Upfront vascular imaging in acute stroke: Impact on thrombectomy transfer time at a primary stroke center.

OBJECTIVES: Early cerebral arterial imaging is currently only recommended in the subgroup of acute ischemic stroke (AIS) patients suspected of having large vessel occlusion (LVO). There is limited data on the impact of early cerebrovascular imaging in all suspected AIS patients presenting within 24 h of symptom onset and the impact on door in-door out (DIDO) time. MATERIALS AND METHODS: In January 2020, our Primary Stroke Center implemented a protocol to perform upfront head and neck CT angiography (CTA) with initial non-contrast CT head for all suspected ischemic stroke patients screening positive for BE-FAST stroke symptoms within 24 h from last known normal time. We retrospectively reviewed IV alteplase and thrombectomy-eligible patients before (January 1-December 31, 2019) and after protocol implementation (January 1, 2020-June 30, 2022). RESULTS: Of 86 patients meeting study criteria, up-front CTA was associated with significant reductions in door-to-CTA start (median 37 vs 15 min, p = 0.003), door-to-CTA result (median 83 vs 52 min, p = 0.023) and DIDO times (median 150 vs 106 min, p = 0.023). There was no significant difference in door-to-needle time before and after protocol implementation (median 48 vs 43 min, p = 0.450). CONCLUSION: Up-front cerebrovascular imaging with CTA in suspected AIS patients presenting within 24 h resulted in shorter DIDO times without delaying door-to-needle times. Primary Stroke Centers should consider this approach to detect LVO early and expedite patient transport to thrombectomy capable centers.

Subjects with carotid webs demonstrate pro-thrombotic hemodynamics compared to subjects with carotid atherosclerosis.

Carotid artery webs (CaW) are non-atherosclerotic projections into the vascular lumen and have been linked to up to one-third of cryptogenic strokes in younger patients. Determining how CaW affects local hemodynamics is essential for understanding clot formation and stroke risk. Computational fluid dynamics simulations were used to investigate patient-specific hemodynamics in carotid artery bifurcations with CaW, bifurcations with atherosclerotic lesions having a similar degree of lumen narrowing, and with healthy carotid bifurcations. Simulations were conducted using segmented computed tomography angiography geometries with inlet boundary conditions extracted from 2D phase contrast MRI scans. The study included carotid bifurcations with CaW (n = 13), mild atherosclerosis (n = 7), and healthy bifurcation geometries (n = 6). Hemodynamic parameters associated with vascular dysfunction and clot formation, including shear rate, oscillatory shear index (OSI), low velocity, and flow stasis were calculated and compared between the subject groups. Patients with CaW had significantly larger regions containing low shear rate, high OSI, low velocity, and flow stasis in comparison to subjects with mild atherosclerosis or normal bifurcations. These abnormal hemodynamic metrics in patients with CaW are associated with clot formation and vascular dysfunction and suggest that hemodynamic assessment may be a tool to assess stroke risk in these patients.

Apixaban to Prevent Recurrence After Cryptogenic Stroke in Patients With Atrial Cardiopathy: The ARCADIA Randomized Clinical Trial.

Importance: Atrial cardiopathy is associated with stroke in the absence of clinically apparent atrial fibrillation. It is unknown whether anticoagulation, which has proven benefit in atrial fibrillation, prevents stroke in patients with atrial cardiopathy and no atrial fibrillation. Objective: To compare anticoagulation vs antiplatelet therapy for secondary stroke prevention in patients with cryptogenic stroke and evidence of atrial cardiopathy. Design, Setting, and Participants: Multicenter, double-blind, phase 3 randomized clinical trial of 1015 participants with cryptogenic stroke and evidence of atrial cardiopathy, defined as P-wave terminal force greater than 5000 µV × ms in electrocardiogram lead V1, serum N-terminal pro-B-type natriuretic peptide level greater than 250 pg/mL, or left atrial diameter index of 3 cm/m2 or greater on echocardiogram. Participants had no evidence of atrial fibrillation at the time of randomization. Enrollment and follow-up occurred from February 1, 2018, through February 28, 2023, at 185 sites in the National Institutes of Health StrokeNet and the Canadian Stroke Consortium. Interventions: Apixaban, 5 mg or 2.5 mg, twice daily (n = 507) vs aspirin, 81 mg, once daily (n = 508). Main Outcomes and Measures: The primary efficacy outcome in a time-to-event analysis was recurrent stroke. All participants, including those diagnosed with atrial fibrillation after randomization, were analyzed according to the groups to which they were randomized. The primary safety outcomes were symptomatic intracranial hemorrhage and other major hemorrhage. Results: With 1015 of the target 1100 participants enrolled and mean follow-up of 1.8 years, the trial was stopped for futility after a planned interim analysis. The mean (SD) age of participants was 68.0 (11.0) years, 54.3% were female, and 87.5% completed the full duration of follow-up. Recurrent stroke occurred in 40 patients in the apixaban group (annualized rate, 4.4%) and 40 patients in the aspirin group (annualized rate, 4.4%) (hazard ratio, 1.00 [95% CI, 0.64-1.55]). Symptomatic intracranial hemorrhage occurred in 0 patients taking apixaban and 7 patients taking aspirin (annualized rate, 1.1%). Other major hemorrhages occurred in 5 patients taking apixaban (annualized rate, 0.7%) and 5 patients taking aspirin (annualized rate, 0.8%) (hazard ratio, 1.02 [95% CI, 0.29-3.52]). Conclusions and Relevance: In patients with cryptogenic stroke and evidence of atrial cardiopathy without atrial fibrillation, apixaban did not significantly reduce recurrent stroke risk compared with aspirin. Trial Registration: ClinicalTrials.gov Identifier: NCT03192215.

Learning From Alarms: A Robust Learning Approach for Accurate Photoplethysmography-Based Atrial Fibrillation Detection Using Eight Million Samples Labeled With Imprecise Arrhythmia Alarms.

Atrial fibrillation (AF) is a common cardiac arrhythmia with serious health consequences if not detected and treated early. Detecting AF using wearable devices with photoplethysmography (PPG) sensors and deep neural networks has demonstrated some success using proprietary algorithms in commercial solutions. However, to improve continuous AF detection in ambulatory settings towards a population-wide screening use case, we face several challenges, one of which is the lack of large-scale labeled training data. To address this challenge, we propose to leverage AF alarms from bedside patient monitors to label concurrent PPG signals, resulting in the largest PPG-AF dataset so far (8.5 M 30-second records from 24,100 patients) and demonstrating a practical approach to build large labeled PPG datasets. Furthermore, we recognize that the AF labels thus obtained contain errors because of false AF alarms generated from imperfect built-in algorithms from bedside monitors. Dealing with label noise with unknown distribution characteristics in this case requires advanced algorithms. We, therefore, introduce and open-source a novel loss design, the cluster membership consistency (CMC) loss, to mitigate label errors. By comparing CMC with state-of-the-art methods selected from a noisy label competition, we demonstrate its superiority in handling label noise in PPG data, resilience to poor-quality signals, and computational efficiency.

New-onset as opposed to established atrial fibrillation as a risk factor for incident stroke.

BACKGROUND: Atrial fibrillation (AF) is an established risk factor for acute ischemic stroke (AIS). It remains unclear if new-onset AF confers a higher risk of AIS than longer-standing AF. METHODS: We retrospectively analyzed all stroke-free patients who underwent transthoracic echocardiography (TTE) in the Henry Ford Health System between March 6 and September 6, 2016. Incident AIS and new-onset AF were ascertained by the presence of new diagnostic codes in the electronic medical record over a follow-up period of up to 5 years. Cox proportional hazards regression was used to identify risk factors for new-onset AF or AIS. RESULTS: Of 7310 patients who underwent baseline TTE the mean age was 65 years, 54% were female, 51% were Caucasian, and 46% had left atrial enlargement (LAE). Of at-risk patients, 10.9% developed new-onset AF and 2.9% experienced incident AIS. The risk of new-onset AF among at-risk patients was 3.1 times higher among patients with any degree of LAE compared to those with normal LA size (95% CI 2.6-3.6, P < 0.0001). New-onset AF, more than established AF, in turn had a powerful association with incident AIS. The cumulative 5-year risk of AIS was 3.5% in those without AF, 5.9% in those with established AF prior to TTE, and 20.1% in those with new-onset AF (P < 0.0001). In multivariable analysis new-onset AF had the strongest association with incident AIS (P < 0.0001), followed by increasing age (P = 0.0025), black race (P = 0.0032), and smoking (P = 0.0063). CONCLUSIONS: New-onset AF has a strong relationship with incident AIS. LAE was present in nearly half of stroke-free patients undergoing TTE, and was associated with a significantly higher likelihood of new-onset AF during follow-up. Vigilant cardiac monitoring for AF in individuals with LAE, coupled with the timely initiation of anticoagulation, may be an important strategy for the primary prevention of AF-related stroke.

Assessment of Complex Flow Patterns in Patients With Carotid Webs, Patients With Carotid Atherosclerosis, and Healthy Subjects Using 4D Flow MRI.

BACKGROUND: Carotid webs (CaWs) are fibromuscular projections in the internal carotid artery (ICA) that cause mild luminal narrowing (<50%), but may be causative in up to one-third of seemingly cryptogenic strokes. Understanding hemodynamic alterations caused by CaWs is imperative to assessing stroke risk. Time-Average Wall Shear Stress (TAWSS) and Oscillatory Shear Index (OSI) are hemodynamic parameters linked to vascular dysfunction and thrombosis. PURPOSE: To test the hypothesis: "CaWs are associated with lower TAWSS and higher OSI than mild atherosclerosis or healthy carotid bifurcation." STUDY TYPE: Prospective study. POPULATION: A total of 35 subjects (N = 14 bifurcations with CaW, 11F, age: 49 ± 10, 10 mild atherosclerosis 6F, age: 72 ± 9, 11 healthy 9F, age: 42 ± 13). FIELD STRENGTH/SEQUENCE: 4D flow/STAR-MATCH/3D TOF/3T MRI, CTA. ASSESSMENT: 4D Flow velocity data were analyzed in two ways: 1) 3D ROI in the ICA bulbar segment (complex flow patterns are expected) was used to quantify the regions with low TAWSS and high OSI. 2) 2D planes were placed perpendicular to the centerline of the carotid bifurcation for detailed analysis of TAWSS and OSI. STATISTICAL TESTS: Independent-samples Kruskal-Wallis-H test with 0.05 used for statistical significance. RESULTS: The percent surface area where low TAWSS was present in the ICA bulb was 12.3 ± 8.0% (95% CI: 7.6-16.9) in CaW subjects, 1.6 ± 1.9% (95% CI: 0.2-2.9) in atherosclerosis, and 8.5 ± 7.7% (95% CI: 3.6-13.4) in healthy subjects, all differences were statistically significant (ƞ2 = 0.3 [95% CI: 0.05-0.5], P-value CaW vs. healthy = 0.2). OSI had similar values in the CCA between groups (ƞ2 = 0.07 [95% CI: 0.0-0.2], P-value = 0.5), but OSI was significantly higher downstream of the bifurcation in CaW subjects compared to atherosclerosis and normal subjects. OSI returned to similar values between groups 1.5 diameters distal to the bifurcation (ƞ2 = 0.03 [95% CI: 0.0-0.2], P-value = 0.7). CONCLUSION: Lower TAWSS and higher OSI are present in the ICA bulb in patients with CaW when compared to patients with atherosclerotic or healthy subjects. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Underlying intracranial atherosclerotic disease is associated with worse outcomes in acute large vessel occlusion undergoing endovascular thrombectomy.

BACKGROUND: Data on large vessel occlusion (LVO) management due to intracranial atherosclerotic disease (ICAD) are scarce. OBJECTIVE: To compare clinical outcomes between patients with ICAD and those without ICAD following mechanical thrombectomy (MT). METHODS: We performed a retrospective analysis of consecutive patients who underwent MT for LVO in a large academic comprehensive stroke center, and compared in-hospital mortality, 90-day mortality, favorable functional outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) using chi-squared tests and multivariate logistic regression analyses. We defined ICAD as observable plaque at occlusion site post-thrombectomy. RESULTS: Among 215 patients (mean age 67.1 ± 16.0 years; 60.5% female; 83.6% Black, median NIHSS score 16), ICAD was present in 38 patients (17.7%). Diabetes and dyslipidemia were more common in those with ICAD (57.9% vs. 38.4%, p = 0.027 and 29.0% vs. 14.7%, p = 0.035, respectively). Substantial reperfusion (TICI ≥2b) was achieved less often (84.2% vs. 94.4%, p = 0.031) but symptomatic ICH was also less common in ICAD patients (0% vs. 9.0%, p = 0.081). In-hospital and 90-day mortality were more common (36.8% vs. 15.8%, p = 0.003 and 52.6% vs. 26.6%, p = 0.002, respectively) and favorable functional outcome (mRS 0-2) at 90 days was less common (7.9% vs. 33.9%, p = 0.001) in ICAD patients. After adjusting for prognostic variables, ICAD was independently associated with in-hospital mortality (OR=4.1, 95% CI 1.7-9.7), 90-day mortality (OR=3.7, 95% CI 1.6-8.6), and poor functional outcome at 90 days (OR=5.5, 95% CI 1.6-19.4). CONCLUSION: Symptomatic ICAD in a predominantly African American cohort is associated with increased odds of mortality and poor functional outcome at 90 days in patients with LVO undergoing MT.

Factors associated with stroke after COVID-19 vaccination: a statewide analysis.

Background: The objective of our study was to evaluate vaccine type, COVID-19 infection, and their association with stroke soon after COVID-19 vaccination. Methods: In a retrospective cohort study, we estimated the 21-day post-vaccination incidence of stroke among the recipients of the first dose of a COVID-19 vaccine. We linked the Georgia Immunization Registry with the Georgia Coverdell Acute Stroke Registry and the Georgia State Electronic Notifiable Disease Surveillance System data to assess the relative risk of stroke by the vaccine type. Results: Approximately 5 million adult Georgians received at least one COVID-19 vaccine between 1 December 2020 and 28 February 2022: 54% received BNT162b2, 41% received mRNA-1273, and 5% received Ad26.COV2.S. Those with concurrent COVID-19 infection within 21 days post-vaccination had an increased risk of ischemic (OR = 8.00, 95% CI: 4.18, 15.31) and hemorrhagic stroke (OR = 5.23, 95% CI: 1.11, 24.64) with no evidence for interaction between the vaccine type and concurrent COVID-19 infection. The 21-day post-vaccination incidence of ischemic stroke was 8.14, 11.14, and 10.48 per 100,000 for BNT162b2, mRNA-1273, and Ad26.COV2.S recipients, respectively. After adjusting for age, race, gender, and COVID-19 infection status, there was a 57% higher risk (OR = 1.57, 95% CI: 1.02, 2.42) for ischemic stroke within 21 days of vaccination associated with the Ad26.COV2.S vaccine compared to BNT162b2; there was no difference in stroke risk between mRNA-1273 and BNT162b2. Conclusion: Concurrent COVID-19 infection had the strongest association with early ischemic and hemorrhagic stroke after the first dose of COVID-19 vaccination. Although not all determinants of stroke, particularly comorbidities, were considered in this analysis, the Ad26.COV2.S vaccine was associated with a higher risk of early post-vaccination ischemic stroke than BNT162b2.

Telemedicine impact on post-stroke outpatient follow-up in an academic healthcare network during the COVID-19 pandemic.

BACKGROUND: The expansion of telemedicine associated with the COVID-19 pandemic has influenced outpatient medical care. The objective of our study was to determine the impact of telemedicine on post-acute stroke clinic follow-up. METHODS: We retrospectively evaluated the impact of telemedicine in Emory Healthcare, an academic healthcare system of comprehensive and primary stroke centers in Atlanta, Georgia, on post-hospital stroke clinic follow-up. We compared the frequency of 90-day follow-up in a centralized subspecialty stroke clinic among patients hospitalized before the local COVID-19 pandemic (January 1, 2019- February 28, 2020), during (March 1- April 30, 2020) and after telemedicine implementation (May 1- December 31, 2020). A comparison was made across hospitals less than 1 mile, 10 miles, and 25 miles from the stroke clinic. RESULTS: Of 1096 ischemic stroke patients discharged home or to a rehab facility during the study period, 342 (31%) had follow-up in the Emory Stroke Clinic (comprehensive stroke center 46%, primary stroke center 10 miles away 18%, primary stroke center 25 miles away 14%). Overall, 90-day follow-up increased from 19% to 41% after telemedicine implementation (p<0.001) with telemedicine appointments amounting for up to 28% of all follow-up visits. In multivariable analysis, factors associated with teleneurology follow-up (vs no follow-up) included discharge from the comprehensive stroke center, thrombectomy treatment, private insurance, private transport to the hospital, NIHSS 0-5 and history of dyslipidemia. CONCLUSIONS: Despite telemedicine implementation at an academic healthcare network successfully increasing post-stroke discharge follow-up in a centralized subspecialty stroke clinic, the majority of patients did not complete 90-day follow-up during the COVID-19 pandemic.

Stroke Lesion Volume and Injury to Motor Cortex Output Determines Extent of Contralesional Motor Cortex Reorganization.

BACKGROUND: After stroke, increases in contralesional primary motor cortex (M1CL) activity and excitability have been reported. In pre-clinical studies, M1CL reorganization is related to the extent of ipsilesional M1 (M1IL) injury, but this has yet to be tested clinically. OBJECTIVES: We tested the hypothesis that the extent of damage to the ipsilesional M1 and/or its corticospinal tract (CST) determines the magnitude of M1CL reorganization and its relationship to affected hand function in humans recovering from stroke. METHODS: Thirty-five participants with a single subacute ischemic stroke affecting M1 or CST and hand paresis underwent MRI scans of the brain to measure lesion volume and CST lesion load. Transcranial magnetic stimulation (TMS) of M1IL was used to determine the presence of an electromyographic response (motor evoked potential (MEP+ and MEP-)). M1CL reorganization was determined by TMS applied to M1CL at increasing intensities. Hand function was quantified with the Jebsen Taylor Hand Function Test. RESULTS: The extent of M1CL reorganization was related to greater lesion volume in the MEP- group, but not in the MEP+ group. Greater M1CL reorganization was associated with more impaired hand function in MEP- but not MEP+ participants. Absence of an MEP (MEP-), larger lesion volumes and higher lesion loads in CST, particularly in CST fibers originating in M1 were associated with greater impairment of hand function. CONCLUSIONS: In the subacute post-stroke period, stroke volume and M1IL output determine the extent of M1CL reorganization and its relationship to affected hand function, consistent with pre-clinical evidence.ClinicalTrials.gov Identifier: NCT02544503.

Comparative analysis between 1-D, 2-D and 3-D carotid web quantification.

BACKGROUND: Carotid webs (CaW) are now recognized as a cause of ischemic stroke in young patients. The thromboembolic potential appears related to the CaW's morphology and consequent impact on local flow dynamics. We aim to evaluate the reliability of different measurement methods for the quantification of CaW and their relationship to symptomatic status, presence of large vessel occlusion stroke (LVOS), clot burden and final infarct volume. METHODS: This was a retrospective analysis of the local comprehensive stroke center CaW database (September 2014-July 2019). CT angiograms (CTAs) were reviewed independently by two raters, blinded to the clinical information and laterality of the stroke/transient ischemic attack. CaW were quantified with 1-D (length), 2-D (area) and 3-D (volume) measurements via Osirix software. Final infarct volume was calculated on MRI. Patients with superimposed CaW thrombus and no repeat imaging were excluded. RESULTS: Forty-eight CaW (37 symptomatic and 11 contralateral/asymptomatic) in 38 patients were included. Mean age (±SD) was 48.7 (±8.5) years, 78.9% were women and 77.1% were black. Inter-rater agreement was 0.921 (p<0.001) for 1-D, 0.930 (p<0.001) for 2-D, and 0.937 (p<0.001) for 3-D CaW measurements. When comparing symptomatic with asymptomatic CaW, mean web length was 3.2 mm versus 2.5 mm (p<0.02), median area was 5.8 versus 5.0 mm2 (p=0.35) and median volume was 15.0 versus 10.6 mm3 (p<0.04), respectively. CaW with a thinner profile (longer intraluminal projection compared with the base) were more likely to be symptomatic (0.67±0.17 vs 0.88±0.37; p=0.01). Average CaW 1-D and final infarct volume had a weak but positive association (Κ=0.230, p<0.05), while no association among web measurements and the presence of LVOS or clot burden was observed. CONCLUSION: CaW dimension quantification (1-D, 2-D and 3-D) is highly reproducible. Linear and volumetric measurements were more strongly associated with symptoms. The impact of CaW size on the presence of LVOS, clot burden and final infarct volume is unclear.

Comparisons of healthy human brain temperature predicted from biophysical modeling and measured with whole brain MR thermometry.

Brain temperature is an understudied parameter relevant to brain injury and ischemia. To advance our understanding of thermal dynamics in the human brain, combined with the challenges of routine experimental measurements, a biophysical modeling framework was developed to facilitate individualized brain temperature predictions. Model-predicted brain temperatures using our fully conserved model were compared with whole brain chemical shift thermometry acquired in 30 healthy human subjects (15 male and 15 female, age range 18-36 years old). Magnetic resonance (MR) thermometry, as well as structural imaging, angiography, and venography, were acquired prospectively on a Siemens Prisma whole body 3 T MR scanner. Bland-Altman plots demonstrate agreement between model-predicted and MR-measured brain temperatures at the voxel-level. Regional variations were similar between predicted and measured temperatures (< 0.55 °C for all 10 cortical and 12 subcortical regions of interest), and subcortical white matter temperatures were higher than cortical regions. We anticipate the advancement of brain temperature as a marker of health and injury will be facilitated by a well-validated computational model which can enable predictions when experiments are not feasible.

Evaluating the Abnormality of Bilateral Motor Cortex Activity in Subacute Stroke Patients Executing a Unimanual Motor Task With Increasing Demand on Precision.

Abnormal contralesional M1 activity is consistently reported in patients with compromised upper limb and hand function after stroke. The underlying mechanisms and functional implications of this activity are not clear, which hampers the development of treatment strategies targeting this brain area. The goal of the present study was to determine the extent to which contralesional M1 activity can be explained by the demand of a motor task, given recent evidence for increasing ipsilateral M1 activity with increasing demand in healthy age-matched controls. We hypothesized that higher activity in contralesional M1 is related to greater demand on precision in a hand motor task. fMRI data were collected from 19 patients with ischemic stroke affecting hand function in the subacute recovery phase and 31 healthy, right-handed, age-matched controls. The hand motor task was designed to parametrically modulate the demand on movement precision. Electromyography data confirmed strictly unilateral task performance by all participants. Patients showed significant impairment relative to controls in their ability to perform the task in the fMRI scanner. However, patients and controls responded similarly to an increase in demand for precision, with better performance for larger targets and poorer performance for smaller targets. Patients did not show evidence of elevated ipsilesional or contralesional M1 blood oxygenation level-dependent (BOLD) activation relative to healthy controls and mean BOLD activation levels were not elevated for patients with poorer performance relative to patients with better task performance. While both patients and healthy controls showed demand-dependent increases in BOLD activation in both ipsilesional/contralateral and contralesional/ipsilateral hemispheres, patients with stroke were less likely to show evidence of a linear relationship between the demand on precision and BOLD activation in contralesional M1 than healthy controls. Taken together, the findings suggest that task demand affects the BOLD response in contralesional M1 in patients with stroke, though perhaps less strongly than in healthy controls. This has implications for the interpretation of reported abnormal bilateral M1 activation in patients with stroke because in addition to contralesional M1 reorganization processes it could be partially related to a response to the relatively higher demand of a motor task when completed by patients rather than by healthy controls.

Cincinnati Prehospital Stroke Scale Implementation of an Urban County Severity-Based Stroke Triage Protocol: Impact and Outcomes on a Comprehensive Stroke Center.

BACKGROUND AND PURPOSE: Screening scales are recommended to assist field-based triage of acute stroke patients to designated stroke centers. Cincinnati prehospital stroke scale (CPSS) is a commonly used prehospital stroke screening tool and has been validated to identify large vessel occlusion (LVO). This study addresses the impact of county-based CPSS implementation to triage suspected LVO patients to a comprehensive stroke center (CSC). MATERIALS AND METHODS: Dekalb County in Atlanta, Georgia, implemented CPSS-based protocol with score of 3 and last seen normal time < 24 h mandating transfer to the nearest CSC if the added bypass time was <15 min. Frequency of stroke codes, LVO, IV-tPA use, and thrombectomy treatment were compared six months before and after protocol change (November 1, 2020). RESULTS: During the study period, 907 stroke patients presented to the CSC by EMS, including 289 (32%) with CPSS score 3. There was an increase in monthly ischemic stroke volume (pre-16 ± 2 vs.19 ± 3 p = 0.03), LVO (pre-4.3 ± 1.7 vs. post-7.0 ± 2.4; p = 0.03), EVT (pre-15% vs. post-30%; p = 0.001), without significant increase in stroke mimic volume or delay in mean time from last seen normal to IV-tPA (pre-165 ± 66, post-158 ± 49 min; p = 0.35). CPSS score 3 was associated with increased likelihood of LVO diagnosis (OR 8.5, 95% CI 5.0-14.4; p = 0.001) and decreased the likelihood of stroke mimics (OR 0.66, 95% CI 0.50-0.88; p = 0.004). CONCLUSION: CPSS is a quick, easy to implement, and reliable prehospital severity scale for EMS to triage LVO to CSC without delaying IV-tPA treatment or significantly increasing stroke mimics.

Alterations in Functional Network Topology Within Normal Hemispheres Contralateral to Anterior Circulation Steno-Occlusive Disease: A Resting-State BOLD Study.

The purpose of this study was to assess spatially remote effects of hemodynamic impairment on functional network topology contralateral to unilateral anterior circulation steno-occlusive disease (SOD) using resting-state blood oxygen level-dependent (BOLD) imaging, and to investigate the relationships between network connectivity and cerebrovascular reactivity (CVR), a measure of hemodynamic stress. Twenty patients with unilateral, chronic anterior circulation SOD and 20 age-matched healthy controls underwent resting-state BOLD imaging. Five-minute standardized baseline BOLD acquisition was followed by acetazolamide infusion to measure CVR. The BOLD baseline was used to analyze network connectivity contralateral to the diseased hemispheres of SOD patients. Compared to healthy controls, reduced network degree (z-score = -1.158 ± 1.217, P < 0.001, false discovery rate (FDR) corrected), local efficiency (z-score = -1.213 ± 1.120, P < 0.001, FDR corrected), global efficiency (z-score = -1.346 ± 1.119, P < 0.001, FDR corrected), and enhanced modularity (z-score = 1.000 ± 1.205, P = 0.002, FDR corrected) were observed in the contralateral, normal hemispheres of SOD patients. Network degree (P = 0.089, FDR corrected; P = 0.027, uncorrected) and nodal efficiency (P = 0.089, FDR corrected; P = 0.045, uncorrected) showed a trend toward a positive association with CVR. The results indicate remote abnormalities in functional connectivity contralateral to the diseased hemispheres in patients with unilateral SOD, despite the absence of macrovascular disease or demonstrable hemodynamic impairment. The clinical impact of remote functional disruptions requires dedicated investigation but may portend far reaching consequence for even putatively unilateral cerebrovascular disease.

PRES and RCVS: Two Distinct Entities or a Spectrum of the Same Disease?

OBJECTIVES: To report a case of a patient with overlapping posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS), and review the existing literature emphasizing the pathophysiological overlap of these two entities. MATERIALS AND METHODS: We conducted a literature search in electronic database PubMed identifying studies reporting the overlap of PRES and RCVS. RESULTS: PRES and RCVS are two increasingly recognized entities that share similar clinical and imaging features. PRES is characterized by vasogenic edema predominantly in the parieto-occipital regions, associated with acute onset of neurological symptoms including encephalopathy, seizures, headaches, and visual disturbances. RCVS is characterized by reversible segmental and multifocal vasoconstriction of the cerebral arteries and classically presents with thunderclap headache, with or without associated focal neurological deficits and seizures. PRES is frequently associated with uncontrolled hypertension but can also be seen in the setting of renal failure, exposure to cytotoxic agents, or pre-eclampsia. RCVS is often triggered by exposure to vasoactive agents, postpartum state, or immunosuppression. We report a case of a patient presenting with vision changes and hemiparesis, and found to have extensive cytotoxic and vasogenic edema involving the cortex and subcortical white matter on brain imaging. These changes were primarily noted in the parieto-occipital and brainstem regions, along with features of reversible vasculopathy on vascular imaging suggestive of coexisting PRES and RCVS. CONCLUSIONS: PRES and RCVS share precipitating factors, clinical and radiological features, and frequently co-exist, suggesting a common pathophysiological mechanism related to reversible dysregulation of cerebral vasculature, endothelial dysfunction, and breakdown of the blood-brain barrier.

Carotid Web Phenotype Is Uncommonly Associated With Classic Fibromuscular Dysplasia: A Retrospective Observational Study.

BACKGROUND AND PURPOSE: Carotid web (CaW) is an intimal form of fibromuscular dysplasia (FMD) involving the carotid bulb which has been increasingly recognized as a potential cause of recurrent ischemic strokes. It is overlooked as a separate entity and often dismissed if no coexistent signs of classic FMD changes are observed. We aim to evaluate the frequency of classic FMD in high-yield vascular territories in patients with symptomatic CaW. METHODS: This was a retrospective analysis of a symptomatic CaW database of 2 comprehensive stroke centers (spanning September 2014-October 2020). The diagnosis of a CaW during a stroke workup was defined as the presence of a shelf-like linear filling defect in the posterior aspect of the carotid bulb on computed tomography angiography in patients with acute ischemic stroke or transient ischemic attack of undetermined cause after a thorough evaluation. Neck computed tomography angiography and renal conventional angiography images were independently evaluated by two readers blinded to the laterality and clinical details to inspect the presence of underlying classic FMD. RESULTS: Sixty-six patients with CaW were identified. Median age was 51 years (interquartile range, 42-57), and 74% were women. All patients had neck computed tomography angiography (allowing for bilateral vertebral and carotid evaluation), whereas 47 patients had additional digital subtraction angiography (which evaluated 47 carotids ipsilateral to the stroke and 10 contralateral carotids). Internal carotid artery classic FMD changes were noted in only 6 out of 66 (9%) in the ipsilateral carotids. No contralateral carotid or vertebral artery classic FMD changes were observed. Renal artery catheter-based angiography was obtained in 16 patients/32 arteries and only 1 patient/2 renal arteries demonstrated classic FMD changes. CONCLUSIONS: CaW phenotype is uncommonly associated with classic FMD changes. Coexistent classic FMD does not constitute a useful marker to corroborate or exclude CaW diagnosis.

Carotid web: an under-recognized and misdiagnosed ischemic stroke etiology.

BACKGROUND: Carotid web (CaW) constitutes a possible cause of ischemic stroke, particularly large vessel occlusion syndromes. We aim to evaluate misdiagnosis rates and diagnosis trends for CaW. METHODS: Based on CT angiography (CTA), we prospectively identified a cohort of patients with symptomatic CaW treated at two comprehensive stroke centers (CSC) from 2014 to 2020 to assess misdiagnosis. Official CTA reports from the CSCs and referring hospitals were then reviewed for mention of CaW. For diagnosis trends, we retrospectively analyzed a CSC electronic medical record, identifying patients with CaW mentioned in an official CTA report from 2011 to 2020. RESULTS: For misdiagnosis, 56 patients with symptomatic CaW were identified in the CSCs; 16 (28%) had bilateral CaW, totaling 72 CaWs. Only one CaW (5.5%) was reported at referring facilities, from 14 patients/18 CaWs imaged with CTA. Conversely, 43 (69%) CaWs were reported from 49 patients/62 CaWs at the CSC (p<0.01). For diagnosis trends, from 2011 to 2020, 242 patients at a CSC accounted for 266 CTA reports mentioning CaW. The majority of these reports (n=206, 77%) were associated with stroke/transient ischemic attack (TIA) ICD-9/ICD-10 codes. The rate of CaW diagnosis adjusted per 1000 patients with stroke/TIA increased over time, 2015 being the most significant point of change ('joinpoint'; p=0.01). The analysis of CaW mentions normalized per 1000 CTA reports also showed increasing rates of diagnosis over time (joinpoint:2014; p<0.02). CONCLUSION: CaW was predominantly identified in patients with strokes/TIAs rather than asymptomatic patients. CaW was commonly overlooked in facilities with lower levels of cerebrovascular certification. Recognition of CaW at a CSC has significantly increased over time, independent of overall imaging and stroke patient volume.

Clinical Outcomes of Critically III Patients with COVID-19 by Race.

BACKGROUND: Studies of COVID-19 have shown that African Americans have been affected by the virus at a higher rate compared to other races. This cohort study investigated comorbidities and clinical outcomes by race among COVID-19 patients admitted to the intensive care unit. METHODS: This is a case series of critically ill patients admitted with COVID-19 to an academic healthcare system in Atlanta, Georgia. The study included all critically ill hospitalized patients between March 6, 2020, and May 5, 2020. Clinical outcomes during hospitalization included mechanical ventilation, renal replacement therapy, and mortality stratified by race. RESULTS: Of 288 patients included (mean age, 63 ± 16 years; 45% female), 210 (73%) were African American. African Americans had significantly higher rates of comorbidities compared to other races, including hypertension (80% vs 59%, P = 0.001), diabetes (49% vs 34%, P = 0.026), and mean BMI (33 kg/m2 vs 28 kg/m2, P < 0.001). Despite African Americans requiring continuous renal replacement therapy during hospitalization at higher rates than other races (27% vs 13%, P = 0.011), rates of intubation, intensive care unit length of stay, and overall mortality (30% vs 24%, P = 0.307) were similar. CONCLUSION: This racially diverse series of critically ill COVID-19 patients shows that despite higher rates of comorbidities at hospital admission in African Americans compared with other races, there was no significant difference in mortality.