Stroke networks

Intravenous thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) for acute ischaemic stroke is more effective when delivered early (figure 3).⁵

Figure 3: Days of disability-free life gained PER MINUTE of faster rt-PA¹  

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Source: Meretoja et al. Stroke 2014;45(4):1053-1058.

The shortest hospital-based delays have been reported from the Helsinki University Central Hospital (HUCH), which covers the city of Helsinki and the surrounding province of Uusimaa in Finland.²

The Helsinki model consists of multiple concurrent strategies aimed at reducing treatment delays prior to thrombolysis. It aims to maximise therapeutic intervention during transport to hospital, whilst reducing intervention following patient arrival at the emergency room.^3,4   

Figure 4: The Helsinki protocol⁷

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Adapted from: Meretoja et al. Neurology 2012;79(4):306-313.

NIHSS: National Institutes of Health Stroke Scale; INR: international normalised ratio.

Using this strategy, it is possible to cut median in-hospital delay to 20 minutes, and adaptation of this model resulted in an 18-minute reduction in thrombolysis delay (to 25 minutes) in Melbourne within 4 months.^3,4 The Helsinki model is transferrable with real-world resources, and can reduce stroke door-to-needle time (DNT) by over 50%.⁵

Results have demonstrated that a decentralised telestroke thrombolysis service can achieve similar treatment rates and time delays for a rural population as a centralised system can achieve for an urban population.²

Management of stroke networks is complex, and it is important to have clearly defined network territories (as in Finland) in order to avoid competing networks.⁶

Take a look at Dr. Meretoja’s webinar from ESOC 2019 to get more information on stroke networks around the world and their effective management

Reaching out to remotely located patients remains difficult, and telestroke is recognised as a potential solution.² Beginning with the Indian Space Research Organisation (ISRO)’s pilot telemedicine project of 2001, the telemedicine network in India presently stretches to around 100 hospitals all over the country, with 78 remote/rural/district hospitals/health centres connected to 22 specialty hospitals located in the major cities, thus providing treatment to more than 25,000 patients, which includes stroke patients.²

Telemedicine is currently used in India for diagnosing stroke patients, subtyping stroke as ischaemic or haemorrhagic, and treating accordingly. However, a dedicated telestroke system for providing acute stroke care is needed.²

A major telestroke initiative has been taken up by the state of Himachal Pradesh (HP; figure 5).³ The Telestroke Management Program has been piloted for the first time in HP in collaboration with All India Institute of Medical Sciences (AIIMS). Under this program, 18 primary stroke centres are being set up in HP state hospitals, which have CT scan facilities. Success of this program will pave the path for comprehensive treatment of stroke patients in more parts of the country.^1,3

Figure 5. Himachal Pradesh telestroke network

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Source: Sharma et al. Neurol India 2016;64(5):934.

Telestroke facilities could increase the pool of patients eligible for thrombolysis. But this primary aim of telestroke can be achieved in India only if thrombolysis and imaging techniques are made available at all levels of health care.²

Smartphone-based telestroke services could provide a much cheaper alternative to video-conferencing-based telestroke services, and are more portable with less technical glitches.³ This is the first telestroke model being reported from India, and seems to be the way forward in providing timely treatment in acute ischaemic stroke in underserved and resource poor settings.³

The Canadian stroke network was established in 1999, with the goal of reducing the impact of stroke in Canada.¹ To date, the network has enabled the implementation of telestroke programs in several provinces, establishment of various regional networks, and numerous other developments which have improved outcomes and reduced the impact of stroke nationwide. In Ontario, the rt-PA rate increased from 10% (2003) to 39% (2013).²

Figure 6. Telestroke schematic, Canada stroke network

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Source: Expanding telestroke in Canada, 2012.

A citywide prehospital acute stroke activation protocol implemented in Toronto resulted in:³

• Immediate doubling in the number of patients with acute stroke arriving at regional stroke centres within 2.5 hours of symptom onset
• 4-fold increase in patients who were eligible for and treated with rt-PA
• rt-PA treatment rate for ischaemic stroke patients increased from 9.5% to 23.4%, and one in 2 patients with ischaemic stroke arriving within 2.5 hours received thrombolysis during this period (one in 5 of patients with ischaemic stroke overall)
• Significantly reduced median onset-to-needle time for rt-PA -treated patients

The National Acute Stroke Services Framework was developed by the Australian Stroke Foundation in 2008 to outline where stroke services should be developed, provide a basis for measuring adequacy of current structures and resources, guide decisions about resource requirements, and provide an outline for monitoring of quality of acute stroke care.² In addition, numerous regional studies provide growing evidence for improved stroke response protocols. For example:

• The Victorian Stroke Telemedicine (VST) program was a 12-month pilot study which aimed to enhance acute stroke care in regional Australia.³ Compared to pre-VST data, thrombolysis use increased from 17% to 26%. Clinical process timelines improved including door to computed tomography (CT) time (reduced by 29 min), and door to needle time (reduced by 21 min).³
• In 2007, the Victorian Government employed clinical facilitators for three years in eight public hospitals to improve stroke care.⁴ Cost containment of acute inpatient episodes was observed after the implementation of stroke clinical facilitators, likely associated with the shorter lengths of stay (average length of stay reduced by 22%).⁴
• By 2013, the framework for regional acute stroke services in Victoria were well established (figure 7).¹

Figure 7. Victoria State Government: Framework for regional acute stroke services in Victoria 2013

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Source: Meretoja A. ESOC 2019 - Timing is everything - Effective organisation and comparison of stroke networks around the world – Experience from Helsinki and Melbourne. 2019.

Link to webinars

More information on stroke networks in Australia and around the world is available in Dr. Meretoja’s ESOC 2019 webinar.

Telestroke is currently being successfully implemented in France.^1–3 For example:

• A telestroke system (Virtuall) in Lorraine (Grand Est region, France), is supported by a financial agreement between the hub and its six spokes to obtain the best economic balance in all sites. The model is based on payment of tele-expertise, sharing of costs according to the fees perceived by the centres, and the transfer of patients between the hub and the spokes. This economic model can be applied to any telestroke system to ensure the optimal balance between hub and spoke centres.³
• In order to address low thrombolysis rates and limited stroke infrastructures, a telestroke network was implemented in Burgundy (1.6 million inhabitants; figure 8). Implementation of a regional telemedicine network for the management of acute ischaemic stroke appeared to be effective and safe. Thanks to this network, the proportion of patients who benefit from thrombolysis will increase.¹
   

Figure 8. Geographical organisation of the Burgundy telemedicine stroke network during the study period

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Source: Legris et al. Eur J Neurol 2016;23(9):1433-1440.

More information on French stroke networks is available in Dr. Goldstein’s BI webcast from ESC 2017.

Timely delivery is challenging particularly in rural areas with long distances.¹ The Telemedical Project for Integrative Stroke Care (TEMPiS) addressed this challenge by setting up a decentralised system of telemedicine-linked stroke facilities (TeleStroke Units) in rural South-East Bavaria, Germany.^1,2 Within the covered area (figure 9), network implementation increased the number of patients with stroke and transient ischaemic attack treated in hospitals with (Tele-) Stroke Units substantially from 19% to 78%.³
 

Figure 9. Map of Southeast Bavaria with TeleMedical Project for integrative Stroke Care (TEMPiS) TeleStroke Units

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Dark area indicates original rural TEMPiS region, and bright area indicates area extensions.

Source: Müller-Barna et al. Stroke 2014;45(9):2739-2744. doi:10.1161/STROKEAHA.114.006141

A 2018 survey concluded that a local stroke network was established in 87.5% of stroke cases in Italy. The results suggested that adequate access to telemedicine equipment may optimise the work of physicians and help access to stroke treatment as prescribed by evidence based statement.¹

Agostini et al. defined the main elements constituting the optimal pathway of stroke management in Italian care settings, in line with recommendations coming from current national and international guidelines. The conclusions from the key notes of the Italian Neurological Society and of the Italian Stroke Organisation were as follows:

• Close cooperation with EMS, with pre-notification of the emergency department of the receiving hospital, is required to reduce the avoidable delay and to increase promptly the number of treated patients.²

• The centralisation of resources as well as the experienced providers and support staff is required to reach the positive results observed in interventional stroke trials.²

• The organisational network which best fits with this time dependent disease is the ‘Hub and Spoke’ model (Figure 10).²

  • The comprehensive stroke centres (‘hub’) should be strategically located to optimise access to as many stroke patients as possible and at the same time in resulting to access high-quality care.

  • Every spoke hospital must have a close working relationship with a comprehensive stroke centre by shared protocols and pathways to ensure the access of all stroke patients to the highest level of care.

• Baseline and continuous training for each subject involved in the pathway for acute stroke management is needed, and the expertise of a single stroke centre is based on the trained team and the volume of managed patients.²

Figure 10.

a.  Possible scenarios of acute pre-hospital stroke management with drip-and-ship model (A1 and A2) and mothership model (B).

b.  Typical hub and spoke system.

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Source: Agostoni et al, Neurological Sciences 2017;39(3):415-422

https://doi.org/10.1007/s10072-017-3200-6

In Catalonia, reperfusion treatment rates have increased in recent years and currently are among the highest in Europe (17.3% overall, 14.3% for IVT, and 6% for EVT in 2016).¹ Catalonia has a population of 7.5 M, and an organized and highly territorialized stroke system of care administered by the Stroke Programme, an organization created in 2004 by the Catalan Health Department.¹ In 2006, the Stroke Programme implemented the Stroke Code System in 2006 to cover all the territory (figure 11).¹ 

Figure 11. Geographical distribution of the Stroke Centres in Catalonia

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Source: Vivanco-Hidalgo et al, Front. Neurol. 2018;9(427-432). https://doi.org/10.3389/fneur.2018.00427

Access to EVT continues to be based on the patient’s geographic location at stroke onset. Patients living in areas where the primary referral hospital is an endovascular-capable stroke center (EVT-SC) have much higher chances of undergoing EVT than patients primarily referred to local CSCs (Figure 12).²

Figure 12. Distribution of mechanical thrombectomies performed in 2015 by patient’s location at stroke onset according to three geographical areas (inner and outer metropolitan areas and the provinces). CPI, primary stroke centre

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Source: Ossa et al. Endovascular Today 2018.

Current criteria for Stroke Code activation are clinical suspicion of acute stroke, less than 8 h from symptom onset (or unknown), and previous functional independence (Rankin 0–2) with no age limit.¹

Upon Stroke Code activation, the EMS coordinates patient transport to the nearest Stroke Centre (SC) according to predefined pathways. After initial recognition of stroke symptoms, the destination SC is pre-alerted by the EMS. The Stroke Code can be activated directly from EMS upon identification of a stroke patient in the field (60% of all Stroke Code activations) or at the Emergency Department of any hospital when patients arrive at the hospital by their own means.¹

In recent years, the network of acute hospitals that are active in the stroke code system has grown to include 26 centers: (1) Twelve TSCs with capacity to deliver IVT via tele-consultation with a vascular neurologist who covers all tele-consultations from the 7 TSCs in the outer metropolitan area of Barcelona; the remaining 5 TSCs are located in the Catalan provinces and are usually covered by the neurologist on call at the nearest provincial PSC, with the central on-call service acting as a backup. (2) Eight PSCs with capacity to deliver IVT and admit patients to a certified Stroke Unit. (Six EVT-capable centers or CSCs, all of them located in the inner metropolitan area of Barcelona).¹

According to the Stroke Code protocol, patients with a suspected acute stroke are transferred to the closest SC or TSC in order to prioritize urgent expert evaluation and rapid IVT if indicated. This strategy is extremely effective and safe, increasing IVT treatment and reducing the time from symptom onset to IVT initiation; however, this decentralized model is associated with delayed EVT initiation and lower rates of EVT, compared to areas where patients are directly transferred to a CSC.¹

Innovation in stroke systems of care is a key factor to achieve the main aim in stroke care: to build a national stroke plan capable of offering the best possible treatment to all patients eligible for reperfusion therapies. Necessary elements include a high level of organization, close cooperation with EMS (prehospital assessment), strong commitment of all stroke physicians at Stroke Centres, the availability of a disease-specific registry, and finally local government involvement to establish stroke care as a priority.¹

Several US stroke networks have been established, each demonstrating great value for stroke outcomes. For example:

• The weekend effect is a well-recognised phenomenon in which patient outcomes worsen for acute strokes presenting outside routine business hours. A US study demonstrated that the use of institutional protocols can mitigate the weekend effect for patients undergoing endovascular stroke therapy for large vessel occlusion (LVO) at centres that receive a substantial proportion of patients in transfer. It also demonstrated that protocol adherence and familiarity accelerate treatment times, particularly in off-hours presentations, and lead to further decreases in treatment intervals over time.¹
• To address the challenges of stroke treatment, Saint Luke’s Hospital, a tertiary care community hospital in Kansas City, Missouri, developed a dedicated stroke centre in 1993. It subsequently expanded into a full-service Neuroscience Institute and regionally organised stroke referral network of >70 hospitals. A 2013 study concluded that regionally coordinated stroke programs such as this can substantially improve access and patient outcomes.²
• In 2013, approximately half of South Carolina residents did not have access to a primary stroke centre within a 30-minute drive of their home, and 30% did not have access within 60 minutes.³ The addition of telestroke centres in areas without primary stroke centres increased these figures to 76% and 95% respectively (drive time to primary stroke centre or telestroke centre - figure 13).³

Figure 13. South Carolina primary stroke centres and telestroke centres and the population within a 30-minute or 60-minute drive time

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Source: Samson M. Prev Chronic Dis. 2015;12. doi:10.5888/pcd12.150418.

In the ‘mothership’ stroke model, patients are directly transferred to a comprehensive stroke centre (CSC), whilst in the ‘drip and ship’ model patients are transported patient to the nearest non-endovascular capable centre (nECC) to receive thrombolytic therapy, and then transfer the patient to the nearest endovascular capable centre (ECC) for endovascular therapy (figure 14).^3,4

Figure 14. Different primary transfer options of suspected ELVO stroke patients prioritizing IV tPA treatment (option A) or EVT (option B)²

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Source: Ossa et al. Endovascular Today 2018.

Direct transport of the patient to the nearest EVT-SC, bypassing the nearest local CSC, offers access to all effective treatments. However, this results in a substantial delay in initiation of IV tPA as compared with drip and ship. The time to admission to the EVT-SC will only be determined by the distance to stroke onset location.²

Patient transfer to the nearest local CSC for immediate care including IV tPA offers rapid access to the less effective treatment. The patient is then secondarily transferred to an EVT-SC, where the patient may arrive: (1) already recanalised (no further specific treatment needed), (2) with a large infarct and no mismatch (no further specific treatment needed), or (3) with persistent occlusion and salvable brain tissue (will receive EVT with a time delay as compared with the direct ship option). The time to admission in the CSC will be determined by the initial distance to the EVT-SC and the door-in/door-out time at the local CSC.²

The door-to-needle time at the nECC must be reduced to an average of 30 minutes for the drip and ship model to be viable.⁴ In most urban and suburban areas where hospitals are geographically close together, the mothership model is always superior to the drip and ship model when transport times between the nECC and ECC are short.⁴

The RACECAT study (Abilleira et al, 2019) aims to establish whether stroke subjects with rapid arterial occlusion evaluation scale based suspicion of LVO evaluated by emergency medical services in the field have higher rates of favourable outcome when transferred directly to an endovascular centre (endovascular treatment stroke centre), as compared to the standard transfer to the closest local stroke centre (local-SC).⁵

The Stroke Code system of Catalonia offers the potential for innovative studies, such as the RACECAT trial, as it is based on a well-established stroke network of acute hospitals working in close collaboration with the EMS and the existence of an exhaustive, population-based registry validated for research quality.¹

Stroke networks comprised of numerous hospitals and ambulance services can help to overcome geographical, political, financial and other constraints (such as lack of expertise in remote locations) in acute stroke care.^1,11

Hub and spoke models are utilised in several successful stroke models, and serve to minimize treatment times and maximise treatment outcomes in this time dependent disease.^9,12 The ‘drip and ship’ model should be increasingly implemented for eligible patients, but is only possible where regional networks are in place and well-functioning.¹⁰

Telemedicine represents a core component of contemporary stroke networks worldwide, facilitating reduced treatment times and improved outcomes.^7,8,13

As demonstrated by the Helsinki model, maximising therapeutic intervention during transport to hospital whilst reducing intervention following patient arrival at the emergency room can significantly reduce treatment time.^2–5 Proceeding directly to CT, with prenotification of patient information, is vitally important in reducing door-to-needle times.⁵

In addition to these benefits for all acute stroke patients, telemedicine specifically helps to reduce the ‘weekend effect’ in stroke care, and is invaluable in rural settings with long travel distances.^1,6,14

Bringing swift treatment to the patient, instead of the conventional approach of awaiting the patient's arrival at the hospital for treatment, is a potential strategy to improve clinical outcomes after stroke.¹⁵ This strategy is based on the use of an ambulance (mobile stroke unit) equipped with an imaging system, a point-of-care laboratory, a telemedicine connection to the hospital, and appropriate medication. Studies of prehospital stroke treatment consistently report a reduction in delays before thrombolysis and cause-based triage in regard to the appropriate target hospital (eg, primary vs comprehensive stroke centre).¹⁵

MSUs, equipped with an integrated CT scanner, can shorten time to thrombolytic treatment and may improve outcomes in patients with acute ischaemic stroke.^5,16

First experiences of programs using ambulances with CT indicate that for selected settings treatment time can be shortened, with over a hundred patients already treated in Berlin and Hamburg.¹⁷ However, the cost-effectiveness of this approach remains to be seen.¹⁷

In the future, mobile stroke units might allow the investigation of novel diagnostic (eg, biomarkers and automated imaging evaluation) and therapeutic (eg, neuroprotective drugs and treatments for haemorrhagic stroke) options in the prehospital setting, thus functioning as a tool for research on prehospital stroke management.¹⁵

The experience and data obtained from existing stroke networks will allow continuing improvements in quality, and the ability to deliver the same service 24/7.⁵
Continued data transparency and inter-hospital cooperation will maximise network efficiency, allowing stroke networks to develop and improve globally over the coming decade and beyond.⁵