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BACKGROUND: Left ventricular (LV) dysfunction is a potential cardioembolic source of ischemic stroke, but its role in recurrent stroke risk and treatment response remains unclear. We explore whether LV injury associates with the risk of recurrent stroke and modifies the association between anticoagulation and stroke recurrence using real-world data. METHODS: We performed a multicenter, retrospective study of Cardiac Abnormalities in Stroke Prevention and Recurrence cohort across 27 US sites. Patients with LV ejection fraction ≥20% were included. LV injury, defined as LV ejection fraction 20% to 40% and wall motion abnormality, was the primary exposure and treatment effect modifier. The treatment of interest was anticoagulant versus antiplatelet therapy. The composite outcome included recurrent stroke, major bleeding, or death. Outcomes were evaluated using unadjusted and inverse probability weighting adjusted Cox proportional hazards models, with treatment effect modification tested by LV injury status. RESULTS: Among 2685 patients enrolled, 2328 with complete data were analyzed (median age, 65 years; 49.8% female; median follow-up, 1.6 years). LV injury was present in 310 patients (13.3%). Overall, 535 events occurred: 258 recurrent ischemic strokes, 28 hemorrhagic strokes, 67 major hemorrhages, and 256 deaths. LV injury was associated with a higher unadjusted risk of the primary outcome (hazard ratio [HR], 1.51 [95% CI, 1.21–1.87]), though nonsignificant after inverse probability weighting adjustment (adjusted HR, 1.29 [95% CI, 0.97–1.70]). In the LV injury subgroup, anticoagulation versus antiplatelet therapy was associated with a lower risk of the primary outcome (adjusted HR, 0.24 [95% CI, 0.10–0.59]), relative to the non-LV injury subgroup (adjusted HR, 1.28 [95% CI, 0.83–1.95]; p[LV-interaction], 0.001). Similar interactions were seen for EF 20% to 40% (versus >40%; adjusted HR, 0.19 [95% CI, 0.04–0.86]; p[LV-interaction], 0.001) and wall motion abnormality (versus no wall motion abnormality; adjusted HR, 0.33 [95% CI, 0.15–0.73]). CONCLUSIONS: After cryptogenic stroke, anticoagulation in those with LV injury was associated with lower rates of recurrent stroke, major bleeding, and death. These findings warrant confirmation in a dedicated randomized controlled trial. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT06398366.

Background: Embolic stroke of undetermined source (ESUS) comprises infarct mechanisms presumed to be embolic and non-lacunar. One explanation for the lack of superiority of anticoagulation over aspirin is the inclusion of subcortical infarcts with white matter disease (WMD), reflecting small vessel pathology. We hypothesized that WMD is associated with recurrent ischemic stroke (RIS) in ESUS and this risk is not lessened by anticoagulation. Methods: We conducted a secondary analysis of the multicenter Cardiac Abnormalities in Stroke Prevention and Recurrence (CASPR) registry, including ESUS patients from 27 U.S. centers (2015–2024). WMD severity was graded using the Fazekas scale from MRI and dichotomized as mild (0–1) vs. moderate-to-severe (2–3). The primary outcome was RIS. Secondary outcomes were major bleeding and all-cause mortality. Inverse probability of treatment weighting (IPTW) adjusted for baseline differences. Cox proportional hazards models assessed associations between WMD and outcomes. Subgroup analyses explored effect modification by age, risk factors, and treatment type. Results: Among 1,890 ESUS patients with MRI data, 684 (36.2%) had Fazekas 2–3. These patients were older with more vascular risk factors, but IPTW achieved covariate balance. In the weighted cohort, RIS occurred more frequently in Fazekas 2–3 vs. 0–1 (7.1% vs. 4.6%/year; HR 1.56, 95% CI 1.10–2.22, p = 0.01). Major bleeding and mortality were similar (bleeding: 1.7% vs. 1.8%/yr, HR 0.96, p = 0.92; death: 7.0% vs. 6.7%/yr, HR 1.04, p = 0.81). Subgroup analyses showed no interaction between WMD and age, vascular risk factors, or treatment type (antiplatelet vs. anticoagulation), suggesting consistent RIS risk in those with higher WMD. Discussion: Moderate-to-severe WMD identifies ESUS patients at higher risk of ischemic stroke recurrence, with no mitigation by anticoagulation. These findings suggest that WMD may indicate non-embolic mechanisms and support the use of imaging-based risk stratification in ESUS.

Background: High-grade intracranial atherosclerosis (ICAS) is associated with an elevated risk of recurrent ischemic stroke, particularly in patients with severe stenosis (70–99%). Identifying predictors of early recurrence can inform risk stratification and guide treatment strategies. Methods: The Biomarkers and Recurrence Risk in Symptomatic Intracranial Arterial Stenosis (BIORISK-ICAS) study is a multicenter, international, retrospective cohort analysis pooling data from 35 comprehensive stroke centers. We included hospitalized adult patients with symptomatic ICAS, defined as 50–99% stenosis of an intracranial artery (intracranial vertebral, basilar, distal ICA, or M1 MCA), confirmed by vascular imaging and associated with a qualifying ischemic event. Patients with only high-grade stenosis (70-99%) were included in this analysis. The primary outcome was to determine predictors of recurrent ischemic stroke in the territory of the symptomatic artery within 90 days of the index event. Baseline demographic, clinical, and imaging characteristics were recorded. Multivariable Cox proportional hazards regression with stepwise selection (p < 0.1) was used to identify independent predictors of recurrence; model discrimination was assessed using Harrell’s C-statistics. Results: Among 2,050 patients, 1,476 had high-grade (70-99%) symptomatic ICAS. The mean age was 67 ± 12.5 years, and 767 (55%) were male. Most patients were non-Hispanic (90.1%), taking dual antiplatelet therapy (77.8%), and statins (94.5%). Recurrent stroke occurred in 160 patients (10.8%) within 90 days. In multivariable Cox model, independent predictors of recurrence included atrial fibrillation (HR 2.05; 95% CI, 1.26–3.33; p = 0.004), hyperlipidemia (HR 1.57; 95% CI, 1.10–2.24; p = 0.014), diabetes mellitus (HR 1.36; 95% CI, 0.98–1.88; p = 0.064), and home use of dual antiplatelet therapy (HR 1.60; 95% CI, 1.01–2.54; p = 0.043)(Harrell’s C-statistic=0.62). In patients who underwent perfusion(n=402), mistmatch >10seconds were associated with increased recurrence (HR 1.80; 95% CI 0.95-3.38, p=0.07) and atrial fibrillation (HR 2.06: 95% CI 0.03-4.60, p=0.78) though did not reach statistical significance. Conclusion: In this population, diabetes, hyperlipidemia, atrial fibrillation, and prior use of dual antiplatelet therapy were associated with increased risk of 90-day recurrent ischemic stroke. Perfusion imaging may help identify high-risk patients who could benefit from intensified secondary prevention.

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: 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.

BACKGROUND: Intracranial atherosclerosis (ICAS) is associated with an increased risk of early recurrent ischemic stroke. We evaluated whether biomarkers of impaired distal perfusion—specifically, anterior circulation borderzone infarct, and hypoperfusion mismatch volume—were associated with recurrent ischemic stroke within 90 days. METHODS: The BIORISK ICAS (Biomarkers and Recurrence Risk in Symptomatic Intracranial Atherosclerosis) is a multicenter retrospective international study (35 sites) that included hospitalized patients with symptomatic ICAS (50%–99% luminal stenosis of the intracranial vertebral, basilar, distal internal carotid, or proximal middle cerebral artery) from January 2019 to June 2024. The primary outcome was recurrent ischemic stroke in the territory of the symptomatic artery within 90 days. In the primary analysis, the exposure was an acute anterior circulation borderzone infarct. In secondary analysis of the subset with presentation within 72 hours of last known normal and perfusion imaging completed, the exposure of interest was prespecified as hypoperfusion mismatch volume at T max (time to maximum) threshold of 6 seconds, dichotomized at the Youden index. We performed multivariable Cox regression to test associations between exposure variables and the outcome, adjusting for clinically relevant variables and those associated with the outcome ( P <0.1). RESULTS: Of 2050 patients with symptomatic ICAS, 1737 (84.7%) presented within 72 hours of symptom onset, among whom 509 (29.3%) underwent perfusion imaging. The primary analysis included 1891 patients; 174 (9.2%) patients had recurrent ischemic stroke in the symptomatic arterial territory. In adjusted Cox regression models, there was an association between anterior circulation borderzone infarct and recurrent ischemic stroke at 90 days (adjusted hazard ratio, 1.40 [95% CI, 1.02–1.93]). In the perfusion imaging analysis, hypoperfusion mismatch of ≥10 mL was associated with recurrent ischemic stroke (adjusted hazard ratio, 1.83 [95% CI, 1.03–3.28]). CONCLUSIONS: Biomarkers of impaired distal perfusion, anterior circulation borderzone infarct, and hypoperfusion mismatch were associated with increased risk of recurrent ischemic stroke. These findings support the use of perfusion imaging in ICAS as well as future trials investigating early reperfusion in high-risk patients with ICAS.

Background Intracranial occlusions in embolic stroke of undetermined source are histopathologically similar to cardiac sources of embolism. Whether patients with embolic stroke of undetermined source and intracranial occlusion benefit from anticoagulation is unknown. Methods A multicenter retrospective cohort of adults with cryptogenic stroke was queried for patients with proximal or medium/distal vessel occlusion. The primary outcome was recurrent ischemic stroke, which was assessed in unadjusted and adjusted Cox proportional hazards models and repeated following 1:1 propensity score matching and biweight kernel density matching. Results Of the 2328 patients who were followed over a median of 1.31 years (interquartile range, 0.34–2.85), 999 (42.6%) had an intracranial occlusion. When compared with patients without an intracranial occlusion, those with an occlusion had fewer atherosclerotic vascular risk factors, more severe symptoms, and less severe cerebral microvascular disease. The rate of recurrent stroke was similar between patients with versus without an intracranial occlusion (6.8%/year [95% CI, 5.7–8.2] versus 7.0%/year [95% CI 6.0–8.1]; adjusted hazard ratio [HR], 1.09 [95% CI, 0.77–1.55]). There was no association between occlusion and recurrent stroke in the adjusted propensity score matching (HR, 1.01 [95% CI, 0.64–1.59]) or kernel density models (HR, 0.95 [95% CI, 0.62–1.45]). There was no interaction between occlusion and treatment with anticoagulation, sex, age, or high‐risk sources of embolism for the primary outcome in the unmatched and matched analyses. Conclusions Intracranial occlusion in patients with embolic stroke of undetermined source is not associated with a greater risk of recurrence when compared with patients without an intracranial occlusion. There was no difference in rate of recurrent stroke with anticoagulation when stratified by presence or absence of occlusion.

Importance The APOE ε4 variant is causally linked to cerebral amyloid angiopathy and is a risk factor for intracranial hemorrhage (ICH) among warfarin-treated patients with atrial fibrillation. Nevertheless, its impact on those treated with apixaban remains unknown. Objective To test the hypothesis that APOE ε4 allele carriership is associated with an increased risk of ICH in patients with atrial fibrillation taking apixaban. Design, Setting, and Participants This cohort study involved data from the All of Us Research Program, a longitudinal, population-based study in the United States. Inclusion criteria were age older than 50 years, history of atrial fibrillation, and anticoagulation with apixaban. Participants with a history of ischemic stroke or ICH were excluded. Up to 3 years of follow-up data were available. Data were collected from 2017 to 2022 and analyzed from November 2023 to December 2024. Exposure APOE ε2, ε3, and ε4 were ascertained using variants rs429358 and rs7412. APOE ε4 was modeled dichotomously (noncarriers [no alleles] vs carriers [1 or 2 alleles]). Main Outcomes and Measures Incident ICH, including any new intraparenchymal, subdural, or subarachnoid hemorrhage after initiation of apixaban therapy. Results Of 413 477 All of Us participants, 2038 were eligible. Their mean (SD) age was 71 (9) years; 918 (45%) were female, 1120 (55%) were male, and 1710 (83%) had European ancestry. Among these participants, 483 (23.7%) were carriers of at least 1 APOE ε4 allele. After a median follow-up of 2.9 years, 26 participants sustained an ICH (cumulative incidence, 1.5%; 95% CI, 1.0%-2.2%), of whom 12 (cumulative incidence, 3.1%; 95% CI, 1.7%-5.3%) were carriers and 14 (cumulative incidence, 1%; 95% CI, 0.6%-1.7%) were noncarriers ( P = .007). Multivariable Cox proportional hazard models confirmed this association: compared with noncarriership, APOE ε4 carriership was associated with a 3-fold increase in the risk of ICH (hazard ratio, 3.07; 95% CI, 1.42-6.65). APOE information improved the discrimination of risk prediction scores (C statistic of 0.74 and 0.68 for models with and without APOE , respectively; P = .03). Conclusions and Relevance Further research is needed to evaluate whether cerebral amyloid angiopathy mediates the observed association and whether APOE e4 information improves clinical decision-making about anticoagulation therapy in patients with atrial fibrillation. The latter is important now that APOE information is used in clinical settings to guide antiamyloid treatment for Alzheimer disease and has been returned to millions of persons by direct-to-consumer genotyping companies.