Kasab, Sami Al

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.

Background: Cervical artery dissection (CeAD) accounts for nearly 25% of all ischemic strokes in young adults. CeAD can lead to the development of dissecting aneurysms (DA). However, the incidence, risk factors and outcomes of CeAD patients with DA is not well established. This study aims to identify risk factors for developing DA, subsequent growth, and impact on patient outcomes. Methods: This is a secondary analysis of the Antithrombotics for Stroke Prevention in Cervical Artery Dissection (STOP-CAD), a multicenter cross-sectional international retrospective study. CeAD patients were stratified for the presence of DA. We used multivariable regression to identify factors associated with DA. Patients with DA were further analyzed for DA growth. The primary outcome was ischemic stroke after CeAD+DA diagnosis. Secondary outcomes included ischemic stroke after CeAD+DA with DA growth. Multivariable logistic regression analysis was used to assess the association between DA and risk factors. We also performed univariate Cox regression and generated Kaplan-Meier survival curves comparing study outcomes based on presence of DA and subsequent growth. Results: Of the 4023 patients included in the STOP-CAD study, 4008 were included in this analysis and 767 (19%) patients had DA (546 with DA on initial presentation). Patients with DA had a mean age of 46 [IQR 37-55] years and 50% (383) were women. In combined adjusted analyses, DA patients were more often non-Hispanic (aOR 0.63, 95% CI 0.41-0.94, p<0.02), more commonly had a history of migraine (aOR 1.27, 95% CI 1.01-1.59, p=0.037), connective tissue disorder (aOR 2.02, 95% CI 1.22-3.36, p=0.007), minor neck trauma (aOR 1.70, 95% CI 1.29-2.26, p<0.001) and were more likely to present with ischemic stroke (aOR 1.73, 95% CI 1.05-2.87, p=0.031). DA growth was noted in 55 out of 546 (10%) patients with DA on presentation. There was no significant difference in the risk of ischemic stroke by day 180 in patients with DA (hazard ratio [HR] 0.92 [95% CI, 0.65-1.30]; P =0.63) or DA growth (HR 2.40, [95% CI, 0.79-7.24]; P =0.12). Conclusion: In this subanalysis of STOP-CAD, nearly one in five patients with CeAD developed a DA. Factors associated with a higher likelihood of DA included non-Hispanic ethnicity, history of migraine, connective tissue disorder, minor neck trauma, and ischemic stroke at presentation. DA diagnosis and DA growth did not impact the risk of subsequent ischemic stroke at 6 months.

Background: The clinical characteristics and complications associated with de novo pseudoaneurysm formation beyond the acute phase of cervical artery dissection remain poorly defined. In this study, we examined the incidence, risk factors, and related ischemic and hemorrhagic events of post-acute de novo pseudoaneurysm formation. Methods: We analyzed data from the STOP-CAD study (Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection). A de novo pseudoaneurysm was defined as a new (not present on initial imaging) focal enlargement in the diameter of the artery, greater than the native lumen. The incidence of de novo pseudoaneurysm was assessed at 90 days, 180 days, and beyond 180 days of follow-up. Univariate and multivariate regression analyses were conducted to identify risk factors for post-acute de novo pseudoaneurysm formation. Kaplan-Meier survival estimates were used to compare ischemic and hemorrhagic events between patients with and without de novo pseudoaneurysms. Results: Among 4008 patients, 546 were excluded as they had dissecting pseudoaneursyms on initial presentation. Therefore, 3,462 patients were included in this analysis of whom 220 patients (6.35%) developed a de novo pseudoaneurysm over a maximum follow-up of 4.4 years. Of these, 127 (57.72%) were detected within the first 90 days, and 172 (78.18%) within the first 180 days. In multivariate regression analyses, in addition to hypertension, active smoking and Hispanic ethnicity, fibromuscular dysplasia (FMD) was an independent risk factor for post-acute de novo pseudoaneurysm formation (adjusted OR: 2.160; 95% CI: 1.408–3.315; p < 0.001). Notably, the presence of a de novo pseudoaneurysm was not associated with a significant increase in ischemic (hazard ratio [HR] 1.43 [95% CI, 0.89–2.30]; P=0.14) or hemorrhagic events (hazard ratio [HR] 1.42 [95% CI, 0.43–4.69]; P=0.57). Conclusion: De novo pseudoaneurysm formation following a diagnosis of a cervical artery dissection is not uncommon and most frequently occurs within the first 180 days. FMD was independently associated with this complication. The development of a de novo pseudoaneurysm did not significantly increase the risk of subsequent ischemic or hemorrhagic events.

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.

BACKGROUND: Cervical artery dissection (CeAD) may result in dissecting aneurysm (DA) formation. We aimed to characterize risk factors and clinical outcomes associated with DA in a large, international CeAD cohort. METHODS: We performed a secondary analysis of STOP-CAD (Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection), an international, multicenter, retrospective cohort. Patients with spontaneous CeAD were assessed for DA at baseline and de novo DA formation. Significant covariates in univariable analysis were included in multivariable regression models aiming to identify factors associated with DA formation. Logistic regression and Cox proportional hazards models evaluated the association of DA with ischemic and hemorrhagic outcomes. RESULTS: Among 4008 patients with CeAD, 546 (13.6%) had a DA at baseline, and 221/2938 (7.5%) patients developed a de novo DA during follow-up, of which 172/221 (78.2%) were detected in the first 180 days. Patients with DA had a mean age of 47 years, and 383 (49.9%) were women. Baseline or de novo DA was associated with a history of connective tissue disorder (adjusted odds ratio [aOR], 2.02 [95% CI, 1.22–3.36]), fibromuscular dysplasia (aOR, 1.69 [95% CI, 1.28–2.25]), and multiple vessel dissection (aOR, 1.53 [95% CI, 1.19–1.98]). Lower odds of DA were seen in Hispanic ethnicity (aOR, 0.64 [95% CI, 0.43–0.97]) and ischemic stroke presentation (aOR, 0.41 [95% CI, 0.34–0.49]). Fibromuscular dysplasia was associated with de novo DA formation (aOR, 2.30 [95% CI, 1.52–3.49]). DA was not associated with ischemic stroke (hazard ratio, 0.71 [95% CI, 0.44–1.16]; P =0.173) or intracranial hemorrhage (HR, 1.09 [95% CI, 0.42–2.84]; P =0.86) by day 180. CONCLUSIONS: DAs are relatively common manifestations of CeAD, typically occurring within 6 months of CeAD diagnosis. DA was not associated with an increased risk of subsequent ischemic stroke or intracranial hemorrhage.