Imaging of Amyloid-beta-related Arteritis

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder marked by the accumulation of amyloid-beta peptide (Aβ) within the leptomeninges and smaller blood vessels of the brain. CAA can be both noninflammatory and inflammatory, and the inflammatory version includes Aβ-related angiitis (ABRA). ABRA is a vasculitis of the central nervous system related to an inflammatory response to Aβ in the vascular walls, which necessitates differentiating ABRA from noninflammatory CAA, as ABRA may require immunosuppressive treatment. MR imaging is typically the most effective imaging modality of choice to screen for these conditions, and they should be obtained at varying time points to track disease progression.

National- and State-Level Trends in Medicare Hospice Beneficiaries for Stroke During 2013 to 2019 in the United States

BACKGROUND

Stroke is the fifth leading cause of death in the United States, one of the leading contributors to Medicare cost, including through Medicare hospice benefits, and the rate of stroke mortality has been increasing since 2013. We hypothesized that hospice utilization among Medicare beneficiaries with stroke has increased over time and that the increase is associated with trends in stroke death rate.

METHODS

Using Medicare Part A claims data and Centers for Disease Control mortality data at a national and state level from 2013 to 2019, we report the proportion and count of Medicare hospice beneficiaries with stroke as well as the stroke death rate (per 100 000) in Medicare-eligible individuals aged ≥65 years.

RESULTS

From 2013 to 2019, the number of Medicare hospice beneficiaries with stroke as their primary diagnosis increased 104.1% from 78 812 to 160 884. The number of stroke deaths in the United States in individuals aged ≥65 years also increased from 109 602 in 2013 to 129 193 in 2019 (17.9% increase). In 2013, stroke was the sixth most common primary diagnosis for Medicare hospice, while in 2019 it was the third most common, surpassed only by cancer and dementia. The correlation between the change from 2013 to 2019 in state-level Medicare hospice for stroke and stroke death rate for Medicare-eligible adults was significant (Spearman ρ=0.5; P<0.001). In a mixed-effects model, the variance in the state-level proportion of Medicare hospice for stroke explained by the state-level stroke death rate was 48.2%.

CONCLUSIONS

From 2013 to 2019, the number of Medicare hospice beneficiaries with a primary diagnosis of stroke more than doubled and stroke jumped from the sixth most common indication for hospice to the third most common. While increases in stroke mortality in the Medicare-eligible population accounts for some of the increase of Medicare hospice beneficiaries, over half the variance remains unexplained and requires additional research.

Improvement in the Prediction of Cerebrovascular Events With White Matter Hyperintensity

Background It remains unclear if white matter hyperintensity (WMH) on magnetic resonance imaging adds relevant cerebrovascular prognostic information beyond vascular risk factors and demographics alone. Methods and Results We performed a post hoc analysis of hypertensive individuals in SPRINT-MIND (Systolic Blood Pressure Intervention Trial-Memory and Cognition in Decreased Hypertension). The primary outcome was incident stroke or cognitive impairment (mild cognitive impairment or dementia). We fit logistic regression models with the predictors of Atherosclerotic Cardiovascular Disease Risk Score, age, sex, race, education, current cigarette smoking, and the SPRINT-MIND randomization arm. WMH was subsequently included in the model to determine if it improved area under the receiver operating curve using the DeLong test. We used a structural equation model to determine the indirect effect on the primary outcome mediated through WMH. We included 727 individuals (mean age at baseline 67.7±8.4 years, 61.1% were men, 62.6% were non-Hispanic White, and mean years of follow-up was 3.6±0.9). Of the 727 individuals, 67 (9.2%) developed incident stroke or cognitive decline. The area under the receiver operating curve of the baseline model (without WMH) was 0.75 (95% CI, 0.70-0.81), and after the addition of WMH it increased to 0.81 (95% CI, 0.76-0.86) (P=0.004 for difference). The mediation analysis showed that 26.3% of the vascular risk's effect on the primary outcome is indirectly mediated through WMH. Conclusions In adult hypertensive individuals, we found that the addition of WMH to models predicting incident stroke or cognitive impairment improved the prognostic ability above vascular risk and demographics alone to a level consistent with excellent prediction. Registration Information REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

Large Vessel Occlusion Stroke due to Intracranial Atherosclerotic Disease: Identification, Medical and Interventional Treatment, and Outcomes

Large vessel occlusion stroke due to underlying intracranial atherosclerotic disease (ICAD-LVO) is prevalent in 10 to 30% of LVOs depending on patient factors such as vascular risk factors, race and ethnicity, and age. Patients with ICAD-LVO derive similar functional outcome benefit from endovascular thrombectomy as other mechanisms of LVO, but up to half of ICAD-LVO patients reocclude after revascularization. Therefore, early identification and treatment planning for ICAD-LVO are important given the unique considerations before, during, and after endovascular thrombectomy. In this review of ICAD-LVO, we propose a multistep approach to ICAD-LVO identification, pretreatment and endovascular thrombectomy considerations, adjunctive medications, and medical management. There have been no large-scale randomized controlled trials dedicated to studying ICAD-LVO, therefore this review focuses on observational studies.

Secondary Ischemic Stroke Prevention

The health burden of ischemic stroke is high and will continue to increase with an aging population. Recurrent ischemic stroke is increasingly recognized as a major public health concern with potentially debilitating sequelae. Thus, it is imperative to develop and implement effective strategies for stroke prevention. When considering secondary ischemic stroke prevention, it is important to consider the mechanism of the first stroke and the related vascular risk factors. Secondary ischemic stroke prevention typically includes multiple medical and, potentially, surgical treatments, but with the shared goal of reducing the risk of recurrent ischemic stroke. Providers, health care systems, and insurers also need to consider the availability of treatments, their cost and patient burden, methods for improving adherence, and interventions that target lifestyle risk factors such as diet or activity. In this article, we discuss aspects from the 2021 AHA Guideline on Secondary Stroke Prevention as well as highlight additional information relevant to best practices for reducing recurrent stroke risk.

Effect of Alteplase on Ischemic Stroke Mortality Is Dependent on Stroke Severity

OBJECTIVE

Although intravenous alteplase (IV-tPA) has a beneficial effect on functional outcome after ischemic stroke (IS), prior studies of IV-tPA's impact on post-stroke mortality did not have sufficient representation of more severe stroke.

METHODS

We determined if the interaction between the baseline National Institutes of Health (NIH) Stroke Scale (NIHSS) and IV-tPA modified the risk of mortality after IS in two cohorts: (1) National Inpatient Sample 2016-2020, and (2) a harmonized cohort of IS patients from the NINDS IV-tPA, ALIAS part 2, SHINE, FAST-MAG, IMS-III, POINT, and DEFUSE 3 trials. We fit logistic regression models to the outcome of in-hospital mortality (National Inpatient Sample [NIS] cohort) or mortality within 90 days (harmonized cohort), adjusted for baseline variables.

RESULTS

We included 198,668 patients in the NIS cohort, of which 14.0% received IV-tPA and 3.4% died in hospital. We included 7,138 patients in the harmonized cohort, of which 33.2% received IV-tPA and 9.4% died by 90 days. Mortality in the NIS cohort was associated with older age, female sex, non-Hispanic white race, atrial fibrillation, and higher NIHSS. In the harmonized cohort, mortality was associated with older age, diabetes, atrial fibrillation, and higher NIHSS. In both cohorts, the interaction between NIHSS and IV-tPA was significant. In the NIS cohort, the separation became significant at NIHSS 15 and in the harmonized cohort at NIHSS 23, at which point, IV-tPA began to have a significant benefit for both in-hospital and 90-day mortality, respectively.

INTERPRETATION

IV-tPA is associated with a reduction in both in-hospital and 90-day mortality for patients with more severe IS. ANN NEUROL 2023.

Abstract 127: White Matter Hyperintensity And Atherosclerotic Cardiovascular Disease Risk

Introduction: White matter hyperintensity (WMH) is a neuroimaging manifestation of cerebrovascular disease that is associated with vascular risk factors and the development of cognitive impairment and stroke. Estimating atherosclerotic cardiovascular disease (ASCVD) risk is a method of measuring the extent of vascular risk for a given individual and, thus, there exists a potential link between ASCVD risk and WMH volume.

Methods: We included participants in the SPRINT MIND study who underwent a research MRI with volumetric quantification of the burden of WMH in mL. We report the WMH burden by categories of 10-year ASCVD risk using the Pooled Cohort Equations CV Risk (2014 edition). The ASCVD categories include low (0-5%), borderline (5-7.49%), intermediate (7.5-19.9%), and high (>20%). We used a violin plot to show the results graphically and also report the medians and IQR. As a secondary outcome we report WMH progression, which is the difference in WMH burden between the baseline MRI and a follow-up MRI performed 48 months later.

Results: We included 727 individuals, of which 22 (3.0%) were low, 46 (6.3%) were borderline, 370 (50.9%) were intermediate, and 289 (39.8%) were high ASCVD risk. The median (IQR) WMH burden was 1.6 mL (0.9-2.9) in the low, 1.7 mL (1.1-3.0) in the borderline, 2.7 mL (1.4-5.1) in the intermediate, and 4.7 mL (2.5-10.7) in the high ASCVD risk group (p<0.001) (Figure 1). The progression of WMH was 0.2 mL (-0.1-0.7) in the low, 0.4 mL (-.2-1.5) in the borderline, 0.6 mL (0.01-1.7) in the intermediate, and 1.1 mL (0.2-3.0) in the high ASCVD risk group (p=0.001).

Conclusions: There is a positive association between ASCVD risk and WMH volume and progression. ASCVD risk, which can be assessed through demographic and clinical variables, may be a useful predictor of the volume of WMH, which is traditionally obtained through an MRI scan.

Abstract WP193: Neighborhood-level Ethnic And Racial Segregation And Incident Stroke Risk

Background: Neighborhood-level ethnic and racial segregation has been linked to health status. We explored whether community level segregation is associated with incident stroke.

Methods: We used data from Multi-Ethnic Study of Atherosclerosis (MESA). The exposure was neighborhood racial/ethnic segregation measured separately for self-identified White, Black and Hispanic participants and calculated as the Getis-Ord Gi* statistic based on the geocoded address of the participant. The Gi* statistic was categorized using the validated cut points of low, medium, and high neighborhood racial/ethnic segregation (high segregation means that the participant’s neighborhood primarily contained individuals of their race/ethnicity). The primary outcome was incident stroke (ischemic and hemorrhagic) during follow-up. We fit time-to-event Cox models with an interaction between race*segregation and adjustment for age, sex, hypertension, diabetes, hyperlipidemia, and current smoking. The results were further evaluated using marginal effects after logistic regression.

Results: We included 5,411 MESA participants (mean age 62.0±10.1, 47.4% male, 44.4% White, 31.0% Black, 24.6% Hispanic), of which 111 (2.1%) had incident stroke during 8.0±1.3 years of follow-up. In the low, medium, and high neighborhood segregation categories there were 1,603 (29.6%), 1,667 (30.8%), and 2,141 (39.6%) individuals. High neighborhood segregation was more common in Black (45.7%) and Hispanic (39.7%) individuals than White (14.6%) (p<0.001). In Cox regression, the interaction between race and segregation was significant (p<0.1). Compared to low segregation, high segregation among White individuals was associated with 3.1% LOWER probability of incident stroke (p<0.001, from 3.4% to 0.3%), among Black individuals with 1.2% HIGHER probability of incident stroke (p=0.046, from 0.7% to 1.9%), and in Hispanic individuals there was an insignificant difference (p=0.842).

Conclusions: For White individuals, a high level of segregation is associated with a lower probability of stroke, but for Black individuals with a higher probability of stroke. These findings call for further research into the mechanisms by which neighborhood segregation may mediate stroke risk.

Abstract 58: ASCVD Risk Score Trajectories During 25 Years Of Follow-up And Risk Of Ischemic Stroke And Cognitive Impairment

Background: An individual’s atherosclerotic burden is associated with the cumulative exposure to vascular risk factors across the lifespan. We used the ARIC study to identify trajectories of atherosclerotic cardiovascular disease (ASCVD) risk over time and to evaluate their association with risk of stroke and cognitive impairment.

Methods: We included cardiovascular disease-free ARIC participants with low or borderline ASCVD risk at the baseline study visit (10-year ASCVD Risk Score <7.5%) and those who attended all 5 ARIC study visits (~25 years of follow-up). We used group-based trajectory modelling to define ASCVD trajectories. We report baseline characteristics of individuals in the four trajectories and the incidence of stroke (ischemic and hemorrhagic) and cognitive impairment (either MCI or dementia) during follow-up.

Results: We included 3,470 ARIC participants. The four trajectories of ASCVD risk during follow-up are in Figure 1. The low and high increase trajectories comprised 46.5% and 7.0% of participants. Vascular risk factors such as hypertension, diabetes, hyperlipidemia, and obesity were more common in trajectories with higher ASCVD risk (Table 1). The rate of ARIC-adjudicated stroke during follow-up increased from 1.6% in the low trajectory to 4.6% in the high trajectory (p<0.001), of self-reported stroke from 8.6% to 16.6% (p<0.001), and of ARIC-adjudicated cognitive impairment from 16.0% to 35.0% (p<0.001).

Conclusions: We found four main trajectories of ASCVD risk over 25 years of follow-up in individuals with baseline low or borderline ASCVD risk, which are associated with the risk of incident stroke and cognitive impairment.

assessment.

Abstract WMP62: Stroke Severity Is The Primary Mediator Of Increased Stroke Mortality In The Elderly

Background: The risk of ischemic stroke mortality increases with age, but the impact of stroke severity on this relationship has not been fully examined.

Methods: We included adults in the National Inpatient Sample from 2016-2019 who had a primary discharge diagnosis of ischemic stroke (I63*) and a baseline NIH Stroke Scale (NIHSS). The primary outcome was in-hospital death. The exposure of age had left skew, so we transformed it into deciles. We fit a logistic regression model adjusted for sex, race/ethnicity, diabetes, atrial fibrillation, hypertension, thrombolytic therapy, and endovascular therapy. We report the predicted probability of the primary outcome with and without NIHSS and use structural equation modeling (SEM) to estimate the proportion of age’s effect on the primary outcome that is mediated by stroke severity.

Results: We included 138,637 individuals, of which 3.5% died in-hospital. The proportion of in-hospital death and an NIHSS violinplot by decile of age are seen in Figure 1, both of which had a positive linear relationship. The AUC of the multivariable model without NIHSS was 0.70 and with NIHSS was 0.86 (p<0.001). The predicted probability of death is seen without and with NIHSS in Figure 2, illustrating the importance of adjusting for NIHSS. In the SEM model, we observed that 57.7% of age’s effect on in-hospital death is mediated by stroke severity.

Conclusions: We found that elderly individuals in the United States have more severe stroke and higher stroke mortality, but the effect of age on stroke mortality is primarily mediated by elderly individuals having more severe stroke. Additional research is needed to better understand this novel finding.