Artificial intelligence to enhance prehospital stroke diagnosis and triage: a perspective.

As health systems organize to deliver the highest quality stroke care to their patients, there is increasing emphasis being placed on prehospital stroke recognition, accurate diagnosis, and efficient triage to improve outcomes after stroke. Emergency medical services (EMS) personnel currently rely heavily on dispatch accuracy, stroke screening tools, bypass protocols and prehospital notification to care for patients with suspected stroke, but novel tools including mobile stroke units and telemedicine-enabled ambulances are already changing the landscape of prehospital stroke care. Herein, the authors provide our perspective on the current state of prehospital stroke diagnosis and triage including several of these emerging trends. Then, we provide commentary to highlight potential artificial intelligence (AI) applications to improve stroke detection, improve accurate and timely dispatch, enhance EMS training and performance, and develop novel stroke diagnostic tools for prehospital use.

Prehospital stroke scales outperform National Institutes of Health Stroke Scale in predicting large vessel occlusion in a large academic telestroke network.

INTRODUCTION: Prehospital telestroke evaluations may improve stroke triage compared to paramedic-applied large vessel occlusion scales, but ambulance-based video National Institutes of Health Stroke Scale assessments are challenging. The accuracy of telestroke-administered large vessel occlusion scales has not been investigated, so we sought to evaluate this further. METHODS: This retrospective study included all in-hospital telestroke encounters in a large academic telestroke network from 2019 to 2020. We retrospectively calculated seven large vessel occlusion scales using the in-hospital telestroke National Institutes of Health Stroke Scale (Rapid Arterial oCclusion Evaluation, Cincinnati Stroke Triage Assessment Tool, Field Assessment Stroke Triage for Emergency Destination, 3-Item Stroke Scale, Prehospital Acute Stroke Severity, Vision-Aphasia-Neglect, and Gaze-Face-Arm-Speech-Time). Diagnostic performance was assessed via sensitivity, specificity, negative predictive value, positive predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy using established scale thresholds. These results were compared to the National Institutes of Health Stroke Scale at thresholds of 6, 8, and 10. The area under curve was calculated using c-statistics by treating scales as continuous variables. RESULTS: A total of 625 patients were included; 111 (17.8%) patients had an anterior large vessel occlusion, 118 (18.9%) patients had any large vessel occlusion, and 182 (29.1%) patients had stroke mimic diagnosis. The mean age (SD) was 67.9 (15.9), 48.3% were female, and 93.4% were white. The Mean National Institutes of Health Stroke Scale (SD) was 14.9 (8.4) for patients with anterior large vessel occlusion, 4.7 (5.0) for patients with non-large vessel occlusion ischemic stroke, and 4.4 (5.8) for stroke mimic (p < 0.001). Compared to the National Institutes of Health Stroke Scale, Field Assessment Stroke Triage for Emergency Destination, and Rapid Arterial oCclusion Evaluation scales demonstrated higher accuracy and area under curve for large vessel occlusion detection. DISCUSSION: Both the Field Assessment Stroke Triage for Emergency Destination and Rapid Arterial oCclusion Evaluation scales outperformed the National Institutes of Health Stroke Scale for large vessel occlusion detection in patients evaluated by in-hospital telestroke. These scales may be valid alternatives to the National Institutes of Health Stroke Scale examination in this setting.

Emergent use of ticagrelor during endovascular reperfusion in large arterial occlusions.

OBJECTIVE: Given many emerging indications for endovascular interventions in ischemic strokes, a safe and effective adjuvant antiplatelet regimen for acute revascularization has become a subject of interest. Ticagrelor is a direct oral P2Y12 inhibitor that may achieve rapid platelet suppression than standard oral therapies. We report our experience of Ticagrelor use in revascularization of acute large arterial steno-occlusive disease, describing procedural post-procedure thrombotic events, major hemorrhages, and other clinical outcomes. METHODS: This was a single-center retrospective case series of large steno-occlusive disease requiring endovascular reperfusion with emergent adjuvant Ticagrelor, defined as 30 min of the procedure from skin puncture to closure of the arteriotomy. Major outcomes investigated were thromboembolism in the target artery, and symptomatic intracranial or extracranial major hemorrhages. Additional analyses were performed with respect to timing of the administration and use of rescue GPIIb/IIIa inhibitors if any. RESULTS: 73 consecutive patients were identified, presenting with severe ischemic stroke (median NIHSS 16) of large artery origin. 67% required stent placement (45% cervical carotid, 22% intracranial artery), 9.5% angioplasty and 23% mechanical thrombectomy only. Two experienced symptomatic in-stent occlusion, and 7 experienced major hemorrhages (9.5%) including 3 fatal symptomatic intracranial hemorrhages (4.1%). Among 19 subjects (26%) who received pretreatment with Ticagrelor, there were fewer GPIIb/IIIa administration, angioplasty and stenting, without yielding benefit in functional outcome or mortality. GPIIb/IIIa was administered as rescue therapy in 45 subjects (62%), which was found associated with increased bleeding compared to patients receiving Ticagrelor only, in whom no bleeding complications were recorded (16% vs. 0%; p = 0.03). CONCLUSION: We report our findings on Ticagrelor as an adjuvant antiplatelet therapy in ischemic stroke of large arterial origin requiring emergent revascularization. Effectiveness, safety, need for additional rescue treatment, and comparison to other commonly used oral antiplatelets should be investigated in future prospective studies.

Donation after circulatory death: A transplant cardiologist's take on neuroprognostication.

Donation after circulatory death (DCD) is becoming increasingly utilized in heart transplantation and has the potential to further expand the donor pool. As transplant cardiologists gain more familiarity with DCD donor selection, there are many issues that lack consensus including how we incorporate the neurologic examination, how we measure functional warm ischemic time (fWIT), and what fWIT thresholds are acceptable. DCD donor selection calls for prognostication tools to help determine how quickly a donor may expire, and in current practice there is no standardization in how we make these predictions. Current scoring systems help to determine which donor may expire within a specified time window either require the temporary disconnection of ventilatory support or do not incorporate any neurologic examination or imaging. Moreover, the specified time windows differ from other DCD solid organ transplantation without standardization or strong scientific justification for these thresholds. In this perspective, we highlight the challenges faced by transplant cardiologists as they navigate the muddy waters of neuroprognostication in DCD cardiac donation. Given these difficulties, this is also a call to action for the creation of a more standardized approach to improve the DCD donor selection process for appropriate resource allocation and organ utilization.

Telestroke's Role Through the COVID-19 Pandemic and Beyond.

Purpose of review: The goal of this paper is to discuss the role and utilization of telestroke services through the COVID-19 pandemic and to suggest future directions to sustain and increase patients' access to stroke expertise. Recent findings: Telestroke is an innovative and effective tool that has been shown to improve access, quality of care, and outcomes of patients with acute stroke syndromes in resource-limited areas for the last two decades. The COVID-19 pandemic posed a significant challenge and strained healthcare systems worldwide, but it created novel and unique opportunities to expand and increase the utilization of telehealth and telestroke services to deliver personalized healthcare across the continuum of stroke care outside of traditional settings. This rapid and widespread increase in telestroke use was facilitated by the removal of many legislative and regulatory barriers which have limited patients' access to stroke expertise for many years. Summary: As the public health emergency ends, there exists a unique opportunity to optimize and expand upon the pandemic-related rapid growth of telestroke care. Optimal utilization of telehealth and telestroke services will depend on maintaining and improving required infrastructure, laws, and regulations, particularly those governing reimbursement and licensing.

Improving the Telemedicine Evaluation of Patients With Acute Vision Loss: A Call to Eyes.

Acute vision loss related to cerebral or retinal ischemia is a time-sensitive emergency with potential treatment options including IV or intra-arterial thrombolysis and mechanical thrombectomy. However, patients either present in a delayed fashion or present to an emergency department that lacks the subspecialty expertise to recognize and treat these conditions in a timely fashion. Moreover, health care systems in the United States are becoming increasingly reliant on telestroke and teleneurology services for acute neurologic care, making the accurate diagnosis of acute vision loss even more challenging due to critical limitations to the remote video evaluation, including the inability to perform routine ophthalmoscopy. The COVID-19 pandemic has led to a greater reliance on telemedicine services and helped to accelerate the development of novel tools and care pathways to improve remote ophthalmologic evaluation, but these tools have yet to be adapted for use in the remote evaluation of acute vision loss. Permanent vision loss can be disabling for patients, and efforts must be made to increase and improve early diagnosis and management. Herein, the authors outline the importance of improving acute ophthalmologic diagnosis, outline key limitations and barriers to the current video-based teleneurology assessments, highlight opportunities to leverage new tools to enhance the remote assessment of vision loss, and propose new avenues to improve access to emergent ophthalmology subspecialty.

Influence of Platelet Count on Procedure-Related Outcomes After Mechanical Thrombectomy for Large Vessel Occlusion: A Systematic Review and Meta-Analysis.

OBJECTIVE: To compare outcomes between patients who underwent mechanical thrombectomy for large vessel occlusion based on platelet count: low versus normal. METHODS: Three studies were included with a pooled cohort of 1125 patients. Data points were collected and pooled by meta-analysis of proportions via a logit transformation to provide a summary statistic. Both fixed-effect and random-effects models were recruited for the analysis. In this meta-analysis, risk of developing symptomatic intracranial hemorrhage, unfavorable clinical outcomes (modified Rankin Scale score >3), and mortality of patients with low platelet counts were compared with patients with normal platelet counts according to the criteria for inclusion used by each study. RESULTS: Of patients, 50 (4.7%) had low platelet count, and 1075 (95.3%) had normal platelet count. Patients in the low platelet count group had a substantially higher risk of mortality (risk ratio 1.93, 95% confidence interval 1.43-2.60, P < 0.0001, I2 = 0%), but no differences in clinical outcomes (risk ratio 0.66, 95% confidence interval 0.40-1.11, P = 0.12, I2 = 0%) or symptomatic intracranial hemorrhage (risk ratio 2.03, 95% confidence interval 0.87-4.70, P = 0.10, I2 = 15%) were noted. CONCLUSIONS: Patients with low platelet counts had increased mortality compared with patients with normal platelet counts following mechanical thrombectomy for large vessel occlusion.

Telemedicine-enabled ambulances and mobile stroke units for prehospital stroke management.

The recognition and management of stroke in the prehospital setting has become increasingly important to improve patient outcomes. Several strategies to advance prehospital stroke care have been developed, including the mobile stroke unit and the telemedicine-enabled ambulance-or "mini-MSU." These strategies both incorporate ambulance-based audio-visual telemedicine evaluation with a vascular neurologist to facilitate faster treatment but differ in several areas including upfront and recurring costs, scalability or growth potential, ability to integrate into existing emergency medical services systems, and interoperability across multiple specialties or conditions. While both the mobile stroke unit and mini-mobile stroke unit model are valid approaches to improve stroke care, the authors aim to compare these models based on costs, scalability, integration, and interoperability in order to guide our prehospital leaders to find the best solutions for their communities.

Acute Epstein-Barr virus infection presenting as Guillain-Barre syndrome.

An 18-year-old man presented with 5-days of a lower extremity rash, sore throat, rapidly progressive bilateral facial numbness and paresthesias in his distal extremities. His neurological examination acutely deteriorated to include moderate bilateral facial weakness in a lower motor neuron pattern, mild flaccid dysarthria, mild bilateral interossei weakness, and diffuse hyporeflexia. In addition to neurological examination, EMG results of acute demyelinating polyradiculoneuropathy were suggestive of Guillain-Barre Syndrome (GBS). Infectious laboratory testing demonstrated acute infection of Epstein-Barr Virus (EBV) with relatively low EBV DNA quantitative values. The patient subsequently developed fever and cervical lymphadenopathy during his hospital course. Contrasting typical GBS, which presents weeks after an acute infection, the patient's presenting symptom of EBV infection was GBS. GBS as a presenting symptom of EBV has not previously been described. This case may represent a unique mechanism for the pathogenesis of GBS in acute infections as opposed to the traditional post-infectious antibody-mediated process.

Vascular Spinal Cord Disorders.

Vascular disorders of the spinal cord are uncommon yet under-recognized causes of myelopathy. Etiologies can be predominantly categorized into clinical and radiographic presentations of arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage. While vascular myelopathies often produce significant morbidity, recent advances in the understanding and recognition of these disorders should continue to expedite diagnosis and proper management, and ideally improve patient outcomes. This article comprehensively reviews relevant spinal cord vascular anatomy, clinical features, radiographic findings, treatment, and prognosis of vascular disorders of the spinal cord.

Reliability of Field Assessment Stroke Triage for Emergency Destination Scale Use by Paramedics: Mobile Stroke Unit First-Year Experience.

Background and Purpose: Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale is a helpful tool to triage patients with stroke in the field. However, data on its reliability in the prehospital setting are lacking. We aim to test the reliability of FAST-ED scale when used by paramedics in a mobile stroke unit covering a metropolitan area. Methods: As part of standard operating mobile stroke unit procedures, paramedics initially evaluated patients. If the event characterized a stroke alert, the FAST-ED score was determined by the paramedic upon patient contact (in-person) and then independently by a vascular neurologist (VN) immediately after paramedic evaluation (remotely/telemedicine). This allowed testing of the interrater agreement of the FAST-ED scoring performance between on-site prehospital providers and remotely located VN. Results: Of a total of 238 patients transported in the first 15 months of the mobile stroke unit's activity, 173 were included in this study. Median age was 63 (interquartile range, 55.5­75) years and 52.6% were females. A final diagnosis of ischemic stroke was made in 71 (41%), transient ischemic attack in 26 (15%), intracranial hemorrhage in 15 (9%), whereas 61 (35%) patients were stroke mimics. The FAST-ED scores matched perfectly among paramedics and VN in 97 (56%) instances, while there was 0 to 1-point difference in 158 (91.3%), 0 to 2-point difference in 171 (98.8%), and 3 or more point difference in 2 (1.1%) patients. The intraclass correlation between VN and paramedic FAST-ED scores showed excellent reliability, intraclass correlation coefficient 0.94 (95% CI, 0.92­0.96; P<0.001). When VN recorded FAST-ED score ≥3, paramedics also scored FAST-ED≥3 in majority of instances (63/71 patients; 87.5%). A large vessel occlusion was identified in 16 (9.2%) patients; 13 occlusions were identified with a FAST-ED≥3 while 3 were missed. All of the latter patients had National Institutes of Health Stroke Scale score ≤5. Conclusions: We demonstrate excellent reliability of FAST-ED scale performed by paramedics when compared with VN, indicating that it can be accurately performed by paramedics in the prehospital setting.

Safety of Ticagrelor in Moderate and Severe Acute Ischemic Stroke: A Single-Center Retrospective Review.

OBJECTIVES: Ticagrelor may be superior to aspirin after minor ischemic stroke or TIA, particularly in patients with symptomatic atherosclerotic disease. However, there may be an increased risk of intracerebral hemorrhage in patients with moderate to severe ischemic stroke, and ticagrelor has not been studied in this patient population. Therefore, we sought to evaluate the safety of ticagrelor after moderate or severe ischemic stroke. MATERIALS AND METHODS: Retrospective chart review of all patients admitted with acute ischemic stroke and NIHSS 6 or greater who were discharged on ticagrelor between January 2016 and December 2019. Patients who underwent angioplasty, stenting or carotid revascularization during the hospitalization were excluded. RESULTS: Of 183 patients discharged on ticagrelor, 61 patients were included. Median age was 61 (IQR 52-68); 33 (54%) patients were men. Median NIHSS was 11 (IQR 8-15). Fourteen (23%) patients received IV alteplase and 35 (57%) patients received mechanical thrombectomy. Stroke mechanism was large artery atherosclerosis in 53 (87%) of patients, of which 40 (71%) were deemed intracranial atherosclerosis. Final infarct volume was greater than 10 mL in 32 (52%) patients. Follow-up information was available for 53 (87%) patients; median length of follow-up was 3 (IQR 2-6) months. Six (10%) patients experienced recurrent ischemic stroke. No patients experienced symptomatic intracerebral hemorrhage after initiation of ticagrelor. One (2%) patient experienced major bleeding. CONCLUSIONS: This study provides preliminary evidence supporting the potential safety of ticagrelor following moderate or severe acute ischemic stroke. These findings support the need for future prospective studies.

Neurologic complications of diseases of the aorta.

Neurologic complications of diseases of the aorta are common, as the brain and spinal cord function is highly dependent on the aorta and its branches for blood supply. Any disease impacting the aorta may have significant impact on the ability to deliver oxygenated blood to the central nervous system, resulting in ischemia-and if prolonged-cerebral and spinal infarct. The breadth of pathology affecting the aorta is diverse and neurologic complications can vary dramatically based on the location, severity, and underlying etiology. This chapter outlines the major pathology of the aorta while highlighting the associated neurologic complications. This chapter covers the entire spectrum of neurologic complications associated with aortic disease by beginning with a detailed overview of the spinal cord vascular anatomy followed by a discussion of the most common aortic pathologies affecting the nervous system, including aortic aneurysm, aortic dissection, aortic atherosclerosis, inflammatory and infectious aortopathies, congenital abnormalities, and aortic surgery.

Safety and efficacy of ticagrelor as single antiplatelet therapy in prevention of thromboembolic complications associated with the Pipeline Embolization Device (PED): multicenter experience.

BACKGROUND: Flow diversion (FD) is a common treatment modality for complex intracranial aneurysms. A major concern regarding the use of FD is thromboembolic events (TEE). There is debate surrounding the optimal antiplatelet regimen to prevent TEE. We aim to evaluate the safety and efficacy of ticagrelor as a single antiplatelet therapy (SAPT) for the prevention of TEE following FD for complex aneurysm treatment. METHODS: A retrospective review of a prospectively maintained neuroendovascular database at three endovascular centers was performed. Patients were included if they had an intracranial aneurysm that was treated with FD between January 2018 and September 2019 and were treated with ticagrelor as SAPT. Primary outcomes included early (within 72 hours post-procedure) and late (within 6 months) ischemic events. RESULTS: A total of 24 patients (mean age 47.7 years) with 36 aneurysms were eligible for analysis, including 15 (62.5%) females. 14 (58.3%) patients presented with subarachnoid hemorrhage. 35 aneurysms arose from the anterior circulation and 1 from the posterior circulation. 23 aneurysms had a saccular morphology, whereas 7 were fusiform and 6 were blister. For the treatment of all 36 aneurysms, 30 procedures were performed with 32 FD devices. Procedural in-stent thrombosis occurred in 2 cases and was treated with intra-arterial tirofiban without complications. Aneurysm re-bleeding was reported in 1 (4.2%) patient. There were no reported early or late TEE. Three patients discontinued ticagrelor due to systemic side effects. CONCLUSION: Ticagrelor is a safe and effective SAPT for the prevention of TEE after FD. Large multicenter prospective studies are warranted to validate our findings.

Spinal cord transient ischemic attack: Insights from a series of spontaneous spinal cord infarction.

OBJECTIVE: To define the prevalence and characteristics of spinal cord transient ischemic attack (sTIA) in a large retrospective series of patients who met diagnostic criteria for spontaneous spinal cord infarction (SCI). METHODS: An institution-based search tool was used to identify patients evaluated at the Mayo Clinic in Rochester, MN, from 1997 to 2017 with spontaneous SCI (n = 133). Cases were subsequently reviewed for transient myelopathic symptoms preceding infarction that were suspected ischemic in nature. We performed a descriptive analysis of patients with sTIA before SCI. RESULTS: Of 133 patients with a diagnosis of spontaneous SCI, we identified 4 patients (3%) who experienced sTIA before SCI. The median age at presentation was 61.5 years (range 46-75 years), 2 (50%) were women, and 3 (75%) had traditional vascular risk factors. Localization was cervical cord in 2 cases (50%) and thoracic cord in 2 cases (50%); all patients developed SCI in the same distribution as their preceding sTIA symptoms. All patients experienced recurrent sTIA before SCI. Symptoms ranged from seconds to a few minutes before returning to baseline. No patients had pain as a feature of sTIA. CONCLUSIONS: sTIAs are possible but rare in patients who subsequently have a SCI. Clinical features are similar to those of SCI, with rapid onset of severe myelopathic deficits, followed by prompt resolution. Vascular risk factors are common in these patients. Thus, recognition of a sTIA may represent a valuable opportunity for vascular risk factor modification and stroke prevention. However, given the rarity, physicians should explore other possible explanations when sTIA is considered.

Causes of Death in Status Epilepticus.

OBJECTIVES: To determine the causes of death in patients with status epilepticus. To analyze the relative contributions of seizure etiology, seizure refractoriness, use of mechanical ventilation, anesthetic drugs for seizure control, and medical complications to in-hospital and 90-day mortality, hospital length of stay, and discharge disposition. DESIGN: Retrospective cohort. SETTING: Single-center neuroscience ICU. PARTICIPANTS: Patients with status epilepticus were identified by retrospective search of electronic database from January 1, 2011, to December 31, 2016. INTERVENTIONS: Review of electronic medical records. MEASUREMENTS AND MAIN RESULTS: Demographics, clinical characteristics, treatments, and outcomes were collected. Univariable and multivariable logistic regression analysis were used to determine whether the use of anesthetic drugs, mechanical ventilation, Status Epilepticus Severity Score, refractoriness of seizures, etiology of seizures, or medical complications were associated with in-hospital, 90-day mortality or discharge disposition. Among 244 patients with status epilepticus (mean age was 64 yr [interquartile range, 42-76], 55% male, median Status Epilepticus Severity Score 3 [interquartile range, 2-4]), 24 received anesthetic drug infusions for seizure control. In-hospital and 90-day mortality rates were 9.2% and 19.2%, respectively. Death was preceded by withdrawal of life-sustaining treatment in 19 patients (86.3%) and cardiac arrest in three (13.7%). Only Status Epilepticus Severity Score was associated with in-hospital and 90-day mortality, whereas the use of anesthetic drugs for seizure control, mechanical ventilation, medical complications, etiology, and refractoriness of seizures were not. Hospital length of stay was longer in patients with medical complications (p = 0.0091), refractory seizures (p = 0.0077), and in those who required anesthetic drugs for seizure control (p = 0.0035). Patients who had refractory seizures were less likely to be discharged home (odds ratio, 0.295; CI, 0.143-0.608; p = 0.0009). CONCLUSIONS: In this cohort, death primarily resulted from the underlying neurologic disease and withdrawal of life-sustaining treatment and not from our treatment choices. Use of anesthetic drugs, medical complications, and mechanical ventilation were not associated with in-hospital and 90-day mortality.

Acute truncal ataxia in a healthy adult with varicella zoster virus cerebellitis: A case report and literature review.

Acute cerebellitis is a well recognized complication of varicella zoster virus (VZV) infection in children. It has been described in adults in the setting of virus reactivation with a preceding herpes zoster rash, but it is exceedingly rare in adults who are not elderly or immunocompromised, particularly in the absence of a rash. To our knowledge, there has been only one reported case of acute cerebellitis in an immunocompetent adult less than age 65 with virological confirmation of acute VZV infection. We describe a 59-year-old immunocompetent man who presented with acute truncal ataxia without rash and was diagnosed with VZV cerebellitis, supported by anti-VZV IgM and anti-VZV IgG antibodies in the serum and a positive VZV polymerase chain reaction in cerebrospinal fluid. He had robust improvement with intravenous acyclovir treatment and was free of neurologic disability at two month follow-up. This case highlights the importance of virological evaluation in patients with acute ataxia, even in the absence of typical features of infection.