCs (45.4%) had an ECC within a 30 min drive.

CONCLUSION

Nearly one-third of the US population lacks 60 min access to endovascular stroke care, but this is highly variable. Transport models and planning of additional centers should be tailored to each state depending on location and proximity of existing facilities.

A Neurodisparity Index of Nationwide Access to Neurological Health Care in Northern Ireland

Nationwide disparities in managing neurological patients have rarely been reported. We compared neurological health care between the population who reside in a Health and Social Care Trust with a tertiary neuroscience center and those living in the four non-tertiary center Trusts in Northern Ireland. Using the tertiary center Trust population as reference, neurodisparity indices (NDIs) defined as the number of treated patients resident in each Trust per 100,000 residents compared to the same ratio in the tertiary center Trust for a fixed time period. NDIs were calculated for four neurological pathways—intravenous thrombolysis (iv-tPA) and mechanical thrombectomy (MT) for acute ischemic stroke (AIS), disease modifying treatment (DMT) in multiple sclerosis (MS) and admissions to a tertiary neurology ward. Neurological management was recorded in 3,026 patients. Patients resident in the tertiary center Trust were more likely to receive AIS treatments (iv-tPA and MT) and access to the neurology ward (p < 0.001) than patients residing in other Trusts. DMT use for patients with MS was higher in two non-tertiary center Trusts than in the tertiary center Trust. There was a geographical gradient for MT for AIS patients and ward admissions. Averaged NDIs for non-tertiary center Trusts were: 0.48 (95%CI 0.32–0.71) for patient admissions to the tertiary neurology ward, 0.50 (95%CI 0.38–0.66) for MT in AIS patients, 0.78 (95%CI 0.67–0.92) for iv-tPA in AIS patients, and 1.11 (95%CI 0.99–1.26) for DMT use in MS patients. There are important neurodisparities in Northern Ireland, particularly for MT and tertiary ward admissions. Neurologists and health service planners should be aware that geography and time-dependent management of neurological patients worsen neurodisparities.

Triage and systems of care in stroke

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

Spatial analysis of service areas for stroke centers in a city with high traffic congestion

The effect that traffic congestion has on the service areas of stroke centers has received scarce attention. We aimed to determine the effect of traffic conditions on the characteristics of service areas of stroke centers in Bogotá, Colombia. Using a webservice, we sampled travel times from a set of census blocks to medical centers offering stroke management in the city. We obtained 179.340 transport times under different conditions. The size of service areas was reduced significantly with congestion (up to 94.83%). Overlap in the locations of centers led to large areas covered by only five centers. We identified areas with transport times to the closest center consistently exceeding 30-minutes to 1-hour in the west and south-west. Traffic conditions in Bogotá significantly affect service areas of centers capable of offering comprehensive stroke care. Spatial overlap of centers led to small catchment areas.

Quantifying the Impact of Acute Stroke System of Care Transfer Protocols on Patient Outcomes

BACKGROUND

We quantify the impact of implementing a stroke system of care requiring transport of individuals believed to have stroke to a primary stroke center, in rural and urban settings, based on time from symptom recognition to treatment, probability of receiving treatment within 3 hours of stroke onset, and probability of overcrowding. We use Indiana as an example.

METHODS

We used discrete-event simulation to estimate outcomes for 2 scenarios: stroke system of care with enabling technology (mobile stroke unit, stroke team expansion) and stroke system of care with no enabling technology, as compared with the status quo. We considered patient flow from symptom recognition to treatment. Patient locations and stroke events were generated for the 92 Indiana counties in Indiana, subdivided into 1009 locations. We considered time from emergency medical service (EMS) arrival at onset to treatment, probability of tissue plasminogen activator administered within 3 h of onset, and percentage of patients admitted beyond the occupancy level at the comprehensive stroke center.

RESULTS

Results varied by urbanicity. Under no enabling technology, having a stroke system of care improved outcomes for individuals in urban and suburban settings. However, in rural settings, the implementation of stroke system of care guidelines decreased the average rate of treatment within 3 h of stroke onset and increased the EMS arrival to treatment times compared with sending the individual to the closest provider. Enabling technologies improved outcomes regardless of setting.

DISCUSSION

Geographic disparities tend to increase the number of transfers, decrease the rate of treatment within 3 h of onset, and increase transit time. This could be overcome through federal and state initiatives to reduce quality gaps in stroke care in rural settings and promote care with dedicated stroke wards.

Weekend Effect on in-Hospital Mortality for Ischemic and Hemorrhagic Stroke in US Rural and Urban Hospitals

INTRODUCTION

Previous studies have reported a "weekend effect" on stroke mortality, whereby stroke patients admitted during weekends have a higher risk of in-hospital death than those admitted during weekdays.

AIMS

We aimed to investigate whether patients with different types of stroke admitted during weekends have a higher risk of in-hospital mortality in rural and urban hospitals in the US.

METHODS

We used data from the 2016 National Inpatient Sample and used logistic regression to assess in-hospital mortality for weekday and weekend admissions among stroke patients aged 18 and older by stroke type (ischemic or hemorrhagic) and rural or urban status.

RESULTS

Crude stroke mortality was higher in weekend admissions (p <0.001). After adjusting for confounding variables, in-hospital mortality among hemorrhagic stroke patients was significantly greater (22.0%) for weekend admissions compared to weekday admissions (20.2%, p = 0.009). Among rural hospitals, the in-hospital mortality among hemorrhagic stroke patients was also greater among weekend admissions (36.9%) compared to weekday admissions (25.7%, p = 0.040). Among urban hospitals, the mortality of hemorrhagic stroke patients was 21.1% for weekend and 19.6% for weekday admissions (p = 0.026). No weekend effect was found among ischemic stroke patients admitted to rural or urban hospitals.

CONCLUSIONS

Our results help to understand mortality differences in hemorrhagic stroke for weekend vs. weekday admissions in urban and rural hospitals. Factors such as density of care providers, stroke centers, and patient level risky behaviors associated with the weekend effect on hemorrhagic stroke mortality need further investigation to improve stroke care services and reduce weekend effect on hemorrhagic stroke mortality.

Initial Emergency Room Triage of Acute Ischemic Stroke

Early recognition and differentiation of acute ischemic stroke from intracranial hemorrhage and stroke mimics and the identification of large vessel occlusion (LVO) are critical to the appropriate management of stroke patients. In this review, we discuss the current evidence and practices surrounding safe and efficient triage in the emergency room. As the indications of stroke intervention are evolving to further improve stroke care, focus has begun to revolve around recognition of LVO and provision of endovascular thrombectomy with or without the administration of tissue plasminogen activator. Systems of stroke care are being organized to achieve this goal without delay. Clinical history is important in determining time of onset or last known well time, but, alone or along with an examination, it cannot reliably predict an LVO or exclude intracranial hemorrhage and stroke mimics. The choice of imaging is influenced mainly by the duration of symptoms. On the basis of recent trials, patients presenting after the 6-h therapeutic window can be considered for endovascular thrombectomy if the computed tomographic or magnetic resonance perfusion imaging shows favorable findings. The Society of NeuroInterventional Surgery has established time metrics for each step of triage and initial management. Hospitals are required to develop multidisciplinary stroke teams and emergency protocols to meet these goals. There also needs to be coordination of the emergency medical services with the emergency facility of an appropriate stroke center (a primary stroke center, comprehensive stroke care center, or a thrombectomy-capable stroke center).

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

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

A Network Approach to Stroke Systems of Care

The landscape of stroke systems of care is evolving as patients are increasingly transferred between hospitals for access to higher levels of care. This is driven by time-sensitive disability-reducing interventions such as mechanical thrombectomy. However, coordination and triage of patients for such treatment remain a challenge worldwide, particularly given complex eligibility criteria and varying time windows for treatment. Network analysis is an approach that may be applied to this problem. Hospital networks interlinked by patients moved from facility to facility can be studied using network modeling that respects the interdependent nature of the system. This allows understanding of the central hubs, the change of network structure over time, and the diffusion of innovations. This topical review introduces the basic principles of network science and provides an overview on the applications and potential interventions in stroke systems of care.

Community and Hospital Factors Associated With Stroke Center Certification in the United States, 2009 to 2017

IMPORTANCE

The increased number of stroke centers in the United States may not be equitably distributed across all populations. Anecdotal reports suggest there may be differential proliferation in wealthier and urban communities.

OBJECTIVE

To examine hospital characteristics and economic conditions of communities surrounding hospitals with and without stroke centers.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included all general, short-term, acute hospitals in the continental United States and used merged data from the Joint Commission, Det Norske Veritas, Healthcare Facilities Accreditation Program, state health departments, the Centers for Medicare & Medicaid Services, the American Hospital Association, the Dartmouth Atlas of Health Care, and the US Census Bureau from January 1, 2009, to September 30, 2017, to compare hospital and community characteristics of stroke-certified and non-stroke-certified hospitals and assessed characteristics of early and late adopters of stroke certification.

MAIN OUTCOMES AND MEASURES

Stroke center certification was the primary outcome. Risk factors were grouped into 3 categories: economic and financial, hospital, and community characteristics. Survival analyses were performed using a Cox proportional hazards regression model.

RESULTS

The study included 4546 US hospitals. During the study period, 1689 hospitals (37.2%) were stroke certified (961 adopted certification on or before January 1, 2009, 728 afterward). After controlling for other area and hospital characteristics, hospitals in low-income hospital service areas and the lower tertile of profit-margin distribution were less likely to adopt stroke certification (hazard ratio [HR], 0.62; 95% CI, 0.52-0.74 and HR, 0.87; 95% CI, 0.78-0.98, respectively). Urban hospitals had a higher likelihood of stroke certification than rural hospitals (HR, 12.79; 95% CI, 10.64-15.37).

CONCLUSIONS AND RELEVANCE

This study found that stroke centers have proliferated unevenly across geographic localities, where hospitals in high-income hospital service areas and with higher profit margins have a greater likelihood of being stroke certified. These findings suggest that market-driven factors may be associated with stroke center certification.

Recommendations for the Establishment of Stroke Systems of Care: A 2019 Update

In 2005, the American Stroke Association published recommendations for the establishment of stroke systems of care and in 2013 expanded on them with a statement on interactions within stroke systems of care. The aim of this policy statement is to provide a comprehensive review of the scientific evidence evaluating stroke systems of care to date and to update the American Stroke Association recommendations on the basis of improvements in stroke systems of care. Over the past decade, stroke systems of care have seen vast improvements in endovascular therapy, neurocritical care, and stroke center certification, in addition to the advent of innovations, such as telestroke and mobile stroke units, in the context of significant changes in the organization of healthcare policy in the United States. This statement provides an update to prior publications to help guide policymakers and public healthcare agencies in continually updating their stroke systems of care in light of these changes. This statement and its recommendations span primordial and primary prevention, acute stroke recognition and activation of emergency medical services, triage to appropriate facilities, designation of and treatment at stroke centers, secondary prevention at hospital discharge, and rehabilitation and recovery.

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.

Spatial Methods to Enhance Public Health Surveillance and Resource Deployment in the Opioid Epidemic

OBJECTIVES

To improve public health surveillance and response by using spatial optimization.

METHODS

We identified cases of suspected nonfatal opioid overdose events in which naloxone was administered from April 2013 through December 2016 treated by the city of Pittsburgh, Pennsylvania, Bureau of Emergency Medical Services. We used spatial modeling to identify areas hardest hit to spatially optimize naloxone distribution among pharmacies in Pittsburgh.

RESULTS

We identified 3182 opioid overdose events with our classification approach, which generated spatial patterns of opioid overdoses within Pittsburgh. We then used overdose location to spatially optimize accessibility to naloxone via pharmacies in the city. Only 24 pharmacies offered naloxone at the time, and only 3 matched with our optimized solution.

CONCLUSIONS

Our methodology rapidly identified communities hardest hit by the opioid epidemic with standard public health data. Naloxone accessibility can be optimized with established location-allocation approaches. Public Health Implications. Our methodology can be easily implemented by public health departments for automated surveillance of the opioid epidemic and has the flexibility to optimize a variety of intervention strategies.

Modeling the Impact of Interhospital Transfer Network Design on Stroke Outcomes in a Large City

BACKGROUND AND PURPOSE

We sought to model the effects of interhospital transfer network design on endovascular therapy eligibility and clinical outcomes of stroke because of large-vessel occlusion for the residents of a large city.

METHODS

We modeled 3 transfer network designs for New York City. In model A, patients were transferred from spoke hospitals to the closest hub hospitals with endovascular capabilities irrespective of hospital affiliation. In model B, which was considered the base case, patients were transferred to the closest affiliated hub hospitals. In model C, patients were transferred to the closest affiliated hospitals, and transfer times were adjusted to reflect full implementation of streamlined transfer protocols. Using Monte Carlo methods, we simulated the distributions of endovascular therapy eligibility and good functional outcomes (modified Rankin Scale score, 0-2) in these models.

RESULTS

In our models, 200 patients (interquartile range [IQR], 168-227) with a stroke amenable to endovascular therapy present to New York City spoke hospitals each year. Transferring patients to the closest hub hospital irrespective of affiliation (model A) resulted in 4 (IQR, 1-9) additional patients being eligible for endovascular therapy and an additional 1 (IQR, 0-2) patient achieving functional independence. Transferring patients only to affiliated hospitals while simulating full implementation of streamlined transfer protocols (model C) resulted in 17 (IQR, 3-41) additional patients being eligible for endovascular therapy and 3 (IQR, 1-8) additional patients achieving functional independence.

CONCLUSIONS

Optimizing acute stroke transfer networks resulted in clinically small changes in population-level stroke outcomes in a dense, urban area.

Ischemic Strokes Due to Large-Vessel Occlusions Contribute Disproportionately to Stroke-Related Dependence and Death: A Review

Background

Since large-vessel occlusion (LVO)-related acute ischemic strokes (AIS) are associated with more severe deficits, we hypothesize that the endovascular thrombectomy (ET) may disproportionately benefit stroke-related dependence and death.

Methods

To delineate LVO-AIS impact, systematic search identified studies measuring dependence or death [modified Rankin Scale (mRS) 3–6] or mortality following ischemic stroke among consecutive patients presenting with both LVO and non-LVO events within 24 h of symptom onset.

Results

Among 197 articles reviewed, 2 met inclusion criteria, collectively enrolling 1,467 patients. Rates of dependence or death (mRS 3–6) within 3–6 months were higher after LVO than non-LVO ischemic stroke, 64 vs. 24%, odds ratio (OR) 4.46 (CI: 3.53–5.63, p < 0.0001). Mortality within 3–6 months was higher after LVO than non-LVO ischemic stroke, 26.2 vs. 1.3%, OR 4.09 (CI: 2.5–6.68), p < 0.0001. Consequently, while LVO ischemic events accounted for 38.7% (CI: 21.8–55.7%) of all acutely presenting ischemic strokes, they accounted for 61.6% (CI: 41.8–81.3%) of poststroke dependence or death and 95.6% (CI: 89.0–98.8%) of poststroke mortality. Using literature-based projections of LVO cerebral ischemia patients treatable within 8 h of onset, ET can be used in 21.4% of acutely presenting patients with ischemic stroke, and these events account for 34% of poststroke dependence and death and 52.8% of poststroke mortality.

Conclusion

LVOs cause a little more than one-third of acutely presenting AIS, but are responsible for three-fifths of dependency and more than nine-tenths of mortality after AIS. At the population level, ET has a disproportionate benefit in reducing severe stroke outcomes.

Acute Ischemic Stroke Intervention

Acute ischemic stroke (AIS) is the leading cause of disability worldwide and among the leading causes of mortality. Although intravenous tissue plasminogen activator (IV-rtPA) was approved nearly 2 decades ago for treatment of AIS, only a minority of patients receive it due to a narrow time window for administration and several contraindications to its use. Endovascular approaches to recanalization in AIS developed in the 1980s, and recently, 5 major randomized trials showed an overwhelming superior benefit of combining endovascular mechanical thrombectomy with IV-rtPA over IV-rtPA alone. In this paper, we discuss the evolution of catheter-based treatment from first-generation thrombectomy devices to the game-changing stent retrievers, results from recent trials, and the evolving stroke systems of care to provide timely access to acute stroke intervention to patients in the United States.

Recent advances in the management of acute ischemic stroke

In recent years, several landmark trials have transformed acute ischemic stroke care. The most dramatic results from the field of acute endovascular intervention demonstrate unequivocal benefit for a select group of patients with moderate to severe deficits presenting within 7 hours from onset and with occlusions of proximal arteries in the anterior circulation. In addition, technological advances and workflow efficiencies have facilitated more rapid delivery of acute stroke interventions. This review provides an overview of recent advances in the management of acute ischemic stroke.

Intravenous thrombolysis for ischemic stroke in the golden hour: propensity-matched analysis from the SITS-EAST registry

As there are scarce data regarding the outcomes of acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT) within 60 min from symptom onset ("golden hour"), we sought to compare outcomes between AIS patients treated within [GH(+)] and outside [GH(-)] the "golden hour" by analyzing propensity score matched data from the SITS-EAST registry. Clinical recovery (CR) at 2 and 24 h was defined as a reduction of ≥10 points on NIHSS-score or a total NIHSS-score of ≤3 at 2 and 24 h, respectively. A relative reduction in NIHSS-score of ≥40% at 2 h was considered predictive of complete recanalization (CREC). Symptomatic intracranial hemorrhage (sICH) was defined using SITS-MOST criteria. Favorable functional outcome (FFO) was defined as a mRS-score of 0-1 at 3 months. Out of 19,077 IVT-treated AIS patients, 71 GH(+) patients were matched to 6882 GH(-) patients, with no differences in baseline characteristics (p > 0.1). GH(+) had higher rates of CR at 2 (31.0 vs. 12.4%; p < 0.001) and 24 h (41 vs. 27%; p = 0.010), CREC at 2 h (39 vs. 21%; p < 0.001) and FFO (46.5 vs. 34.0%; p = 0.028) at 3 months. The rates of sICH and 3-month mortality did not differ (p > 0.2) between the two groups. GH(+) was associated with 2-h CR (OR: 5.34; 95% CI 2.53-11.03) and CREC (OR: 2.38; 95% CI 1.38-4.09), 24-h CR (OR: 1.88; 95% CI 1.08-3.26) and 3-month FFO (OR: 2.02; 95% CI 1.15-3.54) in multivariable logistic regression models adjusting for potential confounders. In conclusion, AIS treated with IVT within the GH seems to have substantially higher odds of early neurological recovery, CREC, 3-month FFO and functional improvement.

Development and Assessment of a Computer Algorithm for Stroke Vascular Localization Using Components of the National Institutes of Health Stroke Scale

BACKGROUND

The National Institutes of Health Stroke Scale (NIHSS) was not intended to be used to determine the stroke's vascular distribution. The aim of this study was to develop, assess the reliability, and validate a computer algorithm based on the NIHSS for this purpose.

METHODS

Two cohorts of patients with ischemic stroke having similar distributions of Oxfordshire localizations (total anterior, partial anterior, lacunar, and posterior circulation) based on neuroimaging were identified. The first cohort (n = 40) was used to develop a computer algorithm for vascular localization using a modified version of the NIHSS (NIHSS-Localization [NIHSS-Loc]) that included the laterality of selected deficits; the second (n = 20) was used to assess the reliability of algorithm-based localizations compared to those of 2 vascular neurologists. The validity of the algorithm-based localizations was assessed in comparison to neuroimaging. Agreement was assessed using the unweighted kappa (κ) statistic.

RESULTS

Agreement between the 2 raters using the standard NIHSS was slight to moderate (κ = .36, 95% confidence interval [CI] .10-.61). Inter-rater agreement significantly improved to the substantial to almost perfect range using the NIHSS-Loc (κ = .88, 95% CI .73-1.00). Agreement was perfect when the 2 raters entered the data into the NIHSS-Loc computer algorithm (κ = 1.00, 95% CI 1.00-1.00). Agreement between the algorithm localization and neuroimaging results was fair to moderate (κ = .59, 95% CI .35-.84) and not significantly different from the localizations of either rater using the NIHSS-Loc.

CONCLUSION

A computerized, modified version of the standard NIHSS can be used to reliably and validly assign the vascular distribution of an acute ischemic stroke.

Endovascular Clot Retrieval Therapy

Endovascular acute ischemic stroke therapy is now proven by randomized controlled trials to produce large, clinically meaningful benefits. In response, stroke systems of care must change to increase timely and equitable access to this therapy. In this review, we provide a North American perspective on implications for stroke systems, focusing on the United States and Canada, accompanied by initial recommendations for changes. Most urgently, every community must create access to a hospital that can safely and quickly provide intravenous tissue-type plasminogen activator and immediately transfer appropriate patients onward to a more capable center as required. Safe and effective therapy in the community setting will be ensured by certification programs, performance measurement, and data entry into registries.