Mandatory Neuroendovascular Evolution: Meeting the New Demands

Telestroke

Advancements in acute stroke care include telestroke technology [24, 25, 26, 27]. The concepts of telemedicine and telestroke were pioneered in the 1990s, with the aim of improving care in remote areas or those with limited access to care, such as rural settings [24]. With telestroke, community hospitals without the capabilities to treat an acute stroke can now access the expertise of a stroke neurologist and an endovascular interventionalist to facilitate acute stroke patients faster to the appropriate stroke center for treatment and management. This way, telestroke networks can decrease the burden of stroke at smaller hospitals.

Telestroke systems typically follow a centralized “hub and spoke” design, wherein smaller satellite centers without comprehensive stroke capabilities connect with a stroke specialty hub hospital. When the spoke hospital receives a stroke patient, a consultation with a specialist is triggered at the hub via telestroke network. This model shows an increase in utilized resources and capabilities of the hub as seen in the increase in the number of patients treated with IV tPA and mechanical thrombectomy [28]. Access to endovascular treatment is also enhanced, as candidacy can be rapidly determined and patients can be routed efficiently. In one study, patients transferred to telestroke-equipped centers are more likely to undergo intra-arterial treatment by 11% (66 vs. 55%) [27]. Availability of telestroke networks can also facilitate rapid endovascular intervention as advanced notice allows adequate facility and team preparation while the patient is en route [29].

In one model study, the telestroke model was shown to hold several advantages over traditional care. Apart from improving clinical outcomes and costs (Fig. ​(Fig.2),2), the hub and spoke model proved to be economically feasible for systems comprising more than 2 spoke centers. Although the hub hospital incurred increased costs nearing USD 410,000, the overall savings for the system led to a net positive result [30].

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Fig. 2

Hub-and-spoke model.

Electronic Aids

The advent of smartphones and tablets brought an explosion in the field of mobile programs [31]. There are nearly 5,000,000 smartphone applications between the leading smartphone platforms [32], with more than 165,000 of these focused on health [33].

Several applications have been developed for primary and secondary prevention purposes. For instance, the Korea University Health Monitoring System for Stroke provides patients that experienced a past stroke with information regarding ongoing preventive vascular risk management [34]. Another example is mHealth, an application designed to aid stroke patients in long-term care such as providing instructions of care and medication management [35]. Artificial intelligence was utilized in an application to predict and combat anticoagulation nonadherence in patients with limited smartphone experience [36].

A number of these programs focus on streamlining EMS operations. Some of these programs do so by including stroke scale calculators, which may tally scores automatically, such as MDCalc or Stroke Pocketcards. Other applications allow real-time encrypted communication between emergency responders and hospital personnel, such as Twiage or Pulsara. These programs allow paramedics to share real-time information with receiving hospitals, including photographs or videos to hospitals to prepare for patient arrival. Applications may also be used to telecast suggestive symptoms to telestroke networks or stroke physicians [37, 38].

Numerous other applications have been developed to aid first-line personnel in quickly relaying information to stroke specialists for deciding upon the course of acute treatment and management for patients that likely experienced an acute stroke. For instance, Stroke119 is a comprehensive application with a built-in CPSS-based screening scale that aids in the initial recognition of stroke symptoms [39]. End users select from a set of images that best describes the present symptoms and a stroke probability is calculated. The application also directs users to nearby hospitals with the appropriate stroke capabilities. In addition, there is a hybrid web-portal functionality for hospitals to keep their geographic information upon the application up-to-date through a web browser [39].

Electronic medical records such as Epic may offer remote access and image viewing. Other applications, such as ResolutionMD, may directly route acquired images such as CT scans to telestroke network physicians' smart devices, expediting diagnostic or treatment determinations [40]. In one study, ResolutionMD versus a widely available system, the Picture Archiving and Communication System (PACS), showed very high inter-rater agreement [41]. The use of ResolutionMD as an adjuvant to PACS allows the user to access PACS images upon their smartphones and reduces the amount of time for the stroke specialist to choose appropriate treatment for the patient. Although smartphone display screens may have limitations in the resolution and quality of displaying images, smartphones continue to rapidly advance and have shown good inter-rater agreement when compared to images viewed on a proper medical station desktop [42, 43].

Mobile Stroke and Interventional Units

Despite the implementation of telestroke and other efforts to streamline acute stroke care, the time between symptom onset and treatment of stroke has plateaued around an average of 130 min [10, 25, 44, 45, 46, 47, 48, 49, 50]. The greatest delay in the treatment of stroke patients has been shown to be in the prehospital phase, in which the patient is triaged and transported to a specialized facility [51].

With the goal of decreasing time to treatment, a system that made portable many stroke care capabilities to the patient was devised, thus leading to the creation of the mobile stroke unit (MSU). The MSU is a modified ambulance that contains a CT scanner and healthcare specialists with the authority to determine the patient's treatment and management or seek expertise via the appropriate telestroke network.

The first unit was developed in Berlin and resulted in a decrease in time to diagnosis and treatment in stroke patients [50, 52]. The Prehospital Acute Neurological Treatment and Optimization of Medical Care in Stroke Study compared MSUs with standard of care [53]. Notification to treatment was reduced by 25 min, while patients receiving thrombolysis increased by 12% with no comparative increase in complications secondary to thrombolysis [45]. Another controlled German study showed MSUs a reduction in notification to therapy time averaging 41 min, with MSUs having a median time of 35 vs. 76 min without the MSUs [50].

Neurointerventional-trained specialists are not universally available, with prior estimates putting the number of practitioners at nearly 800 in the United States [54]. Mobile neurointerventional teams were piloted in the Kanazawa Mobile Embolectomy Team con ducted in Japan. Local physicians within an 80-km radius would administer tPA as they deemed appropriate and would alert the Kanazawa Mobile Embolectomy Team unit. Results have been promising, with a revascularization rate of 80% and mean onset to puncture times of 224 min, not dissimilar to those seen in traditional teams [55]. Although the radius for this study was somewhat limited, it did show promise in terms of feasibility for mobile endovascular teams. However, cost effectiveness and applicability remain to be evaluated upon a larger scale.

CT angiography (CTA) capable units could allow endovascular candidates to be rapidly identified on the field, enabling efficient routing of potential thrombectomy candidates to endovascular-capable centers. In one study, this approach nearly halved door-to-puncture time eligible patients (93 vs. 200 min) [56]. This study used telestroke to contact the stroke center's vascular neurologist to determine the patient's eligibility for CTA. Having MSUs with this level of neuroimaging would greatly expedite determining a stroke patient's candidacy for endovascular intervention.

Another way to reduce treatment times is to transport a neurointerventionalist to where the patient is having the stroke. Hui et al. [57] designed and implemented a proof-of-concept case to demonstrate the potential cost-savings of transporting a neurointerventionalist via helicopter to the patient in an angiographic-capable hospital. Transporting a patient via helicopter can require advanced levels of care, such as personnel to manage intravenous lines and endotracheal tubes, which can increase the hospital bill for the patient [57]. The hospital in which the patient was admitted had an angiography suite that the authors had supplied with the appropriate catheters and devices; however, there was no neurointerventionalist on site. This case had a total time from last well known to groin closure of 153 min, with a total time from decision to treat to groin closure of 77 min, times competitive with those reported in the literature [58]. However, Friedrich et al. [59] discusses potential problems that may arise from this reverse spoke-and-hub model. For instance, in the case discussed by Hui et al. [57], they had to supply the angiography suite with appropriate equipment. Neurointerventionalists may have to be stocked with the appropriate equipment and travel to angiography suites that may not be amenable for treating patients with mechanical thrombectomy [59].

Some EMS systems utilize “lights and siren” when transporting stroke patients to the hospital [60, 61]. Transporting an acute ischemic stroke patient to the hospital can otherwise have time delays, which can reduce the chances for brain tissue to be salvageable. Allowing a neurointerventional specialist to utilize “lights and sirens” to reduce the time from patient's last well known to decision to treat could greatly increase the chances of saving a patient's life. For instance, Dr. Kaushal at Palmetto General Hospital uses emergency lights upon his own vehicle to drive past roads with heavy traffic while still abiding by traffic laws [62]. This could be useful in conjunction with the concept of helistroke, especially for regional hospitals that do not have neurointerventional expertise on site.

Although the reduction in notification to treatment times would be expected to improve clinical outcomes, analyses have yielded unchanged patient survival and disability scores at 90 days [45]. Another issue MSUs face is poor cost-effectiveness given the necessary initial investment and high operational costs as compared to the reaped benefits of improved patient outcomes. In one analysis of Cleveland-based MSUs, 317 deployments of the units yielded 16 tPA administrations, 4 within 1 h of initial notification [63]. Nevertheless, MSUs remain a value proposition in rural areas where access to a stroke center is limited [64].

Hospital-Based Strategies

How can comprehensive stroke centers increase their capabilities of handling increased amounts of patients that may be candidates for mechanical thrombectomy? The shortage of neurovascular specialists is well recognized with only about 1,100 physicians currently available, and stroke incidence projected to outstrip supply [2]. Since 2012, only 10 new ACGME-Recognized Vascular Neurology fellowships have been inaugurated, which totals 82 at the time of this manuscript. The heterogeneous distribution of neurovascular specialists complicates matters, with underserved areas exhibiting the lowest density of vascular neurologists [65, 66, 67]. Several strategies have been suggested to meet this need, including increasing the number of vascular neurology training positions, decreasing accumulated tuition bur dens, and improving reimbursement for this specialty [2].

Stroke Education in the Setting of Pop Culture

Much focus has been placed upon educating healthcare personnel like EMS workers to recognize and transport potential stroke patients to the appropriate hospital facility. Another approach to reduce the door to needle time for acute stroke patients is to reduce the time from stroke recognition to activation of the emergency response system [14]. Williams and Noble [68] published a study where the use of hip hop music and dance was used to teach elementary school children in Harlem, NYC to recognize the FAST symptoms of stroke. Since the demographic in central Harlem consists of adults with risk factors for stroke, educating the children this way could increase the spread of knowledge of symptom recognition and prevention to the adults with trouble accessing healthcare [68].

Bundy et al. [69] performed an analysis of a Twitter network geared toward stroke education and care found by searching using the key term #Stroke from March 20, 2012 to January 31, 2018. They noted that advances in stroke care, especially since the results of the DAWN and DEFUSE3 trials, have increased tweets regarding thrombectomy [69]. Since the upcoming generation of adolescents and adults use social media for communication and information, such media platforms can reach out to and educate millions of laypersons about acute stroke symptom recognition, treatment, and care.

Other forms of social media are also utilized to quickly disperse information relating to stroke awareness and education. For instance, YouTube is a popular platform to view videos with content ranging from entertainment to education. Several healthcare organizations and physicians utilize this to include didactic visuals and audio to explain disease prevention and treatment for various medical conditions like acute stroke. Similarly to Twitter, millions of users access YouTube daily, making this an extremely effective tool to educate the general population in stroke symptom recognition and prevention. Future studies should correlate the effect of the availability of such information to the education level of stroke patients and their family and friends. This could help determine if the content created is understood at a layperson level and engaging enough to attract the attention of the general population.

Novel Imaging Applications

Stroke centers must possess the necessary imaging modalities to determine endovascular or intravenous treatment candidacy. Thus, expanding image acquisition capabilities should be pursued. CT modalities are more widely available than MRI, with generally shorter acquisition times, and potentially more cost-effective to implement.

CT Perfusion (CTP) scans have been shown to best depict salvageable tissue for intervention. Another way to approach this is to increase the amount of hospitals with CTP capabilities to potentially decrease the door-to-puncture time for ET candidates [70, 71]. A retrospective cohort study used diffusion-weighted and perfusion-weighted imaging to identify large-vessel occlusions and resulted in 95.9% sensitivity and 98.4% specificity, suggesting the utilization of these imaging modalities to identify candidates for endovascular therapy [72]. In addition, cone-beam CT can be used in conjunction with the aforementioned abbreviated stroke scales to reduce door to groin puncture times [73]. Another modality to consider is volume perfusion CT with CTA vessel reconstruction, which was shown to reduce time to puncture in initial trials [74].

Other novel imaging applications include image analytic software. In one trial, an automated image processing software package termed RAPID was employed. This system was able to process perfusion and diffusion weighted MRI images and effectively identify advantageous reperfusion candidates [75]. With the increased window of endovascular treatment from within 6 h to within 24 h, such imaging software becomes vital for determining candidates for endovascular intervention from the anticipated increase in patients from the DAWN and DEFUSE3 trials [7, 8]. In conjunction with the pre-hospital abbreviated screening scales, automated imaging software and CTP can form the basis of a streamlined process of triaging patients for the appropriate level of care needed.

None.