Liebeskind, D

Background: Patients with cervical artery dissection (CAD) have a higher prevalence of cerebral aneurysms, likely due to underlying vasculopathies. Understanding risk factors and outcomes in this population may inform screening and management strategies. Methods: We conducted a post-hoc analysis of the STOP-CAD study, a multicenter international registry of patients with non-major trauma-related CAD across 63 centers. Cerebral aneurysms were identified based on medical history and intracranial vascular imaging obtained for dissection diagnosis. We compared demographic, clinical, laboratory, and imaging characteristics between patients with and without aneurysms. Variables with p<0.05 in univariate analysis were entered into a multivariable binary logistic regression to identify independent predictors. Clinical outcomes including ischemic stroke and symptomatic intracranial hemorrhage at follow-up were compared between both groups. Results: Out of 4023 patients included in the STOP-CAD study, 116 (2.9%) had at least one incidental cerebral aneurysm. In adjusted binary logistic regression, patients with cerebral aneurysm were more likely to have a history of migraine (aOR 1.78 95% CI 1.15-2.75, p=0.009), history of hypertension (aOR 1.65 95% CI 1.12-2.43, p = 0.010), known connective tissue disorder (aOR 3.47 95% CI 1.71-7.03), history of dissection (aOR 2.63 95% CI 1.31-5.28, p = 0.007), and a dissecting aneurysm at the site of the dissection (aOR 1.94 95% CI 1.25-3.01, p = 0.003). At follow-up, the presence of a cerebral aneurysm was not associated with ischemic stroke (7.8% vs. 5.6% p>0.1), but with a trend towards increased odds of symptomatic intracranial hemorrhage (3.4% vs. 1.2%, p = 0.062). Conclusions: Patients with CAD and concurrent incidental cerebral aneurysm were more likely to have a history of migraine headaches and markers of underlying vasculopathy and had a non-significantly increased risk of intracranial hemorrhage at follow-up. Further studies are needed to identify best practices for surveillance and risk stratification in this subgroup.

Introduction: Embolic stroke of undetermined source (ESUS) is a clinical construct encompassing heterogenous possible mechanisms of incident stroke, potentially with variable responsiveness to anticoagulation and antiplatelet treatment. This study aims to identify differences in recurrent stroke risk based on phenotypic clusters in an ESUS population, and whether some clusters may benefit relatively more from anticoagulation over antiplatelet therapy. Methods: We identified patient phenotypes from a multicenter, retrospective cohort study of 1909 ESUS patients by dividing them into groups using Partitioning Around Medoids (PAM) with correlation-weighted Gower distance over 23 baseline demographic, clinical, laboratory, radiographic, and cardiac features. We confirmed optimal clustering at 3 groups. We assessed cluster associations with time to recurrent stroke using Kaplan-Meier survival analysis. We then employed a causal survival forest to estimate conditional average treatment effects (CATE) of anticoagulation versus antiplatelet therapy using the same baseline features as predictors with a 365-day horizon for restricted mean survival time differences. Finally, we used best linear projection to identify baseline features predictive of treatment effect and assessed whether effects differed significantly by cluster. Results: Cluster 1 (n=542) identified a low-risk, younger sample with minimal baseline disability and comorbidity burden. Cluster 2 (n=743) comprised a moderate-risk phenotype with intermediate comorbidity. Cluster 3 (n=626) represented the oldest and highest-risk phenotype. Kaplan-Meier analysis demonstrated significant differences in stroke-free survival across patient clusters (p < 0.001), where Cluster 1 experienced the lowest recurrent stroke rate and Cluster 3 had the highest. The clustering algorithm successfully identified clinically meaningful phenotypes with distinct risk profiles. While CATE varied across clusters, the differences were not statistically significant. Conclusion: In a multicenter ESUS population, we identified 3 distinct phenotypic clusters, each comprising nearly one-third of the sample and with a differential risk of recurrent stroke. Although cluster was not a significant effect modifier, substantial CATE variability by cluster was observed. Future clinical trials may consider evaluating secondary stroke prevention therapies among phenotypically similar patients who may respond differentially to novel therapies.

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.

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.