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Introduction: Emerging evidence highlights the increased white matter hyperintensity (WMH) burden in APOE4 homozygotes, the greatest genetic risk factor for late-onset Alzheimer's disease (AD). The link between WMH and cerebral amyloid-beta (Aβ) accumulation remains unclear, especially in presymptomatic AD phases. We aimed to determine whether WMH burden (global or regional) mediates the association between APOE4 homozygosity and amyloid-PET Aβ deposition in a population of subjects with intact cognition. Methods: WMH were segmented using a deep learning model applied to T1 and T2-FLAIR MRI scans from 49 cognitively intact individuals older than 50. The global and regional (periventricular, lobar, basal ganglia, infratentorial) WMH volumes were adjusted for total intracranial volume and log-transformed to normalize distribution. Amyloid-PET cerebral Aβ burden was quantified in centiloid units; individuals with centiloid > 20 were classified as Aβ-positive. To examine our mediation hypothesis, we tested three pathways using logistic and linear regression models: 1) Path a, the association between APOE4 and global or regional WMH volumes (outcome); 2) Path b, the association between WMH volumes and Aβ positivity (outcome); 3) Path c (total) and c' (direct) effects of APOE4on Aβ positivity (outcome), before and after adjusting for WMH volumes. All models incorporated age and vascular risk factors (hypertension, diabetes, hypercholesterolemia, cigarette smoking). Results: We included 11 APOE4 homozygotes, of whom 7 were Aβ-positive and 38 non-carriers (35 3/3 and 3 3/2) (6 Aβ-positive). Compared to APOE4 non-carriers, APOE4 homozygotes had significantly greater WMH volumes in the posterior periventricular region only (p= 0.0453) (path a). Homozygotes were significantly more likely to be Aβ-positive compared to non-carriers (total effect, path c p=0.0019). This association remained significant after adjusting for WMH (direct effect, path c'= 0.0027). However, neither global (p=0.72) nor posterior periventricular (p=0.84) WMH volumes predicted Aβ positivity (path b) (Figure). Conclusions: In our cohort of cognitively normal individuals including preclinical AD, neither global nor regional WMH burden mediated the relationship between APOE4 homozygosity and Aβ positivity. Larger studies are needed to further evaluate the mechanistic relationship between WMH and neurodegeneration in APOE4 carriers.

Objective: To assess the link between retinal vascular health and cognitive performance in a diverse population, using a novel mobile laboratory platform and portable color fundus photography. Background: The retina is an accessible window into brain health. Studies that had highlighted the link between retinal vasculature and cognition included clinical populations or narrowly defined research cohorts, with limited generalizability. To address the need to expand this research to demographic and geographic diverse communities, we launched a mobile laboratory platform across rural and urban Arizona zip codes. Methods: 240 subjects were recruited in our prospective community-based study. We assessed cognition using the MindCrowd web-based testing platform and analyzed verbal paired associates (VPA) task, a validated measure of verbal associative memory sensitive to age-related cognitive decline. Non-mydriatic color fundus photographs were obtained using the portable hand-held Aurora camera (Optomed), two images per eye (disc- and macula-centered). Image processing and vascular feature quantification were automatically conducted using Automorph software. Linear regression models examined the associations between retinal vascular metrics and VPA, adjusting for age, sex, education attainment, and risk factors. Results: Our cohort’s mean age was 45 +/-16.7 years, 32.9% were male and 39.5% had a college degree. In disc-centered fundus images, fractal dimension strongly associated with chronological age (p = 1.04E-10). Greater artery tortuosity in the retinal zones B and C was associated with lower VPA (p = 0.02 and p = 0.004, respectively). In macula-centered images, fractal dimension showed the strongest association with age (p = 4.31E-11), reinforcing its utility as a robust biomarker of vascular aging. Males had wider average artery caliber in zone B (p=0.02). Zone B vein fractal dimension (p=0.002) and vein vessel density (p=0.006) were the strongest predictors of VPA. Conclusions: This study demonstrates the safety, feasibility, and utility of a mobile laboratory to collect high-quality non-mydriatic color photos and cognitive data across a geographically diverse cohort. Arterial tortuosity and venous fractal dimension and density, particularly in retinal zone B, were predictive of cognitive performance, after adjusting for vascular health covariates. Retina may become a scalable and accessible platform for studying brain aging in the general population.

Introduction: Intracranial atherosclerosis (ICAS) is a leading cause of ischemic stroke (IS) worldwide and carries a high risk of recurrence. Current guidelines favor 90 days of dual antiplatelet therapy (DAPT) for severe symptomatic ICAS, but recurrence remain high. Limited data suggest possible benefit of single antiplatelet plus anticoagulation (SAPT+AC). We compared the effectiveness and safety of DAPT versus SAPT+AC. We hypothesized that DAPT would lower 90-day recurrent IS risk without significantly increasing bleeding. Methods: This substudy of the Biomarkers and Recurrence Risk in Symptomatic Intracranial Arterial Stenosis (BIORISK-ICAS) included patients from 35 centers (Jan 2019–Jun 2024) with symptomatic 50–99% ICAS in the intracranial internal carotid, vertebral, basilar, or M1 segment of the MCA, presenting ≤72 hours from last known well. The primary efficacy outcome was recurrent IS in the same vascular territory at 90 days; the primary safety outcome was severe bleeding (symptomatic intracranial hemorrhage or major extracranial bleeding). Categorical variables were compared using χ 2 and continuous variables with the Student's t test; multivariable Cox regression adjusted for key covariates. Results: Of 2050 BIORISK-ICAS patients, 1658 met criteria (DAPT n=1499; SAPT+AC n=159). Mean age was 67 vs. 73 years, and 44% were women. At 90 days, recurrent IS occurred in 121 DAPT patients (8.07%) vs. 13 SAPT+AC patients (8.17%); unadjusted HR 0.83 (95% CI, 0.50–1.36; p=0.46). After adjustment for age, diabetes, coronary heart disease, atrial fibrillation, active smoking, and borderzone infarct, the adjusted HR was 0.99 (95% CI, 0.52–1.86; p=0.97). Severe bleeding occurred in 34 DAPT patients (2.26%) and 5 SAPT+AC patients (3.14%); unadjusted HR 0.79 (95% CI, 0.28–1.85; p=0.50), adjusted HR 0.66 (95% CI, 0.21–2.09; p=0.47). Conclusions: In patients with symptomatic ICAS, DAPT and SAPT+AC were associated with similar risks of 90-day recurrent ischemic stroke and severe bleeding. Well-powered randomized trials are needed to determine the optimal antithrombotic regimen in this high-risk population.

Background: Studies have suggested that administering antithrombotics—oral anticoagulants (OACs) and antiplatelets (APLT)—after acute ischemic stroke(AIS) with hemorrhagic transformation (HT) is safe and can reduce ischemic recurrence. However, the safety of their early initiation after HT remains unclear. Method: This study utilized data from nine centers across several countries. The study population included patients with AIS who subsequently experienced HT. Patients with a specific HT type—hemorrhagic infarction(HI) or parenchymal hematoma(PH)—were categorized based on the time between HT and antithrombotic initiation, and their outcomes were compared. Outcomes included 30-day HT exacerbation and composite outcomes of recurrent stroke and systemic emboli, as well as 90-day vascular death and functional outcome. Results: Of 748 patients,496 received APLT, and 252 were prescribed OACs after HT. The median HT-to-APLT time was significantly shorter among HI patients than PH patients(1[IQR:0-2] vs. 3[IQR:1-5] days,p<0.001). The rates of 30-day HT exacerbation and composite outcomes, as well as 90-day vascular death and unfavorable functional outcomes, did not significantly differ between patients who received same-day, early (HI:<1day;PH:<3days), or late (HI:>1day;PH:>3days) APLTs after either HI or PH. Among patients who received OACs, those with HI had a significantly shorter median HT-to-OAC time than PH (7[IQR:2-15] vs. 15[IQR:7-32] days,p<0.001). However, 30-day HT exacerbation rates were comparable between early (HI:<7days;PH:<15days) and late (HI:>7days;PH:>15days) OAC initiation among patients with either HI or PH, late initiation among patients with PH was associated with higher rates of 30-day composite outcomes than early initiation(20.7% vs. 3%,p=0.044). Based on regression models adjusted for NIHSS and stroke severity, early initiation of APLTs or OACs was not associated with increased risk of HT exacerbation. Conclusion: Findings suggest that the same-day initiation of APLTs after HI or PH-1, and within 1-3days following PH-2, might not be associated with HT exacerbation or worsening outcomes. Similarly, OACs initiated 2-7days after HI and 7-15days after PH may not be associated with worsened patients' outcomes, whereas delays beyond these timeframes can be associated with higher thromboembolic risk.

Background: Although the embolic stroke of undetermined source (ESUS) construct was proposed as a unifying concept for embolic-appearing strokes without an identified cause, it includes patients with diverse and often unrecognized underlying mechanisms. This study investigates the differential rate of recurrent stroke according to the completeness of neurodiagnostic testing in a diverse multicenter cohort. Methods: This was a retrospective analysis of a multicenter observational cohort study (n=27 sites). Patients with ESUS were categorized into three groups: (1) established mechanism after further work up (ESUS-E), (2) patients who underwent a comprehensive diagnostic workup without an identified etiology (ESUS 2.0), and (3) no advanced workup (ESUS-NAW). The primary outcome of recurrent ischemic stroke was assessed by comparing ESUS 2.0 to both ESUS-E and ESUS-NAW groups using adjusted Cox proportional hazards models. Results: Of the 2,281 patients included, 694 (30%) were classified as ESUS-E, 344 (15%) as ESUS 2.0, and 1,443 (55%) as ESUS-NAW. The ESUS 2.0 group had a significantly lower annualized recurrence rate (1.98 per 100 person-years) compared to both the ESUS-NAW group (7.7 per 100 person-years; aHR 0.27, 95% CI: 0.11–0.62; p=0.002) and the ESUS-E group (6.10 per 100 person-years; aHR = 0.35; 95% CI 0.15–0.85, p=0.020). Within the ESUS-E group, cancer (aHR 5.33; 95% CI: 2.09–13.63; p < 0.001) and non-stenosing atherosclerotic disease or arch atheroma (aHR 3.40; 95% CI: 1.18–9.83; p = 0.023) were associated with significantly increased risk of recurrence when compared to ESUS 2.0. Conclusion: These findings demonstrate a lower risk of recurrent stroke in patients classified as ESUS 2.0, diverging from the 5–6% annual recurrence rates observed in prior ESUS trials. These findings suggest that patients who receive comprehensive diagnostic evaluation without identification of a specific etiology have a lower risk of recurrent stroke, an important consideration for the design of future ESUS studies.

Objectives: Cerebral hemodynamic impairment in patients with asymptomatic high-grade internal carotid artery (ICA) stenosis confers a risk of stroke and cognitive decline, but correlations between degree of stenosis and hemodynamic impairment are derived from small case series only. Using baseline data from 282 participants in the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis – Hemodynamics (CREST-H) study, we hypothesized that degree of stenosis, measured by peak systolic velocity (PSV) and end diastolic velocity (EDV) in the ipsilateral ICA, would correlate with time-to-peak (TTP) delay using MR (n=275) or CT (n=7) perfusion scans, adjusting for demographic and cardiovascular risk variables. Methods: Using a 7-10MHz Doppler probe, ICA PSV and EDV were assessed. Doppler results were adjudicated centrally. Dynamic contrast perfusion imaging was standardized across 61 CREST-H sites, using sequential T2*-weighted time-sequence scanning (e.g. TR=1500, TE=25ms, flip angle=60deg, phase=128, slice thickness=5mm for GE 3T magnet). CTP was acquired with standard clinical protocols. TTP delay was calculated in the ipsilateral versus contralateral MCA/ACA territories using OLEA software. Linear regression used TTP delay as the outcome variable and PSV and EDV as predictor variables, adjusting for covariates.The 282 with complete data for all variables were included in the analysis. Results: Among 392 CREST-H participants, 63% were men, 7% Black, 3% Hispanic, 33% with less than college education. Tables 1a/b show the regression results for PSV and EDV as main predictor variables. PSV and EDV on the index side significantly correlated with TTP delay (p=0.004, p=0.002 respectively). Neither PSV nor EDV on the non-index side correlated with TTP delay (p=0.49, p=0.82). Compared with moderate exercise, vigorous exercise correlated with lower TTP delay in both models (p=0.05. p=0.04). Compared with college graduates, those with HS education had longer TTP delays in both models (p=0.03. p=0.02). Conclusions: In this large cohort of patients with high-grade asymptomatic carotid stenosis, higher flow velocities correlated with greater TTP delays, suggesting an increasing hemodynamic impairment with greater degree of stenosis above 70%. Our findings have implications for management of asymptomatic carotid stenosis which are being tested in the CREST-H and CREST-2 studies. Exercise and education may independently impact cerebral hemodynamics.

Background: The rate of intracardiac thrombus detection in the hyperacute phase of stroke varies from 5% to 12% between studies. Our aim was to compare the thrombus detection rate between ECG-gated and non-ECG-gated cardiac CT protocols in acute stroke patients, using data from a large, international, multicentre registry. Methods: We conducted an individual patient data meta-analysis by pooling prospective and retrospective observational data from stroke patients assessed at four comprehensive stroke centres who underwent either ECG-gated or non-ECG-gated cardiac CT (extended CT angiography or two-phase non-ECG-gated cardiac CT) as part of the acute stroke imaging protocol between May 2018 and June 2024. The primary outcome was the proportion of patients with a cardiac thrombus in gated vs non gated techniques. Results: Of 3,940 patients, 1,474 (37.4%) underwent ECG-gated and 2,466 (62.6%) non-ECG-gated cardiac CT. Patients in the ECG-gated group were younger (median age 72 [IQR 62–81] vs. 74 [IQR 64–82] years, p = 0.000) and had a lower NIHSS at baseline (median 5 [IQR 2–12] vs. 6 [IQR 3–13], p < 0.00). There was a higher rate of thrombus detection with ECG-gated CT compared to non-gated CT (7.5% vs. 5.5%, p = 0.011. The association remained significant after adjusting for age, sex, baseline NIHSS score, and baseline atrial fibrillation (adjusted OR 1.87, 95% CI 1.42–2.47, p = 0.000). ECG-gated CT was associated with lower radiation dose (3.6 vs. 6.3 mSv, p = 0.000) but longer acquisition time (5.8 vs. 0.28 min, p = 0.000). Conclusion: ECG-gated cardiac CT has a higher detection rate for intracardiac thrombus detection compared to non-ECG-gated CT in patients with acute ischemic stroke.

Background: Periodontitis is a potential modifiable factor influencing dementia risk. We examined whether improving periodontal health via regular flossing is associated with lower dementia risk. Methods: A total of 9,766 Atherosclerosis Risk in Communities (ARIC) study participants with teeth were followed from visit 4 (1996-1998) through 2021. Cox proportional hazards regression was used to estimate associations between regular dental flossing (≥1/week) and incident dementia. Covariates included age, race, gender, hypertension, diabetes, alcohol use, smoking status, obesity, physical activity, education level, income, insurance status, brushing frequency, regular dental care use and apolipoprotein E4 (APOE4) allele status . Cumulative incidence functions were estimated using death as a competing event. Results: Participants had mean age 62.6 years (SD = 5.6), 56% female, 79% white, 21% black, 63% reported regular flossing and 29.2% participants carry at least one APOE4 allele. The cumulative incidence of dementia was 52.6 % overall over 25 years. Regular flossing was independently and significantly associated with a lower hazard of developing dementia (HR = 0.90, 95% CI: 0.82–0.98, p = 0.02) after adjustment for all the covariates. In contrast, tooth brushing frequency (p=0.55) and regular dental care visit (p=0.22) were not significantly associated with dementia risk. By 25 years of follow-up, the cumulative incidence of dementia was 50% among flossers compared with 57% among non-flossers (Gray’s test p<0.0001, Figure). This translated to an Absolute Risk Reduction of 7%, Relative Risk Reduction of 12%, Number Needed to Floss 14. Conclusion: Flossing, but not tooth brushing or regular dental care, is independently associated with a reduced hazard of incident dementia. Dental flossing may be an additional strategy to reduce dementia risk. For every 14 individuals who floss ≥1/week, one fewer person will develop dementia.

Background and Objectives: Cervical artery dissection (CeAD) is a common cause of ischemic stroke in young adults. We aim to identify age-based differences in clinical presentation, imaging findings, and outcomes after CeAD. Methods: This was a sub-study using the STOP-CAD registry, a multicenter cross-sectional international retrospective study of patients diagnosed with CeAD and treated with an antithrombotic from January 1, 2015 to December 31, 2021. Baseline clinical and imaging characteristics were compared between younger and older adults with CeAD (≤45 versus >45 years of age) using multivariable logistic regression. We chose this age cut off due to its frequent usage in stroke in the young literature. Multiple logistic regression models were used to determine association between young age and outcomes after CeAD (ischemic stroke at 180 days, excellent functional outcome with modified Rankin Scale of 0-1 at 90 days, and mortality) after adjusting for sex, vascular risk factors, CeAD characteristics, and NIHSS on presentation. Results: Among 4023 CeAD patients included in the study, 1901 (47.3%) were ≤45 years of age. Patients were followed for a median of 307 days (IQR 102-831). Young adults with CeAD were more likely to be women (Odds Ratio [OR], 2.4; 95% CI, 2.1-2.9; p<0.001), of Hispanic ethnicity (OR, 1.8; 95% CI 1.3-2.5; p<0.001), have a history of migraines (OR, 1.6; 95% CI, 1.3-2.0; p<0.001) and recent neck trauma (OR, 1.6; 95% CI, 1.3-1.9; p<0.001) while having fewer traditional vascular risk factors. Young adults with CeAD had higher odds of a non-ischemic presentation (OR, 1.3; 95% CI, 1.1-1.5; p=0.013), vertebral artery dissection (OR 2.5; 95% CI, 2.2-3.0; p<0.001), and multivessel involvement (OR 1.5; 95% CI, 1.1-1.9; p=0.004). In adjusted analysis, younger age was not associated with an increased risk of recurrent ischemic stroke (adjusted Hazard Ratio [HR], 0.48; 95% CI 0.2-1.2; p=0.119). Younger age was associated with significantly greater odds of excellent functional outcome at 90 days (aOR, 1.48; 1.20-1.84, p<0.001) and lower risk of death at follow up (aHR, 0.37; 95% CI, 0.17-0.81; p=0.012) after CeAD. Conclusion: In a large international cohort, young adults with CeAD had a distinct clinical phenotype with higher odds of non-ischemic presentation, vertebral artery dissection, and multivessel involvement while having fewer traditional vascular risk factors. Young adults had a decreased odds of disability and mortality after CeAD.

Background: Timely and accurate triage of stroke patients in rural settings remains a critical challenge, especially for patients with large vessel occlusions (LVO) requiring rapid access to comprehensive stroke centers (CSCs). This project aimed to improve the efficiency and accuracy of transport decisions for EMS stroke care in rural Michigan by adapting American Heart Association (AHA) guidelines on prehospital management and EMS routing. Method: We established a novel database involving linking regional EMS records, regional hospital stroke code quality improvement data, and Get With The Guidelines–Stroke (GWTG-S) registry data for suspected and confirmed stroke cases originating from five counties within 60 minutes of an urban CSC in West Michigan. Using a stepped-wedge design, we adapted the model AHA Severity-Based Stroke Triage Algorithm and implemented it in four rural EMS agencies through a staged roll-out of educational programs delivered to EMS providers and regional ED staff. We analyzed pre- and post-intervention data to assess protocol compliance, bypass frequency, and time from EMS scene arrival to CT acquisition and reperfusion therapy delivery. Results: Among 949 (598 pre- and 351 post-intervention) stroke transports occurred between November 2021 to December 2024, guideline-compliant hospital destination selection improved from 62% to 71% (p=0.018). Stroke mimics saw the greatest improvement (72% to 88%, p<0.001) through reduced unnecessary bypass. LVO screening documentation increased (10% to 23%, p<0.001), and EMS scene arrival-to-CT time decreased by 7 minutes (95% CI: 3–11). Trends toward improved thrombolysis rates (18% to 26%, p=0.055) and faster EMS-to-needle times (99 to 87 min, p=0.059) were observed. Mechanical thrombectomy rates and transfer metrics remained unchanged. Conclusions: This project successfully implemented a rural stroke triage protocol aligned with AHA guidelines, improving EMS routing decisions and reducing time to imaging. The intervention enhanced access to thrombolysis, however did not expedite mechanical thrombectomy. Findings support the AHA protocol’s scalability and underscore the feasibility of rural stroke system optimization.