Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)

Practical Use of a Communication Application on Mobile Devices by Our Stroke Team

Objective

To describe our 1-year experience of the practical use of a mobile communication application by our stroke team.

Methods

The mobile Join application (Allm Inc., Tokyo, Japan) was introduced into our stroke team for the purpose of immediate sharing of the patient information. We analyzed the usage situation for 1 year after the introduction of Join, particularly its efficacy in improving the door-to-puncture time (D2P) for thrombectomy cases, and reported our inter-hospital collaboration with the use of Join.

Results

The total number of events notified by Join was 337, and they included acute stroke potentially leading to reperfusion therapy in 23% (76 events), head trauma in 14%, brain hemorrhage in 12%, other infarction in 10%, subarachnoid hemorrhage in 8%, and the others in 34%. The information of the patients was shared among the team members before arrival to our hospital in 42% of acute stroke cases. Of 31 patients undergoing mechanical thrombectomy, the median interval between arrival and groin puncture for the directly transported patients with/without pre-hospital information was 77.5 min/87 min, respectively, whereas that of the patients transferred from primary hospitals with/without pre-hospital information was 19 min/71 min (p <0.0001), respectively, demonstrating the efficacy of information sharing in advance through Join in improving the timing of endovascular therapy. For inter-hospital collaboration using the telestroke system, we concluded the partnership agreement with three local primary hospitals by communication via Join at a reasonable cost.

Conclusion

Active and effective utilization of the mobile Join application for communication by our stroke team was demonstrated, and it is expected to promote inter-hospital collaboration in stroke treatment.

Direct admission versus secondary transfer for acute ischemic stroke patients treated with thrombectomy: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Randomized controlled trials have demonstrated that mechanical thrombectomy (MT) could provide more benefit than standard medical care for acute ischemic stroke (AIS) patients due to emergent large vessel occlusion. However, most primary stroke centers (PSCs) are unable to perform MT, and MT can only be performed in comprehensive stroke centers (CSCs) with on-site interventional neuroradiologic services. Therefore, there is an ongoing debate regarding whether patients with suspected AIS should be directly admitted to CSCs or secondarily transferred to CSCs from PSCs. This meta-analysis was aimed to investigate the two transportation paradigms of direct admission and secondary transfer, which one could provide more benefit for AIS patients treated with MT.

METHODS

We conducted a systematic review and meta-analysis through searching PubMed, Embase and the Cochrane Library database up to March 2020. Primary outcomes are as follows: symptomatic intracerebral hemorrhage (sICH) within 7 days; favorable functional outcome at 3 months; mortality in hospital; mortality at 3 months; and successful recanalization rate.

RESULTS

Our pooled results showed that patients directly admitted to CSCs had higher chances of achieving a favorable functional outcome at 3 months than those secondarily transferred to CSCs (OR = 1.26; 95% CI, 1.12-1.42; P < 0.001). In addition, no significant difference was found between the two transportation paradigms in the rate of sICH (OR = 0.86; 95% CI, 0.62-1.18; P = 0.35), mortality in hospital (OR = 0.84; 95% CI, 0.51-1.39; P = 0.51), mortality at 3 months (OR = 1.01; 95% CI, 0.85-1.21; P = 0.91), and successful recanalization (OR = 1.03; 95% CI, 0.88-1.20; P = 0.74). However, in the 100% bridging thrombolysis usage rate subgroup, our subgroup analysis indicated that no difference was found in any outcome between the two transportation paradigms.

CONCLUSION

Patients with AIS directly admitted to CSCs for MT may be a feasible transportation paradigm for AIS patients. However, more large-scale randomized prospective trials are required to further investigate this issue.

Impact of EMS bypass to endovascular capable hospitals: geospatial modeling analysis of the US STRATIS registry

BACKGROUND

Routing patients directly to endovascular capable centers (ECCs) would decrease time to mechanical thrombectomy (MT), but may delay intravenous thrombolysis (IVT).

OBJECTIVE

To study the clinical outcomes of patients with a stroke transferred directly to ECCs compared with those transferred to ECCs from non-endovascular capable centers (nECCs).

METHODS

Data from the STRATIS registry were analyzed to evaluate process and clinical outcomes under five routing policies: (1) transport to nearest nECC; (2) transport to STRATIS ECC over any distance or (3) within 20 miles; (4) transport to ideal ECC (iECC), over any distance or (5) within 20 miles.

RESULTS

Among 236 patients, 117 (49.6%) were transferred by ground, of whom 62 (53%) were transferred within 20 miles. Median MT start time was accelerated in all direct transport models. IVT start was prolonged with direct transport across all distances, but accelerated with direct transport to iECC ≤20 miles. With bypass limited to ≤20 miles, the median modeled EMS arrival to IVT interval decreased for both iECCs and ECCs (by 12 min and 6 min, respectively), and median EMS arrival to puncture time decreased by up to 94 min. In this cohort, no patient would have become ineligible for IVT. Bypass to iECC modeling under 20 miles showed a significant reduction in the level of disability at 3 months, with freedom from disability (modified Rankin Scale score 0-1) at 3 months increased by 12%.

CONCLUSIONS

Direct routing of patients with a large vessel occlusion to ECCs, especially when within 20 miles, may lead to better clinical outcomes by accelerating the start of MT without any delay of IVT.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Management of acute ischemic stroke in patients with COVID-19 infection: Report of an international panel

Background and purpose

On 11 March 2020, World Health Organization (WHO) declared the COVID-19 infection a pandemic. The risk of ischemic stroke may be higher in patients with COVID-19 infection similar to those with other respiratory tract infections. We present a comprehensive set of practice implications in a single document for clinicians caring for adult patients with acute ischemic stroke with confirmed or suspected COVID-19 infection.

Methods

The practice implications were prepared after review of data to reach the consensus among stroke experts from 18 countries. The writers used systematic literature reviews, reference to previously published stroke guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate practice implications. All members of the writing group had opportunities to comment in writing on the practice implications and approved the final version of this document.

Results

This document with consensus is divided into 18 sections. A total of 41 conclusions and practice implications have been developed. The document includes practice implications for evaluation of stroke patients with caution for stroke team members to avoid COVID-19 exposure, during clinical evaluation and performance of imaging and laboratory procedures with special considerations of intravenous thrombolysis and mechanical thrombectomy in stroke patients with suspected or confirmed COVID-19 infection.

Conclusions

These practice implications with consensus based on the currently available evidence aim to guide clinicians caring for adult patients with acute ischemic stroke who are suspected of, or confirmed, with COVID-19 infection. Under certain circumstances, however, only limited evidence is available to support these practice implications, suggesting an urgent need for establishing procedures for the management of stroke patients with suspected or confirmed COVID-19 infection.

Emerging Technologies in Optimizing Pre-Intervention Workflow for Acute Stroke

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

Interhospital transfer vs. direct presentation of patients with a large vessel occlusion not eligible for IV thrombolysis

Background and purpose

Direct presentation of patients with acute ischemic stroke to a comprehensive stroke center (CSC) reduces time to endovascular treatment (EVT), but may increase time to treatment for intravenous thrombolysis (IVT). This dilemma, however, is not applicable to patients who have a contraindication for IVT. We examined the effect of direct presentation to a CSC on outcomes after EVT in patients not eligible for IVT.

Methods

We used data from the MR CLEAN Registry (2014–2017). We included patients who were not treated with IVT and compared patients directly presented to a CSC to patients transferred from a primary stroke center. Outcomes included treatment times and 90-day modified Rankin Scale scores (mRS) adjusted for potential confounders.

Results

Of the 3637 patients, 680 (19%) did not receive IVT and were included in the analyses. Of these, 389 (57%) were directly presented to a CSC. The most common contraindications for IVT were anticoagulation use (49%) and presentation > 4.5 h after onset (26%). Directly presented patients had lower baseline NIHSS scores (median 16 vs. 17, p = 0.015), higher onset-to-first-door times (median 105 vs. 66 min, p < 0.001), lower first-door-to-groin times (median 93 vs. 150 min; adjusted β = − 51.6, 95% CI: − 64.0 to − 39.2) and lower onset-to-groin times (median 220 vs. 230 min; adjusted β = − 44.0, 95% CI: − 65.5 to − 22.4). The 90-day mRS score did not differ between groups (adjusted OR: 1.23, 95% CI: 0.73–2.08).

Conclusions

In patients who were not eligible for IVT, treatment times for EVT were better for patients directly presented to a CSC, but without a statistically significant effect on clinical outcome.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09812-5) contains supplementary material, which is available to authorized users.

Impact of interhospital transfer on patients undergoing endovascular thrombectomy for acute ischaemic stroke in an Australian setting

Objective

To assess the impact of interhospital transfer on the interplay between functional outcome, mortality, reperfusion rates and workflow time metrics in patients undergoing endovascular thrombectomy (EVT) for acute ischaemic stroke due to large vessel occlusion (LVO) in the anterior cerebral circulation.

Design setting and participants

This is an analysis of a prospective database of consecutive patients undergoing EVT for LVO presenting between January 2017 and December 2018 at a single Australian comprehensive stroke centre (CSC). Patients presented directly or were transferred to the CSC from 21 sites across New South Wales and the Australian Capital Territory.

Main outcome measures

The main outcome measures were rate of good 90-day functional outcome (modified Rankin Scale 0-2), successful reperfusion (Thrombolysis in Cerebral Infarction scale grade 2b or 3), symptomatic intracerebral haemorrhage (sICH) and 90-day mortality. Key workflow time metric milestones were examined.

Results

154 of 213 (72%) patients were interhospital transfers. There was no significant difference in baseline characteristics including age, National Institutes of Health Stroke Scale score, intravenous thrombolysis administration or procedure time between transferred and direct presenters (all p>0.05). Transferred patients had worse 90-day functional outcome (39.6% vs 61.0%, OR 0.42, 95% CI 0.23 to 0.78), higher mortality (25.3% vs 6.8%, OR 4.66, CI 1.59 to 13.70) and longer stroke onset to treatment (groin puncture) time (298 min vs 205 min, p<0.01). Successful reperfusion rates and sICH were similar between the cohorts (96.8% vs 98.3%, and 7.8% vs 3.4%).

Conclusion

Interhospital transfer is associated with longer stroke onset to treatment, worse 90-day functional outcome and higher mortality compared with patients presenting directly to the CSC.

Organizing Healthcare for Optimal Acute Ischemic Stroke Treatment

Stroke is a major health-care problem that represents a leading cause of death and also the top cause of disability in adulthood. In recent years there has been a significant paradigm shift in treatments for acute ischemic stroke to favor earlier reperfusion therapy, mainly using the systemic infusion of recombinant tissue plasminogen activator. Subsequent trials found that combining this treatment with endovascular therapy was effective in selected patients. The increased complexity of acute stroke treatments has resulted in a substantial reorganization of stroke care. This review reports on the evolution of acute ischemic stroke treatment and describes the main organizational models based on the hub-and-spoke system. The lack of evidence for comparisons of the effectiveness of different paradigms means that some decision-analysis models predicting the best organizational pathways are also reported, with a particular emphasis on the workflow timing in the prehospital and in-hospital settings. Major benchmarks and performance measures are also reported, focusing on the timing of interventions and rates of process indicators. Finally, future directions are illustrated, including using telemedicine for stroke, mobile stroke units, and artificial intelligence and automated machines to produce software for detecting large-vessel occlusion.

Safety of inter-hospital transfer of patients with acute ischemic stroke for evaluation of endovascular thrombectomy

Stroke networks facilitate access to endovascular treatment (EVT) for patients with ischemic stroke due to large vessel occlusion. In this study we aimed to determine the safety of inter-hospital transfer and included all patients with acute ischemic stroke who were transferred within our stroke network for evaluation of EVT between 06/2016 and 12/2018. Data were derived from our prospective EVT database and transfer protocols. We analyzed major complications and medical interventions associated with inter-hospital transfer. Among 615 transferred patients, 377 patients (61.3%) were transferred within our telestroke network and had transfer protocols available (median age 76 years [interquartile range, IQR 17], 190 [50.4%] male, median baseline NIHSS score 17 [IQR 8], 246 [65.3%] drip-and-ship i.v.-thrombolysis). No patient suffered from cardio-respiratory failure or required emergency intubation or cardiopulmonary resuscitation during the transfer. Among 343 patients who were not intubated prior departure, 35 patients (10.2%) required medical interventions during the transfer. The performance of medical interventions was associated with a lower EVT rate and higher mortality at three months. In conclusion, the transfer of acute stroke patients for evaluation of EVT was not associated with major complications and transfer-related medical interventions were required in a minority of patients.

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

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

Clinical Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke in Transfer Cases

Objective

There are regional disparities in endovascular thrombectomy, and problems with emergency transport systems and hospital collaboration when transferring need to be addressed. In this study, the clinical outcomes of endovascular thrombectomy for transferred patients were analyzed.

Methods

Acute ischemic stroke patients who underwent endovascular thrombectomy between January 2016 and March 2019 were enrolled. They were retrospectively reviewed and divided into the direct group and transfer group, and we compared treatment results and clinical outcomes between them.

Results

In all, 122 patients met the inclusion criteria, comprising 93 patients in the direct group and 29 patients in the transfer group. The time from onset to door of our hospital was longer in the transfer group than in the direct group (73 minutes vs. 158 minutes, P = 0.80), but the time from arrival to reperfusion was significantly shorter in the transfer group (139 minutes vs. 106 minutes, P = 0.001). As the time from onset to reperfusion did not differ significantly between the two groups (220 minutes vs. 256 minutes, P = 0.60), there was no significant difference in good outcome at discharge (38.7 vs. 41.3%, P = 0.79).

Conclusion

Clinical outcomes of transferred patients for endovascular thrombectomy may be equivalent to those of directly transported patients. Promoting close hospital cooperation may improve clinical outcomes and resolve regional disparities.

Trends in hospital procedure volumes for intra-arterial treatment of acute ischemic stroke: results from the paul coverdell national acute stroke program

BACKGROUND

Rates of intra-arterial revascularization treatments (IAT) for acute ischemic stroke (AIS) are increasing in the USA. Using a multi-state stroke registry, we studied the trend in IAT use among patients with AIS over a period spanning 11 years. We examined the impact of IAT rates on hospital procedure volumes and patient outcome after stroke.

METHODS

We used data from the Paul Coverdell National Acute Stroke Program (PCNASP) and explored trends in IAT between 2008 and 2018. Patient outcomes were examined by rates of IAT procedures across hospitals. Specifically, outcomes were compared across low-volume (<15 IAT per year), medium-volume (15-30 IAT per year), and high-volume hospitals (>30 IAT per year). Favorable outcome was defined as discharge to home.

RESULTS

There were 612 958 patients admitted with AIS to 687 participating hospitals within the PCNASP during this study. Only 2.9% of patients (mean age 68.5 years, 49.3% women) received IAT. The percent of patients with AIS receiving IAT increased from 1% in 2008 to 5.3% in 2018 (p<0.001). The proportion of low-volume hospitals decreased over time (p<0.001), and the proportions of medium-volume (p=0.007) and high-volume hospitals (p<0.001) increased between 2008 and 2018. When compared with medium-volume hospitals, high-volume hospitals had a higher (p<0.0001) and low-volume hospitals had a lower (p<0.0001) percent of patients discharged to home.

CONCLUSION

High-volume hospitals were associated with a higher rate of favorable outcome. With the increased use of IAT among patients with AIS, the proportion of low-volume hospitals performing IAT significantly decreased.

Increased Access to and Use of Endovascular Therapy Following Implementation of a 2-Tiered Regional Stroke System

Background and Purpose—

We quantified population access to endovascular-capable centers, timing, and rates of thrombectomy in Los Angeles County before and after implementing 2-tiered routing in a regional stroke system of care.

Methods—

In 2018, the Los Angeles County Emergency Medical Services Agency implemented transport of patients with suspected large vessel occlusions identified by Los Angeles Motor Scale ≥4 directly to designated endovascular-capable centers. We calculated population access to a designated endovascular-capable center within 30 minutes comparing 2016, before 2-tiered system planning began, to 2018 after implementation. We analyzed data from stroke centers in the region from 1 year before and after implementation to delineate changes in rates and speed of administration of tPA (tissue-type plasminogen activator) and thrombectomy and frequency of interfacility transfer.

Results—

With implementation of the 2-tier system, certified endovascular-capable hospitals increased from 4 to 19 centers, and within 30-minute access to endovascular care for the public in Los Angeles County, from 40% in 2016 to 93% in 2018. Comparing Emergency Medical Services–transported stroke patients in the first post-implementation year (N=3303) with those transported in the last pre-implementation year (N=3008), age, sex, and presenting deficit severity were similar. The frequency of thrombolytic therapy increased from 23.8% to 26.9% (odds ratio, 1.2 [95% CI, 1.05–1.3]; P =0.006), and median first medical contact by paramedic-to-needle time decreased by 3 minutes ([95% CI, 0–5] P =0.03). The frequency of thrombectomy increased from 6.8% to 15.1% (odds ratio, 2.4 [95% CI, 2.0–2.9]; P <0.0001), although first medical contact-to-puncture time did not change significantly, median decrease of 8 minutes ([95% CI, −4 to 20] P =0.2). The frequency of interfacility transfers declined from 3.2% to 1.0% (odds ratio, 0.3 [95% CI, 0.2–0.5]; P <0.0001).

Conclusions—

After implementation of 2-tiered stroke routing in the most populous US county, thrombectomy access increased to 93% of the population, and the frequency of thrombectomy more than doubled, whereas interfacility transfers declined.

Bypassing the Closest Stroke Center for Thrombectomy Candidates

Background and Purpose—

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

Methods—

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

Results—

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

Conclusions—

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

Outcomes of Thrombectomy in Transferred Patients With Ischemic Stroke in the Late Window: A Subanalysis From the DEFUSE 3 Trial

Importance

Although thrombectomy benefit was maintained in transfer patients with ischemic stroke in early-window trials, overall functional independence rates were lower in thrombectomy and medical management-only groups.

Objective

To evaluate whether the imaging-based selection criteria used in the Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE 3) trial would lead to comparable outcome rates and treatment benefits in transfer vs direct-admission patients.

Design, Setting, and Participants

Subgroup analysis of DEFUSE 3, a prospective, randomized, multicenter, blinded-end point trial. Patients were enrolled between May 2016 and May 2017 and were followed up for 90 days. The trial comprised 38 stroke centers in the United States and 182 patients with stroke with a large-vessel anterior circulation occlusion and initial infarct volume of less than 70 mL, mismatch ratio of at least 1.8, and mismatch volume of at least 15 mL, treated within 6 to 16 hours from last known well. Patients were stratified based on whether they presented directly to the study site or were transferred from a primary center. Data were analyzed between July 2018 and October 2018.

Interventions or Exposures

Endovascular thrombectomy plus standard medical therapy vs standard medical therapy alone.

Main Outcomes and Measures

The primary outcome was the distribution of 90-day modified Rankin Scale scores.

Results

Of the 296 patients who consented, 182 patients were randomized (66% were transfer patients and 34% directly presented to a study site). Median age was 71 years (interquartile range [IQR], 60-79 years) vs 70 years (IQR, 59-80 years); 69 transfer patients were women (57%) and 23 of the direct group were women (37%). Transfer patients had longer median times from last known well to study site arrival (9.43 vs 9 hours) and more favorable collateral profiles (based on hypoperfusion intensity ratio): median for transfer, 0.35 (IQR, 0.18-0.47) vs 0.42 (IQR, 0.25-0.56) for direct (P = .05). The primary outcome (90-day modified Rankin Scale score shift) did not differ in the direct vs transfer groups (direct OR, 2.9; 95% CI, 1.2-7.2; P = .01; transfer OR, 2.6; 95% CI, 1.3-4.8; P = .009). The overall functional independence rate (90-day modified Rankin Scale score 0-2) in the thrombectomy group did not differ (direct 44% vs transfer 45%) nor did the treatment effect (direct OR, 2.0; 95% CI, 0.9-4.4 vs transfer OR, 3.1; 95% CI, 1.6-6.1). Thrombectomy reperfusion rates, mortality, and symptomatic intracranial hemorrhage rates did not differ.

Conclusions and Relevance

In late-window patients selected by penumbral mismatch criteria, both the favorable outcome rate and treatment effect did not decline in transfer patients. These results have health care implications indicating transferring potential candidates for late-window thrombectomy is associated with substantial clinical benefits and should be encouraged.

Trial Registration

ClinicalTrials.gov identifier: NCT02586415.

Factors Associated with Failure of Reperfusion in Endovascular Therapy for Acute Ischemic Stroke : A Multicenter Analysis

Aim

In acute large vessel occlusions, endovascular therapy (EVT) achieves flow restoration in the majority of cases; however, EVT fails to achieve sufficient reperfusion in a substantial minority of patients. This study aimed to identify predictors of failed reperfusion.

Methods

In this study 2211 patients from the German Stroke Registry who received EVT for anterior circulation stroke were retrospectively analyzed. Failure of reperfusion was defined as thrombolysis in cerebral infarction (TICI) grades 0/1/2a, and sufficient reperfusion as TICI 2b/3. In 1629 patients with complete datasets, associations between failure of reperfusion and baseline clinical data, comorbidities, location of occlusion, and procedural data were assessed with multiple logistic regression.

Results

Failure of reperfusion occurred in 371 patients (16.8%) and was associated with the following locations of occlusion: cervical internal carotid artery (ICA, adjusted odds ratio, OR 2.01, 95% confidence interval, CI 1.08–3.69), intracranial ICA without carotid T occlusion (adjusted OR 1.79, 95% CI 1.05–2.98), and M2 segment (adjusted OR 1.86, 95% CI 1.21–2.84). Failed reperfusion was also associated with cervical ICA stenosis (>70% stenosis, adjusted OR 2.90, 95% CI 1.69–4.97), stroke of other determined etiology by TOAST (Trial of ORG 10172 in acute stroke treatment) criteria (e.g. nonatherosclerotic vasculopathies, adjusted OR 2.73, 95% CI 1.36–5.39), and treatment given outside the usual working hours (adjusted OR 1.41, 95% CI 1.07–1.86). Successful reperfusion was associated with higher Alberta stroke program early CT score (ASPECTS) on initial imaging (adjusted OR 0.85, 95% CI 0.79–0.92), treatment with the patient under general anesthesia (adjusted OR 0.72, 95% CI 0.54–0.96), and concomitant ICA stenting in patients with ICA stenosis (adjusted OR 0.20, 95% CI 0.11–0.38).

Conclusion

Several factors are associated with failure of reperfusion, most notably occlusions of the proximal ICA and low ASPECTS on admission. Conversely, stent placement in the proximal ICA was associated with reperfusion success.

Electronic supplementary material

The online version of this article (10.1007/s00062-020-00880-8) contains supplementary material, which is available to authorized users.

Management of acute ischemic stroke

Stroke is the leading cause of long term disability in developed countries and one of the top causes of mortality worldwide. The past decade has seen substantial advances in the diagnostic and treatment options available to minimize the impact of acute ischemic stroke. The key first step in stroke care is early identification of patients with stroke and triage to centers capable of delivering the appropriate treatment, as fast as possible. Here, we review the data supporting pre-hospital and emergency stroke care, including use of emergency medical services protocols for identification of patients with stroke, intravenous thrombolysis in acute ischemic stroke including updates to recommended patient eligibility criteria and treatment time windows, and advanced imaging techniques with automated interpretation to identify patients with large areas of brain at risk but without large completed infarcts who are likely to benefit from endovascular thrombectomy in extended time windows from symptom onset. We also review protocols for management of patient physiologic parameters to minimize infarct volumes and recent updates in secondary prevention recommendations including short term use of dual antiplatelet therapy to prevent recurrent stroke in the high risk period immediately after stroke. Finally, we discuss emerging therapies and questions for future research.

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.

Prehospital selection of thrombectomy candidates beyond large vessel occlusion

Objective

Current prehospital scales used to detect large vessel occlusion reveal very low endovascular thrombectomy (EVT) rates among selected patients. We developed a novel prehospital scale, the Madrid-Direct Referral to Endovascular Center (M-DIRECT), to identify EVT candidates for direct transfer to EVT-capable centers (EVT-Cs). The scale evaluated clinical examination, systolic blood pressure, and age. Since March 2017, patients closer to a stroke unit without EVT capabilities and an M-DIRECT positive score have been transferred to the nearest EVT-C. To test the performance of the scale-based routing protocol, we compared its outcomes with those of a simultaneous cohort of patients directly transferred to an EVT-C.

Methods

In this prospective observational study of consecutive patients with stroke code seen by emergency medical services, we compared diagnoses, treatments, and outcomes of patients who were closer to an EVT-C (mothership cohort) with those transferred according to the M-DIRECT score (M-DIRECT cohort).

Results

The M-DIRECT cohort included 327 patients and the mothership cohort 214 patients. In the M-DIRECT cohort, 227 patients were negative and 100 were positive. Twenty-four (10.6%) patients required secondary transfer, leaving 124 (38%) patients from the M-DIRECT cohort admitted to an EVT-C. EVT rates were similar for patients with ischemic stroke in both cohorts (30.9% vs 31.5%). The M-DIRECT scale had 79% sensitivity, 82% specificity, and 53% positive predictive value for EVT. Recanalization and independence rates at 3 months did not differ between the cohorts.

Conclusions

The M-DIRECT scale was highly accurate for EVT, with treatment rates and outcomes similar to those of a mothership paradigm, thereby avoiding EVT-C overload with a low rate of secondary transfers.

Local Leukocyte Invasion during Hyperacute Human Ischemic Stroke

OBJECTIVE

Bridging the gap between experimental stroke and patients by ischemic blood probing during the hyperacute stage of vascular occlusion is crucial to assess the role of inflammation in human stroke and for the development of adjunct treatments beyond recanalization.

METHODS

We prospectively observed 151 consecutive ischemic stroke patients with embolic large vessel occlusion of the anterior circulation who underwent mechanical thrombectomy. In all these patients, we attempted microcatheter aspiration of 3 different arterial blood samples: (1) within the core of the occluded vascular compartment and controlled by (2) carotid and (3) femoral samples obtained under physiological flow conditions. Subsequent laboratory analyses comprised leukocyte counting and differentiation, platelet counting, and the quantification of 13 proinflammatory human chemokines/cytokines.

RESULTS

Forty patients meeting all clinical, imaging, interventional, and laboratory inclusion criteria could be analyzed, showing that the total number of leukocytes significantly increased under the occlusion condition. This increase was predominantly driven by neutrophils. Significant increases were also apparent for lymphocytes and monocytes, accompanied by locally elevated plasma levels of the T-cell chemoattractant CXCL-11. Finally, we found evidence that short-term clinical outcome (National Institute of Health Stroke Scale at 72 hours) was negatively associated with neutrophil accumulation.

INTERPRETATION

We provide the first direct human evidence that neutrophils, lymphocytes, and monocytes, accompanied by specific chemokine upregulation, accumulate in the ischemic vasculature during hyperacute stroke and may affect outcome. These findings strongly support experimental evidence that immune cells contribute to acute ischemic brain damage and indicate that ischemic inflammation initiates already during vascular occlusion. Ann Neurol 2020;87:466-479.

Effect of Interhospital Transfer on Endovascular Treatment for Acute Ischemic Stroke

Background and Purpose- To assess the effect of inter-hospital transfer on time to treatment and functional outcome after endovascular treatment (EVT) for acute ischemic stroke, we compared patients transferred from a primary stroke center to patients directly admitted to an intervention center in a large nationwide registry. Methods- MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry is an ongoing, prospective, observational study in all centers that perform EVT in the Netherlands. We included adult patients with an acute anterior circulation stroke who received EVT between March 2014 to June 2016. Primary outcome was time from arrival at the first hospital to arterial groin puncture. Secondary outcomes included the 90-day modified Rankin Scale score and functional independence (modified Rankin Scale score of 0-2). Results- In total 821/1526 patients, (54%) were transferred from a primary stroke center. Transferred patients less often had prestroke disability (227/800 [28%] versus 255/699 [36%]; P=0.02) and more often received intravenous thrombolytics (659/819 [81%] versus 511/704 [73%]; P<0.01). Time from first presentation to groin puncture was longer for transferred patients (164 versus 104 minutes; P<0.01, adjusted delay 57 minutes [95% CI, 51-62]). Transferred patients had worse functional outcome (adjusted common OR, 0.75 [95% CI, 0.62-0.90]) and less often achieved functional independence (244/720 [34%] versus 289/681 [42%], absolute risk difference -8.5% [95% CI, -8.7 to -8.3]). Conclusions- Interhospital transfer of patients with acute ischemic stroke is associated with delay of EVT and worse outcomes in routine clinical practice, even in a country where between-center distances are short. Direct transportation of patients potentially eligible for EVT to an intervention center may improve functional outcome.

Decision Analysis Model for Prehospital Triage of Patients With Acute Stroke

Background and Purpose- We used a decision analysis approach to analyze triage strategies for patients with acute stroke symptoms while accounting for prehospital large vessel occlusion (LVO) screening methods and key time metrics. Methods- Our decision analysis compared anticipated functional outcomes for patients within the IV-tPA (intravenous tissue-type plasminogen activator) treatment window in the mothership and drip-and-ship frameworks. Key branches of the model included IV-tPA eligibility, presence of an LVO, and endovascular therapy eligibility. Our decision analysis evaluated 2 prehospital LVO screening approaches: (1) no formal screening and (2) the use of clinical LVO screening scales. An excellent outcome was defined as modified Rankin Scale scores 0-1. Probabilities and workflow times were guideline-based or imputed from published studies. In sensitivity analyses, we individually and jointly varied transport time to the nearest primary stroke center, additional time required to transport directly to a comprehensive stroke center, and LVO screening scale predictive probabilities. We evaluated 2 separate scenarios: one in which ideal time metrics were achieved and one under current real-world metrics. Results- In the ideal metrics scenario, the drip-and-ship strategy was almost always favored in the absence of formal LVO screening. For patients screened positive for an LVO, mothership was favored if the additional transport time to the comprehensive stroke center was <3 to 23 minutes. Under real-world conditions, in which primary stroke center workflow is slower than ideal, the mothership strategy was favored in more scenarios, regardless of formal LVO screening. For example, mothership was favored with an additional transport time to the comprehensive stroke center of <32 to 99 minutes for patients screened positive for an LVO and <28 to 39 minutes in the absence of screening. Conclusions- Joint consideration of LVO probability, screening, workflow times, and transport times may improve prehospital stroke triage. Drip-and-ship was more favorable when more ideal primary stroke center workflow times were modeled.

Time Metrics to Endovascular Thrombectomy in 3 Triage Concepts

Background and Purpose—

NEUROSQUAD (Stroke Treatment: Quality and Efficacy in Different Referral Systems) is a prospective, observational, bi-center study comparing 3 triage pathways in endovascular stroke treatment: mothership (MS), drip and ship (DS) and transferring a neurointerventionalist to a remote hospital for thrombectomy (drive the doctor [DD]).

Methods—

Between February and October 2018, all stroke patients undergoing thrombectomy at 2 university hospitals and 2 associated remote hospitals were included. Primary outcome measures were time from onset to groin puncture and time from imaging to groin puncture. Secondary outcome measures were time from onset to imaging and time from onset to thrombolysis.

Results—

In total, 440 patients were included (mothership 32.3%, DS 55.9%, DD 11.8%). Median time from onset to groin puncture (168 minutes) and time from imaging to groin puncture (51 minutes) were the shortest in the mothership group. Time from onset to groin puncture (DD median 225 versus DS median 300 minutes; P =0.001) and time from imaging to groin puncture (DD median 118 versus DS median 172 minutes; P <0.001) were shorter in the DD group compared with DS. Time from onset to imaging was similar among mothership, DS, and DD ( P =0.363). In patients receiving thrombolysis, time from onset to needle was similar among the groups ( P =0.620).

Conclusions—

The NEUROSQUAD study adds evidence that DD may be a feasible alternative to DS, leading to shorter delay between symptom onset and groin puncture. Both are time-wise inferior compared with mothership, though.

Drip and ship for mechanical thrombectomy within the Neurovascular Network of Southwest Bavaria

Objective

To determine feasibility and safety of stroke care organization within our Neurovascular Network of Southwest Bavaria (NEVAS) in a rural area with distances of up to 100 kilometers, we compared patients who underwent mechanical thrombectomy (MT) in large vessel occlusion admitted directly to our center (direct to center [DTC]) to patients who were transferred for MT via NEVAS (drip and ship [DS]).

Methods

This is a retrospective analysis of prospectively collected data of all MT patients between January 2015 and May 2018. Successful recanalization was defined as a thrombolysis in cerebral infarction score of 2b-3. Symptomatic intracerebral hemorrhage (sICH) was defined according to European Cooperative Acute Stroke Study 3. Modified Rankin Scale (mRS) score of 0–2 at 3 months indicated good outcome.

Results

MT was performed in 410 patients: 221 DTC and 189 DS. Median NIH Stroke Scale (NIHSS) score was 16 and premorbid mRS score was 0. Thrombolysis was applied in 62.2% with the same time from symptom onset in both groups (94.5 vs 95 minutes). Successful recanalization (79.3% vs 77.8%) and NIHSS score reduction from admission to discharge (16–7 vs 17–6) were comparable. Time delay from onset to revascularization was 96 minutes in DS (212 vs 308 minutes, p = 0.001). At follow-up, DTC patients had a trend to better outcome (33.5% vs 24.3%, p = 0.056). Neither sICH (6.3% vs 5.9%, p = 0.840) nor mortality (31.2% vs 34.4%, p = 0.387) differed between the groups.

Conclusion

DS patients benefit from MT without relevant safety concerns, but with a trend to unfavorable outcome compared to DTC patients. These results suggest that DS is suitable to provide MT in rural areas where DTC is not possible.

Outcome of patients with large vessel occlusion stroke after first admission in telestroke spoke versus comprehensive stroke center

Introduction

While telestroke allows early intravenous thrombolysis (IVT) for ischemic strokes in spoke centers, mechanical thrombectomy (MT) for large vessel occlusion (LVO) is mainly performed at comprehensive stroke centers (CSCs). We aimed to compare 3 month outcome in patients with LVO after admission to a spoke center using telestroke compared with first CSC admission in our large regional stroke network, irrespective of final treatment decision.

Methods

All consecutive LVO patients who were admitted to one of six spoke centers or to the regional CSC within 6 hours of symptom onset were prospectively included from September 1, 2015 to August 31, 2017. All patients admitted to spoke centers were assessed on site with cerebral and vessel imaging. Primary outcome was 3 month favorable outcome (modified Rankin Scale score of 0–2).

Results

Distances between spoke centers and CSC ranged from 36 to 77 miles. Among 207 included patients, 132 (63.8%) were first admitted to CSCs and 75 (36.2%) to spoke centers. IVT was administered more in spoke centers (81.3% vs 53.8%, p<0.0001) while MT was performed less (26.7% vs 49.2%, p=0.001) and with a longer time from onset (303 vs 200 min, p<0.0001). No difference was found in 3 month favorable outcome between spoke centers compared with CSCs (32.0% and 35.1%, respectively; OR=0.68; 95% CI 0.42 to 1.10; p=0.12).

Conclusions

Despite different distribution of reperfusion therapies for LVO patients managed by telemedicine, we could not demonstrate a difference in functional outcome according to admission location in a large area with long distances between centers.

Emergency management of stroke in the era of mechanical thrombectomy

Emergency management of stroke has been directed at the delivery of recombinant tissue plasminogen activator (tPA) in a timely fashion. Because of the many limitations attached to the delivery of tPA and the perceived benefits accrued to tPA, its use has been limited. Mechanical thrombectomy, a far superior therapy for the largest and most disabling strokes, large vessel occlusions (LVOs), has changed the way acute strokes are managed. Aside from the rush to deliver tPA, there is now a need to identify LVO and refer those patients with LVO to physicians and facilities capable of delivering urgent thrombectomy. Other parts of emergency department management of stroke are directed at identifying and mitigating risk factors for future strokes and at preventing further damage from occurring. We review here the most recent literature supporting these advances in stroke care and present a framework for understanding the role that emergency physicians play in acute stroke care.

Personalized Prehospital Triage in Acute Ischemic Stroke

Supplemental Digital Content is available in the text.

Background and Purpose—

Direct transportation to a center with facilities for endovascular treatment might be beneficial for patients with acute ischemic stroke, but it can also cause harm by delay of intravenous treatment. Our aim was to determine the optimal prehospital transportation strategy for individual patients and to assess which factors influence this decision.

Methods—

We constructed a decision tree model to compare outcome of ischemic stroke patients after transportation to a primary stroke center versus a more distant intervention center. The optimal strategy was estimated based on individual patient characteristics, geographic location, and workflow times. In the base case scenario, the primary stroke center was located at 20 minutes and the intervention center at 45 minutes. Additional sensitivity analyses included an urban scenario (10 versus 20 minutes) and a rural scenario (30 versus 90 minutes).

Results—

Direct transportation to the intervention center led to better outcomes in the base case scenario when the likelihood of a large vessel occlusion as a cause of the ischemic stroke was >33%. With a high likelihood of large vessel occlusion (66%, comparable with a Rapid Arterial Occlusion Evaluation score of 5 or above), the benefit of direct transportation to the intervention center was 0.10 quality-adjusted life years (=36 days in full health). In the urban scenario, direct transportation to an intervention center was beneficial when the risk of large vessel occlusion was 24% or higher. In the rural scenario, this threshold was 49%. Other factors influencing the decision included door-to-needle times, door-to-groin times, and the door-in-door-out time.

Conclusions—

The preferred prehospital transportation strategy for suspected stroke patients depends mainly on the likelihood of large vessel occlusion, driving times, and in-hospital workflow times. We constructed a robust model that combines these characteristics and can be used to personalize prehospital triage, especially in more remote areas.

Brain Emergency Management Initiative for Optimizing Hub-Helicopter Emergency Medical Systems-Spoke Transfer Networks

OBJECTIVE

Embolectomy is standard for select occlusions up to 24 hours. Transfer patients may have worse outcomes than those originating in embolectomy centers. We developed the Brain Emergency Management Initiative (BEMI) protocol to streamline this transfer process and mimic the urgency that surrounds ST-elevation myocardial infarction cardiac evaluations.

METHODS

We conducted an exploratory assessment of consecutive acute telestroke patients transferred for potential intervention in pre-BEMI versus BEMI periods. Times included spoke in, spoke out, hub in, and groin puncture. Outcomes included discharge destination and symptomatic intracranial hemorrhage.

RESULTS

Overall, 68 transfers were assessed. There was a higher National Institute of Neurological Disorders and Stroke in BEMI (11 pre-BEMI vs. 20 B.M., P = .01). There were shorter spoke door in to door out (143 vs. 118 minutes, P = .01) and spoke door out to hub door in times (23 minutes pre-BEMI vs. 21 minutes BEMI, P = .001). For embolectomy patients, there was shorter hub door in to reperfusion (83 minutes pre-BEMI vs. 74 minutes BEMI, P = .04) and recombinant tissue plasminogen decision to groin puncture (155 minutes pre-BEMI vs. 130 minutes BEMI; P = .01). There were no symptomatic intracranial hemorrhage or discharge differences.

CONCLUSION

In our hub-helicopter emergency medical services-spoke telestroke network, BEMI led to improved evaluation times. BEMI may serve as a model for future rapid stroke transfer pathways.

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.

Effects of irisin on the dysfunction of blood-brain barrier in rats after focal cerebral ischemia/reperfusion

OBJECTIVE

To investigate whether irisin could protect against blood-brain barrier (BBB) dysfunction following focal cerebral ischemia/reperfusion in rats.

METHODS AND MATERIALS

Seventy-two adult male Sprague Dawley rats weighing 280-320 g were randomly divided into three groups: sham operation group (S), focal cerebral ischemia/reperfusion group (FC), and irisin group (IR). Focal cerebral ischemia was induced by improved thread occlusion of right middle cerebral artery (MCAO) for 2 hr followed by reperfusion for 24 hr in rats. After 24 hr of reperfusion, the neurological evaluation was performed by the method of Longa's score. The histopathological changes were observed by HE staining. The brain water content was determined by detecting the wet weight and dry weight. The BBB permeability was assessed by fluorescence spectrophotometer and fluorescence microscopy for Evans blue (EB) extravasation. The activity and expression of matrix metalloproteinase-9 (MMP-9) in different groups were detected by immunohistochemical staining, Western blot, and gel gelatin zymography.

RESULTS

After MCAO, the neurological deficit scores, the infarct volume, the brain water content, and the EB content were higher in the FC group than those in the S group (p < .05). While after irisin treatment, these indicators mentioned above were lower than those in the IR group (p < .05). Moreover, the protein expression of MMP-9 in the cortex increased significantly after MCAO, while irisin treatment could decrease the protein expression of MMP-9 in the cortex (p < .05).

CONCLUSION

Our data suggest that irisin can attenuate brain damage both morphologically and functionally and protect BBB from disruption after focal cerebral ischemia/reperfusion, which is highly associated with the inhibition of the expression and activity of MMP-9 in the brain tissue.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

[Mothership or drip and ship?]

BACKGROUND

The scientific evidence of the high efficacy of endovascular stroke treatment in large vessel occlusion (LVO) led to this treatment being accepted as the gold standard in these patients.

OBJECTIVE

This review article presents the various organizational models for thrombectomy and analyzes which model is preferred under which circumstances.

MATERIAL AND METHODS

In an analysis of the recent scientific literature the models for optimizing patient transport (drip and ship or mothership) and optimizing the availability of interventionalists (drip and drive or remote mentoring) are presented and compared. In addition, considerations are made on thrombectomy rates and the prevalence of LVOs and the construction of organizational models.

RESULTS

If the location of the stroke patient is just as far from or closer to a comprehensive stroke center (CSC) than a primary stroke center (PSC), the patient should be transported directly to the CSC by mothership. If, on the other hand, a PSC is closer to the stroke site than a CSC and the time after the onset of symptoms lies within the lysis time window, this decision depends on many variables.

CONCLUSION

Based on the unambiguous data situation, no recommendations can currently be made for a generally superior organizational model.

Clinical Outcomes of Endovascular Thrombectomy in Tissue Plasminogen Activator versus Non-Tissue Plasminogen Activator Patients at Primary Stroke Care Centers

Background:

The effect of intravenous tissue plasminogen activator (IV tPA) administration before endovascular intervention as compared to without at thrombectomy-capable low-volume centers on procedural aspects and patient outcomes has not been investigated.

Methods:

Retrospective chart review was performed in all consecutive large vessel cerebrovascular accident patients treated with endovascular therapy at two select rural primary stroke centers between 2011 and 2015. Patients’ data regarding age, sex, and medical history, as well as thrombus location by catheter-based cerebral angiography, postprocedural reperfusion status, and clinical outcomes were reviewed. The primary outcome measure of the study was a comparison of modified Rankin scale (MRS) at 90 days in patients’ postendovascular thrombectomy with prior IV tPA administration versus those who underwent thrombectomy and did not qualify for preprocedural IV tPA.

Results:

After application of the set inclusion and exclusion criteria, data of 46 out of 65 patients were analyzed. Twenty-three patients (50%) received IV tPA before thrombectomy and 23 patients did not qualify for IV tPA (50%). Successful recanalization (thrombolysis in cerebral infarction 2b/3) was achieved in 86% (20/23 patients) of thrombectomy patients without preprocedural IV tPA and 82% (19/23) of patients who received it (odds ratio [OR]: 0.03, confidence interval [CI]: 95% 0.062–0.16, P < 0.0001). MRS of 2 or less at 90 days was 43.4% (10/23) in patients with no preprocedural IV tPA and 39.1% (9/23) in the combined therapy group (OR: 0.84, CI: 0.26–2.70, P = 0.8).

Conclusion:

Patients undergoing endovascular thrombectomy for large vessel occlusion at select low-volume rural centers showed benefit from this treatment regardless of IV tPA administration. Clinical outcomes and complications at select low-volume thrombectomy-proficient centers are comparable to large volume comprehensive stroke centers as well as the landmark studies proving the efficacy of endovascular treatment.

Site Experience and Outcomes in the Trevo Acute Ischemic Stroke (TRACK) Multicenter Registry

Background and Purpose—

It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry.

Methods—

The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (<2 cases/month), medium-volume (2–4 cases/month), and high-volume centers (>4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes.

Results—

A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P =0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P =0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8–442.5), 239 (175–389), and 336.5 (221.3–466.5) minutes in low-, medium-, and high-volume centers, respectively ( P =0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P <0.001), higher balloon guide catheter use (40% versus 36% versus 59%; P ≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P =0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03–2.7; P =0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1–2.9; P =0.03) centers, but there were no significant differences between high- and medium-volume centers ( P =0.86).

Conclusions—

Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.

Magnitude of Benefit of Combined Endovascular Thrombectomy and Intravenous Fibrinolysis in Large Vessel Occlusion Ischemic Stroke

Background and Purpose—

Quantifying the benefit magnitude of combined endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT) versus nonreperfusion care in patients with acute ischemic stroke caused by large vessel occlusion would aid organization of regional stroke care systems.

Methods—

NINDS rt-PA Study (National Institute for Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator) and SWIFT PRIME trial (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment) patients were matched for prognosis (based on age and National Institutes of Health Stroke Scale) and definite/likely anterior circulation large vessel occlusion (based on National Institutes of Health Stroke Scale total score and item pattern), using optimal inverse variance matching, to determine comparative outcomes with nonreperfusion care alone, IVT alone, and IVT+EVT.

Results—

Matching yielded 240 patients, including 80 each treated with nonreperfusion care, IVT alone, and IVT+EVT, with, respectively, mean age 67.1, 67.1, and 66.9 and presenting deficit severity (National Institutes of Health Stroke Scale) mean 15.8, 15.9, and 15.9. Outcomes at 3 months for IVT+EVT versus nonreperfusion care included freedom from disability (modified Rankin Scale score, 0–1) 48.1% versus 21.3%, P =0.0004; functional independence (modified Rankin Scale score, 0–2) 62.9% versus 32.6, P =0.0001; and reduced disability over all 7 modified Rankin Scale levels, common odds ratio 3.34, P <0.0001. Outcomes for IVT alone versus nonreperfusion care included: freedom from disability 30.0% versus 21.3%, P =0.28 and reduced disability over all 7 modified Rankin Scale levels, common odds ratio 1.14, P =0.65. Compared with nonreperfusion care, the number needed to treat with EVT+IVT for 1 more patient to have reduced disability was 1.8.

Conclusions—

Matched patient analysis across randomized trials provides evidence that the strategy of combined IVT and mechanical thrombectomy is a highly beneficial treatment strategy for acute ischemic stroke caused by large vessel occlusion patients. A reasonable effect magnitude estimate is that, among every 100 patients treated, combined IVT+EVT reperfusion therapy, compared with no reperfusion therapy, reduces long-term disability in 57, including conferring functional independence upon 30.

An Introduction to Software Tools, Data, and Services for Geospatial Analysis of Stroke Services

Background: There is interest in the use geospatial data for development of acute stroke services given the importance of timely access to acute reperfusion therapy. This paper aims to introduce clinicians and citizen scientists to the possibilities offered by open source softwares (R and Python) for analyzing geospatial data. It is hoped that this introduction will stimulate interest in the field as well as generate ideas for improving stroke services.

Method: Instructions on installation of libraries for R and Python, source codes and links to census data are provided in a notebook format to enhance experience with running the software. The code illustrates different aspects of using geospatial analysis: (1) creation of choropleth (thematic) map which depicts estimate of stroke cases per post codes; (2) use of map to help define service regions for rehabilitation after stroke.

Results: Choropleth map showing estimate of stroke per post codes and service boundary map for rehabilitation after stroke. Conclusions The examples in this article illustrate the use of a range of components that underpin geospatial analysis. By providing an accessible introduction to these areas, clinicians and researchers can create code to answer clinically relevant questions on topics such as service delivery and service demand.

Workflow Intervals of Endovascular Acute Stroke Therapy During On- Versus Off-Hours: The MR CLEAN Registry

Background and Purpose- Endovascular treatment (EVT) of patients with acute ischemic stroke because of large vessel occlusion involves complicated logistics, which may cause a delay in treatment initiation during off-hours. This might lead to a worse functional outcome. We compared workflow intervals between endovascular treatment-treated patients presenting during off- and on-hours. Methods- We retrospectively analyzed data from the MR CLEAN Registry, a prospective, multicenter, observational study in the Netherlands and included patients with an anterior circulation large vessel occlusion who presented between March 2014 and June 2016. Off-hours were defined as presentation on Monday to Friday between 17:00 and 08:00 hours, weekends (Friday 17:00 to Monday 8:00) and national holidays. Primary end point was first door to groin time. Secondary end points were functional outcome at 90 days (modified Rankin Scale) and workflow time intervals. We stratified for transfer status, adjusted for prognostic factors, and used linear and ordinal regression models. Results- We included 1488 patients of which 936 (62.9%) presented during off-hours. Median first door to groin time was 140 minutes (95% CI, 110-182) during off-hours and 121 minutes (95% CI, 85-157) during on-hours. Adjusted first door to groin time was 14.6 minutes (95% CI, 9.3-20.0) longer during off-hours. Door to needle times for intravenous therapy were slightly longer (3.5 minutes, 95% CI, 0.7-6.3) during off-hours. Groin puncture to reperfusion times did not differ between groups. For transferred patients, the delay within the intervention center was 5.0 minutes (95% CI, 0.5-9.6) longer. There was no significant difference in functional outcome between patients presenting during off- and on-hours (adjusted odds ratio, 0.92; 95% CI, 0.74-1.14). Reperfusion rates and complication rates were similar. Conclusions- Presentation during off-hours is associated with a slight delay in start of endovascular treatment in patients with acute ischemic stroke. This treatment delay did not translate into worse functional outcome or increased complication rates.

Outcome in Direct Versus Transfer Patients in the DAWN Controlled Trial

Background and Purpose—

The impact of transfer status on clinical outcomes in the DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) population is unknown. We analyzed workflow and clinical outcome differences between direct versus transfer patients in the DAWN population.

Methods—

The following time metrics were analyzed for each group: (1) last known well to hospital arrival, (2) hospital arrival to eligibility imaging, (3) hospital arrival to arterial puncture, (4) qualifying imaging to arterial puncture, (5) last known well to arterial puncture, (6) last known well to reperfusion. The primary end point was the rate of functional independence (90-day modified Rankin Scale [mRS] score, 0–2). Using univariate unconditional logistic regression, we calculated odds ratios and 95% CIs for the association between clinically relevant time metrics, transfer status, and functional independence (mRS 0–2).

Results—

A total of 206 patients were enrolled. Among these, 121 (59%) patients were transferred, and 85 (41%) patients presented directly to a thrombectomy capable center. Median time last seen well to hospital arrival time was similar between the 2 groups (678 versus 696 minutes). The time from hospital arrival to groin puncture was significantly longer in direct patients compared with transferred patients 140 minutes (interquartile range, 105.5–177.5 minutes) and 88 minutes (interquartile range, 55–125 minutes), respectively ( P <0.001). Differences in treatment effect or differences in rates of mRS 0–2 in the thrombectomy treated patients were not statistically significant in direct versus transfer patients (odds ratios for mRS 0–2, thrombectomy versus control, were 5.62 in direct and 6.63 in transfer patients, respectively, Breslow-Day P =0.817).

Conclusions—

Although transfer patients had a faster door to puncture time, benefits of thrombectomy, and rates of mRS 0 to 2 in the treatment group were similar between direct and transferred patients in the DAWN population. These results may inform prehospital and primary stroke centers triage protocols in patients presenting in the late time window.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02142283.

Sepsis as the primary admitting diagnosis of transferred patients who died within 48 hours of arrival at a Central Texas hospital

Interhospital transfers are independently associated with inpatient mortality, and transferred patients have worse outcomes. The aim of this study was to retrospectively assess the 48-hour mortality rate in interhospital transfer cohorts of all transfers to a Central Texas teaching hospital and to identify a primary admitting diagnosis for potential intervention. A total of 15,435 patients with 19,161 transfers over the course of the study were retrospectively reviewed and placed in 18 different categories based upon the primary admitting diagnosis. There were about 5000 transfer patients yearly with ∼1.4% deaths within 48 hours of arrival. The three leading categories for transferred patients were cardiovascular, neurologic, and psychiatric. In this group, 268 of 19,161 transfers died within 48 hours of arrival. Despite being the 10th leading category for transfer, sepsis was the leading primary admitting diagnosis of patients who died within 48 hours of arrival, accounting for nearly 22% of those patients. Given the significant association found between sepsis and 48-hour mortality after transfer, we devised a novel interhospital transfer checklist based upon the Surviving Sepsis guidelines in an attempt to decrease mortality associated with these transfers.

Electronic Alberta Stroke Program Early CT score change and functional outcome in a drip-and-ship stroke service

Background

Debate continues as to whether patients with acute ischemic stroke with (suspected) large vessel occlusion benefit from direct referral versus secondary transportation.

Aims

To analyze the change in early infarct signs, collaterals, and acute ischemia volume and their association with transfer time and functional outcome.

Methods

We retrospectively analyzed consecutive transfers between 2013 and 2016 for patients with anterior circulation stroke transported from referring hospitals to our center as potential candidates for thrombectomy. Alberta Stroke Programme Early CT Scores (ASPECTS) were automatically calculated on external and in-house CT using the Brainomix e-ASPECTS software, and collaterals were assessed using the e-CTA tool. Functional status after stroke using the modified Rankin scale (mRS) was obtained.

Results

102 patients with CT scans both at the referring hospital and our center were identified. During patient transfer, e-ASPECTS declined by a median of 1 point (0–2). Functional outcome correlated with the change in e-ASPECTS (decline, n=54) (Spearman rs=0.322, 95% CI 0.131 to 0.482, p=0.001). The median image-to-image time was 149 min (IQR 113–190), but did not correlate with change in e-ASPECTS (p=0.754) and mRS score at 3 months (p=0.25). Preserved good collateral status assessed at the comprehensive stroke center was associated with better functional outcome (rs=−0.271, 95% CI −0.485 to −0.037, p=0.02).

Conclusions

Patient transfer in a drip-and-ship network was associated with declines in e-ASPECTS associated with worse functional outcome. Image-to-image time did not influence this association, but worsening collateral status did.

Non-invasive sensor technology for prehospital stroke diagnosis: Current status and future directions

BACKGROUND

The diagnosis of stroke in the prehospital environment is the subject of intense interest and research. There are a number of non-invasive external brain monitoring devices in development that utilize various technologies to function as sensors for stroke and other neurological conditions. Future increased use of one or more of these devices could result in substantial changes in the current processes for stroke diagnosis and treatment, including transportation of stroke patients by emergency medical services.

AIMS

The present review will summarize information about 10 stroke sensor devices currently in development, utilizing various forms of technology, and all of which are external, non-invasive brain monitoring devices.

SUMMARY OF REVIEW

Ten devices are discussed including the technology utilized, the indications for use (stroke and, when relevant, other neurological conditions), the environment(s) indicated for use (with a focus on the prehospital setting), a description of the physical structure of each instrument, and, when available, findings that have been published in peer-reviewed journals or otherwise reported. The review is organized based on the technology utilized by each device, and seven distinct forms were identified: accelerometers, electroencephalography (EEG), microwaves, near-infrared, radiofrequency, transcranial doppler ultrasound, and volumetric impedance phase shift spectroscopy.

CONCLUSIONS

Non-invasive external brain monitoring devices are in various stages of development and have promise as stroke sensors in the prehospital setting. Some of the potential applications include to differentiate stroke from non-stroke, ischemic from hemorrhage stroke, and large vessel occlusion (LVO) from non-LVO ischemic stroke. Successful stroke diagnosis prior to hospital arrival could transform the current diagnostic and treatment paradigm for this disease.

Googling Service Boundaries for Endovascular Clot Retrieval (ECR) Hub Hospitals in Metropolitan Sydney

Background and Purpose: Endovascular clot retrieval (ECR) has revolutionized acute stroke therapy but is expensive to run and staff with accredited interventional neuroradiologists 24/7; consequently, it is only feasible for each metropolitan city to have a minimum number of hubs that is adequate to service the population. This method is applied to search the minimum number of hospitals to be designated as ECR hubs in Sydney as well as the population at risk of stroke reachable within 30 min. Methods: Traveling time from the centroids of each suburbs to five ECR capable hubs [Royal Prince Alfred/RPA, Prince of Wales/POW, Royal North Shore/RNS, Liverpool/LH and Westmead/WH]. This step was performed using ggmap package in R to interface with Google Map application program interface (API). Next, we calculate the percentage of suburbs within each catchment in which traveling time to the ECR hub is <30 min. This step was performed for all possible combination of ECR hubs. The maps are available at https://gntem3.shinyapps.io/ambsydney/. The population at risk of stroke was estimated using stroke incident studies in Melbourne and Adelaide. Results: The best 3-hospital combinations are LPH/WH/RNS (82.3, 45.7, and 79.7% of suburbs reachable within 30 min or 187 of 226 suburbs) follow by RPA/LPH/RNS (100.0, 80.9, and 73.1% of suburbs) and LPH/POW/RNS (83.3, 90.7, and 76.6% of suburbs). The best 4-hospital model is LPH/WH/POW/RNS (84.2%, 91.1%, 90.7%, 77.8%). In the 5-hospital model, ECR is available for 191 suburbs within 30 min: LPH (83%), RPA (100%), WH (90.2%), RNS (72.7%), POW (88.9%). Based on 3-hospital model and 15% of patient eligible for ECR, the expected number of cases to be handled by each hospital is 465. This number drops down to 374 if a 4-hospital model is preferred. Conclusions: The simulation studies supported a minimum of 4 ECR hubs servicing Sydney. This model provides data on number of suburbs and population at risk of stroke that can reach these hubs within 30 min.

Application of Strategic Transport Model and Google Maps to Develop Better Clot Retrieval Stroke Service

Background and purpose: Two hubs are designated to provide endovascular clot retrieval (ECR) for the State of Victoria, Australia. In an earlier study, Google Maps application programming interface (API) was used to perform modeling on the combination of hospitals optimizing for catchment in terms of current traveling time and road conditions. It is not known if these findings would remain the same if the modeling was performed with a large-scale transport demand model such as Victorian Integrated Transport Model (VITM). This model is developed by the Victorian State Government Transport has the capability to forecast travel demand into the future including future road conditions which is not possible with a Google Maps based applications. The aim of this study is to compare the travel time to potential ECR hubs using both VITM and the Google Maps API and model stability in the next 5 and 10 years.

Methods: The VITM was used to generate travel time from randomly generated addresses to four existing ECR capable hubs in Melbourne city, Australia (i.e., Royal Melbourne Hospital/RMH, Monash Medical Center/MMC, Alfred Hospital/ALF, and Austin Hospital/AUS) and the optimal service boundaries given a delivering time threshold are then determined.

Results: The strategic transport model and Google map methods were similar with the R² of 0.86 (peak and off peak) and the Nash-Sutcliffe model of efficiency being 0.83 (peak) and 0.76 (off-peak travel). Futures modeling using VITM found that this proportion decreases to 82% after 5 years and 80% after 10 years. The combination of RMH and ALF provides coverage for 74% of cases, 68% by 5 years, and 66% by 10 years. The combination of RMH and AUS provides coverage for 70% of cases in the base case, 65% at 5 years, and 63% by 10 years.

Discussion: The results from strategic transport model are similar to those from Google Maps. In this paper we illustrate how this method can be applied in designing and forecast stroke service model in different cities in Australia and around the world.

Centrally Guided Identification of Patients With Large Vessel Occlusion: Lessons From Trauma Systems

OBJECTIVE

Improve prehospital identification of acute ischemic stroke patients with large vessel occlusion (LVO) by using a trauma system-based emergency communication center (ECC) to guide the emergency medical service (EMS).

METHODS

We trained 24 ECC paramedics in the Emergency Medical Stroke Assessment (EMSA). ECC-guided EMS in performance of the EMSA on patients with suspected stroke. During the second half of the study, we provided focused feedback to ECC after reviewing recorded ECC-EMS interactions. We compared the sensitivity, specificity, and area under the receiver operator characteristics curve (AUC) and 95% confidence interval of ECC-guided EMSA to the NIH Stroke Scale (NIHSS) for predicting a discharge diagnosis of LVO.

RESULTS

We enrolled 569 patients from September 2016 through February 2018. Of 463 patients analyzed, 236 (51%) had a discharge diagnosis of stroke and 227 (49%) had a nonstroke diagnosis. There were 45 (19%) stroke patients with LVO. For predicting LVO, there was no significant difference between the EMSA AUC = .68 (.59-.77) and the NIHSS AUC = .73 (.65-.81). An EMSA score greater than or equal to 4 had sensitivity = 75.6 (60.5-87.1) and specificity = 62.4 (57.6-67.1) for LVO. During the first 9 months of the study, the EMSA AUC = .61 (.44-.77) compared to an AUC = .74 (.64-.84) during the second 9 months.

CONCLUSIONS

ECC-guided prehospital EMSA is feasible, has similar ability to predict LVO compared to the NIHSS, and has sustained performance over time.