Dumitrascu, Oana M.

Introduction: Although primarily supplied by the vertebrobasilar system, the hippocampus is partially supplied by ipsilateral carotid artery branches through the anterior choroidal artery or a prominent posterior communicating artery. We report a patient with acute hippocampus infarction likely due to symptomatic ipsilateral tandem carotid stenosis and discuss acute vascular-mediated hippocampal injury. Case Report: An 80-year-old female with obesity, dyslipidemia, hypertension, alcohol use disorder, history of breast cancer on letrozole, and traumatic brain injury was brought into our emergency department for 24 hours of confusion. On examination, she exhibited limited registration, recall, and executive dysfunction with otherwise normal language, visuo-spatial orientation, and praxis. Brain MRI showed a small area of diffusion restriction in the anterior right hippocampus with matched FLAIR hyperintensity, consistent with acute infarction. Computed tomography angiogram head and neck showed 90% stenosis of the proximal right internal carotid artery (ICA), <50% narrowing of the proximal left ICA, and moderate bilateral narrowing of the paraclinoid ICAs, all due to calcific atheromatous plaques. The etiology of the hippocampal infarction was suspected embolism from the ipsilateral severe carotid stenosis. Planning for right cervical carotid revascularization ensued. Conclusion: This case highlights the dual hippocampal vascular supply and that hippocampal embolic infarcts could be a sign of a symptomatic severe carotid artery stenosis that may require urgent revascularization for stroke secondary prevention.

Background: Multiple randomized clinical trials failed to show benefit of anticoagulation over antiplatelets in the secondary prevention for embolic stroke of undetermined source (ESUS). However, the benefit of combination antithrombotic regimens remains unexplored in the same patient population. Methods: This is a subgroup analysis of a multicenter retrospective observational cohort of consecutive adult patients with ESUS (n=27 sites, 2015-2024). Comparisons were made between patients treated with single (SAPT) or dual antiplatelet therapy (DAPT), exclusive anticoagulation (AC) (direct oral anticoagulant, vitamin K antagonist, low molecular weight heparin) and combination anticoagulation and antiplatelet therapy initiated within the first 7 days of index stroke. The primary composite outcome of recurrent ischemic stroke, major bleeding, or death was assessed using unadjusted and adjusted Cox proportional hazards regression. Secondary outcomes were individual outcomes of recurrent ischemic stroke, major bleeding, or death. Results: Of the 2201 included patients, 1456 (66.1%) were on SAPT, 527 (23.9%) were on DAPT, 195 (8.8%) were on exclusive AC and 23 (1.0%) were on AC+AP (all of which were on DAPT). Patients treated with AC+AP were older (median 66 years [IQR 51-78]), more likely to have history of hypertension, stroke, hyperlipidemia, PFO and left atrial enlargement. Compared to SAPT, all treatment strategies were associated with similar risk of the primary outcomes in the unadjusted and adjusted cox regression. Similarly, there was no difference in individual outcomes including recurrent stroke, major bleeding and death in the adjusted cox regression. However, there was an increased risk of major bleeding with AC+AP in the unadjusted cox regression (HR 4.0, [95% CI 1.2-12.8], p=0.02) but not in the adjusted model when compared to SAPT. Also, DAPT was associated with lower risk of death than SAPT in the unadjusted model (HR 0.61 [95% CI 0.4-0.8],p=0.005) but not the adjusted model. Additionally, when adjusted by the HASBLED score, there was no difference in major bleeding when AC+AP was compared to SAPT. Conclusion: Over 90% of ESUS patients in this cohort were prescribed SAPT or DAPT. Antithrombotic therapy with DAPT, exclusive AC, or AC+AP was not associated with any lower risk of recurrent ischemic stroke, major bleeding and death compared with SAPT in an unselected cohort of ESUS patients.

Background: Retinal vasculopathy had been reported across the continuum of neurodegeneration. Retinal color fundus photography coupled with automated retinal vascular analysis offers potential to non-invazively screen for Alzheimer’s disease (AD) neurodegeneration. Amyloid positron emission tomography (PET) and apolipoprotein 4 (APOE4) carrier status are known biomarkers of AD risk. Herein, we examined the relationship between retinal vascular fractal dimensions in non-mydriatic color fundus photographs, amyloid-PET burden and APOE4 carrier status in a cohort of cognitively intact individuals. Methods: Our dataset included 91 macula-centered and 39 optic disc-centered images from 96 cognitively intact participants (29% male). 25 (26%) were amyloid-PET positive, defined as amyloid-PET standardized uptake value ratio centiloid cut-off > 20. AutoMorph software automatically determined retinal arteriolar and venular density, tortuosity and width, among other fractal dimensions. To test the effect of amyloid-PET status on the retinal vascular parameters, we used a generalized linear model compensated for age, sex and the interaction between APOE4 carrier and amyloid-PET status. We also compared amyloid-PET positive and negative subjects for vascular fractal dimensions correcting for age and gender. We adjusted for multiple comparisons using the False Discovery Rate correction and reported significant P values less than 0.05. Results: Compared to amyloid-PET negative, cognitively intact amyloid-PET positive cohort had greater mean age (71 vs 66 years, P=0.06), more males (60% vs 35%, P=0.02), more APOE4 carriers (P<0.001), similar vascular risk factors (hypertension, dyslipidemia, diabetes mellitus, smoking, P>0.05 for all) and significantly lower macular vessel tortuosity density (P=0.019). The amyloid-PET positive status had a significant effect on the retinal artery distance tortuosity (corrected P=8.75E-04, β=13.9, 95% CI [7.75-19.99]) and artery squared curvature tortuosity (corrected P=8.91E-10, β=464, 95% CI [359.10-569.15]). Conclusions: Automatically determined retinal vascular fractal dimension on non-mydriatic color fundus photographs predicts amyloid-PET burden in cognitively intact individuals. Future longitudinal studies should asssess the utility of automated quantitative retinal vasculopathy analysis to screen for presymptomatic AD.

Introduction: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebral small vessel disease, yet there is currently no biomarker for early detection. This study aims to identify retinal biomarkers of NOTCH3 carriers using optical coherence tomography (OCT) from the UK Biobank. Methods: We conducted a cross-sectional, matched case-control study of individuals with or without CADASIL from the UK Biobank between 2006 and 2010. All participants had retinal OCT scan and cognitive assessment. Cases were identified based on pathogenic NOTCH3 mutations and 1:1 matched with healthy controls based on age, sex, hypertension, diabetes mellitus, and smoking status. Baseline characteristics and cognitive test scores were compared using chi-square or Mann-Whitney-U test appropriately. Macular thickness (central, inner, and outer subfields) (Figure) and retinal nerve fiber layer (RNFL) thickness were compared using Wilcoxon signed-rank test. Results: Our analysis included 134 participants (67 CADASIL cases, 67 controls) with a mean age of 54±8 years. There were no differences in visual acuity between the two groups. CADASIL performed worse in prospective memory (0.043), verbal and numerical reasoning (p=0.178), visual memory (p=0.227), and processing speed (p=0.101) than matched controls. Participants with CADASIL had significantly thinner macular inner subfield at the superior (p=0.006), temporal (p=0.008), and nasal (p=0.034) quadrants, and significantly thinner RNFL (p=0.008) compared to controls (Table). Conclusion: Individuals with CADASIL have reduced thickness in the inner macular subfield and RFNL relative to matched controls. These retinal group differences were not associated with differences in visual acuity and may reflect early pericyte dysfunction and microvascular ischemia. Longitudinal studies are needed to assess the temporal relationship between these retinal changes and disease progression.

Introduction: Previous studies have established the safety and economic benefits of outpatient Transient Ischemic Attack (TIA) management, highlighting reduced expenses for outpatient evaluation. This context underscores the potential advantages of refined outpatient TIA management, a focus of our study, through the implementation of a novel expedited outpatient TIA workflow and assessment of its economic, administrative and clinical impact. Methods: We implemented a novel TIA pathway including streamlined assessments by emergency department (ED) physicians, a structured expedited set of diagnostic tests and outpatient follow-up with vascular neurologists within 48-72 hours of ED presentation. We conducted a retrospective cost-efficacy analysis, contrasting two phases: pre-implementation (standard ED-to-hospital admission TIA workflow from May 1, 2020 - December 31, 2020) and post-implementation (ED-to- outpatient TIA workflow from May 1, 2021 - December 31, 2021). We also compared the clinical outcomes of patients with a final diagnosis of TIA or minor ischemic stroke syndrome from the implementation cohort (May 2021-May 2022) with those from an ABCD2-matched inpatient TIA cohort evaluated in the pre-implementation period (2017-2021). Results: The newly implemented outpatient TIA workflow resulted in a 7% decrease in admissions to hospital observation status, 14.8% reduction in hospital admissions, whereas ED discharge rates rose by 20.4%. Within 8 months, these changes equated to 21 fewer hospitalizations or admissions, reducing costs by approximately $103,320 (Figure1). Laboratories, diagnostic imaging, and neurology evaluations were completed faster in the inpatient pathway. Both pathways had similar vascular risk factors and outcomes regarding final diagnosis, - diagnostic testing achieved, preventative treatments prescribed, stroke/TIA recurrences, re-admissions, TIA-related morbidity and mortality, and related ED return visits (Table 1). Conclusion: The deployment of an optimized outpatient TIA management workflow at Mayo Clinic Arizona had demonstrated improved administrative and cost efficiency, with similar clinical outcomes as inpatient TIA pathway. This investigation corroborates the efficacy of workflow enhancements in outpatient TIA settings and suggests a scalable model for analogous strategies in other medical centers.

Introduction: Four randomized clinical trials have not demonstrated the superiority of anticoagulation over antiplatelet therapy in the prevention of recurrent embolic stroke of undetermined source (ESUS). In this multicenter observational cohort study, we evaluated long-term outcomes associated with various antithrombotic strategies according to potential embolic sources. Methods: A multicenter retrospective observational cohort of consecutive adult patients with ESUS was queried (n=27 sites). Comparisons were made between patients treated with single or combination antiplatelet therapy versus anticoagulation (direct oral anticoagulant, vitamin K antagonist, low molecular weight heparin) with or without antiplatelet therapy initiated within 7 days of stroke. The primary composite outcome of recurrent stroke, major bleeding, or death was assessed using unadjusted and adjusted Cox proportional hazards regression, with clustering by site. Causal inference was assessed using inverse probability of treatment weighted regression adjustment (IPTWRA), accounting for propensity for antiplatelet treatment, with effect estimates summarized as the average treatment effect (ATE) over time (in days). Adjusted models accounted for age, stroke severity, vascular risk factors, and major categories of potential embolic sources. Results: Of the 2201 included patients (n=218 treated with anticoagulation) followed over a median of 564 days (interquartile range [IQR] 154-1124), the median age was 65y (IQR 54-74) and 49.8% were female. Patients treated with anticoagulation were older with more frequent previous stroke, concomitant left ventricular dysfunction, and more severe deficits. Over 4541 person-years of follow-up, the annualized incidence rate of the primary outcome was 14.6% (95% confidence interval [CI], 13.6%-15.8%). Compared to anticoagulation, antiplatelet(s) use was not associated with a lower risk of the primary outcome in the adjusted Cox model (HR 0.91, 95% CI, 0.64-1.29) or in the IPTWRA model (average treatment effect 0.14, 95% CI, -1376.6 to 1376.9). Major bleeding events trended toward significance in the adjusted Cox model (HR 0.51, 95% CI 0.25-1.04) but were no different with IPTWRA (ATE 58.9, 95% CI, -125.4 to 243.2). Conclusions: These results validate the observations of randomized trials indicating a lack of benefit of anticoagulation over antiplatelet therapy in ESUS. A more detailed analysis of heterogeneity of treatment effect is under way.