Clinical and Technological Approaches to the Prehospital Diagnosis of Large Vessel Occlusion

Acute Middle Cerebral Artery Occlusion Detection Using Mobile Non-Imaging Brain Perfusion Ultrasound-First Case

Mobile brain perfusion ultrasound (BPU) is a novel non-imaging technique creating only hemispheric perfusion curves following ultrasound contrast injection and has been specifically designed for early prehospital large vessel occlusion (LVO) stroke identification. We report on the first patient investigated with the SONAS^® system, a portable point-of-care ultrasound system for BPU. This patient was admitted into our stroke unit about 12 h following onset of a fluctuating motor aphasia, dysarthria and facial weakness resulting in an NIHSS of 3 to 8. Occlusion of the left middle cerebral artery occlusion was diagnosed by computed tomography angiography. BPU was performed in conjunction with injection of echo-contrast agent to generate hemispheric perfusion curves and in parallel, conventional color-coded sonography (TCCS) assessing MCAO. Both assessments confirmed the results of angiography. Emergency mechanical thrombectomy (MT) achieved complete recanalization (TICI 3) and post-interventional NIHSS of 2 the next day. Telephone follow-up after 2 years found the patient fully active in professional life. Point-of-care BPU is a non-invasive technique especially suitable for prehospital stroke diagnosis for LVO. BPU in conjunction with prehospital stroke scales may enable goal-directed stroke patient placement, i.e., directly to comprehensive stroke centers aiming for MT. Further results of the ongoing phase II study are needed to confirm this finding.

Plasma chromogranin A levels are associated with acute ischemic stroke with anterior circulation large vessel occlusion

BACKGROUND AND AIMS

To investigate the relationship between chromogranin A (CgA) levels and acute ischemic stroke (AIS), especially anterior circulation large vessel occlusion (LVO).

METHODS AND RESULTS

587 subjects were included in this study, including 205 AIS patients with anterior circulation LVO and 205 nonocclusive patients, as well as 177 healthy controls. On admission, plasma CgA levels were measured and neurological deficits were assessed by the NIH Stroke Scale. Outcomes were assessed by the modified Rankin Scale at 3 months. The predictive properties of CgA were evaluated by receiver operating characteristic (ROC) curve analysis. Binary logistic analysis assessed the association of CgA levels and AIS or anterior circulation LVO. AIS patients had lower CgA levels than health controls (p < 0.001). Anterior circulation LVO patients had lower CgA levels than nonocclusive patients (p < 0.001). The area under the ROC curve of plasma CgA levels in predicting anterior circulation LVO from AIS was 0.744 and the optimal cutoff value was 15.49 ng/mL with a Youden value of 0.332. Logistic analysis showed that CgA ≤15.49 ng/mL remained an independent risk factor for anterior circulation LVO after adjusting for related factors (OR = 6.519, 95% CI: 3.790-11.214, p < 0.001). CgA was an independent protective factor for mild stroke and good prognosis (p = 0.009, p = 0.005); however, the association disappeared after adjusting for occlusion (p = 0.768, p = 0.335).

CONCLUSION

CgA levels were lower in AIS patients, especially in anterior circulation LVO patients. Lower CgA levels are potential biomarker for anterior circulation LVO, and they may indicate good prognosis at 3 months in AIS.

Trauma Communications Center Coordinated Severity-Based Stroke Triage: Protocol of a Hybrid Type 1 Effectiveness-Implementation Study

Background: Mechanical thrombectomy (MT) can improve the outcomes of patients with large vessel occlusion (LVO), but a minority of patients with LVO are treated and there are disparities in timely access to MT. In part, this is because in most regions, including Alabama, the emergency medical service (EMS) transports all patients with suspected stroke, regardless of severity, to the nearest stroke center. Consequently, patients with LVO may experience delayed arrival at stroke centers with MT capability and worse outcomes. Alabama's trauma communications center (TCC) coordinates EMS transport of trauma patients by trauma severity and regional hospital capability. Our aims are to develop a severity-based stroke triage (SBST) care model based on Alabama's trauma system, compare the effectiveness of this care pathway to current stroke triage in Alabama for improving broad, equitable, and timely access to MT, and explore stakeholder perceptions of the intervention's feasibility, appropriateness, and acceptability.

Methods: This is a hybrid type 1 effectiveness-implementation study with a multi-phase mixed methods sequential design and an embedded observational stepped wedge cluster trial. We will extend TCC guided stroke severity assessment to all EMS regions in Alabama; conduct stakeholder interviews and focus groups to aid in development of region and hospital specific prehospital and inter-facility stroke triage plans for patients with suspected LVO; implement a phased rollout of TCC Coordinated SBST across Alabama's six EMS regions; and conduct stakeholder surveys and interviews to assess context-specific perceptions of the intervention. The primary outcome is the change in proportion of prehospital stroke system patients with suspected LVO who are treated with MT before and after implementation of TCC Coordinated SBST. Secondary outcomes include change in broad public health impact before and after implementation and stakeholder perceptions of the intervention's feasibility, appropriateness, and acceptability using a mixed methods approach. With 1200 to 1300 total observations over 36 months, we have 80% power to detect a 15% improvement in the primary endpoint.

Discussion: This project, if successful, can demonstrate how the trauma system infrastructure can serve as the basis for a more integrated and effective system of emergency stroke care.

Direct Transfer to Angiosuite in Acute Stroke: Why, When, and How?

Time to reperfusion is one of the strongest predictors of functional outcome in acute stroke due to a large vessel occlusion (LVO). Direct transfer to angiography suite (DTAS) protocols have shown encouraging results in reducing in-hospital delays. DTAS allows bypassing of conventional imaging in the emergency room by ruling out an intracranial hemorrhage or a large established infarct with imaging performed before transfer to the thrombectomy-capable center in the angiography suite using flat-panel CT (FP-CT). The rate of patients with stroke code primarily admitted to a comprehensive stroke center with a large ischemic established lesion is <10% within 6 hours from onset and remains <20% among patients with LVO or transferred from a primary stroke center. At the same time, stroke severity is an acceptable predictor of LVO. Therefore, ideal DTAS candidates are patients admitted in the early window with severe symptoms. The main difference between protocols adopted in different centers is the inclusion of FP-CT angiography to confirm an LVO before femoral puncture. While some centers advocate for FP-CT angiography, others favor additional time saving by directly assessing the presence of LVO with an angiogram. The latter, however, leads to unnecessary arterial punctures in patients with no LVO (3%-22% depending on selection criteria). Independently of these different imaging protocols, DTAS has been shown to be effective and safe in improving in-hospital workflow, achieving a reduction of door-to-puncture time as low as 16 minutes without safety concerns. The impact of DTAS on long-term functional outcomes varies between published studies, and randomized controlled trials are warranted to examine the benefit of DTAS.

Large Vessel Occlusion Stroke Detection in the Prehospital Environment

Purpose of Review

Endovascular therapy for acute ischemic stroke secondary to large vessel occlusion (LVO) is time-dependent. Prehospital patients with suspected LVO stroke should be triaged directly to specialized stroke centers for endovascular therapy. This review describes advances in LVO detection among prehospital suspected stroke patients.

Recent Findings

Clinical prehospital stroke severity tools have been validated in the prehospital setting. Devices including EEG, SSEPs, TCD, cranial accelerometry, and volumetric impedance phase-shift-spectroscopy have recently published data regarding LVO detection in hospital settings. Mobile stroke units bring thrombolysis and vessel imaging to patients.

Summary

The use of a prehospital stroke severity tool for LVO triage is now widely supported. Ease of use should be prioritized as there are no meaningful differences in diagnostic performance amongst tools. LVO diagnostic devices are promising, but none have been validated in the prehospital setting. Mobile stroke units improve patient outcomes and cost-effectiveness analyses are underway.

How to Improve the Management of Acute Ischemic Stroke by Modern Technologies, Artificial Intelligence, and New Treatment Methods

Stroke remains one of the leading causes of death and disability in Europe. The European Stroke Action Plan (ESAP) defines four main targets for the years 2018 to 2030. The COVID-19 pandemic forced the use of innovative technologies and created pressure to improve internet networks. Moreover, 5G internet network will be helpful for the transfer and collecting of extremely big databases. Nowadays, the speed of internet connection is a limiting factor for robotic systems, which can be controlled and commanded potentially from various places in the world. Innovative technologies can be implemented for acute stroke patient management soon. Artificial intelligence (AI) and robotics are used increasingly often without the exception of medicine. Their implementation can be achieved in every level of stroke care. In this article, all steps of stroke health care processes are discussed in terms of how to improve them (including prehospital diagnosis, consultation, transfer of the patient, diagnosis, techniques of the treatment as well as rehabilitation and usage of AI). New ethical problems have also been discovered. Everything must be aligned to the concept of “time is brain”.

Extracellular Vesicles in Acute Stroke Diagnostics

There is a large unmet need for fast and reliable diagnostics in several diseases. One such disease is stroke, where the efficacy of modern reperfusion therapies is highly time-dependent. Diagnosis of stroke and treatment initiation should be performed as soon as possible, and preferably before arrival at the stroke center. In recent years, several potential blood biomarkers for stroke have been evaluated, but without success. In this review, we will go into detail on the possibility of utilizing extracellular vesicles (EVs) released into the blood as novel biomarkers for stroke diagnostics. EVs are known to reflect the immediate state of the secreting cells and to be able to cross the blood–brain barrier, thus making them attractive as diagnostic biomarkers of brain diseases. Indeed, several studies have reported EV markers that enable differentiation between stroke patients and controls and, to a lesser extent, the ability to correctly classify the different stroke types. Most of the studies rely on the use of sophisticated and time-consuming methods to quantify specific subpopulations of the nanosized EVs. As these methods cannot be easily implemented in a rapid point of care (POC) test, technical developments followed by prospective clinical studies are needed.

A scoping review of pre-hospital technology to assist ambulance personnel with patient diagnosis or stratification during the emergency assessment of suspected stroke

BACKGROUND

Pre-hospital identification of key subgroups within the suspected stroke population could reduce delays to emergency treatment. We aimed to identify and describe technology with existing proof of concept for diagnosis or stratification of patients in the pre-hospital setting.

METHODS

A systematic electronic search of published literature (from 01/01/2000 to 06/06/2019) was conducted in five bibliographic databases. Two reviewers independently assessed eligibility of studies or study protocols describing diagnostic/stratification tests (portable imaging/biomarkers) or technology facilitating diagnosis/stratification (telemedicine) used by ambulance personnel during the assessment of suspected stroke. Eligible descriptions required use of tests or technology during the actual assessment of suspected stroke to provide information directly to ambulance personnel in the pre-hospital setting. Due to study, intervention and setting heterogeneity there was no attempt at meta-analysis.

RESULTS

2887 articles were screened for eligibility, 19 of which were retained. Blood biomarker studies (n = 2) were protocols of prospective diagnostic accuracy studies, one examining purines and the other a panel of known and novel biomarkers for identifying stroke sub-types (versus mimic). No data were yet available on diagnostic accuracy or patient health outcomes. Portable imaging studies (n = 2) reported that an infrared screening device for detecting haemorrhages yielded moderate sensitivity and poor specificity in a small study, whilst a dry-EEG study to detect large vessel occlusion in ischaemic stroke has not yet reported results. Fifteen evaluations of pre-hospital telemedicine were identified (12 observational and 3 controlled comparisons) which all involved transmission of stroke assessment data from the pre-hospital setting to the hospital. Diagnosis was generally comparable with hospital diagnosis and most telemedicine systems reduced time-to-treatment; however, it is unknown whether this time saving translated into more favourable clinical outcomes. Telemedicine systems were deemed acceptable by clinicians.

CONCLUSIONS

Pre-hospital technologies to identify clinically important subgroups amongst the suspected stroke population are in development but insufficient evidence precludes recommendations about routine use in the pre-hospital setting. Multi-centre diagnostic accuracy studies and clinical utility trials combining promising technologies are warranted.

Prehospital selection of thrombectomy candidates beyond large vessel occlusion

Objective

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

Methods

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

Results

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

Conclusions

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

Use, Temporal Trends, and Outcomes of Endovascular Therapy After Interhospital Transfer in the United States

BACKGROUND

The use of endovascular therapy (EVT) in patients with acute ischemic stroke who have large vessel occlusion has rapidly increased in the United States following pivotal trials demonstrating its benefit. Information about the contribution of interhospital transfer in improving access to EVT will help organize regional systems of stroke care.

METHODS

We analyzed trends of transfer-in EVT from a cohort of 1 863 693 patients with ischemic stroke admitted to 2143 Get With The Guidelines-Stroke participating hospitals between January 2012 and December 2017. We further examined the association between arrival mode and in-hospital outcomes by using multivariable logistic regression models.

RESULTS

Of the 37 260 patients who received EVT at 639 hospitals during the study period, 42.9% (15 975) arrived at the EVT-providing hospital after interhospital transfer. Transfer-in EVT cases increased from 256 in the first quarter 2012 to 1422 in the fourth quarter 2017, with sharply accelerated increases following the fourth quarter 2014 ( P<0.001 for change in linear trend). Transfer-in patients were younger and more likely to be of white race, to arrive during off-hours, and to be treated at comprehensive stroke centers. Transfer-in patients had significantly longer last-known-well-to-EVT initiation time (median, 289 minutes versus 213 minutes; absolute standardized difference, 67.33) but were more likely to have door-to-EVT initiation time of ≤90 minutes (65.6% versus 23.6%; absolute standardized difference, 93.18). In-hospital outcomes were worse for transfer-in patients undergoing EVT in unadjusted and in risk-adjusted models. Although the difference in in-hospital mortality disappeared after adjusting for delay in EVT initiation (14.7% versus 13.4%; adjusted odds ratio, 1.01; 95% CI, 0.92-1.11), transfer-in patients were still more likely to develop symptomatic intracranial hemorrhage (7.0% versus 5.7%; adjusted odds ratio, 1.15; 95% CI, 1.02-1.29) and less likely to have either independent ambulation at discharge (33.1% versus 37.1%; adjusted odds ratio, 0.87; 95% CI, 0.80-0.95) or to be discharged to home (24.3% versus 29.1%; adjusted odds ratio, 0.82; 95% CI, 0.76-0.88).

CONCLUSIONS

Interhospital transfer for EVT is increasingly common and is associated with a significant delay in EVT initiation highlighting the need to develop more efficient stroke systems of care. Further evaluation to identify factors that impact EVT outcomes for transfer-in patients is warranted.

The role of the Cincinnati Prehospital Stroke Scale in the emergency department: evidence from a systematic review and meta-analysis

Introduction

Stroke is one of the leading causes of morbidity, disability, and mortality in high-income countries. Early prehospital stroke recognition plays a fundamental role, because most clinical decisions should be made within the first hours after onset of symptoms. The Cincinnati Prehospital Stroke Scale (CPSS) is a validated screening tool whose utilization is suggested during triage. The aim of this study is to review the role of the CPSS by assessing its sensitivity and specificity in prehospital and hospital settings.

Methods

A systematic review and a meta-analysis of the literature reporting the CPSS sensitivity and specificity among patients suspected of stroke were undertaken. Electronic databases were searched up to December 2018, and the quality assessment was carried out by using the Revised Quality Assessment of Diagnostic Accuracy Studies −2  (QUADAS-2).

Results

Eleven studies were included in the meta-analysis. Results showed an overall sensitivity of 82.46% (95% confidence interval [CI] 74.83–88.09%) and specificity of 56.95% (95% CI 41.78–70.92). No significant differences were found in terms of sensitivity when CPSS was performed by physicians (80.11%, 95% CI 66.14–89.25%) or non-physicians (81.11%, 95% CI 69.78–88.87%). However, administration by physicians resulted in higher specificity (73.57%, 95% CI 65.78–80.12%) when compared to administration by non-physicians (50.07%, 95% CI 31.54–68.58%). Prospective studies showed higher specificity 71.61% (95% CI 61.12–80.18%) and sensitivity 86.82% (95% CI 74.72–93.63) when compared to retrospective studies which showed specificity of 33.37% (95% CI 22.79–45.94%) and sensitivity of 78.52% (95% CI 75.08–81.60).

Conclusions

The CPSS is a standardized and easy-to-use stroke screening tool whose implementation in emergency systems protocols, along with proper and consistent coordination with local, regional, and state agencies, medical authorities and local experts are suggested.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Speech Arm Vision Eyes (SAVE) scale predicts large vessel occlusion stroke as well as more complicated scales

INTRODUCTION

The Speech Arm Vision Eyes (SAVE) scale, a 4-item clinical scale emphasizing binary scoring and avoidance of nuanced examination distinctions, predicts LVOs with similar characteristics as more complex scales.

METHODS

Receiver operating characteristic analyses of the prospective STOPStroke study assessed the ability of the SAVE scale and other published scales to predict LVO. We identified scale thresholds with positive likelihood ratios with 95% confidence intervals of ≥5.0 or negative likelihood ratios with 95% confidence intervals of ≤0.5.

RESULTS

735patients were studied. LVO prevalence was 33%. Area under the curve was 0.79 for SAVE, 0.82 for FAST-ED, 0.80 for mNIHSS and NIHSS, and lower for all other scales. SAVE=4, EMSA=6, mNIHSS≥10, NIHSS≥16, and RACE≥8 had positive likelihood ratios with 95% confidence intervals ≥5.0. SAVE≥2, CPSS≥2, C-STAT≥1, EMSA≥4, FAST-ED≥3, G-FAST≥3, mNIHSS≥6, NIHSS≥9, PASS≥1, RACE≥2, VAN=1, and 3I-SS≥1 had negative likelihood ratios with 95% confidence intervals ≤0.5.

CONCLUSIONS

SAVE=4 performed similarly to more complex scales at predicting LVO. Other simplified scales did not have thresholds with positive likelihood ratios with 95% confidence intervals ≥5.0. Validation is need in a prehospital cohort of patients with suspected stroke.