Stroke Mimics Research Articles

Prospective Validation of Glial Fibrillary Acidic Protein, d ‐Dimer, and Clinical Scales for Acute Large‐Vessel Occlusion Ischemic Stroke Detection

Background Large‐vessel occlusion (LVO) ischemic stroke is responsible for significant morbidity and mortality. We have previously described a novel tool for acute LVO detection that combines blood‐based biomarkers (glial fibrillary acidic protein and d ‐dimer) with stroke severity scales to achieve high accuracy. Accordingly, the present study sought to prospectively validate cutoff values that we had previously established for biomarkers and scales. Methods The TIME (Testing for Identification Markers of Stroke) trial was designed as a prospective observational diagnostic accuracy study. All ambulance‐identified stroke code activations <18 hours from symptom onset were recruited at Brandon Regional Hospital (Brandon, FL) between May 2021 and August 2022. Previously determined cutoff concentrations of plasma glial fibrillary acidic protein (213 pg/mL) and d ‐dimer (600 ng/mL) were used in combination with prehospital stroke scales to detect LVO. We compared rates of LVO detection against a reference standard using computed tomography/magnetic resonance angiography. Results A total of 382 patients with suspected stroke were recruited. The final cohort was composed of 323 patients with suspected stroke with the following distribution: LVO ischemic stroke (n = 29, 9%), non‐LVO ischemic stroke (n = 48, 15%), hemorrhagic stroke (n = 13, 4%), transient ischemic attack (n = 12, 3.9%), and stroke mimics (n = 220, 68.1%). Combining blood‐based biomarkers (glial fibrillary acidic protein and d ‐dimer) with the scale field assessment stroke triage for emergency destination yielded the best performance for LVO detection, with specificity of 94% and sensitivity of 71%. Performance was found to be higher in a subanalysis focusing on patients presenting <6 hours from symptom onset, with 93% specificity and 81% sensitivity. Critically, application of the biomarker and stroke scale algorithms ruled out all patients with hemorrhage. Conclusion The present work prospectively validated the potential utility of previously defined glial fibrillary acidic protein and d ‐dimer cutoff levels (ie, 213 pg/mL and 600 ng/mL, respectively), demonstrating their value for discrimination of LVO stroke from differential diagnoses during code stroke workups. (ClinicalTrials.gov number, NCT04292600.)

Stroke Mimics in Children With Moyamoya Arteriopathy

Background Comorbid conditions may result in symptoms that mimic stroke in children with moyamoya arteriopathy. Health care usage for stroke mimics is not well characterized. Methods Consecutive children (aged <18 years) with moyamoya syndrome or disease treated at a single center (2007–2021) were identified from a registry. Data including documentation of headache, anxiety, and functional neurologic disorders were retrospectively abstracted using standardized forms. Encounters were attributed to the comorbid condition when (1) related symptoms led to the visit; (2) the condition was documented as the visit diagnosis; and (3) in the absence of stroke, transient ischemic attack, or seizure. Results We identified 32 children (63% female) with symptomatic moyamoya arteriopathy diagnosed via imaging at a median age of 7.5 years (range, 0.7–17) years, all treated with revascularization surgery. During follow‐up (median, 6.7 years after diagnosis [interquartile range, 4.0–8.3]), 81% of patients reported headache, 53% reported anxiety, 19% reported panic attacks, and 6% developed a functional neurologic disorder. Both patients with functional neurologic disorder also had migraines and anxiety. In 10 patients (31% of the cohort), a stroke mimic led to 33 emergency department encounters and 9 hospital admissions; 9 received head imaging (magnetic resonance imaging, computed tomography, or computed tomographic angiography) as part of the workup. Conclusion Headaches, anxiety, and functional neurologic disorders may mimic stroke symptoms in children with moyamoya arteriopathy, leading to significant health care usage. While providers should remain vigilant for stroke, early recognition of stroke mimics should promote interventions to address comorbid conditions.

The Burden of Stroke Mimics Among Hyperacute Stroke Unit Attendees with Special Emphasis on Migraine: A 10-Year Evaluation.

Stroke and migraine are common neurological illnesses that cause tremendous suffering for patients. Certain diseases can mimic the clinical manifestations of an actual stroke. Migraine is one of the most commonly reported stroke mimics. The main goals of this study are to look at the prevalence of stroke mimics on the stroke pathway of Sheffield Teaching Hospitals and how many of them are migraines. A retrospective service evaluation was conducted at the hyperacute stroke unit (HASU) of the Royal Hallamshire Hospital (RHH) in the United Kingdom. The total admissions from 2013 to 2022 were collected from the Sentinel Stroke National Audit Programme database, and the number of stroke mimics was evaluated each year. The burden of migraine stroke mimics was also evaluated. Then, a one-year sample of stroke mimics was extracted to look for the types of each mimic. From 2013 to 2022, 45.75% (n = 12156) of the stroke pathway patients (n = 26573) were stroke mimics, with an increment of up to 55% in the years 2021and 2022. During these10 years, migraine stroke mimics accounted for 10.21% of admissions (n = 1240). The three most common mimics in a one-year sample of stroke pathway patients were migraine (14.70%) (n = 373), functional neurological disorders (FNDs) (7.17%) (n = 182), and Guillain-Barré syndrome (6.66%) (n = 169). Seizures, syncope, and metabolic derangements were reported as mimics in 4.17% (n = 106), 3.14% (n = 80), and 1.77% (n = 45), respectively. About half of the HASU attendees were stroke mimics rather than actual strokes, and the most common mimics were migraines.

Stroke Mimics: Experience in a Colombian Fourth Level Hospital (P10-5.016)

Stroke Mimics: Experience in a Colombian Fourth Level Hospital (P10-5.016)

Contrast Extravasation in a Patient with Right MCA Stroke Mimicking Cerebral Edema (P8-5.007)

Contrast Extravasation in a Patient with Right MCA Stroke Mimicking Cerebral Edema (P8-5.007)

Stroke Mimics Profile in a Tertiary Hospital in Salvador, Bahia, Brazil

Introduction: Strokes mimics are a set of non-vascular disorders that mimic an acute stroke. There are several studies in the literature about this theme, but we still have little information about this condition in Brazil. Method: This is a series of stroke case mimics evaluated by neurologists at a tertiary hospital in Salvador-BA from December/2020 to August/2023. Results: 441 patients were admitted, and 152 strokes were found to mimic (34%). Of these, 99 women with a mean age of 61.7 years and a median NIHSS of 4 at admission. One hundred ten patients (72.4%) had some risk factor, of which 100 had hypertension, 57 had DM, 24 had a previous stroke, 11 had CAD, and 9 had AF. The most prevalent etiology for stroke mimics was epileptic events, with 29.6%. None of the patients with stroke mimics underwent thrombolysis or thrombectomy, but 25 received mono-anti-aggregation and 30 dual- anti-aggregation on admission. The median mRs at discharge was 0, with 7.2% of deaths. Conclusion: The stroke mimics represent a considerable portion of patients admitted with suspected stroke to the service, drawing attention to the prevalence being higher than the average found in the literature, with epileptic events being the most prevalent etiology.Keywords: Stroke Mimics; Stroke; Epidemiology. Introdução: as mimetizações de AVC são um conjunto de distúrbios não vasculares que imitam um AVC agudo. Existem vários estudos na literatura sobre esse tema, mas ainda temos pouca informação sobre essa condição no Brasil. Método: esta é uma série de casos de mimetizações de AVC avaliados por neurologistas em um hospital terciário em Salvador-BA de dezembro de 2020 a agosto de 2023. Resultados: Foram admitidos 441 pacientes, e 152 casos de AVC mimetizadores foram identificados (34%). Destes, 99 eram mulheres com idade média de 61,7 anos e um NIHSS mediano de 4 na admissão. Cento e dez pacientes (72,4%) apresentavam algum fator de risco, dos quais 100 tinham hipertensão, 57 tinham DM, 24 tinham histórico de AVC anterior, 11 tinham DAC e 9 tinham FA. A etiologia mais prevalente para os mimetizadores de AVC foi eventos epilépticos, com 29,6%. Nenhum dos pacientes que mimetizaram um AVC foi submetido a trombólise ou trombectomia, mas 25 receberam terapia com mono-antiagregantes e 30 duplo-antiagregantes na admissão. A mediana do mRs na alta foi 0, com 7,2% de óbitos. Conclusão: os mimetizadores de AVC representam uma parcela considerável de pacientes admitidos com suspeita de AVC no serviço, chamando a atenção para a prevalência ser maior do que a média encontrada na literatura, com eventos epilépticos sendo a etiologia mais prevalente.Palavras-chave: Mimetizadores de AVC; AVC; Epidemiologia.

Time of the day and season distribution among stroke code subtypes: differences between ischemic stroke, intracranial hemorrhage, and stroke mimic.

Circadian variations in the timing of the onset of stroke symptoms have been described, showing a morning excess of cardiovascular risk. To date, no differences have been found between stroke subtype and time distribution throughout the day. The present study aims to compare the seasonal and circadian rhythm of symptoms onset in ischemic, hemorrhagic, and stroke mimic patients. This study was conducted prospectively at a hospital and involved a cohort of stroke alert patients from 2018 to 2021. Stroke subtypes were classified as ischemic stroke, intracerebral hemorrhage (ICH), transient ischemic attack (TIA), and stroke mimic. Clinical variables were recorded, and each patient was assigned to a 4-h interval of the day according to the time of onset of symptoms; unwitnessed stroke patients were analyzed separately. Seasonal changes in stroke distribution were analyzed at 3-month intervals. A total of 2,348 patients were included in this analysis (ischemic 67%, ICH 13%, mimic 16%, and TIA 3%). Regardless of stroke subtype, most of the patients were distributed between 08-12 h and 12-16 h. Significant differences were found in the time distribution depending on stroke subtype, with ICH predominating in the 4-8 h period (dawn), most of which were hypertensive, TIA in the 12-16 h period (afternoon), and stroke mimic in the 20 h period (evening). The ischemic stroke was evenly distributed throughout the different periods of the day. There were no differences in the seasonal pattern between different stroke subtypes, with winter being the one that accumulated the most cases. The present study showed different circadian patterns of stroke subtypes, with a predominance of ICH at dawn and stroke mimic in the afternoon. The stroke circadian rhythm resembles previous studies, with a higher incidence in the morning and a second peak in the afternoon.

Epidemiological profile of stroke in Qatar: Insights from a seven-year observational study

ObjectivesStroke prevalence is progressively increasing in developing countries due to increased vascular risk factors. This study aims to describe the epidemiology, prevalent risk factors, and outcomes of stroke in a multi-ethnic society of Qatar. Materials and MethodsWe conducted a retrospective analysis of all patients with suspected stroke admitted to stroke services between January 2014 and September 2020. ResultsA total of 11,892 patients were admitted during this period with suspected stroke. Of these, the diagnosis was ischemic stroke (48.8 %), transient ischemic attack (10.3 %), intracerebral hemorrhage (10.9 %), cerebral venous sinus thrombosis (1.3 %), and stroke mimics (28.6 %). The median age was 52 (43–62), with a male–female ratio of 3:1. The study population was predominantly Asian (56.8 %) and Arab (36 %). The majority of the patients were hypertensive (66.8 %), diabetic (47.9 %), and dyslipidemic (45.9 %). A history of prior stroke was observed in 11.7 %, while 0.9 % had prior transient ischemic attack. Among ischemic strokes, 31.7 % arrived within 4.5 h, 12.5 % received thrombolysis, and 4.6 % underwent thrombectomy. Median Door-to-Needle time was 51 (33–72) minutes. The average length of stay was 5.2 ± 9.0 days, with 71.5 % discharged home, 13.8 % transferred to rehabilitation, 9.3 % to other specialties, 3 % to long-term care, and 2.4 % suffered in-hospital mortality. ConclusionStroke in Qatar is characterized by a younger, expatriate-dominant cohort, with notable prevalence of ischemic and hemorrhagic stroke and a distinct risk factor profile. Further analysis of epidemiological differences among different population groups can inform targeted policies for prevention and management to reduce the burden of disease.

Moving From CT to MRI Paradigm in Acute Ischemic Stroke: Feasibility, Effects on Stroke Diagnosis and Long-Term Outcomes.

The relative value of computed tomography (CT) and magnetic resonance imaging (MRI) in acute ischemic stroke (AIS) is debated. In May 2018, our center transitioned from using CT to MRI as first-line imaging for AIS. This retrospective study aims to assess the effects of this paradigm change on diagnosis and disability outcomes. We compared all consecutive patients with confirmed diagnosis of AIS admitted to our center during the MRI-period (May 2018-August 2022) and an identical number of patients from the preceding CT-period (December 2012-April 2018). Univariable and multivariable analyses were performed to evaluate outcomes, including the number and delay of imaging exams, the rate of missed strokes, stroke mimics treated with thrombolysis, undetermined stroke mechanisms, length of hospitalization, and 3-month disability. The median age of the 2972 included patients was 76 years (interquartile range, 65-84), and 46% were female. In the MRI-period, 80% underwent MRI as first acute imaging. The proportion of patients requiring a second acute imaging modality for diagnostic ± revascularization reasons increased from 2.1% to 5% (Punadj <0.05), but it decreased in the subacute phase from 79.0% to 60.1% (Padj <0.05). In thrombolysis candidates, there was a 2-minute increase in door-to-imaging delay (Padj <0.05). The rates of initially missed AIS diagnosis was similar (3.8% versus 4.4%, Padj=0.32) and thrombolysis in stroke mimics decreased by half (8.6% versus 4.3%; Padj <0.05). Rates of unidentified stroke mechanism at hospital discharge were similar (22.8% versus 28.1%; Padj=0.99). The length of hospitalization decreased from 9 (interquartile range, 6-14) to 7 (interquartile range, 4-12) days (Padj=0.62). Disability at 3 months was similar (common adjusted odds ratio for favorable Rankin shift, 0.98 [95% CI, 0.71-1.36]; Padj=0.91), as well as mortality and symptomatic intracranial hemorrhage. A paradigm shift from CT to MRI as first-line imaging for AIS seems feasible in a comprehensive stroke center, with a minimally increased delay to imaging in thrombolysis candidates. MRI was associated with reduced thrombolysis rates of stroke mimics and subacute neuroimaging needs.

Unilateral upper and lower limb ischemia mimics stroke: a case report

BackgroundAlthough stroke and acute limb ischemia seem easily distinguishable by anamnesis and physical examination, symptoms may overlap and sometimes mislead the examiner. Such a situation can arise in the occurrence of unilateral neurological symptoms affecting the upper and lower limbs at the same time. As timely diagnosis and a correct therapeutic intervention are crucial to prevent irreversible damage in both diseases, knowledge of the possibility of one disease mimicking the other is essential. We present a unique case of acute unilateral upper and lower limb ischemia mimicking an acute stroke.Case presentationA 69-year-old Caucasian patient with known atherosclerotic risk factors was admitted to the emergency department with a suspected stroke with unilateral paresthesia. After a comprehensive examination of the patient with the need for repeated reevaluation and a negative brain computed tomography scan, acute left-sided upper and lower limb ischemia was eventually diagnosed. The patient underwent surgical revascularization of the upper and lower limbs with a satisfactory result and was discharged from the hospital after a few days.ConclusionIt is of utmost importance to always stay alert for stroke mimics, as overlooking can lead to severe complications and delay adequate therapy. Our case shows that persistent diagnostic effort leads to successful treatment of the patient even on rare occasions, as is the acute unilateral upper and lower limb ischemia.

Abstract 45: Poor Prediction of Stroke Mimics Using Validated Stroke Mimic Scales in a Large Academic Telestroke Network

Introduction: Telestroke enables timely and remote evaluation of patients with acute stroke syndromes. However, stroke mimics represent more than 30% of this population. Given the resources required for management of suspected acute ischemic stroke, several scales have been developed to help identify stroke mimics. Our objective was to externally validate four mimic scales (Khan Score [KS], TeleStroke Mimic Score [TS], simplified FABS [sFABS], and FABS) in a large, academic telestroke network. Methods: This is a retrospective, IRB exempt study of all patients who presented with suspected acute stroke syndromes and underwent video evaluation between 2019-2020 at a large academic telestroke network. Detailed chart review was conducted to extract both the variables needed to apply the mimic scales the final diagnosis confirmed by final imaging and discharge diagnosis (cerebral ischemic vs stroke mimic). Overall score performance was assessed by calculating area under curve (AUC). Youden cutpoint was established for each scale and used to calculate sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy. Results: A total of 1043 patients were included in the final analysis. Final diagnosis of cerebral ischemia was made in 662/1043 patients (63.5%) and stroke mimic was diagnosed in 381/1043 patients (36.5%). To predict stroke mimic, TS had the highest AUC (68.3) and PPV (73%); KS had the highest accuracy (68.6%), sensitivity (86.6%) and NPV (61.5%); and FABS had the highest specificity (54.8%) (Table 1). Conclusions: While each scale offers unique strengths, none was able to identify stroke mimics effectively enough to confidently apply in clinical practice. There remains need for significant clinical judgment to determine the likelihood of stroke mimic at presentation.

Abstract WP35: Elevated Risk of 1-month Post-Traumatic Stress Disorder Among Stroke Mimics Relative to Patients With Stroke

Introduction: A life-threatening medical event such as stroke can trigger symptoms of post-traumatic stress disorder (PTSD). Less is known about the risk of PTSD among individuals who present with stroke-like symptoms but are ultimately diagnosed with a stroke mimic. Aim: To examine the association between final diagnosis of stroke mimic, stroke, or TIA and risk of developing PTSD 1 month after the index event. Methods: We enrolled patients with suspected stroke or TIA from an urban academic medical center. The PTSD Checklist 5 for DSM-5 (PCL-5) was administered at enrollment to assess pre-existing PTSD, and at 1-month after discharge to assess PTSD related to the index event. The index event was adjudicated via chart review as a stroke, TIA, stroke mimic, or equivocal by a neurologist blinded to PTSD status. Logistic regression was used to determine odds of developing clinically significant PTSD (PCL-5 &amp;ge 33) for stroke mimics compared to stroke or TIA at 1 month after adjusting for age, gender, ethnicity, initial NIH Stroke Scale, discharge modified Rankin Score, and prior PTSD. Multiple imputation was used to account for missingness in data. Equivocal cases were excluded. Results: In our sample of suspected stroke ( n = 1,000, 51% female, age = 62 ± 15 y), 596 (59.6%) had a stroke, 79 (7.9%) had a TIA, 274 (27.4%) had a stroke mimic, and 51 (5.1%) were equivocal or missing. PTSD prevalence numbers (rates) at 1 month for stroke mimic, stroke, and TIA, respectively, were 30 (15.1%), 27 (6.3%), and 3 (5.5%). In the fully adjusted model, the odds of 1-month PTSD were higher for stroke mimics vs. patients with stroke, OR = 2.99, 95% CI [1.45, 6.18], p &amp;lt; .01, but not for stroke mimics vs. TIA, OR = 1.67, p = .45. Pre-existing PTSD was associated with increased odds of 1-month PTSD, OR = 10.32, 95% CI [5.30, 20.10], p &amp;lt; .01. No other covariates were associated with PTSD. Conclusion: Experiencing a stroke mimic compared to a stroke was associated with increased risk of having PTSD 1 month after the event. Clinicians should consider the risk of psychological distress particularly among individuals presenting with sudden stroke-like symptoms diagnosed as stroke mimics.

A new stroke mimic prediction scale in a stroke center with a high thrombolysis rate

Patients reaching the emergency department (ED) with symptoms of acute ischemic stroke (AIS) may be affected by a stroke mimics (SMs). A prompt clinical diagnosis could avoid unnecessary thrombolysis. We evaluated a new and rapid approach, the Santa Maria Nuova-Stroke Mimic (SMN-SM) scale, to improve a prompt clinical diagnosis. 340 consecutive patients admitted to the ED with suspected AIS were evaluated. The final diagnosis was: AIS in 267 (78,5%) and SMs in 73 (21,5%) patients. Multivariate logistical analysis showed that the following features – lack of facial paralysis, dizziness, migraine, seizure disorders, blood pressure &lt;150, cognitive impairment, and female sex – were significantly more abundant in patients with SMs than in AIS. To each of these features we assigned a numerical score and we performed a receiver operating characteristic analysis. When the score of the scale was above 8 (cut-point), we obtained a specificity of 93% and a sensitivity of 56% for a SM diagnosis. Thus, the SMN-SM scale seems a rather useful tool to improve SMs diagnosis.

Abstract 57: Rapid Prehospital Diagnosis of Intracerebral Hemorrhage by Measuring GFAP on a Point-of-Care Platform

Background: The rapid differentiation between intracerebral hemorrhage (ICH) and ischemic stroke (IS) in patients with symptoms of acute stroke is decisive for triage and initiation of targeted therapies. Glial fibrillary acidic protein (GFAP) is a highly promising blood biomarker indicating acute ICH. In this study we investigated the potential of a new GFAP plasma test on a point-of-care (POC) platform for rapidly distinguishing ICH from IS in the prehospital phase. Methods: Patients with symptoms of acute stroke admitted within 6 hours of symptom onset were enrolled. Blood samples were collected already in the prehospital phase in most patients. Plasma GFAP measurements were performed on the i-STAT Alinity® (Abbott) device (duration of analysis 15 min). The primary endpoint was the final diagnosis at hospital discharge categorized as ICH, IS or stroke mimics. Results: 155 patients were enrolled (mean age 75±13, 49% females; final diagnosis 33 ICH, 115 IS, 7 stroke mimics). Prehospital GFAP serum concentrations were strongly elevated in ICH patients compared to IS patients (mean 2283±3821 pg/mL, median 144 [IQR 52.5-2562] vs. mean 45±25 pg/mL, median 29 [IQR 29-53]; p&lt;0.001). In patients with a moderate to severe neurological deficit (NIHSS &gt; 7), GFAP values below 30 pg/mL were associated with a negative predictive value of 100% (i.e. ruling out ICH). The probability of ICH increased in parallel with higher GFAP levels. GFAP concentrations above 120 pg/mL indicated ICH with a positive predictive value of 94%. Conclusion: Rapid prehospital GFAP measurements on a point-of-care platform allow a reliable differentiation between patients with IS and ICH. This opens the potential for optimized triage and for the administration of antidots in severely affected patients with suspected anticoagulation-associated ICH.

Abstract WP283: Association of High-Risk Cardioembolic Sources on Cardiac CT With Acute Ischemic Stroke: A Case-Control Study

Background: Cardiac CT is increasingly used to detect a source of cardioembolism in stroke patients. We assessed the association between sources of embolism on cardiac CT, which were predefined as high-risk, and acute ischemic stroke. Methods: We analyzed data from Mind the Heart, a prospective, single-center, observational cohort study, and included consecutive patients with a suspected stroke who underwent ECG-gated cardiac CT during the initial stroke imaging protocol. Cases were patients with a final diagnosis of acute ischemic stroke (AIS), established by an adjudication committee. Controls were patients with stroke mimics (SMi). We excluded patients with a transient ischemic attack. Cardiovascular radiologists diagnosed structural high-risk sources of cardioembolism on cardiac CT according to predefined criteria. High-risk sources on cardiac CT were: cardiac thrombi, signs of endocarditis, recent myocardial infarction, prosthetic valve abnormalities, atrial myxomata and signs of rheumatic valvular disease. We used logistic regression, adjusting for age, sex, history of atrial fibrillation, and history of myocardial infarction. Results: Of 607 included patients, 452 had AIS (74%, median age 72, 59% male) and 155 had a SMi (26%, median age 70, 46% male). Diagnoses in the SMi group were: seizures (45/155, 29%) peripheral vestibulopathy (22/155, 14%), functional neurologic symptoms (16/155, 10%), benign headache disorder (8/155, 5%), intoxication (7/155, 5%), and other diagnoses (57/155, 37%). Cardiac CT detected a structural high-risk cardioembolic source in 52/452 AIS patients (12%) and in 5/155 SMi patients (3%, three patients with seizures, one with peripheral vestibulopathy and one with traumatic brain injury, aOR: 4.1, 95%CI 1.7-12.1). Cardiac thrombi were the most commonly observed high-risk sources of embolism and were detected in 38 (8%) AIS patients and in 2 (1%) SMi patients (aOR 7.0, 95%CI 2.1-43.9). Discussion and conclusion: A high-risk source of cardioembolism was detected on cardiac CT four times more often in patients with acute ischemic stroke than in patients with a stroke mimic. These data substantiate the clinical relevance of using acute CT to search for sources of cardioembolism in ischemic stroke patients.

Abstract 106: Circulating Interleukin-6 Levels Early During Active Stroke Estimate Time of Stroke Onset: Potential New Clinical Biomarker Tool From a Mobile Stroke Unit

Background: Circulating interleukin-6 (IL-6) concentrations are elevated in acute stroke but the timing of the IL-6 response in humans is unknown. We used a mobile stroke unit (MSU) to identify IL-6 levels within minutes of symptom onset. The results suggest a tool for estimating onset time for nearly 200,000 stroke patients annually in the U.S. in whom this is unknown. Methods: The study is a prospective, cohort investigation of ultra-early blood-derived IL-6 in acute stroke. Blood was obtained on the MSU, at 24 hours, and from hospital stroke patients and healthy controls. Plasma IL-6 was analyzed with ELISA. Confirmed strokes, mimics and controls were compared. Variables included demographics, DWI lesion volume, mRS, and NIHSS. Results: Forty-two adults were analyzed, including 28 patients treated on the MSU between August 2021 and May 2023, and 14 controls. Nineteen (68%) MSU patients were diagnosed as stroke, with 17 (61%) confirmed and 2 likely TIA or stroke averted by thrombolysis; 9 were stroke mimics. For confirmed stroke patients, median age was 72 (range 36-87) years, 47% were female, and 82% white. Median initial NIHSS score was 7 (range 1-22) and 12 (71%) received intravenous thrombolysis with tPA or TNK. Blood was obtained a median of 57 (range 26-158) minutes after symptom onset. IL-6 was elevated in all 17 confirmed stroke patients, a median of 3 times normal, as early as 26 minutes after symptom onset (median 6.4 pg/mL). In 15 (88%) cases, IL-6 increased over 24 hours, (median Δ 8.9 pg/mL). For mimics and healthy controls, median IL-6 was 5.9 and 2.3 pg/mL, respectively. Initial IL-6 in strokes was not associated with lesion volume (Spearman’s r= -0.035, p=894) or initial NIHSS (Spearman’s r=-0.043, p=869). Based on IL-6 trajectories observed, a cutoff for IL-6 set at 8 pg/mL had a sensitivity of 79% and specificity of 36% for estimating the stroke onset time was in the 4.5-hour thrombolysis window. Conclusions: This study found IL-6 was elevated in all confirmed strokes and increased in a linear fashion during the first 2.5 hours. IL-6 was independent of lesion volume and NIHSS. This suggests a rapid measurement of IL-6 from blood early in acute stroke may estimate onset time. The findings may aid development of immunomodulatory therapies for IL-6 in acute stroke.

Abstract WP78: Large Vessel Occlusion Triage and Routing Utilized for Long-Distance Stroke Transports by Emergency Medical Services (LVO TRUST EMS)

Introduction: Endovascular treatment (EVT) is the most effective therapy in acute ischemic stroke (AIS) with large vessel occlusion (LVO) but its practice is limited to comprehensive stroke centers (CSC). Previous studies have suggested that trained Emergency Medical Services (EMS) professionals can successfully detect LVO cases using a validated screening tool. For these cases, direct transfer to CSC bypassing community hospitals could lead to better outcomes. Methods: This is a retrospective cohort study from 01/01/2018-12/31/2022 of patients with suspected stroke transported by EMS providers from 14 community agencies (primarily fire paramedics) in Southeastern Massachusetts (EMS Region V). When stroke was suspected, EMS providers applied the Field Assessment Stroke Triage for Emergency Destination (FAST-ED) score to assess severity. Bypass of local community hospitals for direct transport to CSC was generally considered for patients with FAST-ED ≥4 and approval of the Region V EMS Medical Director, with the goal of early intervention for severe strokes. In addition to standard education on the use of the FAST-ED score, the EMS agencies received annual aggregate performance feedback and individual case feedback (when requested) from the CSC. Data were collected from the Electronic Health Record (EHR) on demographics, comorbidities, final diagnoses, FAST-ED scores, NIHSS and acute treatments. Descriptive statistics were performed to describe the accuracy of diagnosis and rates of treatment. Results: Among 166 triaged patients to go directly to CSC, 57.6% (95/166) were diagnosed with AIS, and 61.1% (58/95) of them were found to have LVO. There was a higher proportion of AIS or intracranial hemorrhage (ICH) in cases with higher FAST-ED scores. Only 23.4% (39/166) of the cases were diagnosed with stroke mimics, primarily related to lower FAST-ED scores. In total, 36.9% of patients with AIS received EVT: thrombectomy with standard window tPA (21.1%) or late presenter tPA (LKW ≥ 4.5 h, 1.1%), and without tPA (14.7%). Conclusions: A diverse group of community-based EMS services in Southeastern Massachusetts using a prehospital tool can identify patients with severe stroke, i.e. AIS due to LVO or ICH, with acceptable diagnostic accuracy.

Abstract TMP52: Modern Thin-Slice CT Perfusion Has High Sensitivity for Supratentorial Lacunar Stroke

Background: Lacunar stroke is a common form of ischaemic stroke with mechanisms poorly understood compared to large vessel stroke. Access to gold standard MRI is often limited in the acute setting. Acute diagnosis of lacunar stroke is difficult with conventional CT, as non-contrast CT and CT angiography have poor sensitivity. Previous studies have demonstrated only low to moderate sensitivity of CT perfusion (CTP). Aims: To test the accuracy of thin-slice CTP to detect lacunar stroke and compare the clinical and radiological characteristics to better understand the limitations of CTP for diagnosis of lacunar stroke. Methods: We reviewed thin-slice CTP (slice thickness &lt;=3mm) of cases presenting with an acute lacunar syndrome without large/medium vessel occlusion, or perfusion lesion detected by automated analysis. Cases presented to two comprehensive stroke centres in Sydney and Newcastle, NSW, Australia, between 2019 and 2022. CTP was reviewed by two independent reviewers, blinded to follow-up MRI but not the clinical syndrome. CTP and DWI were registered to a standard template and DWI lesions were manually segmented. CTP was further reviewed adjacent to DWI, and raw CTP values within the lesion was calculated. Results: We reviewed 394 cases of acute lacunar syndrome including 82 stroke mimics, 48 infratentorial and 250 supratentorial infarcts. Overall sensitivity was 76% and varied by infarct location. Sensitivity was lowest for brainstem (46%), moderate for thalamic (69%) and high for infarcts within the lenticulostriate perforator territory (84%). Factors associated with reduced sensitivity include small infarct volume, increased noise, or artefact, and infratentorial location. Conclusion: Thin-slice CTP has high sensitivity for detection of supratentorial lacunar infarcts however is more susceptible to noise and imaging artefact than larger infarcts. Advanced processing techniques show promise to improve overall diagnosis of lacunar stroke.

A Case Report of Stroke-like Syndrome: Tuberculous Encephalopathy

Background: Stroke-like syndrome is a stroke mimic, usually common in the young and accurate diagnosis has considerable impact in terms of treatment choices and outcomes. Objectives: To emphasise the need for high index of suspicion and the need for multidisciplinary approach and accurate diagnosis of stroke-like syndrome. Case Report: 32 years old woman who presented with recurrent headache of a year duration with right upper limb weakness of 3 months that later involved lower limb 1month and inability to talk 2 days to presentation. Examination revealed a young woman, conscious but aphasic, emaciated, afebrile, anicteric and nil pedal oedema. Neurological findings includes expressive aphasia, right facioparesis and right hemiparesis. Other systemic examinations were essentially normal. A diagnosis of left hemispheric ischaemic stroke was initially entertained. Brain computerized tomography revealed infarct involving the left frontal and temporal lobes but Echocardiography revealed Tuberculous pericarditis, a suspicion of stroke mimic of infective origin was entertained. Diagnosis was confirmed by ‘trial of treatment’ of anti-tuberculosis, which resulted in dramatic resolution of symptoms within 4 weeks of anti-tuberculosis drugs. Conclusion: There is need for high index of suspicion, accurate diagnosis and multidisciplinary approach for appropriate treatment choices and outcomes.

Update on the INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4): progress and baseline features in 2053 participants

Background and aimsUncertainty persists over the effects of blood pressure (BP) lowering in acute stroke. The INTEnsive ambulance-delivered blood pressure Reduction in hyper-Acute stroke Trial (INTERACT4) aims to determine efficacy and safety of hyperacute intensive BP lowering in patients with suspected acute stroke. Given concerns over the safety of this treatment in the pre-hospital setting, particularly in relation to patients with intracerebral hemorrhage, we provide an update on progress of the study and profile of participants to date.MethodsINTERACT4 is an ongoing multicentre, ambulance-delivered, randomized, open-label, blinded endpoint trial of pre-hospital BP lowering in patients with suspected acute stroke and elevated BP in China. Patients are randomized via a mobile phone digital system to intensive (target systolic BP [SBP] <140mmHg within 30 min) or guideline-recommended BP management. Primary outcome is an ordinal analysis of the full range of scores on the modified Rankin scale scores at 90 days.ResultsBetween March 2020 and April 2023, 2053 patients (mean age 70 years, female 39%) were recruited with a mean BP 178/98 mmHg in whom 45% have a diagnosis of primary intracerebral hemorrhage upon arrival at hospital. At the time of presentation to hospital, the mean SBP was 160 and 170mmHg in the intensive and control groups (Δ10 mmHg), respectively. The independent data and safety monitoring board has not identified any safety concerns and recommended continuation of the trial. The sample size was reduced from 3116 to 2320 after meetings in August 2022 as the stroke mimic rate was persistently lower than initially estimated (6% vs 30%). The study is expected to be completed in late 2023 and the results announced in May 2024.ConclusionsINTERACT4 is on track to provide reliable evidence of the effectiveness of ambulance-delivered intensive BP lowering in patients with suspected acute stroke.Trial registrationClinicalTrials.gov NCT03790800; registered on 2 January 2019. Chinese Trial Registry ChCTR1900020534, registered on 7 January 2019.