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

Time-driven activity-based costing (TDABC) of direct-to-angiography pathway for acute ischemic stroke patients with suspected large vessel occlusion

INTRODUCTION

Direct-to-angiography (DTA) is a novel care pathway for endovascular treatment (EVT) of acute ischemic stroke (AIS) that has been shown to reduce time-to-treatment and improve clinical outcomes for EVT-eligible patients. The institutional costs of adopting the DTA pathway and the many factors affecting costs have not been studied. In this study, we assess the costs and main cost drivers associated with the DTA pathway compared to the conventional CT pathway for patients presenting with AIS and suspected LVO in the anterior circulation.

METHODS

Time driven activity based costing (TDABC) model was used to compare costs of DTA and conventional pathways from the healthcare institution perspective. Process mapping was used to outline all activities and resources (personnel, equipment, materials) needed for each step in both pathways. The cost model was developed using our institutional patient database and average New York state wages for personnel costs. Total, incremental and proportional costs were calculated based on institutional and patient factors affecting the pathways.

RESULTS

DTA pathway accrued additional $82,583.61 (9%) in total costs compared to the conventional approach for all AIS patients. For EVT-ineligible patients, the DTA pathway incurred additional $82,964.37 (76%) in total costs compared to the CT pathway. For EVT eligible patients, the total and per-patient costs were greater in the CT pathway by $380.76 (0.04%) and $5.60 (0.04%) respectively.

CONCLUSION

As the DTA pathway incurred additional $82,964.37 for EVT-ineligible patients, appropriate patient selection criteria are needed to avoid transferring EVT-ineligible patients to the angiography suite.

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

OBJECTIVES

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

DESIGN

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

SETTING

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

PARTICIPANTS

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

PRIMARY AND SECONDARY OUTCOMES

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

RESULTS

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

CONCLUSIONS

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

'Drive the doctor' for endovascular thrombectomy in a rural area: a simulation study

BACKGROUND

Patients who present in a primary stroke center (PSC) with ischemic stroke are usually transferred to a comprehensive stroke center (CSC) in case of a large vessel occlusion (LVO) for endovascular thrombectomy (EVT) treatment, the so-called 'drip-and-ship' (DS) model. The 'drive-the-doctor' (DD) model modifies the DS model by allowing mobile interventionalists (MIs) to transfer to an upgraded PSC acting as a thrombectomy capable stroke center (TSC), instead of transferring patients to a CSC. Using simulation we estimated time savings and impact on clinical outcome of DD in a rural region.

METHODS

Data from EVT patients in northern Netherlands was prospectively collected in the MR CLEAN Registry between July 2014 - November 2017. A Monte Carlo simulation model of DS patients served as baseline model. Scenarios included regional spread of TSCs, pre-hospital patient routing to 'the nearest PSC' or 'nearest TSC', MI's notification after LVO confirmation or earlier prehospital, and MI's transport modalities. Primary outcomes are onset to groin puncture (OTG) and predicted probability of favorable outcome (PPFO) (mRS 0-2).

RESULTS

Combining all scenarios OTG would be reduced by 28-58 min and PPFO would be increased by 3.4-7.1%. Best performing and acceptable scenario was a combination of 3 TSCs, prehospital patient routing based on the RACE scale, MI notification after LVO confirmation and MI's transfer by ambulance. OTG would reduce by 48 min and PPFO would increase by 5.9%.

CONCLUSIONS

A DD model is a feasible scenario to optimize acute stroke services for EVT eligible patients in rural regions. Key design decisions in implementing the DD model for a specific region are regional spread of TSCs, patient routing strategy, and MI's notification moment and transport modality.

Factors associated with door-in-door-out times in large vessel occlusion stroke patients undergoing endovascular therapy

INTRODUCTION

In the management of large vessel occlusion stroke (LVOS), patients are frequently evaluated first at a non-endovascular stroke center and later transferred to an endovascular stroke center (ESC) for endovascular treatment (EVT). The door-in-door-out time (DIDO) is frequently used as a benchmark for transferring hospitals though there is no universally accepted nor evidenced-based DIDO time. The goal of this study was to identify factors affecting DIDO times in LVOS patients who ultimately underwent EVT.

METHODS

The Optimizing Prehospital Use of Stroke Systems of Care-Reacting to Changing Paradigms (OPUS-REACH) registry is comprised of all LVOS patients who underwent EVT at one of nine endovascular centers in the Northeast United States between 2015 and 2020. We queried the registry for all patients who were transferred from a non-ESC to one of the nine ESCs for EVT. Univariate analysis was performed using t-tests to obtain a p value. A priori, we defined a p value of <0.05 as significant. Multiple logistic regression was conducted to determine the association of variables to estimate an odds ratio.

RESULTS

511 patients were included in the final analysis. The mean DIDO times for all patients was 137.8 min. Vascular imaging and treatment at a non-certified stroke center were associated with longer DIDO times by 23 and 14 min, respectively. On multivariate analyses, the acquisition of vascular imaging was associated with 16 additional minutes spent at the non-ESC while presentation to a non-stroke certified hospital was associated with 20 additional minutes spent at the transferring hospital. The administration of intravenous thrombolysis (IVT) was associated with 15 min less spent at the non-ESC.

DISCUSSION

Vascular imaging and non-stroke certified stroke centers were associated with longer DIDO times. Non-ESCs should integrate vascular imaging into their workflow as feasible to reduce DIDO times. Further work examining other details regarding the transfer process such as transfer via ground or air, could help further identify opportunities to improve DIDO times.

Cost-effectiveness of improvement strategies for reperfusion treatments in acute ischemic stroke: a systematic review

BACKGROUND

Reducing delays along the acute stroke pathway significantly improves clinical outcomes for acute ischemic stroke patients eligible for reperfusion treatments. The economic impact of different strategies reducing onset to treatment (OTT) is crucial information for stakeholders in acute stroke management. This systematic review aimed to provide an overview on the cost-effectiveness of several strategies to reduce OTT.

METHODS

A comprehensive literature search was conducted in EMBASE, PubMed, and Web of Science until January 2022. Studies were included if they reported 1/ stroke patients treated with intravenous thrombolysis and/or endovascular thrombectomy, 2/ full economic evaluation, and 3/ strategies to reduce OTT. The Consolidated Health Economic Evaluation Reporting Standards statement was applied to assess the reporting quality.

RESULTS

Twenty studies met the inclusion criteria, of which thirteen were based on cost-utility analysis with the incremental cost-effectiveness ratio per quality-adjusted life year gained as the primary outcome. Studies were performed in twelve countries focusing on four main strategies: educational interventions, organizational models, healthcare delivery infrastructure, and workflow improvements. Sixteen studies showed that the strategies concerning educational interventions, telemedicine between hospitals, mobile stroke units, and workflow improvements, were cost-effective in different settings. The healthcare perspective was predominantly used, and the most common types of models were decision trees, Markov models and simulation models. Overall, fourteen studies were rated as having high reporting quality (79%-94%).

CONCLUSIONS

A wide range of strategies aimed at reducing OTT is cost-effective in acute stroke care treatment. Existing pathways and local characteristics need to be taken along in assessing proposed improvements.

Drip-and-ship toward mothership model for mechanical thrombectomy during COVID-19 pandemic: a retrospective analysis

INTRODUCTION

During the first wave of the COVID-19 pandemic in spring 2020, our stroke network shifted from a drip-and-ship strategy (transport of acute ischemic stroke patients to the nearest primary stroke centers) toward a mothership model (direct transportation to the Comprehensive Stroke Center). We retrospectively analyzed stroke network performances comparing the two models.

PATIENTS AND METHODS

All spoke-district patients treated with endovascular thrombectomy (EVT) between 15th March-15th June 2019 (drip-and-ship) and 2020 (mothership) were considered. We compared onset-to-groin time (OGT) and onset-to-needle time (ONT) between the two periods. Secondarily, we investigated other performances parameters (percentage of IV thrombolysis, timing of diagnostic and treatment) and clinical outcome (3-month modified Rankin Scale).

RESULTS

Twenty-four spoke-district patients in 2019 (drip-and-ship) and 26 in 2020 (mothership) underwent EVT. The groups did not differ for age, sex, risk factors, pre-stroke mRS 0-1, NIHSS, and ASPECTS distribution. The MS model showed a significant decrease of the OGT (162.5 min vs 269 min, p = 0.001) without significantly affecting the ONT (140.5 min vs 136 min, p = 0.853), ensuring a higher number of IV thrombolysis in combination with EVT (p = 0.030). The mothership model showed longer call-to-door time (median + 23 min, p < 0.005), but shorter door-to-needle (median - 31 min, p = 0.001), and door-to-groin time (- 82.5 min, p < 0.001). We found no effects of the stroke network model on the 3-month mRS (ordinal shift analysis, p = 0.753).

CONCLUSIONS

The shift to the mothership model during the COVID-19 pandemic guaranteed quicker EVT without significantly delaying IVT.

Prediction modelling the impact of onset to treatment time on the modified Rankin Scale score at 90 days for patients with acute ischaemic stroke

Introduction

Shortening the time from stroke onset to treatment increases the effectiveness of endovascular stroke therapies.

Aim

This study aimed to predict the modified Rankin Scale score at 90 days post-stroke (mRS-90d score) in patients with acute ischaemic stroke (AIS) with respect to four types of treatment: conservative therapy (CVT), intravenous thrombolysis only (IVT), mechanical thrombectomy only (MT) and pretreatment with IVT before MT (IVT+MT).

Patients and methods

This nationwide observational study included 124 484 confirmed cases of acute stroke in Sweden over 6 years (2012–2017). The associations between onset-to-treatment time (OTT), patient age and hospital admission National Institutes of Health Stroke Scale (NIHSS) score with the five-levelled mRS-90d score were retrospectively studied. A generalised linear model (GLM) was fitted to predict the mRS-90d scores for each patient group.

Results

The fitted GLM for CVT patients is a function of age and NIHSS score. For IVT, MT and IVT+MT patients, GLMs additionally employed OTT variables. By reducing the mean OTTs by 15 min, the number needed-to-treat (NNT) for one patient to make a favourable one-step shift in the mRS was 30 for IVT, 48 for MT and 21 for IVT+MT.

Discussion and conclusion

This study demonstrates linear associations of mRS-90d score with OTT for IVT, MT and IVT+MT, and shows in absolute effects measures that OTT reductions for IVT and/or MT produces substantial health gains for patients with AIS. Even moderate OTT reductions led to sharp drops in the NNT.

Fluid biomarkers in stroke: From animal models to clinical care

Stroke is a leading cause of death and disability worldwide. Stroke prevention, early diagnosis, and efficient acute treatment are priorities to successfully impact stroke death and disability. Fluid biomarkers may improve stroke differential diagnostic, patient stratification for acute treatment, and post-stroke individualized rehabilitation. In the present work, we characterized the use of stroke animal models in fluid biomarker research through a systematic review of PubMed and Scopus databases, followed by a literature review on the translation to the human stroke care setting and future perspectives in the field. We found increasing numbers of publications but with limited translation to the clinic. Animal studies are very heterogeneous, do not account for several human features present in stroke, and, importantly, only a minority of such studies used human cohorts to validate biomarker findings. Clinical studies have found appealing candidates, both protein and circulating nucleic acids, to contribute to a more personalized stroke care pathway. Still, brain tissue complexity and the fact that different brain pathologies share lesion biomarkers make this task challenging due to biomarker low specificity. Moreover, the study design and lack of validation cohorts may have precluded a formal integration of biomarkers in different steps of stroke diagnosis and treatment. To overcome such issues, recent pivotal studies on biomarker dynamics in individual patients are providing added value to diagnosis and anticipating patients' early prognosis. Presently, the most consistent protein biomarkers for stroke diagnosis and short- and long-term prognosis are associated with tissue damage at neuronal (TAU), axonal (NFL), or astroglial (GFAP and S100β) levels. Most promising nucleic acids are microRNAs (miR), due to their stability in plasma and ease of access. Still, clinical validation and standardized quantitation place them a step behind compared protein as stroke biomarkers. Ultimately, the definition of clinically relevant biomarker panels and optimization of fast and sensitive biomarker measurements in the blood, together with their combination with clinical and neuroimaging data, will pave the way toward personalized stroke care.

Association Between Use of a Flying Intervention Team vs Patient Interhospital Transfer and Time to Endovascular Thrombectomy Among Patients With Acute Ischemic Stroke in Nonurban Germany

IMPORTANCE

The benefit of endovascular thrombectomy (EVT) for acute ischemic stroke is highly time-dependent, and it is challenging to expedite treatment for patients in remote areas.

OBJECTIVE

To determine whether deployment of a flying intervention team, compared with patient interhospital transfer, is associated with a shorter time to endovascular thrombectomy and improved clinical outcomes for patients with acute ischemic stroke.

DESIGN, SETTING, AND PARTICIPANTS

This was a nonrandomized controlled intervention study comparing 2 systems of care in alternating weeks. The study was conducted in a nonurban region in Germany including 13 primary telemedicine-assisted stroke centers within a telestroke network. A total of 157 patients with acute ischemic stroke for whom decision to pursue thrombectomy had been made and deployment of flying intervention team or patient interhospital transfer was initiated were enrolled between February 1, 2018, and October 24, 2019. The date of final follow-up was January 31, 2020.

EXPOSURES

Deployment of a flying intervention team for EVT in a primary stroke center vs patient interhospital transfer for EVT to a referral center.

MAIN OUTCOMES AND MEASURES

The primary outcome was time delay from decision to pursue thrombectomy to start of the procedure in minutes. Secondary outcomes included functional outcome after 3 months, determined by the distribution of the modified Rankin Scale score (a disability score ranging from 0 [no deficit] to 6 [death]).

RESULTS

Among the 157 patients included (median [IQR] age, 75 [66-80] y; 80 [51%] women), 72 received flying team care and 85 were transferred. EVT was performed in 60 patients (83%) in the flying team group vs 57 (67%) in the transfer group. Median (IQR) time from decision to pursue EVT to start of the procedure was 58 (51-71) minutes in the flying team group and 148 (124-177) minutes in the transfer group (difference, 90 minutes [95% CI, 75-103]; P < .001). There was no significant difference in modified Rankin Scale score after 3 months between patients in the flying team (n = 59) and transfer (n = 57) groups who received EVT (median [IQR] score, 3 [2-6] vs 3 [2-5]; adjusted common odds ratio for less disability, 1.91 [95% CI, 0.96-3.88]; P = .07).

CONCLUSIONS AND RELEVANCE

In a nonurban stroke network in Germany, deployment of a flying intervention team to local stroke centers, compared with patient interhospital transfer to referral centers, was significantly associated with shorter time to EVT for patients with acute ischemic stroke. The findings may support consideration of a flying intervention team for some stroke systems of care, although further research is needed to confirm long-term clinical outcomes and to understand applicability to other geographic settings.

Expediting workflow in the acute stroke pathway for endovascular thrombectomy in the northern Netherlands: a simulation model

OBJECTIVE

The objective of this study is to identify barriers for the timely delivery of endovascular thrombectomy (EVT) and to investigate the effects of potential workflow improvements in the acute stroke pathway.

DESIGN

Hospital data prospectively collected in the MR CLEAN Registry were linked to emergency medical services data for each EVT patient and used to build two Monte Carlo simulation models. The 'mothership (MS) model', reflecting patients who arrived directly at the comprehensive stroke centre (CSC); and the 'drip and ship' (DS) model, reflecting patients who were transferred to the CSC from primary stroke centres (PSCs).

SETTING

Northern region of the Netherlands. One CSC provides EVT, and its catchment area includes eight PSCs.

PARTICIPANTS

248 patients who were treated with EVT between July 2014 and November 2017.

OUTCOME MEASURES

The main outcome measures were total delay from stroke onset until groin puncture, functional independence at 90 days (modified Rankin Scale 0-2) and mortality.

RESULTS

Barriers identified included fast-track emergency department routing, prealert for transfer to the CSC, reduced handover time between PSC and ambulance, direct transfer from CSC arrival to angiography suite entry, and reducing time to groin puncture. Taken together, all workflow improvements could potentially reduce the time from onset to groin puncture by 59 min for the MS model and 61 min for the DS model. These improvements could thus result in more patients-3.7% MS and 7.4% DS-regaining functional independence after 90 days, in addition to decreasing mortality by 3.0% and 5.0%, respectively.

CONCLUSIONS

In our region, the proposed workflow improvements might reduce time to treatment by about 1 hour and increase the number of patients regaining functional independence by 6%. Simulation modelling is useful for assessing the potential effects of interventions aimed at reducing time from onset to EVT.

Detection of large vessel occlusion stroke with electroencephalography in the emergency room: first results of the ELECTRA-STROKE study

Background

Prehospital detection of large vessel occlusion stroke of the anterior circulation (LVO-a) would enable direct transportation of these patients to an endovascular thrombectomy (EVT) capable hospital. The ongoing ELECTRA-STROKE study investigates the diagnostic accuracy of dry electrode electroencephalography (EEG) for LVO-a stroke in the prehospital setting. To determine which EEG features are most useful for this purpose and assess EEG data quality, EEG recordings are also performed in the emergency room (ER). Here, we report data of the first 100 patients included in the ER.

Methods

Patients presented to the ER with a suspected stroke or known LVO-a stroke underwent a single EEG prior to EVT. Diagnostic accuracy for LVO-a stroke of frequency band power, brain symmetry and phase synchronization measures were evaluated by calculating receiver operating characteristic curves. Optimal cut-offs were determined as the highest sensitivity at a specificity of ≥ 80%.

Results

EEG data were of sufficient quality for analysis in 65/100 included patients. Of these, 35/65 (54%) had an acute ischemic stroke, of whom 9/65 (14%) had an LVO-a stroke. Median onset-to-EEG-time was 266 min (IQR 121–655) and median EEG-recording-time was 3 min (IQR 3–5). The EEG feature with the highest diagnostic accuracy for LVO-a stroke was theta–alpha ratio (AUC 0.83; sensitivity 75%; specificity 81%). Combined, weighted phase lag index and relative theta power best identified LVO-a stroke (sensitivity 100%; specificity 84%).

Conclusion

Dry electrode EEG is a promising tool for LVO-a stroke detection, but data quality needs to be improved and validation in the prehospital setting is necessary. (TRN: NCT03699397, registered October 9 2018).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10781-6.

Timely and Blood-Based Multiplex Molecular Profiling of Acute Stroke

Stroke is a leading cause of death and disability in the world. To address such a problem, early diagnosis and tailored acute treatment represent one of the major priorities in acute stroke care. Since the efficacy of reperfusion treatments is highly time-dependent, there is a critical need to optimize procedures for faster and more precise diagnosis. We provide a concise review of the most relevant and well-documented blood-protein biomarkers that exhibit greater potential for translational to clinical practice in stroke differential diagnosis and to differentiate ischemic stroke from hemorrhagic stroke, followed by an overview of the most recent point-of-care technological approaches to address this problem. The integration of fluid-based biomarker profiling, using point-of-care biosensors with demographic, clinical, and neuroimaging parameters in multi-dimensional clinical decision-making algorithms, will be the next step in personalized stroke care.

Application of a computational model in simulating an endovascular clot retrieval service system within regional Australia

INTRODUCTION

The global demand for endovascular clot retrieval (ECR) has grown rapidly in recent years creating challenges to healthcare system planning and resource allocation. This study aims to apply our established computational model to predict and optimise the performance and resource allocation of ECR services within regional Australia, and applying data from the state of South Australia as a modelling exercise.

METHOD

Local geographic information obtained using the Google Maps application program interface and real-world data was input into the discrete event simulation model we previously developed. The results were obtained after the simulation was run over 5 years. We modelled and compared a single-centre and two-centre ECR service delivery system.

RESULTS

Based on the input data, this model was able to simulate the ECR delivery system in the state of South Australia from the moment when emergency services were notified of a potential stroke patient to potential delivery of ECR treatment. In the model, ECR delivery improved using a two-centre system compared to a one-centre system, as the percentage of stroke patients requiring ECR was increased. When 15% of patients required ECR, the proportion of 'failure to receive ECR' cases for a single-centre system was 17.35%, compared to 3.71% for a two-centre system.

CONCLUSIONS

Geolocation and resource utilisation within the ECR delivery system are crucial in optimising service delivery and patient outcome. Under the model assumptions, as the number of stroke cases requiring ECR increased, a two-centre ECR system resulted in increased timely ECR delivery, compared to a single-centre system. This study demonstrated the flexibility and the potential application of our DES model in simulating the stroke service within any location worldwide.

Letter to the Editor: Analysis of stroke patient migration for mechanical thrombectomy and changes in neurointerventional center size in Germany

AIM AND METHODS

To analyse nationwide changes in neurointerventional center size of all German hospitals performing mechanical thrombectomy (MT) in stroke patients from 2016 to 2019. Furthermore, we assessed cross-district patient migration for MT for the first time using hospitals' structured quality reports and German Diagnosis-Related Groups data in 2019.

FINDINGS

Number of hospitals performing more than 100 MT procedures/year doubled in Germany from 2016 (n = 36) to 2019 (n = 71), and these neurointerventional centers performed 71% of all MT procedures in 2019. The overall increase in MT procedures was largely driven by these high-volume neurointerventional centers with ability to perform MT 24/7 (121% increase as compared with 8% increase in hospitals performing less than 100 MT procedures/year). The highest cross-district patient mobility/transfer of stroke patients for MT was observed in districts adjacent to these high-volume neurointerventional centers with existing neurovascular networks.

CONCLUSION

The substantial increase in MT procedures observed in Germany between 2016 and 2019 was almost exclusively delivered by high-volume stroke centers performing more than 100 MT procedures per year in established neurovascular networks. As there is still a reasonable number of districts with low MT rates, further structural improvement including implementation of new or expansion of existing neurovascular networks and regional tailored MT triage concepts is needed.

Longer term patient management following stroke: A systematic review

Background

Tremendous progress in acute stroke therapy has improved short-term outcome but part of this achievement may be lost in the long run. Concepts for a better long-term management of stroke survivors are needed to address their unmet needs and to reduce the burden of post-stroke complications, residual deficits, and recurrent vascular events.

Aims

This review summarizes current knowledge on post-hospital care and the scientific evidence supporting individual programs.

Summary of review

A systematic search of electronic databases according to PRISMA guidelines identified 10,374 articles, 77 of which met the inclusion criteria. One large randomised controlled trial on a multifaceted care program delivered by the multidisciplinary stroke team reduced recurrent vascular events and improved quality of life and functional outcome one year after the event, while a number of studies offer solutions for individual components of post-hospital disease management like patient education, counselling, and self-management or the management of post-stroke complications and residual deficits. A majority of studies, however, was small in size and limited by a short follow-up. Most initiatives with a narrow focus on risk factor control failed to lower the risk of recurrent events. The caregivers’ central role in post-stroke patient management is broadly neglected in research.

Conclusions

Over the past years, first knowledge on how to best organize post-hospital care of stroke patients has emerged. Comprehensive and pragmatic programs operated by the multidisciplinary stroke team hold promise to reduce the long-term health burden of stroke. There is a clear need for further high-quality studies with both clinical endpoints and patient-reported outcomes to establish sustainable solutions in different settings and regions to improve life after stroke, a key priority of the Stroke Action Plan for Europe 2018–2030.