"Picture to puncture": a novel time metric to enhance outcomes in patients transferred for endovascular reperfusion in acute ischemic stroke

Automated Emergent Large Vessel Occlusion Detection Using Viz.ai Software and Its Impact on Stroke Workflow Metrics and Patient Outcomes in Stroke Centers: A Systematic Review and Meta-analysis

The implementation of artificial intelligence (AI), particularly Viz.ai software in stroke care, has emerged as a promising tool to enhance the detection of large vessel occlusion (LVO) and to improve stroke workflow metrics and patient outcomes. The aim of this systematic review and meta-analysis is to evaluate the impact of Viz.ai on stroke workflow efficiency in hospitals and on patients' outcomes. Following the PRISMA guidelines, we conducted a comprehensive search on electronic databases, including PubMed, Web of Science, and Scopus databases, to obtain relevant studies until 25 October 2024. Our primary outcomes were door-to-groin puncture (DTG) time, CT scan-to-start of endovascular treatment (EVT) time, CT scan-to-recanalization time, and door-in-door-out time. Secondary outcomes included symptomatic intracranial hemorrhage (ICH), any ICH, mortality, mRS score < 2 at 90 days, and length of hospital stay. A total of 12 studies involving 15,595 patients were included in our analysis. The pooled analysis demonstrated that the implementation of the Viz.ai algorithm was associated with lesser CT scan to EVT time (SMD -0.71, 95% CI [-0.98, -0.44], p < 0.001) and DTG time (SMD -0.50, 95% CI [-0.66, -0.35], p < 0.001) as well as CT to recanalization time (SMD -0.55, 95% CI [-0.76, -0.33], p < 0.001). Additionally, patients in the post-AI group had significantly lower door-in door-out time than the pre-AI group (SMD -0.49, 95% CI [-0.71, -0.28], p < 0.001). Despite the workflow metrics improvement, our analysis did not reveal statistically significant differences in patient clinical outcomes (p > 0.05). Our results suggest that the integration of the Viz.ai platform in stroke care holds significant potential for reducing EVT delays in patients with LVO and optimizing stroke flow metrics in comprehensive stroke centers. Further studies are required to validate its efficacy in improving clinical outcomes in patients with LVO.

Ultrasound Evaluation for Shortening the Door-to-Puncture Time During Endovascular Treatment of Intracranial Vessel Occlusion

OBJECTIVE

Concerning endovascular treatment for acute ischemic stroke with intracranial vessel occlusion, shortening the door-to-puncture time (DTP) improves the patient's outcome. To determine endovascular treatment, magnetic resonance angiography or computed tomography angiography is performed for occluded vessel detection. Another detection method of internal carotid artery (ICA) occlusion or middle cerebral artery first segment (M1) occlusion is ultrasound (US). Bilateral flow pattern analysis of common carotid arteries by US leads to the diagnosis of ICA or M1 occlusion within a few minutes. Moreover, it can be conducted in the emergency department. The addition of the US for the initial evaluation of vessel occlusion can shorten the DTP. In this study, we evaluated the effectiveness of carotid artery US imaging in detecting large vessel occlusion (LVO) and shortening the DTP.

MATERIALS AND METHODS

This is a retrospective case-control study. Our analysis was based on the data from 150 patients with LVO or medium vessel occlusion who underwent endovascular revascularization treatment at our hospital between January 2015 and December 2022. Among them, 104 patients who had an anterior circulation vessel occlusion were included. They were divided into the US evaluation group and the non-US evaluation group, and their characteristics, treatment time course, and outcomes were compared.

RESULTS

This study included 104 patients with a median age of 81 years (interquartile range: 73-89 years), 57.7% were females, and the pre-stroke modified Rankin Scale (mRS) median was 0.5 (interquartile range: 0-3). Our cohort included advanced aged patients; therefore, this study included 56.7% of patients over 80 years old and 35.6% of pre-stroke mRS over 3. The US (US group) and non-US (non-US group) evaluation groups included 54 and 50 patients, respectively. As magnetic resonance imaging evaluation in the non-US group was performed over the 4.5 hours delayed arrival of patients from the last known well (LKW) to consider the evaluation of tPA administration, selection bias occurred. The US group included high National Institutes of Health Stroke Scale (NIHSS) patients (P = 0.0152) and more ICA occlusions (P = 0.0146). Onset (LKW) to door time was shorter in the US group (median, 75 min (35-146.5 minutes)) than the non-US group (median, 179 minutes (47.3-432.8 minutes); P = 0.0426), and the DTP was shorter for the US group (median, 75.5 minutes (63.8-87.3 minutes)) than for the non-US group (median, 85 minutes (67-129 minutes); P = 0.0102). Statistical difference was not seen in puncture to reperfusion time among the US group (median, 71.5 minutes (51-114 minutes)) and non-US group (median, 67 minutes (42.3-98.5 minutes); P = 0.5581). The onset (LKW) to reperfusion was shorter for the US group (median, 251 minutes (201-327.3 minutes)) than for the non-US group (median, 319 minutes (200-633.5 minutes); P = 0.0348). No statistical differences were seen for thrombolysis in cerebral infarction grade 2b-3 after treatment, improvement of NIHSS, and mRS at 90 days.

CONCLUSION

US is a useful imaging method to identify an anterior circulation LVO. It can distinguish patients with severe internal carotid or middle cerebral artery occlusion from medium vessel occlusion or other peripheral vessel occlusions. US helps to shorten the DTP time of LVO.

Predicting symptomatic intracranial hemorrhage after endovascular treatment of vertebrobasilar artery occlusion: PEACE score

BACKGROUND

Current clinical decision tools for assessing the risk of symptomatic intracranial hemorrhage (sICH) in patients with vertebrobasilar artery occlusion (VBAO) who received endovascular treatment (EVT) have limited performance. This study develops and validates a clinical risk score to precisely estimate the risk of sICH in VBAO patients.

METHODS

The derivation cohort recruited patients with VBAO who received EVT from the Posterior Circulation IschemIc Stroke Registry in China. Based on the posterior circulation-Alberta Stroke Program Early CT Score (pc-ASPECTS) evaluation method, the cohort was further divided into non-contrast CT (NCCT) and diffusion weighted imaging (DWI) cohorts to construct predictive models. sICH was diagnosed according to the Heidelberg Bleeding Classification within 48 hours of EVT. Clinical signature was constructed in the derivation cohort using machine learning and was validated in two additional cohorts from Asia and Europe.

RESULTS

We enrolled 1843 patients who underwent EVT and had complete data. pc-ASPECTS of 1710 patients was evaluated on NCCT and 699 patients on DWI. In the NCCT cohort, 1364 individuals made up the training set, of whom 101 (7.4%) developed sICH. In the DWI cohort, the training set consisted of 560 individuals, with 44 (7.9%) experiencing sICH. Predictors of sICH were: glucose, pc-ASPECTS, time from estimated occlusion to groin puncture (EOT), poor collateral circulation, and modified Thrombolysis in Cerebral Infarction (mTICI) score. From these predictors, we derived the weighted poor collateral circulation-EOT-pc-ASPECTS-mTICI-glucose (PEACE) score. The PEACE score showed good discrimination in the training set (area under the curve (AUC)NCCT=0.85; AUCDWI=0.86), internal validation set (AUCNCCT=0.81; AUCDWI=0.82), and two additional external validation set (Asia: AUCNCCT=0.78, AUCDWI=0.80; Europe: AUCNCCT=0.74, AUCDWI=0.78).

CONCLUSION

The PEACE score reliably predicted the risk of sICH in VBAO patients who underwent EVT.

Influence of vascular imaging acquisition at local stroke centers on workflows in the drip-n-ship model: a RACECAT post hoc analysis

BACKGROUND

The influence of vascular imaging acquisition on workflows at local stroke centers (LSCs) not capable of performing thrombectomy in patients with a suspected large vessel occlusion (LVO) stroke remains uncertain. We analyzed the impact of performing vascular imaging (VI+) or not (VI- at LSC arrival on variables related to workflows using data from the RACECAT Trial.

OBJECTIVE

To compare workflows at the LSC among patients enrolled in the RACECAT Trial with or without VI acquisition.

METHODS

We included patients with a diagnosis of ischemic stroke who were enrolled in the RACECAT Trial, a cluster-randomized trial that compared drip-n-ship versus mothership triage paradigms in patients with suspected acute LVO stroke allocated at the LSC. Outcome measures included time metrics related to workflows and the rate of interhospital transfers and thrombectomy among transferred patients.

RESULTS

Among 467 patients allocated to a LSC, vascular imaging was acquired in 277 patients (59%), of whom 198 (71%) had a LVO. As compared with patients without vascular imaging, patients in the VI+ group were transferred less frequently as thrombectomy candidates to a thrombectomy-capable center (58% vs 74%, P=0.004), without significant differences in door-indoor-out time at the LSC (median minutes, VI+ 78 (IQR 69-96) vs VI- 76 (IQR 59-98), P=0.6). Among transferred patients, the VI+ group had higher rate of thrombectomy (69% vs 55%, P=0.016) and shorter door to puncture time (median minutes, VI+ 41 (IQR 26-53) vs VI- 54 (IQR 40-70), P<0.001).

CONCLUSION

Among patients with a suspected LVO stroke initially evaluated at a LSC, vascular imaging acquisition might improve workflow times at thrombectomy-capable centers and reduce the rate of futile interhospital transfers. These results deserve further evaluation and should be replicated in other settings and geographies.

Interactive Direct Interhospital Transfer Network System for Acute Stroke in South Korea

BACKGROUND AND PURPOSE

Interhospital transfer is an essential practical component of regional stroke care systems. To establish an effective stroke transfer network in South Korea, an interactive transfer system was constructed, and its workflow metrics were observed.

METHODS

In March 2019, a direct transfer system between primary stroke hospitals (PSHs) and comprehensive regional stroke centers (CSCs) was established to standardize the clinical pathway of imaging, recanalization therapy, transfer decisions, and exclusive transfer linkage systems in the two types of centers. In an active case, the time metrics from arrival at PSH ("door") to imaging was measured, and intravenous thrombolysis (IVT) and endovascular treatment (EVT) were used to assess the differences in clinical situations.

RESULTS

The direct transfer system was used by 27 patients. They stayed at the PSH for a median duration of 72 min (interquartile range [IQR], 38-114 min), with a median times of 15 and 58 min for imaging and subsequent processing, respectively. The door-to-needle median times of subjects treated with IVT at PSHs (n=5) and CSCs (n=2) were 21 min (IQR, 20.0-22.0 min) and 137.5 min (IQR, 125.3-149.8 min), respectively. EVT was performed on seven subjects (25.9%) at CSCs, which took a median duration of 175 min; 77 min at the PSH, 48 min for transportation, and 50 min at the CSC. Before EVT, bridging IVT at the PSH did not significantly affect the door-to-puncture time (127 min vs. 143.5 min, p=0.86).

CONCLUSIONS

The direct and interactive transfer system is feasible in real-world practice in South Korea and presents merits in reducing the treatment delay by sharing information during transfer.

Factors Predicting Misidentification of Acute Ischemic Stroke and Large Vessel Occlusion by Paramedics

The emergence of thrombectomy for large vessel occlusions has increased the importance of accurate prehospital identification and triage of acute ischemic stroke (AIS). Despite available clinical scores, prehospital identification is suboptimal. Our objective was to improve the sensitivity of prehospital AIS identification by combining dispatch information with paramedic impression. We performed a retrospective cohort review of emergency medical services and hospital records of all patients for whom a stroke alert was activated in 1 urban, academic emergency department from January 1, 2018, to December 31, 2019. Using admission diagnosis of acute stroke as outcome, we calculated the sensitivity and specificity of dispatch and paramedic impression in identifying AIS and large vessel occlusion. We identified factors that, when included together, would improve the sensitivity of prehospital AIS identification. Two-hundred twenty-six stroke alerts were activated by emergency department physicians after transport by Indianapolis emergency medical services. Forty-four percent (99/226) were female, median age was 58 years (interquartile range, 50-67 years), and median National Institutes of Health Stroke Scale was 6 (interquartile range, 2-12). Paramedics demonstrated superior sensitivity (59% vs. 48%) but inferior specificity (56% vs. 73%) for detection of stroke as compared with dispatch. A strategy incorporating dispatch code of stroke, or paramedic impression of altered mental status or weakness in addition to stroke, would be 84% sensitive and 27% specific for identification of stroke. To optimize rapid and sensitive stroke detection, prehospital systems should consider inclusion of patients with dispatch code of stroke and provider impression of altered mental status or generalized weakness.

Impact of interhospital transfer vs. direct admission on acute ischemic stroke patients: A subset analysis of the COMPLETE registry

Background

Efficacy of thrombectomy treatment in acute ischemic stroke large vessel occlusion (AIS-LVO) patients is time dependent. Direct admission to thrombectomy centers (vs. interhospital transfer) may reduce time to treatment and improve outcomes. In this subset analysis of the COMPLETE registry, we compared outcomes between direct to thrombectomy center (Direct) vs. transfer from another hospital to thrombectomy center (Transfer) in AIS-LVO patients treated with aspiration thrombectomy.

Methods

COMPLETE was a prospective, international registry that enrolled patients from July 2018 to October 2019, with a 90-day follow-up period that was completed in January 2020. Imaging findings and safety events were adjudicated by core lab and independent medical reviewers, respectively. Pre-defined primary endpoints included post-procedure angiographic revascularization (mTICI ≥2b), 90-day functional outcome (mRS 0–2), and 90-day all-cause mortality. Planned collections of procedural time metrics and outcomes were used in the present post-hoc analysis to compare outcomes between transfer and direct patient cohorts.

Results

Of 650 patients enrolled, 343 were transfer [52.8% female; mean (SD) age, 68.2 (13.9) years], and 307 were direct [55.4% female; 68.5 (14.5) years] admit. Median onset-to-puncture time took longer in the transfer vs. direct cohort (5.65 vs. 3.18 h: 2.33 h difference, respectively; p < 0.001). There was no significant difference in successful revascularization rate, mTICI ≥2b (88.3 and 87.3%), sICH at 24 h (3.8 and 3.9%), median length of hospital stay (7 and 6 days), and 90-day mortality (16.9 and 14.0%) between transfer vs. direct patients, respectively. However, achieving 90-day functional independence was less likely in transfer compared with direct patients (mRS 0–2 was 50.3 vs. 61.7%, p = 0.0056).

Conclusions

In the COMPLETE registry, direct to thrombectomy center was associated with significantly shorter onset-to-puncture times, and higher rates of good clinical outcome across different geographies. Additional research should focus on AIS-LVO detection to facilitate direct routing of patients to appropriate treatment centers.

Clinical trial registration

https://clinicaltrials.gov (Unique identifier: NCT03464565).

TACTICS - Trial of Advanced CT Imaging and Combined Education Support for Drip and Ship: evaluating the effectiveness of an 'implementation intervention' in providing better patient access to reperfusion therapies: protocol for a non-randomised controlled stepped wedge cluster trial in acute stroke

INTRODUCTION

Stroke reperfusion therapies, comprising intravenous thrombolysis (IVT) and/or endovascular thrombectomy (EVT), are best practice treatments for eligible acute ischemic stroke patients. In Australia, EVT is provided at few, mainly metropolitan, comprehensive stroke centres (CSC). There are significant challenges for Australia's rural and remote populations in accessing EVT, but improved access can be facilitated by a 'drip and ship' approach. TACTICS (Trial of Advanced CT Imaging and Combined Education Support for Drip and Ship) aims to test whether a multicomponent, multidisciplinary implementation intervention can increase the proportion of stroke patients receiving EVT.

METHODS AND ANALYSIS

This is a non-randomised controlled, stepped wedge trial involving six clusters across three Australian states. Each cluster comprises one CSC hub and a minimum of three primary stroke centre (PSC) spokes. Hospitals will work in a hub and spoke model of care with access to a multislice CT scanner and CT perfusion image processing software (MIStar, Apollo Medical Imaging). The intervention, underpinned by behavioural theory and technical assistance, will be allocated sequentially, and clusters will move from the preintervention (control) period to the postintervention period.

PRIMARY OUTCOME

Proportion of all stroke patients receiving EVT, accounting for clustering.

SECONDARY OUTCOMES

Proportion of patients receiving IVT at PSCs, proportion of treated patients (IVT and/or EVT) with good (modified Rankin Scale (mRS) score 0-2) or poor (mRS score 5-6) functional outcomes and European Quality of Life Scale scores 3 months postintervention, proportion of EVT-treated patients with symptomatic haemorrhage, and proportion of reperfusion therapy-treated patients with good versus poor outcome who presented with large vessel occlusion at spokes.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Hunter New England Human Research Ethics Committee (18/09/19/4.13, HREC/18/HNE/241, 2019/ETH01238). Trial results will be disseminated widely through published manuscripts, conference presentations and at national and international platforms regardless of whether the trial was positive or neutral.

TRIAL REGISTRATION NUMBER

ACTRN12619000750189; UTNU1111-1230-4161.

The Role of Vascular Imaging atReferral Centers in the Drip and Ship Paradigm

BACKGROUND

In drip-and-ship protocols, non-invasive vascular imaging (NIVI) at Referral Centers (RC), although recommended, is not consistently performed and its value is uncertain. We evaluated the role of NIVI at RC, comparing patients with (VI+) and without (VI-) vascular imaging in several outcomes.

METHODS

Observational, multicenter study from a prospective government-mandated population-based registry of code stroke patients. We selected acute ischemic stroke patients, initially assessed at RC from January-2016 to June-2020. We compared and analyzed the rates of patients transferred to a Comprehensive Stroke Center (CSC) for Endovascular Treatment (EVT), rates of EVT and workflow times between VI+ and VI- patients.

RESULTS

From 5128 ischemic code stroke patients admitted at RC; 3067 (59.8%) were VI+, 1822 (35.5%) were secondarily transferred to a CSC and 600 (11.7%) received EVT. Among all patients with severe stroke (NIHSS ≥16) at RC, a multivariate analysis showed that lower age, thrombolytic treatment, and VI+ (OR:1.479, CI95%: 1.117-1.960, p=0.006) were independent factors associated to EVT. The rate of secondary transfer to a CSC was lower in VI+ group (24.6% vs. 51.6%, p<0.001). Among transferred patients, EVT was more frequent in VI+ than VI- (48.6% vs. 21.7%, p<0.001). Interval times as door-in door-out (median-minutes 83.5 vs. 82, p= 0.13) and RC-Door to puncture (median-minutes 189 vs. 178, p= 0.47) did not show differences between both groups.

CONCLUSION

In the present study, NIVI at RC improves selection for EVT, and is associated with receiving EVT in severe stroke patients. Time-metrics related to drip-and-ship model were not affected by NIVI.

Door-In-Door-Out Process Times at Primary Stroke Centers in Chicago

STUDY OBJECTIVE

Acute stroke patients often require interfacility transfer from primary stroke centers to comprehensive stroke centers. Given the time-sensitive benefits of endovascular reperfusion, reducing door-in-door-out time at the primary stroke center is a target for quality improvement. We sought to identify modifiable predictors of door-in-door-out times at 3 Chicago-region primary stroke centers.

METHODS

We performed a retrospective analysis of consecutive patients with acute stroke from February 1, 2018 to January 31, 2020 who required transfer from 1 of 3 primary stroke centers to 1 of 3 affiliated comprehensive stroke centers in the Chicago region. Stroke coordinators at each primary stroke center abstracted data on type of transport, medical interventions and treatments prior to transfer, and relevant time intervals from patient arrival to departure. We evaluated predictors of door-in-door-out time using median regression models.

RESULTS

Of 191 total patients, 67.9% arrived by emergency medical services and 57.4% during off-hours. Telestroke was performed in 84.2%, 30.5% received alteplase, and 48.4% underwent a computed tomography (CT) angiography at the primary stroke center. The median door-in-door-out time was 148.5 (interquartile range 106 to 207.8) minutes. The largest contributors to door-in-door-out time, in minutes, were CT to CT angiography time (22 [7 to 73.5]), transfer center contact to ambulance request time (20 [8 to 53.3]), ambulance request to arrival time (20.5 [14 to 36]), and transfer ambulance time at primary stroke center (26 [21 to 35]). Factors associated with door-in-door-out time were (adjusted median differences, in minutes [95% confidence intervals]): CT angiography performed at primary stroke center (+39 [12.3 to 65.7]), walk-in arrival mode (+53 [4.1 to 101.9]), administration of intravenous alteplase (-29 [-31.3 to -26.7]), intubation at primary stroke center (+23 [7.3 to 38.7]), and ambulance request by primary stroke center (-20 [-34.3 to -5.7]).

CONCLUSION

Door-in-door-out times at Chicago-area primary stroke centers average nearly 150 minutes. Reducing time to CT angiography, receipt of alteplase, and ambulance request are likely important modifiable targets for interventions to decrease door-in-door-out times at primary stroke centers.

Risk Assessment of the Door-In-Door-Out Process at Primary Stroke Centers for Patients With Acute Stroke Requiring Transfer to Comprehensive Stroke Centers

Background Patients with acute stroke at non- or primary stroke centers (PSCs) are transferred to comprehensive stroke centers for advanced treatments that reduce disability but experience significant delays in treatment and increased adjusted mortality. This study reports the results of a proactive, systematic, risk assessment of the door-in-door-out process and its application to solution design. Methods and Results A learning collaborative (clinicians, patients, and caregivers) at 2 PSCs and 3 comprehensive stroke centers in Chicago, Illinois participated in a failure modes, effects, and criticality analysis to identify steps in the process; failures of each step, underlying causes; and to characterize each failure's frequency, impact, and safeguards using standardized scores to calculate risk priority and criticality numbers for ranking. Targets for solution design were selected among the highest-ranked failures. The failure modes, effects, and criticality analysis process map and risk table were completed during in-person and virtual sessions. Failure to detect severe stroke/large-vessel occlusion on arrival at the PSC is the highest-ranked failure and can lead to a 45-minute door-in-door-out delay caused by failure to obtain a head computed tomography and computed tomography angiogram together. Lower risk failures include communication problems and delays within the PSC team and across the PSC comprehensive stroke center and paramedic teams. Seven solution prototypes were iteratively designed and address 4 of the 10 highest-ranked failures. Conclusions The failure modes, effects, and criticality analysis identified and characterized previously unrecognized failures of the door-in-door-out process. Use of a risk-informed approach for solution design is novel for stroke and should mitigate or eliminate the failures.

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

Importance

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

Objective

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

Design, Setting, and Participants

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

Interventions

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

Trial Registration

ClinicalTrials.gov identifier: NCT02465346.

Impact of mobile stroke units

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

Total Transfer Time for Ground vs. Air Transport for Interhospital and Scene Transfers of Acute Stroke Patients

OBJECTIVES

Stroke patients are frequently transported to a comprehensive stroke center for treatment, either from a regional hospital via interhospital transfer or from the field via direct-from-scene transfer, by air or ground transportation. We sought to determine whether air or ground transport was faster in both transfer circumstances.

MATERIALS AND METHODS

A retrospective study of patients transferred to a single comprehensive stroke center for stroke treatment was conducted. EMS and medical records were used to evaluate the time and distance of transfer and functional outcome.

RESULTS

Of the 205 transfers, 47 were interhospital transfers by air (22.9%), 68 were interhospital transfers by ground (33.2%), 40 were scene transfers by air (19.5%), and 50 were scene transfers by ground (24.4%). Ground transfers had shorter alarm to EMS departure times (30 min. vs 40 min.; p<0.0001). Air transfers had shorter EMS departure to arrival times when normalized by transfer distance indicating a faster travel velocity. Interhospital transfers by air were predicted to be faster than ground over 40 miles, and scene transfers by air were predicted to be faster than ground over 28 miles. Transfer mode had no significant effect on functional outcome when controlling for tPA, thrombectomy, and NIH Stroke Scale in this small study.

CONCLUSIONS

Transfer efficiency for stroke patients depends on logistics prior to EMS arrival as well as the speed of travel. While air transport clearly results in faster travel velocity, total interhospital transfer times are faster for air transportation only when traveling more than 40 miles.

Intrinsic hospital factors: overlooked cause for variations in delay to transfer for endovascular thrombectomy

BACKGROUND

Intrinsic hospital factors leading to time delay to inter-hospital transfer for endovascular thrombectomy (EVT) have not been adequately investigated, leading to uncertainty in generalizability of hub and spoke EVT services. We investigated the contribution of intrinsic hospital factors to variations in time delay in a multicenter, retrospective study.

METHODS

The setting was a hub and spoke EVT state-wide system for a population of 6.3 million and 34 spoke hospitals. We collected data on acute large vessel occlusion strokes transferred from spoke to hub for consideration of EVT between January 2016 and December 2018. The primary endpoint was the proportion of variability in delay-time in transfer cases contributed to by intrinsic hospital factors estimated through variance component analysis implemented as a mixed-effect linear regression model with hospitals as random effects.

RESULTS

We included 434 patients. The median age was 72 years (IQR 62-79), 44% were female, and the median baseline National Institutes of Health Stroke Scale (NIHSS) was 16 (IQR 11-20). The median onset to CT time was 100 mins (IQR 69-157) at the spoke hospitals and CT acquisition at the spoke hospital to time of transfer was 93 min (IQR 70-132). 53% of the observed variability in time from CT acquisition at the spoke hospital to transfer to the EVT center was explained by intrinsic hospital factors, as opposed to patient-related factors.

CONCLUSIONS

Intrinsic hospital factors explained more than half of the observed variability in time from CT acquisition at the spoke hospital to departure for transfer. We recommend that the design of hub and spoke EVT services should account for intrinsic hospital factors to minimize hospital transfer delay.

Values of Baseline Posterior Circulation Acute Stroke Prognosis Early Computed Tomography Score for Treatment Decision of Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

This study aimed to analyze the impact of baseline posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS) on the efficacy and safety of endovascular therapy (EVT) for patients with acute basilar artery occlusion.

METHODS

The BASILAR was a nationwide prospective registry of consecutive patients with a symptomatic and radiologically confirmed acute basilar artery occlusion within 24 hours of symptom onset. We estimated the effect of standard medical therapy alone (SMT group) versus SMT plus EVT (EVT group) for patients with documented pc-ASPECTS on noncontrast CT, both as a categorical (0-4 versus 5-7 versus 8-10) and as a continuous variable. The primary outcomes included favorable functional outcomes (modified Rankin Scale ≤3) at 90 days and mortality within 90 days.

RESULTS

In total, 823 cases were included: 468 with pc-ASPECTS 8 to 10 (SMT: 71; EVT: 397), 317 with pc-ASPECTS 5 to 7 (SMT: 85; EVT: 232), and 38 with pc-ASPECTS 0 to 4 (SMT: 13; EVT: 25). EVT was associated with higher rate of favorable outcomes (adjusted relative risk with 95% CI, 4.35 [1.30-14.48] and 3.20 [1.68-6.09]; respectively) and lower mortality (60.8% versus 77.6%, P=0.005 and 35.0% versus 66.2%, P<0.001; respectively) than SMT in the pc-ASPECTS 5 to 7 and 8 to 10 subgroups. Continuous benefit curves also showed the superior efficacy and safety of EVT over SMT in patients with pc-ASPECTS ≥5. Furthermore, the prognostic effect of onset to puncture time on favorable outcome with EVT was not significant after adjustment for pc-ASPECTS (adjusted odds ratio, 0.98 [95% CI, 0.94-1.02]).

CONCLUSIONS

Patients of basilar artery occlusion with pc-ASPECTS ≥5 could benefit from EVT. The baseline pc-ASPECTS appears more important for decision making and predicting prognosis than time to EVT. Registration: URL: http://www.chictr.org.cn. Unique identifier: ChiCTR1800014759.

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.

Pathway Design for Acute Stroke Care in the Era of Endovascular Thrombectomy: A Critical Overview of Optimization Efforts

The efficacy of intravenous thrombolysis and endovascular thrombectomy (EVT) for acute ischemic stroke is highly time dependent. Optimal organization of acute stroke care is therefore important to reduce treatment delays but has become more complex after the introduction of EVT as regular treatment for large vessel occlusions. There is no singular optimal organizational model that can be generalized to different geographic regions worldwide. Current dominant organizational models for EVT include the drip-and-ship- and mothership model. Guidelines recommend routing of suspected patients with stroke to the nearest intravenous thrombolysis capable facility; however, the choice of routing to a certain model should depend on regional stroke service organization and individual patient characteristics. In general, design approaches for organizing stroke care are required, in which 2 key strategies could be considered. The first entails the identification of interventions within existing organizational models for optimizing timely delivery of intravenous thrombolysis and/or EVT. This includes adaptive patient routing toward a comprehensive stroke center, which focuses particularly on prehospital triage tools; bringing intravenous thrombolysis or EVT to the location of the patient; and expediting services and processes along the stroke pathway. The second strategy is to develop analytical or simulation model-based approaches enabling the design and evaluation of organizational models before their implementation. Organizational models for acute stroke care need to take regional and patient characteristics into account and can most efficiently be assessed and optimized through the application of model-based approaches.

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.

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.

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.

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.

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.

Acute ischaemic stroke interventions: large vessel occlusion and beyond

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

Inter-hospital transfer and patient outcomes: a retrospective cohort study

BACKGROUND

Inter-hospital transfer (IHT, the transfer of patients between hospitals) occurs regularly and exposes patients to risks of discontinuity of care, though outcomes of transferred patients remains largely understudied.

OBJECTIVE

To evaluate the association between IHT and healthcare utilisation and clinical outcomes.

DESIGN

Retrospective cohort.

SETTING

CMS 2013 100 % Master Beneficiary Summary and Inpatient claims files merged with 2013 American Hospital Association data.

PARTICIPANTS

Beneficiaries≥age 65 enrolled in Medicare A and B, with an acute care hospitalisation claim in 2013 and 1 of 15 top disease categories.

MAIN OUTCOME MEASURES

Cost of hospitalisation, length of stay (LOS) (of entire hospitalisation), discharge home, 3 -day and 30- day mortality, in transferred vs non-transferred patients.

RESULTS

The final cohort consisted of 53 420 transferred patients and 53 420 propensity-score matched non-transferred patients. Across all 15 disease categories, IHT was associated with significantly higher costs, longer LOS and lower odds of discharge home. Additionally, IHT was associated with lower propensity-matched odds of 3-day and/or 30- day mortality for some disease categories (acute myocardial infarction, stroke, sepsis, respiratory disease) and higher propensity-matched odds of mortality for other disease categories (oesophageal/gastrointestinal disease, renal failure, congestive heart failure, pneumonia, renal failure, chronic obstructivepulmonary disease, hip fracture/dislocation, urinary tract infection and metabolic disease).

CONCLUSIONS

In this nationally representative study of Medicare beneficiaries, IHT was associated with higher costs, longer LOS and lower odds of discharge home, but was differentially associated with odds of early death and 30 -day mortality depending on patients' disease category. These findings demonstrate heterogeneity among transferred patients depending on the diagnosis, presenting a nuanced assessment of this complex care transition.

Patterns and Outcomes of Endovascular Therapy in Mild Stroke

Background and Purpose- We aimed to evaluate the current practice patterns, safety and outcomes of patients who receive endovascular therapy (EVT) having mild neurological symptoms. Methods- From Jan 2010 to Jan 2018, 127,794 ischemic stroke patients were enrolled in the Florida-Puerto Rico Stroke Registry. Patients presenting within 24 hours of symptoms who received EVT were classified into mild (National Institutes of Health Stroke Scale [NIHSS] ≤5) or moderate/severe (NIHSS>5) categories. Differences in clinical characteristics and outcomes were evaluated using multivariable logistic regression. Results- Among 4110 EVT patients (median age, 73 [interquartile range=20] years; 50% women), 446 (11%) had NIHSS ≤5. Compared with NIHSS >5, those with NIHSS ≤5 arrived later to the hospital (median, 138 versus 101 minutes), were less likely to receive intravenous alteplase (30% versus 43%), had a longer door-to-puncture time (median, 167 versus 115 minutes) and more likely treated in South Florida (64% versus 53%). In multivariable analysis younger age, private insurance (versus Medicare), history of hypertension, prior independent ambulation and hospital size were independent characteristics associated with NIHSS ≤5. Among EVT patients with NIHSS ≤5, 76% were discharged home/rehabilitation and 64% were able to ambulate independently at discharge as compared with 53% and 32% of patients with NIHSS >5. Symptomatic intracerebral hemorrhage occurred in 4% of mild stroke EVT patients and 6.4% in those with NIHSS >5. Conclusions- Despite lack of evidence-based recommendations, 11% of patients receiving EVT in clinical practice have mild neurological presentations. Individual, hospital and geographic disparities are observed among endovascularly treated patients based on the severity of clinical symptoms. Our data suggest safety and overall favorable outcomes for EVT patients with mild stroke.

Off-hour admission and impact on neurological outcome in endovascular treatment for acute ischemic stroke

BACKGROUND AND PURPOSE

In the new era of endovascular treatment for acute ischemic stroke, one of the main predictors of good neurological outcome is a short time interval from stroke onset to recanalization of the occluded vessel. In this study, we examined the effect of on-hour vs off-hour admittance on the time intervals from stroke onset to recanalization in patients with acute ischemic stroke (AIS) undergoing endovascular treatment (EVT).

METHODS

One-hundred-ninety-eight patients receiving EVT for anterior AIS between 2007 and 2016 were included. Time of day and weekday for stroke admittance were recorded as well as several time intervals. Age, sex, co-morbidities, admission National Institutes of Health Stroke Scale (NIHSS), intraprocedural blood pressure, blood glucose, modified Thrombolysis in Cerebral Ischemia score (mTICI) and neurological outcome at 3 months, measured as modified Rankin Scale (mRS), were registered. On-hour was defined as 8 am-4 pm weekdays, and off-hour as weekdays outside these hours and weekends.

RESULTS

The time interval from CT (computed tomography) to recanalization was longer during off-hours, while no difference was seen in the time interval from stroke onset to CT. No statistically significant difference was seen in neurological outcome between the on- and off-hour groups in a univariate analysis.

CONCLUSIONS

Stroke admittance during off-hours is associated with longer time interval from CT examination to vessel recanalization. The study highlights the need of logistic improvement and probably more resources off-hour in order to deliver an effective stroke care around the clock.

Imaging of Patients with Suspected Large-Vessel Occlusion at Primary Stroke Centers: Available Modalities and a Suggested Approach

The overwhelming benefit of endovascular therapy in patients with large-vessel occlusions suggests that more patients will be screened than treated. Some of those patients will be evaluated first at primary stroke centers; this type of evaluation calls for standardizing the imaging approach to minimize delays in assessing, transferring, and treating these patients. Here, we propose that CT angiography (performed at the same time as head CT) should be the minimum imaging approach for all patients with stroke with suspected large-vessel occlusion presenting to primary stroke centers. We discuss some of the implications of this approach and how to facilitate them.

Door-in-Door-Out Time at Primary Stroke Centers May Predict Outcome for Emergent Large Vessel Occlusion Patients

Background and Purpose—

Interfacility transfers for thrombectomy in stroke patients with emergent large vessel occlusion (ELVO) are associated with longer treatment times and worse outcomes. In this series, we examined the association between Primary Stroke Center (PSC) door-in to door-out (DIDO) times and outcomes for confirmed ELVO stroke transfers and factors that may modify the interaction.

Methods—

We retrospectively identified 160 patients transferred to a single Comprehensive Stroke Center (CSC) with anterior circulation ELVO between July 1, 2015 and May 30, 2017. We included patients with acute occlusions of the internal carotid artery or proximal middle cerebral artery (M1 or M2 segments), with a National Institutes of Health Stroke Scale score of ≥6. Workflow metrics included time from onset to recanalization, PSC DIDO, interfacility transfer time, CSC arrival to arterial puncture, and arterial puncture to recanalization. Primary outcome measure was National Institutes of Health Stroke Scale at discharge and modified Rankin Scale (mRS) score at 90 days.

Results—

The median (Q1–Q3) age and National Institutes of Health Stroke Scale of the 130 ELVO transfers analyzed was 75 (64–84) and 17 (11–22). Intravenous alteplase was administered to 64% of patients. Regarding specific workflow metrics, median (Q1–Q3) times (in minutes) were 241 (199–332) for onset to recanalization, 85 (68–111) for PSC DIDO, 26 (17–32) for interfacility transport, 21 (16–39) for CSC door to arterial puncture, and 24 (15–35) for puncture to recanalization. Median discharge National Institutes of Health Stroke Scale score was 5 (2–16), and 46 (35%) patients had a favorable outcome at 90 days. Complete reperfusion (modified Thrombolysis in Cerebral Ischemia 2c/3) modified the deleterious association of DIDO on outcome.

Conclusions—

For patients diagnosed with ELVO at a PSC who are being transferred to a CSC for thrombectomy, longer DIDO times may have a deleterious effect on outcomes and may represent the single biggest modifiable factor in onset to recanalization time. PSCs should make efforts to decrease DIDO and routine use of DIDO as a performance measure is encouraged.

Impact of landmark endovascular stroke trials on logistical performance measures: a before-and-after evaluation of real-world data from a regional stroke system of care

Background and purpose

Endovascular treatment of large-vessel occlusion stroke often necessitates patient transfer by a twin-track approach: endovascular thrombectomy (ET) in endovascular-capable facilities preceded by intravenous thrombolysis in primary stroke centers. We tested the open hypothesis that recent landmark trials on ET had any significant effect on logistical performance measures among different modes of admission.

Methods

We retrospectively categorized 250 patients who presented at our institution as: (A) primarily admitted or transferred from (B) inner-city and (C) regional hospitals. The period from May 2015 to June 2017 was compared with the preceding period of August 2009 to April 2015 with respect to real-life transfer distances and sectional time metrics from symptom onset to angiographic recanalization.

Results

Onset-to-recanalization time decreased in the primary admission path, whereas delays persisted for inter-hospital transfer: (A: 261 min (210–315) vs 198 (167–264) P<0.0001; B: 257 (214–306) vs 265 (199– 360) P=0.566; and C: 371 (322–415) vs 346 (307–405) P=0.559). Onset-to-recanalization time was negatively correlated with recanalization success (mTICI; r=-0.4195 P<0.0001). The rate of secondarily referred patients (26% vs 48% P=0.0004) and off-hour presentation (36% vs 44% P=0.004) increased, as did the catchment area (C: 52.2 km (30,4–64,5) vs 64.4 (43,2–78,9) P=0.032). Improvement in door-in-door-out time at the referring hospitals (C: 113 min (30) vs 86 (29) P=0.0236) did not translate into reduced total referral times or the accelerated initiation of ET.

Conclusion

Recent landmark trials already led to a considerable streamlining of ET workflow if patients were directly admitted. Prehospital time management and triage seem to be the major determinants of optimization.

Health Technology Optimization Analysis: Conceptual Approach and Illustrative Application

We present a conceptual approach to determine the optimal solution to delivering a health technology, consistent with the objective of maximizing patient outcomes subject to resources available to a publicly funded health system. The article addresses two key policy questions: 1) adding system values through appropriate planning of health services delivery and 2) considering the tradeoff between patient outcomes and costs to the health system through appropriate use of health technologies for conditions with time-dependent treatment outcomes. We develop a health technology optimization framework that considers geographical variation and searches for the best delivery method through a pairwise comparison of all possible strategies, factoring in controlled variables including disease epidemiology, time or distance to hospitals, available medical services, treatment eligibility, treatment efficacy, and costs. Taking variations of these factors into account would help support a more efficient allocation of health resources. Drawing identified strategies together then creates a map of optimal strategies. We apply the proposed method to a policy-relevant health technology assessment of endovascular therapy (EVT) for treating acute ischemic stroke. The best strategy for providing EVT relies on the geographical location of stroke onset and the decision maker’s preference for either patient outcomes or economic efficiency. The proposed method produced an optimization map showing the optimal strategy for EVT delivery, which maximizes patient outcomes while minimizing health system costs. In the illustrative case study, there were no tradeoffs between health outcomes and costs, meaning that the delivery strategies that were clinically optimal for patients were also the most cost-effective. In conclusion, the health technology optimization approach is a useful tool for informing implementation decisions and coordinating the delivery of complex health services such as EVT.

Consensus Statements by Korean Society of Interventional Neuroradiology and Korean Stroke Society: Hyperacute Endovascular Treatment Workflow to Reduce Door-to-Reperfusion Time

Recent clinical trials demonstrated the clinical benefit of endovascular treatment (EVT) in patients with acute ischemic stroke due to large vessel occlusion. These trials confirmed that good outcome after EVT depends on the time interval from symptom onset to reperfusion and that in-hospital delay leads to poor clinical outcome. However, there has been no universally accepted in-hospital workflow and performance benchmark for rapid reperfusion. Additionally, wide variety in workflow for EVT is present between each stroke centers. In this consensus statement, Korean Society of Interventional Neuroradiology and Korean Stroke Society Joint Task Force Team propose a standard workflow to reduce door-to-reperfusion time for stroke patients eligible for EVT. This includes early stroke identification and pre-hospital notification to stroke team of receiving hospital in pre-hospital phase, the transfer of stroke patients from door of the emergency department to computed tomography (CT) room, warming call to neurointervention (NI) team for EVT candidate prior to imaging, NI team preparation in parallel with thrombolysis, direct transportation from CT room to angiography suite following immediate decision of EVT and standardized procedure for rapid reperfusion. Implementation of optimized workflow will improve stroke time process metrics and clinical outcome of the patient treated with EVT.

Update in the Early Management and Reperfusion Strategies of Patients with Acute Ischemic Stroke

Acute ischemic stroke (AIS) remains a leading cause of death and long-term disability. The paradigms on prehospital care, reperfusion therapies, and postreperfusion management of patients with AIS continue to evolve. After the publication of pivotal clinical trials, endovascular thrombectomy has become part of the standard of care in selected cases of AIS since 2015. New stroke guidelines have been recently published, and the time window for mechanical thrombectomy has now been extended up to 24 hours. This review aims to provide a focused up-to-date review for the early management of adult patients with AIS and introduce the new upcoming areas of ongoing research.

Consensus Statements by Korean Society of Interventional Neuroradiology and Korean Stroke Society: Hyperacute Endovascular Treatment Workflow to Reduce Door-to-Reperfusion Time

Recent clinical trials demonstrated the clinical benefit of endovascular treatment (EVT) in patients with acute ischemic stroke due to large vessel occlusion. These trials confirmed that good outcome after EVT depends on the time interval from symptom onset to reperfusion and that in-hospital delay leads to poor clinical outcome. However, there has been no universally accepted in-hospital workflow and performance benchmark for rapid reperfusion. Additionally, wide variety in workflow for EVT is present between each stroke centers. In this consensus statement, Korean Society of Interventional Neuroradiology and Korean Stroke Society Joint Task Force Team propose a standard workflow to reduce door-to-reperfusion time for stroke patients eligible for EVT. This includes early stroke identification and pre-hospital notification to stroke team of receiving hospital in pre-hospital phase, the transfer of stroke patients from door of the emergency department to computed tomography (CT) room, warming call to neurointervention team for EVT candidate prior to imaging, neurointervention team preparation in parallel with thrombolysis, direct transportation from CT room to angiography suite following immediate decision of EVT and standardized procedure for rapid reperfusion. Implementation of optimized workflow will improve stroke time process metrics and clinical outcome of the patient treated with EVT.

Cincinnati Prehospital Stroke Scale Can Identify Large Vessel Occlusion Stroke

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Delays in the Air or Ground Transfer of Patients for Endovascular Thrombectomy

BACKGROUND AND PURPOSE

For suspected large vessel occlusion patients efficient transfer to centers that provide endovascular therapy (ET) is critical to maximizing treatment opportunity. Our objective was to examine associations between transfer time, modes of transfer, ET, and outcomes within a hub-and-spoke telestroke network.

METHODS

Patients with ischemic stroke were included if transferred to a single hub hospital between January 2011 and October 2015 with National Institutes of Health Stroke Scale>6, onset<12 hours from hub arrival with complete clinical, imaging, and transfer data. Transfer time was the interval between initiation of telestroke consult and arrival at the hub. Algorithms were created for ideal transfer times; ideal time was subtracted from actual time to calculate delay. We examined bivariate relationships between transfer time and several clinical outcomes and used multivariable regression modeling to explore possible predictors of delay.

RESULTS

Of 234 patients that met inclusion criteria, 51% were transferred by ambulance and 49% by helicopter; 27% underwent ET (36% achieved modified Rankin Scale score of 0-2 at 90 days). Median actual transfer time was 132 minutes (interquartile range, 103-165), compared with median ideal transfer time at 102 minutes (interquartile range, 96-123). Longer transfer time was associated with decreased likelihood of undergoing ET (odds ratio, 0.990; P=0.003). Nocturnal transfer (18:00 to 06:00 hours) was associated with significantly longer delay (β=20.5; P<0.0005), whereas intravenous tissue-type plasminogen activator (tPA) delivery at spoke hospital was not. The median delay for nocturnal transfer was 31 minutes (interquartile range, 11-51), compared with daytime at 14 minutes (interquartile range, -9 to 36).

CONCLUSIONS

Within a large telestroke network, there was an association between longer transfer time and decreased likelihood of undergoing ET. Nocturnal transfers were associated with a substantial delay relative to daytime transfers. In contrast, delivery of tPA was not associated with delays, underscoring the impact of effective protocols at spoke hospitals. More efficient transfer may enable higher ET treatment rates. Metrics and protocols for transfer, especially at night, may improve transfer times.

Uncovering the Rosetta Stone: Report from the First Annual Conference on Key Elements in Translating Stroke Therapeutics from Pre-Clinical to Clinical

The first annual Stroke Translational Research Advancement Workshop (STRAW), entitled “Uncovering the Rosetta Stone: Key Elements in Translating Stroke Therapeutics from Pre-Clinical to Clinical” was held at the University of Kentucky on October 4–5, 2017. This workshop was organized by the Center for Advanced Translational Stroke Science. The workshop consisted of 2 days of activities. These included three presentations establishing the areas of research in stroke therapeutics, discussing the routes for translation from bench to bedside, and identifying successes and failures in the field. On day 2, grant funding opportunities and goals for the National Institute for Neurological Diseases and Stroke were presented. In addition, the meeting also included break-out sessions designed to connect researchers in areas of stroke, and to foster potential collaborations. Finally, the meeting concluded with an open discussion among attendees led by a panel of experts.

A Review of Pre-Intervention Prognostic Scores for Early Prognostication and Patient Selection in Endovascular Management of Large Vessel Occlusion Stroke

BACKGROUND

Endovascular therapy (ET) has emerged as a highly effective treatment for acute large vessel occlusion stroke (LVOS). Tools that facilitate optimal patient selection of patients for ET are needed in order to maximize therapeutic benefit in a cost-effective manner. Several pre-intervention prognostic scores for prediction of outcomes in LVOS patients and patient selection for ET have been developed and validated, but their clinical use has been limited. Here, we review existing pre-intervention prognostic scores, compare their prognostic accuracies and levels of validation and identify gaps in current knowledge.

SUMMARY

We have reviewed published literature pertinent to development, validation, and implementation of pre-intervention prognostic scores for LVOS. Using receiver operating characteristic curve analysis, the prognostic accuracies of validated pre-interventional scores (Pittsburgh Response to Endovascular therapy [PRE], Totaled Health Risks in Vascular Events [THRIVE], Houston Intra-Arterial Therapy-2 (HIAT-2), Stroke Prognostication using Age and NIHSS [SPAN-100]) were compared in published work. Pre-intervention scores predicted functional out comes at 3 months with moderate prognostic accuracies (area under the receiver operator characteristic curve range 0.68-0.73). Using successful reperfusion (mTICI 2B/3) as the therapeutic objective of ET and 3-month modified Rankin Score 0-2 as good clinical outcome, patients most likely to clinically benefit from endovascular reperfusion can be identified using the PRE and HIAT-2 scores. Scores that incorporate collateral imaging or perfusion-based estimation of core and penumbra have not been published. Existing scores are predominantly limited to anterior circulation LVOS, and implementation studies of pre-interventional scores are lacking.

KEY MESSAGES

Pre-intervention prognostic scores can serve as useful adjuncts for patient selection in ET for acute LVOS. Pre-intervention scores including HIAT-2, THRIVE, SPAN-100, and PRE have comparable moderate prognostic accuracies for good 3-month outcomes and can identify patients who derive maximal benefit from successful reperfusion. Improvements in prognostic accuracy may be achieved by incorporating variables such as collateral status and perfusion imaging data. Implementation and impact studies using pre-intervention scores are needed to guide clinical application.

Relevance of standard intravenous thrombolysis in endovascular stroke therapy of a tertiary stroke center

The majority of patients undergoing endovascular stroke treatment (EST) in randomized controlled trials received additional systemic thrombolysis ("combination or bridging therapy (C/BT)"). Nevertheless, its usefulness in this subtype of acute ischemic stroke (AIS) is discussed controversially. Of all consecutive AIS patients, who received any kind of reperfusion therapy in a tertiary university stroke center between January 2015 and March 2016, those with large vessel occlusions (LVO) and EST with or without additional C/BT, were compared primarily regarding procedural aspects. Data were extracted from an investigator-initiated, single-center, prospective and blinded end-point study. 70 AIS patients with EST alone and 118 with C/BT were identified. Significant baseline differences existed in pre-existing cardiovascular disease (52.9% (EST alone) vs. 35.6% (C/BT), p = 0.023), use of anticoagulation (30.6% vs. 5.9%, p < 0.001), and frequency of unknown time of symptom onset (65.7% vs. 32.2%, p < 0.001), in-hospital stroke (18.6% vs. 1.7%, p < 0.001), pre-treatment ASPECT scores (7.9 vs. 8.9, p = 0.004), and frequency of occlusion in the posterior circulation (18.6% vs. 5.1%, p = 0.003). Pre-interventional procedural time intervals tended to be shorter in the C/BT group, reaching statistical significance in door-to-image time (30.3 (EST alone) vs. 22.2 min (C/BT), p < 0.001). Good clinical outcome (mRS d90) was reached more often in the C/BT group (24.5% vs. 11.8%, p = 0.064). Rates of symptomatic intracranial hemorrhages (sICH) were comparable (4.3% (EST alone) vs. 6.8% (C/BT), p = 0.481). Additional systemic thrombolysis did not delay EST. On the contrary, application of IVRTPA seemed to be a positive indicator for faster EST without increased side effects.

Pomona Large Vessel Occlusion Screening Tool for Prehospital and Emergency Room Settings

Background

Early identification of patients with acute ischemic strokes due to large vessel occlusions (LVO) is critical. We propose a simple risk score model to predict LVO.

Method

The proposed scale (Pomona Scale) ranges from 0 to 3 and includes 3 items: gaze deviation, expressive aphasia, and neglect. We reviewed a cohort of all acute stroke activation patients between February 2014 and January 2016. The predictive performance of the Pomona Scale was determined and compared with several National Institutes of Health Stroke Scale (NIHSS) cutoffs (≥4, ≥6, ≥8, and ≥10), the Los Angeles Motor Scale (LAMS), the Cincinnati Prehospital Stroke Severity (CPSS) scale, the Vision Aphasia and Neglect Scale (VAN), and the Prehospital Acute Stroke Severity Scale (PASS).

Results

LVO was detected in 94 of 776 acute stroke activations (12%). A Pomona Scale ≥2 had comparable accuracy to predict LVO as the VAN and CPSS scales and higher accuracy than Pomona Scale ≥1, LAMS, PASS, and NIHSS. A Pomona Scale ≥2 had an accuracy (area under the curve) of 0.79, a sensitivity of 0.86, a specificity of 0.70, a positive predictive value of 0.71, and a negative predictive value of 0.97 for the detection of LVO. We also found that the presence of either neglect or gaze deviation alone had comparable accuracy of 0.79 as Pomona Scale ≥2 to detect LVO.

Conclusion

The Pomona Scale is a simple and accurate scale to predict LVO. In addition, the presence of either gaze deviation or neglect also suggests the possibility of LVO.

‘Drip-and-drive’: shipping the neurointerventionalist to provide mechanical thrombectomy in primary stroke centers

Background

To satisfy the increasing demand of mechanical thrombectomy (MT) for acute ischemic stroke treatment, new organizational concepts for patient care are required. This study evaluates time intervals of acute stroke management in two stroke care models, including one based on transportation of the interventionalist from a comprehensive stroke center (CSC) to treat patients in two primary stroke centers (PSC). We hypothesized that time intervals were not inferior for the ‘drip-and-drive’ concept compared with the traditional ‘drip-and-ship’ concept.

Methods

Patients treated with MT at the PSC (‘drip-and-drive’, ‘D+D group’) were compared with patients transferred from PSC to CSC for MT (‘drip-and-ship’, ‘D+S group’) with regard to time delays. Time intervals assessed were: symptom onset to initial CT, to angiography, and to recanalization; time from initial CT to telephone call activation, to arrival, and to angiography; and time from telephone call activation to arrival and from arrival to angiography.

Results

42 patients were treated at the PSC after transfer of the interventionalist, and 32 patients were transferred to the CSC for MT. The groups did not differ with regard to median Onset–CT and CT–Phone times. Significant differences between the groups were found for the primary outcome measure CT–Arrival time (‘D+D group’: median 121 (IQR 108–134) min vs 181 (157–219) min for the ‘D+S group’; P<0.001). Time difference between the groups increased to more than 2 hours for median CT–Angio times (median 123 (IQR 93–147) min vs 252 (228–275) min; P<0.001).

Conclusion

Time intervals for the ‘D+D group’ were not inferior to those of the ‘D+S group’. Moreover, under certain conditions, the ‘drip-and-drive’ concept might even be superior.

Impact of onset-to-groin puncture time within three hours on functional outcomes in mechanical thrombectomy for acute large-vessel occlusion

Introduction Endovascular treatment for acute ischemic stroke with acute large-vessel occlusion (ALVO) has established benefits, and rapid treatment is vital for mechanical thrombectomy in ALVO. Time from onset of stroke to groin puncture (OTP) is a practical and useful clinical marker, and OTP should be shortened to obtain the maximum benefit of thrombectomy. Objective The aim of the present study was to assess the impact of early treatment of anterior circulation stroke within three hours after symptom onset and to evaluate the role of OTP in determining outcomes after endovascular therapy. Methods Consecutive patients with acute stroke due to major artery (internal carotid or middle cerebral arteries) occlusion who underwent endovascular recanalization between March 2014 and January 2017 were retrospectively evaluated. Patients were stratified by OTP into three categories: 0-≤3 h, >3-≤6 h, and >6 h. The primary outcome measure was a 90-day modified Rankin scale score of 0-2 (good outcome). Results Data were analyzed from 100 patients (mean age, 76.6 years; mean National Institutes of Health Stroke Scale score, 17). Groin puncture occurred within 0-≤3 h in 51 patients, >3-≤6 h in 28, and >6 h in 21. Median OTP in each group was 126 min (range, 57-168 min), 238 min (range, 186-360 min) and 728 min (range, 365-1492 min), respectively. On multivariable logistic regression analysis, category of OTP represented an independent predictor of patient outcome (adjusted odds ratio, 0.48; 95% confidence interval, 0.25-0.93; p = 0.029). Conclusions OTP is a prehospital and in-hospital workflow-based indicator. In this single-center study, OTP was found to independently affect functional outcomes after endovascular stroke treatment.

The Relationship between Functional Outcome and Prehospital Time Interval in Patients with Cerebral Infarction

BACKGROUND

When symptoms of cerebral infarction are recognized in a patient, he or she should be transported to a hospital and should be started on the appropriate treatments. The effectiveness of delayed treatment of cerebral infarction with respect to the initial diagnosis or perception of the disease is still unclear.

METHODS

We retrospectively investigated whether the functional outcomes would improve if patients with cerebral infarction were transported to the hospital with minimum delay. One-hundred twenty-two patients who were transported to Mishuku Hospital from January 2012 to August 2015 were included. We conducted multiple regression analyses. The criterion variable included the BI at discharge, and the explanatory variables were age, sex, days of hospital stay, the Barthel Index (BI) on admission, time from symptom onset to hospital arrival, time from emergency medical service perception to hospital arrival, recombinant tissue plasminogen activator (rt-PA) treatment, and the occluded artery type.

RESULTS

In all 122 cases, the BI at the time of discharge was not related to onset time (P = .453) but was significantly related to perception time (P = .026). BI scores at discharge were high for young patients (P = .002) and for patients with short hospital stays (P <.001). In the rt-PA group (52 cases), BI scores at discharge were also high when the perception time was short (P = .036).

CONCLUSIONS

A short interval between perception and hospital arrival improves the functional outcomes for patients with cerebral infarction. Thus, patients with cerebral infarctions must be treated with minimal delay after diagnosis of the condition.