Covert neurological symptoms associated with silent infarcts from midlife to older age: the Atherosclerosis Risk in Communities study

Association of Iatrogenic Infarcts With Clinical and Cognitive Outcomes in the Evaluating Neuroprotection in Aneurysm Coiling Therapy Trial

BACKGROUND AND OBJECTIVES

Small iatrogenic brain infarcts are often seen on diffusion-weighted MRI (DWI) following surgical or endovascular procedures, but there are few data on their clinical effects. We examined the association of iatrogenic infarcts with outcomes in the ENACT (Evaluating Neuroprotection in Aneurysm Coiling Therapy) randomized controlled trial of nerinetide in patients undergoing endovascular repair of intracranial aneurysms.

METHODS

In this post hoc analysis, we used multivariable models to evaluate the association of the presence and number of iatrogenic infarcts on DWI with neurologic impairment (NIH Stroke Scale [NIHSS]), functional status (modified Rankin Scale [mRS]), and cognitive and neuropsychiatric outcomes (30-minute test battery) at 1-4 days and 30 days postprocedure. We also related infarct number to a z score-derived composite outcome score using quantile regression.

RESULTS

Among 184 patients (median age 56 years [interquartile range (IQR) 50-64]), 124 (67.4%) had postprocedural DWI lesions (median 4, IQR 2-10.5). Nerinetide treatment was associated with fewer iatrogenic infarcts but no overall significant clinical treatment effects. Patients with infarcts had lower Mini-Mental State Examination (MMSE) scores at 2-4 days (median 28 vs 29, adjusted coefficient [acoef] -1.11, 95% CI -1.88 to -0.34, p = 0.005). Higher lesion counts were associated with worse day 1 NIHSS (adjusted odds ratio for NIHSS ≥1: 1.07, 1.02-1.12, p = 0.009), day 2-4 mRS (adjusted common odds ratio [acOR] 1.05, 1.01-1.09, p = 0.005), and day 2-4 MMSE (acoef -0.07, -0.13 to -0.003, p = 0.040) scores. At 30 days, infarct number remained associated with worse mRS (acOR 1.04, 1.01-1.07, p = 0.016) and Hopkins Verbal Learning Test (HVLT) delayed recall scores (acoef -0.21, -0.39 to -0.03, p = 0.020). Patients with infarcts trended towards lower 30-day Digit Symbol Substitution Test (DSST) scores (acoef -3.73, -7.36 to -0.10, p = 0.044). Higher lesion count was associated with worse composite outcome scores at both 1-4 days and 30 days (30-day acoef -0.12, 95% CI -0.21 to -0.03, p = 0.008). Among those with infarcts, day 1 NIHSS and day 2-4 mRS correlated with 30-day NIHSS, DSST, HVLT, and mRS scores, whereas day 2-4 MMSE correlated with 30-day NIHSS and DSST scores (Spearman ρ 0.47, p = 0.001).

DISCUSSION

Iatrogenic brain infarcts were associated with subtle differences in postprocedural (1-4 days) and 30-day outcomes on different measures in this middle-aged cohort, with earlier dysfunction correlating with later differences.

TRIAL REGISTRATION INFORMATION

Clinical trials registration NCT00728182.

Atrial Fibrillation and Stroke Symptoms in the REGARDS Study

Background

It is unknown if stroke symptoms in the absence of a stroke diagnosis are a sign of subtle cardioembolic phenomena. The objective of this study was to examine associations between atrial fibrillation (AF) and stroke symptoms among adults with no clinical history of stroke or transient ischemic attack (TIA).

Methods and Results

We evaluated associations between AF and self‐reported stroke symptoms in the national, prospective REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort. We conducted cross‐sectional (n=27 135) and longitudinal (n=21 932) analyses over 8 years of follow‐up of REGARDS participants without stroke/transient ischemic attack and stratified by anticoagulant or antiplatelet agent use. The mean age was 64.4 (SD±9.4) years, 55.3% were women, and 40.8% were Black participants; 28.6% of participants with AF reported stroke symptoms. In the cross‐sectional analysis, comparing participants with and without AF, the risk of stroke symptoms was elevated for adults with AF taking neither anticoagulants nor antiplatelet agents (odds ratio [OR], 2.22; 95% CI, 1.89–2.59) or antiplatelet agents only (OR, 1.92; 95% CI, 1.61–2.29) but not for adults with AF taking anticoagulants (OR, 1.08; 95% CI, 0.71–1.65). In the longitudinal analysis, the risk of stroke symptoms was also elevated for adults with AF taking neither anticoagulants nor antiplatelet agents (hazard ratio [HR], 1.41; 95% CI, 1.21–1.66) or antiplatelet agents only (HR, 1.23; 95% CI, 1.04–1.46) but not for adults with AF taking anticoagulants (HR, 0.86; 95% CI, 0.62–1.18).

Conclusions

Stroke symptoms in the absence of a stroke diagnosis may represent subclinical cardioembolic phenomena or “whispering strokes.” Future studies examining the benefit of stroke symptom screening may be warranted.

Comparing Vascular Brain Injury and Stroke by Cranial Magnetic Resonance Imaging, Physician-Adjudication, and Self-Report: Data from the Strong Heart Study

BACKGROUND

Epidemiologic studies often use self-report as proxy for clinical history. However, whether self-report correctly identifies prevalence in minority populations with health disparities and poor health-care access is unknown. Furthermore, overlap of clinical vascular events with covert vascular brain injury (VBI), detected by imaging, is largely unexamined.

METHODS

The Strong Heart Study recruited American Indians from 3 regions, with surveillance and adjudication of stroke events from 1989 to 2013. In 2010-2013, all 817 survivors, aged 65-95 years, underwent brain imaging, neurological history interview, and cognitive testing. VBI was defined as imaged infarct or hemorrhage.

RESULTS

Adjudicated stroke was prevalent in 4% of participants and separately collected, self-reported stroke in 8%. Imaging-defined VBI was detected in 51% and not associated with any stroke event in 47%. Compared with adjudication, self-report had 76% sensitivity and 95% specificity. Participants with adjudicated or self-reported stroke had the poorest performance on cognitive testing; those with imaging-only (covert) VBI had intermediate performance.

CONCLUSION

In this community-based cohort, self-report for prior stroke had good performance metrics. A majority of participants with VBI did not have overt, clinically recognized events but did have neurological or cognitive symptoms. Data collection methodology for studies in a resource-limited setting must balance practical limitations in costs, accuracy, feasibility, and research goals.

Iatrogenic Diffusion-Weighted Imaging Lesions: What Is Their Impact and How Can It Be Measured?

Infarct volume in acute ischemic stroke is closely linked with clinical outcome, with larger infarct volumes being associated with a worse prognosis. Small iatrogenic infarcts, which can occur as a result of surgical or endovascular procedures, are often only seen on diffusion-weighted MR imaging. They often do not lead to any overtly appreciable clinical deficits, hence the term covert or silent infarcts. There is relative paucity of data on the clinical impact of periprocedural hyperintense diffusion-weighted MR imaging lesions, partly because they commonly remain undiagnosed. Clearly, a better understanding of iatrogenic periprocedural diffusion-weighted MR imaging lesions and their clinical significance is needed. In this article, we describe the current limitations of our understanding of the significance of iatrogenic diffusion-weighted MR imaging lesions using exemplary data from the ENACT trial (Safety and Efficacy of NA-1 in Patients With Iatrogenic Stroke After Endovascular Aneurysm Repair) and outline a framework for how to investigate their clinical impact.

Aging-induced microbleeds of the mouse thalamus compared to sensorimotor and memory defects

The aim of this study is to investigate the relationship between aging and brain vasculature health. Three groups of mice, 3, 17-18, and 24 months, comparable to young adult, middle age, and old human were studied. Prussian blue histology and fast imaging with steady precession T2∗-weighted magnetic resonance imaging were used to quantify structural changes in the brain across age groups. The novel object recognition test was used to assess behavioral changes associated with anatomical changes. This study is the first to show that the thalamus is the most vulnerable brain region in the mouse model for aging-induced vascular damage. Magnetic resonance imaging data document the timeline of accumulation of thalamic damage. Histological data reveal that the majority of vascular damage accumulates in the ventroposterior nucleus and mediodorsal thalamic nucleus. Functional studies indicate that aging-induced vascular damage in the thalamus is associated with memory and sensorimotor deficits. This study points to the possibility that aging-associated vascular disease is a factor in irreversible brain damage as early as middle age.

Neuropsychiatric symptoms associated with cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease, a common cause of vascular dementia, is often considered clinically silent before dementia or stroke become apparent. However, some individuals have subtle symptoms associated with acute MRI lesions. We aimed to determine whether neuropsychiatric and cognitive symptoms vary according to small vessel disease burden.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and PsycINFO for articles published in any language from database inception to Jan 24, 2020. We searched for studies assessing anxiety, apathy, delirium, emotional lability, fatigue, personality change, psychosis, dementia-related behavioural symptoms or cognitive symptoms (including subjective memory complaints), and radiological features of cerebral small vessel disease. We extracted reported odds ratios (OR), standardised mean differences (SMD), and correlations, stratified outcomes by disease severity or symptom presence or absence, and pooled data using random-effects meta-analyses, reporting adjusted findings when possible. We assessed the bias on included studies using the Risk of Bias for Non-randomized Studies tool. This study is registered with PROSPERO, CRD42018096673.

FINDINGS

Of 7119 papers identified, 81 studies including 79 cohorts in total were eligible for inclusion (n=21 730 participants, mean age 69·2 years). Of these 81 studies, 45 (8120 participants) reported effect estimates. We found associations between worse white matter hyperintensity (WMH) severity and apathy (OR 1·41, 95% CI 1·05-1·89) and the adjusted SMD in apathy score between WMH severities was 0·38 (95% CI 0·15-0·61). Worse WMH severity was also associated with delirium (adjusted OR 2·9, 95% CI 1·12-7·55) and fatigue (unadjusted OR 1·63, 95% CI 1·20-2·22). WMHs were not consistently associated with subjective memory complaints (OR 1·34, 95% CI 0·61-2·94) and unadjusted SMD for WMH severity between these groups was 0·08 (95% CI -0·31 to 0·47). Anxiety, dementia-related behaviours, emotional lability, and psychosis were too varied or sparse for meta-analysis; these factors were reviewed narratively. Overall heterogeneity varied from 0% to 79%. Only five studies had a low risk of bias across all domains.

INTERPRETATION

Apathy, fatigue, and delirium associated independently with worse WMH, whereas subjective cognitive complaints did not. The association of anxiety, dementia-related behaviours, emotional lability, and psychosis with cerebral small vessel disease require further investigation. These symptoms should be assessed longitudinally to improve early clinical detection of small vessel disease and enable prevention trials to happen early in the disease course, long before cognition declines.

FUNDING

Chief Scientist Office of the Scottish Government, UK Dementia Research Institute, Fondation Leducq, Stroke Association Garfield-Weston Foundation, Alzheimer's Society, and National Health Service Research Scotland.

N-Terminal pro-B-type natriuretic peptide and stroke risk across a spectrum of cerebrovascular disease: The REasons for Geographic and Racial Differences in Stroke cohort

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP), a commonly used clinical marker of cardiac function, is associated with the presence of stroke symptoms and is a strong risk factor for future atrial fibrillation, stroke, and all-cause mortality. Few data are available on the association between NT-proBNP levels and stroke recurrence.

OBJECTIVE

We studied the relationship between NT-proBNP and risk of future ischemic stroke across the continuum of preexisting cerebrovascular conditions: asymptomatic, prior stroke symptoms, prior transient ischemic attack (TIA), and prior stroke.

METHODS

The Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort enrolled 30,239 black and white Americans aged 45 years and older from 2003 to 2007. With 5.4 years follow-up, baseline NT-proBNP was measured in 892 participants who developed ischemic stroke and a 4328-person cohort random sample. Hazard ratios of stroke by baseline NT-proBNP were calculated in groups based on the presence of prebaseline cerebrovascular conditions.

RESULTS

In the fully adjusted model, elevated NT-proBNP was associated with stroke risk in participants without a preexisting cerebrovascular condition (hazard ratio [HR], 2.32; 95% confidence interval [CI], 1.84-2.94) and in participants with a history of stroke symptoms (HR, 1.67; 95% CI, 1.01-2.78) or transient ischemic attack (HR, 2.66; 95% CI, 1.00-7.04) but not among those with prior stroke (HR, 1.26; 95% CI, 0.71-2.21).

CONCLUSIONS

These findings support the potential for NT-proBNP testing to identify people who are at highest risk for future stroke.

Incident cerebral lacunes: A review

Lacunes on magnetic resonance imaging (MRI) are considered as a key hallmark for evaluating the progression and severity of cerebral small vessel diseases. We aimed to review the MRI diagnostic criteria, frequency, predictors and clinical impact of incident lacunes in the largest longitudinal studies. Analyses were restricted to cohort studies of more than 50 individuals that investigated incident lacunes over a duration of at least one year. We observed that: (1) MRI parameters and definition of lacunes are inconsistent across studies, (2) the frequency of incident lacunes is strongly related to the previous clinical and MRI status at individual level, (3) both age and hypertension diagnosed at onset predict incident lacunes but the exact impact of blood pressure level during follow-up remains undetermined, (4) the clinical correlates of these lesions on cognition are repeatedly observed but the exact consequences on motor or gait performances are not always evaluated. Homogenization of imaging techniques, the use of strict diagnostic criteria and a broader clinical assessment considering motor and gait performances should be recommended in future longitudinal studies of incident lacunes including clinical trials testing preventative treatments in cerebral small vessel diseases.

Reduced Cognitive Assessment Scores Among Individuals With Magnetic Resonance Imaging–Detected Vascular Brain Injury

Background and Purpose—

Little is known about the association between covert vascular brain injury and cognitive impairment in middle-aged populations. We investigated if scores on a cognitive screen were lower in individuals with higher cardiovascular risk, and those with covert vascular brain injury.

Methods—

Seven thousand five hundred forty-seven adults, aged 35 to 69 years, free of cardiovascular disease underwent a cognitive assessment using the Digital Symbol Substitution test and Montreal Cognitive Assessment, and magnetic resonance imaging (MRI) to detect covert vascular brain injury (high white matter hyperintensities, lacunar, and nonlacunar brain infarctions). Cardiovascular risk factors were quantified using the INTERHEART (A Global Study of Risk Factors for Acute Myocardial Infarction) risk score. Multivariable mixed models tested for independent determinants of reduced cognitive scores. The population attributable risk of risk factors and MRI vascular brain injury on low cognitive scores was calculated.

Results—

The mean age of participants was 58 (SD, 9) years; 55% were women. Montreal Cognitive Assessment and Digital Symbol Substitution test scores decreased significantly with increasing age ( P <0.0001), INTERHEART risk score ( P <0.0001), and among individuals with high white matter hyperintensities, nonlacunar brain infarction, and individuals with 3+ silent brain infarctions. Adjusted for age, sex, education, ethnicity covariates, Digital Symbol Substitution test was significantly lowered by 1.0 (95% CI, −1.3 to −0.7) point per 5-point cardiovascular risk score increase, 1.9 (95% CI, −3.2 to −0.6) per high white matter hyperintensities, 3.5 (95% CI, −6.4 to −0.7) per nonlacunar stroke, and 6.8 (95% CI, −11.5 to −2.2) when 3+ silent brain infarctions were present. No postsecondary education accounted for 15% (95% CI, 12–17), moderate and high levels of cardiovascular risk factors accounted for 19% (95% CI, 8–30), and MRI vascular brain injury accounted for 10% (95% CI, −3 to 22) of low test scores.

Conclusions—

Among a middle-aged community-dwelling population, scores on a cognitive screen were lower in individuals with higher cardiovascular risk factors or MRI vascular brain injury. Much of the population attributable risk of low cognitive scores can be attributed to lower educational attainment, higher cardiovascular risk factors, and MRI vascular brain injury.

Frequency of Acute and Subacute Infarcts in a Population-Based Study

OBJECTIVE

To determine the frequency of incidental acute or subacute cerebral infarction (CI) in a population-based study.

PATIENTS AND METHODS

We identified 2095 participants aged 50 to 98 years in the population-based Mayo Clinic Study of Aging from October 23, 2009, to October 5, 2016, with a usable diffusion tensor imaging (DTI) sequence (total scans=3230). Acute and subacute infarcts were identified by neuroradiologists. For each participant, vascular risk factors, medications, clinical symptoms, and neurological examination near the time of the CI were abstracted from the medical record. The probable etiologic mechanism for the CI was determined.

RESULTS

Nine CIs were identified with a frequency of 0.28% among individual magnetic resonance imaging (MRI) scans and 0.43% among unique individuals. Infarctions were detected in 0.097% of scans from participants younger than 70 years and in 0.36% of scans of those 70 years or older. Six CIs were acute, and 3 were subacute. Most participants with infarcts were men (78%), with a mean age of 76.9±6.74 years. All were asymptomatic at the time of CI detection. The probable mechanisms of CI were small vessel (n=6), cardioembolic (n=2), and cryptogenic (n=1).

CONCLUSION

Acute and subacute cerebral infarcts occur as incidental findings in approximately 1 in 230 people aged 50 to 98 years, particularly in elderly men and those with vascular risk factors. As brain MRI becomes more widely used, incidentally detected acute or subacute infarcts will provide an opportunity to improve stroke prevention.

Left Ventricular Mass, Brain Magnetic Resonance Imaging, and Cognitive Performance: Results From the Strong Heart Study

Left ventricular mass (LVM) has been shown to serve as a measure of target organ damage resulting from chronic exposure to several risk factors. Data on the association of midlife LVM with later cognitive performance are sparse. We studied 721 adults (mean age 56 years at baseline) enrolled in the Strong Heart Study (SHS, 1993-1995) and the ancillary CDCAI (Cerebrovascular Disease and Its Consequences in American Indians) Study (2010-2013), a study population with high prevalence of cardiovascular disease. LVM was assessed with transthoracic echocardiography at baseline in 1993 to 1995. Cranial magnetic resonance imaging and cognitive testing were undertaken between 2010 and 2013. Generalized estimating equations were used to model associations between LVM and later imaging and cognition outcomes. The mean follow-up period was 17 years. A difference of 25 g in higher LVM was associated with marginally lower hippocampal volume (0.01%; 95% confidence interval, 0.02-0.00; P=0.001) and higher white matter grade (0.10; 95% confidence interval, 0.02-0.18; P=0.014). Functionally, participants with higher LVM tended to have slightly lower scores on the modified mini-mental state examination (0.58; 95% confidence interval, 1.08-0.08; P=0.024). The main results persisted after adjusting for blood pressure levels or vascular disease. The small overall effect sizes are partly explained by survival bias because of the high prevalence of cardiovascular disease in our population. Our findings emphasize the role of cardiovascular health in midlife as a target for the prevention of deleterious cognitive and functional outcomes in later life.

Neuropsychological state of the population living in the Aral Sea region (zone of ecological crisis)

Background The Aral Sea crisis has led to harmful effects on human habitat. In recent years, mild cognitive impairment is a growing problem. Objectives This article provides the results of studying the neuropsychological state of residents living in the crisis zone of the Aral Sea region in the case of Shalkar city. We have provided an assessment of the neuropsychological state of examined population and determined the leading pathology in this region. Methods The survey sample included 344 persons of reproductive age from 21 to 45 years. We have obtained results in biochemical studies, indicating perturbations of proteometabolism and lipid metabolism. Results A correlation analysis showed dependence between a decrease of albumin and high-density lipoproteins, an increase of low-density lipoproteins and parameters of cognitive function. Conclusions The research suggests a high prevalence of cerebrovascular pathology among the population, changes in cognitive function parameters, long-term and short-term memory problems and high levels of depression.

Findings of Vascular Brain Injury and Structural Loss from Cranial Magnetic Resonance Imaging in Elderly American Indians: The Strong Heart Study

BACKGROUND

The Cerebrovascular Disease and its Consequences in American Indians study conducted cranial MRI examination of surviving participants of the Strong Heart Study, a longitudinal cohort of elderly American Indians.

METHODS

Of the 1,033 recruited participants, some were unable to complete the MRI (n = 22), some scans were unusable due to participant motion or technical errors (n = 13), and one community withdrew consent after data collection (n = 209), leaving 789 interpretable MRI scan images. Six image sequences were obtained in contiguous slices on 1.5T scanners. Neuroradiologists graded white matter hyperintensities (WMH), sulci, and ventricles on a 0- to 9-point scale, and recorded the presence of infarcts and hemorrhages. Intracranial, brain, hippocampal, and WMH volumes were estimated by automated image processing.

RESULTS

The median scores for graded measures were 2 (WMH) and 3 (sulci, ventricles). About one-third of participants had lacunar (20%) or other infarcts (13%); few had hemorrhages (5.7%). Findings of cortical atrophy were also prevalent. Statistical analyses indicated significant associations between older age and findings of vascular injury and atrophy; male gender was associated with findings of cortical atrophy.

CONCLUSIONS

Vascular brain injury is the likely explanation in this elderly American Indian population for brain infarcts, hemorrhages, WMH grade, and WMH volume. Although vascular brain injury may play a role in other findings, independent degenerative other disease processes may underlie abnormal sulcal widening, ventricular enlargement, hippocampal volume, and total brain volume. Further examination of risk factors and outcomes with these findings may expand the understanding of neurological conditions in this understudied population.

Association of stroke risk biomarkers with stroke symptoms: the Reasons for Geographic and Racial Differences in Stroke cohort

Essentials Stroke symptom history predicts future stroke and may indicate prior unrecognized stroke. We studied associations of stroke symptoms with stroke risk biomarkers. Several stroke risk biomarkers were independently associated with stroke symptom history. Findings support a hypothesis that stroke symptoms may represent unrecognized stroke.

SUMMARY

Background History of stroke symptoms in the absence of prior diagnosed stroke or transient ischemic attack (TIA) is associated with future stroke risk, as are biomarkers of inflammation, cardiac function and hemostasis. Objective To better elucidate the pathobiology of stroke symptoms, we studied associations of these biomarkers with history of stroke symptoms. Methods The Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort enrolled 30 239 black and white Americans age 45 years and older in 2003-7. In cross-sectional analyses in a random sample of 960 participants without prior stroke or TIA, levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), fibrinogen, factor VIII (FVIII), factor XI (FXI), C-reactive protein (CRP) and D-dimer were studied in relation to self-reported history of six sudden onset stroke symptoms. Results There were 190 participants with at least one stroke symptom and 770 without. Adjusting for age, race, sex and stroke risk factors, NT-proBNP, FXI, CRP and D-dimer in the top vs. bottom quartile were associated with prevalent stroke symptoms with odds ratios 2.69 (95% confidence interval [CI], 1.45-4.98), 1.65 (95% CI, 1.00-2.73), 2.21 (95% CI, 1.32-3.71) and 2.14 (95% CI, 1.22-3.75), respectively. Conclusions Strong associations of stroke risk biomarkers with stroke symptoms in persons without a clinical history of cerebrovascular disease support a hypothesis that some of these stroke symptoms represent unrecognized cerebrovascular disease. Future work is needed to determine whether these biomarkers identify persons with stroke symptoms who have a particularly high stroke risk.

Cranial Magnetic Resonance Imaging in Elderly American Indians: Design, Methods, and Implementation of the Cerebrovascular Disease and Its Consequences in American Indians Study

The Cerebrovascular Disease and its Consequences in American Indians (CDCAI) Study recruited surviving members of a 20-year, longitudinal, population-based cohort of American Indians focused on cardiovascular disease, its risk factors, and its consequences. The goal of the CDCAI Study is to characterize the burden, risk factors, and manifestations of vascular brain injury identified on cranial MRI. The CDCAI Study investigators enrolled 1,033 participants aged 60 and older from 11 American Indian communities and tribes in the Northern Plains, Southern Plains, and Southwestern United States. In addition to cranial MRI performed according to standardized protocols, participants underwent extensive medical interview, clinical examination, neurocognitive testing, physical function evaluation, electrocardiogram, and provided blood and urine specimens. Participants also self-administered questionnaires covering demographics, quality of life, and medical history. This report describes the design, implementation, and some of the unique challenges of this study and data collection.

Fibroblast Growth Factor 23 Is Associated With Subclinical Cerebrovascular Damage: The Northern Manhattan Study

BACKGROUND AND PURPOSE

Elevated fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis and is linked with mortality, cardiovascular events, and stroke. However, the role of FGF23 as a risk factor for subclinical cerebrovascular damage is unclear.

METHODS

We used multivariable linear and logistic regression to evaluate associations between FGF23, continuously and by quartiles, with white matter hyperintensity volume, expressed as percent intracranial volume (%ICV), and subclinical brain infarction (SBI) in a community-based stroke-free sample.

RESULTS

There were 1170 stroke-free Northern Manhattan Study (NOMAS) participants with FGF23 levels and quantitative magnetic resonance imaging data on white matter hyperintensity volume and SBI. Participants with FGF23 levels in the top quartile (range=85-1425 RU/mL) had greater white matter hyperintensity volume (β=0.19 %ICV; 95% CI, 0.04-0.33 %ICV; P=0.01) compared with those in the lowest quartile (range=15-49 RU/mL), adjusted for demographics, vascular risk factors, and estimated glomerular filtration rate. These findings remained significant in those without evidence of chronic kidney disease (estimated glomerular filtration rate <60 mL/min per 1.73 m(2)). Elevated FGF23 was not associated with SBI overall after adjusting for demographic factors and estimated glomerular filtration rate, but sex modified the effect of FGF23 on odds of SBI (P for interaction=0.03). FGF23 was associated with significantly greater odds of SBI only in men (odds ratio, 1.7; 95% CI, 1.1-2.7; P=0.03) after full adjustment.

CONCLUSIONS

These cross-sectional community-based data from a diverse urban sample show an association between elevated FGF23 and small vessel disease and magnetic resonance imaging-defined brain infarction in men, independent of chronic kidney disease. Data on elevated FGF23 and subclinical cerebrovascular damage progression are needed.

Silent Brain Infarction and Risk of Future Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Silent brain infarction (SBI) on magnetic resonance imaging has been proposed as a subclinical risk marker for future symptomatic stroke. We performed a systematic review and meta-analysis to summarize the association between magnetic resonance imaging-defined SBI and future stroke risk.

METHODS

We searched the medical literature to identify cohort studies involving adults with SBI detected by magnetic resonance imaging who were subsequently followed up for incident clinically defined stroke. Study data and quality assessment were recorded in duplicate with disagreements in data extraction resolved by a third reader. Strength association between magnetic resonance imaging-detected SBI and future symptomatic stroke was measured by an hazard ratio.

RESULTS

The meta-analysis included 13 studies (14 764 subjects) with a mean follow-up ranging from 25.7 to 174 months. SBI predicted the occurrence of stroke with a random effects crude relative risk of 2.94 (95% confidence interval, 2.24-3.86, P<0.001; Q=39.65, P<0.001). In the 8 studies of 10 427 subjects providing hazard ratio adjusted for cardiovascular risk factors, SBI was an independent predictor of incident stroke (hazard ratio, 2.08 [95% confidence interval, 1.69-2.56; P<0.001]; Q=8.99; P=0.25). In a subgroup analysis pooling 9483 stroke-free individuals from large population-based studies, SBI was present in ≈18% of participants and remained a strong predictor of future stroke (hazard ratio, 2.06 [95% confidence interval, 1.64-2.59]; P<0.01).

CONCLUSIONS

SBI is present in ≈1 in 5 stroke-free older adults and is associated with a 2-fold increased risk of future stroke. Future studies of in-depth stroke risk evaluations and intensive prevention measures are warranted in patients with clinically unrecognized radiologically evident brain infarctions.

Stroke Symptoms as a Predictor of Future Hospitalization

BACKGROUND

Stroke symptoms in the general adult population are common and associated with stroke risk factors, lower physical and mental functioning, impaired cognitive status, and future stroke. Our objective was to determine the association of stroke symptoms with self-reported hospitalization or emergency department (ED) visit.

METHODS

Lifetime history of stroke symptoms (sudden weakness, numbness, unilateral or general loss of vision, loss of ability to communicate or understand) was assessed at baseline in a national, population-based, longitudinal cohort study of 30,239 blacks and whites younger than 45 years, enrolled from 2003 to 2007. Self-reported hospitalization or ED visit and reason were collected during follow-up through March 2013. The symptom-hospitalization association was assessed by proportional hazards analysis in persons who were stroke/transient ischemic attack-free at baseline (27,126) with adjustment for sociodemographics and further adjustment for risk factors.

RESULTS

One or more stroke symptoms were reported by 4758 (17.5%). After adjustment for sociodemographics, stroke symptoms were most strongly associated with greater risk of hospitalization/ED for cardiovascular disease (CVD) (hazard ratio [HR] = 1.87, 95% confidence interval [CI]: 1.78-1.96), stroke (HR = 1.69, 95% CI: 1.55-1.85), and any reason (HR = 1.39, 95% CI: 1.34-1.44). These associations remained significant and only modestly reduced after risk factor adjustment.

CONCLUSIONS

Stroke symptoms are a marker for future hospitalization and ED visit not only for stroke but also for CVD in general. Findings suggest a role for stroke symptom assessment as a novel and simple approach for identifying individuals at high risk for CVD including stroke in whom preventive strategies could be implemented.

[Discirculatory encephalopathy and small vessel disease]

The report examines the practicability of the term 'discirculatory encephalopathy' used in the Russian Federation to designate the chronic cerebral ischemia of different origin. The authors discuss the state of small vessel disease which manifests itself through slowly progressive cerebral changes. On the basis of their own research results and literature review the authors conclude that a standardized extract of Ginkgo biloba EGb761 (tanakan) can be effectively used in patients with small vessel disease.

Shoulder surgery in the beach chair position is associated with diminished cerebral autoregulation but no differences in postoperative cognition or brain injury biomarker levels compared with supine positioning: the anesthesia patient safety foundation beach chair study

BACKGROUND

Although controversial, failing to consider the gravitational effects of head elevation on cerebral perfusion is speculated to increase susceptibility to rare, but devastating, neurologic complications after shoulder surgery in the beach chair position (BCP). We hypothesized that patients in the BCP have diminished cerebral blood flow autoregulation than those who undergo surgery in the lateral decubitus position (LDP). A secondary aim was to examine whether there is a relationship between patient positioning during surgery and postoperative cognition or serum brain injury biomarker levels.

METHODS

Patients undergoing shoulder surgery in the BCP (n = 109) or LDP (n = 109) had mean arterial blood pressure (MAP) and regional cerebral oxygen saturation (rScO2) monitored with near-infrared spectroscopy. A continuous, moving Pearson correlation coefficient was calculated between MAP and rScO2, generating the variable cerebral oximetry index (COx). When MAP is in the autoregulated range, COx approaches zero because there is no correlation between cerebral blood flow and arterial blood pressure. In contrast, when MAP is below the limit of autoregulation, COx is higher because there is a direct relationship between lower arterial blood pressure and lower cerebral blood flow. Thus, diminished autoregulation would be manifest as higher COx. Psychometric testing was performed before surgery and then 7 to 10 days and 4 to 6 weeks after surgery. A composite cognitive outcome was determined as the Z-score. Serum S100β, neuron-specific enolase, and glial fibrillary acidic protein were measured at baseline, after surgery, and on postoperative day 1.

RESULTS

After adjusting for age and history of hypertension, COx (P = 0.035) was higher and rScO2 lower (P < 0.0001) in the BCP group than in the LDP group. After adjusting for baseline composite cognitive outcome, there was no difference in Z-score 7 to 10 days (P = 0.530) or 4 to 6 weeks (P = 0.202) after surgery between the BCP and the LDP groups. There was no difference in serum biomarker levels between the 2 position groups

CONCLUSIONS

: Compared with patients in the LDP, patients undergoing shoulder surgery in the BCP are more likely to have higher COx indicating diminished cerebral autoregulation and lower rScO2. There were no differences in the composite cognitive outcome between the BCP and the LDP groups after surgery after accounting for baseline Z-score.

Pharmacological treatment and prevention of cerebral small vessel disease: a review of potential interventions

Small vessel disease encompasses lacunar stroke, white matter hyperintensities, lacunes and microbleeds. It causes a quarter of all ischemic strokes, is the commonest cause of vascular dementia, and the cause is incompletely understood. Vascular prophylaxis, as appropriate for large artery disease and cardioembolism, includes antithrombotics, and blood pressure and lipid lowering; however, these strategies may not be effective for small vessel disease, or are already used routinely so precluding further detailed study. Further, intensive antiplatelet therapy is known to be hazardous in small vessel disease through enhanced bleeding. Whether acetylcholinesterase inhibitors, which delay the progression of Alzheimer's dementia, are relevant in small vessel disease remains unclear. Potential prophylactic and treatment strategies might be those that target brain microvascular endothelium and the blood brain barrier, microvascular function and neuroinflammation. Potential interventions include endothelin antagonists, neurotrophins, nitric oxide donors and phosphodiesterase 5 inhibitors, peroxisome proliferator‐activated receptor‐gamma agonists, and prostacyclin mimics and phosphodiesterase 3 inhibitors. Several drugs that have relevant properties are licensed for other disorders, offering the possibility of drug repurposing. Others are in development. Since influencing multiple targets may be most effective, using multiple agents and/or those that have multiple effects may be preferable. We focus on potential small vessel disease mechanistic targets, summarize drugs that have relevant actions, and review data available from randomized trials on their actions and on the available evidence for their use in lacunar stroke.

Cilostazol decreases cerebral arterial pulsatility in patients with mild white matter hyperintensities: subgroup analysis from the Effect of Cilostazol in Acute Lacunar Infarction Based on Pulsatility Index of Transcranial Doppler (ECLIPse) study

BACKGROUND

The Effect of Cilostazol in Acute Lacunar Infarction Based on Pulsatility Index of the Transcranial Doppler (ECLIPse) study showed a significant decrease in the transcranial Doppler (TCD) pulsatility index (PI) with cilostazol treatment at 90 days after acute lacunar infarction. The aim of the present study was to perform a subgroup analysis of the ECLIPse study in order to explore the effect of cilostazol in acute lacunar infarction based on cerebral white matter hyperintensities (WMH) volume.

METHODS

The ECLIPse study was a multicenter, randomized, double-blind, placebo-controlled trial that evaluated the difference between the efficacy of cilostazol and a placebo to reduce the PI in patients with acute lacunar infarction using serial TCD examinations. The primary outcome was changes in the PIs of the middle cerebral artery (MCA) and basilar artery at 14 and 90 days from the baseline TCD study. For this subgroup analysis, using semi-automated computerized software, the WMH volume was measured for those subjects for whom fluid-attenuated inversion recovery (FLAIR) images were available.

RESULTS

Of the 203 patients in eight hospitals in the ECLIPse study, 130 participants from six hospitals were included in this subgroup analysis. Cilostazol was given to 63 patients (48.5%) and placebo to 67 patients (51.5%). All baseline characteristics were well balanced across the two groups, and there were no significant differences in these characteristics except in the changes of PI from the baseline to the 90-day point. There was a significant decrease of TCD PIs at 90-day study from baseline in the cilostazol group (p = 0.02). The mean WMH volume was 11.57 cm(3) (0.13-68.45, median 4.86) and the mean MCA PI was 0.95 (0.62-1.50). The changes in PIs from the baseline to 14 days and to 90 days were 0.09 (-0.21 to 0.33) and 0.10 (-0.22 to 0.36). While there were no significant correlations between WMH volume and the changes in PIs, a trend of inverse correlation was observed between the WMH volume and the changes in PIs from the baseline to the 90-day point. For the subgroup analysis, the WMH volume was dichotomized based on its median value (4.90 cm(3)). Cilostazol decreased the TCD PIs significantly at the 90-day point in patients with WMH volumes ≤ 4.9 cm(3) (p = 0.002). Significant treatment effects were observed in the cilostazol group.

CONCLUSIONS

This study showed that cilostazol decreased cerebral arterial pulsatility in patients with WMH. Our findings indicate the unique effect of cilostazol in small vessel disease (SVD), especially in patients with mild WMH changes. Further clinical trials focusing on WMH volume and clinical outcomes are required to assess the unique efficacy of cilostazol in SVD.

Topographical disorientation after ischemic mini infarct in the dorsal hippocampus: whispers in silence

Silent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemia-induced deficits. The present study investigated whether an otherwise silent ischemic mini infarct in the hippocampus (HPC) can produce impairments in spatial performance in rats. Spatial performance was assessed in the ziggurat task (ZT) using a 10-trial spatial learning protocol for 4 days prior to undergoing hippocampal ischemic lesion or sham surgery. Hippocampal silent ischemia was induced by infusion of endothelin-1 (ET-1), a potent vasoconstrictor, into either the dorsal or the ventral hippocampus (dHPC and vHPC). When tested postoperatively in the ZT using a standard testing protocol for 8 days, rats with hippocampal lesions exhibited no spatial deficit. Although spatial learning and memory in the ZT were not affected by the ET-1-induced silent ischemia, rats with dHPC stroke showed more returns when navigating the ZT as opposed to the vHPC rats. Comparison of region-specific HPC lesions in the present study indicated that dorsal hippocampal function is critically required for topographic orientation in a complex environment. Topographic disorientation as reflected by enhanced return behaviors may represent one of the earliest predictors of cognitive decline after silent ischemic insult that may be potentially traced with sensitive clinical examination in humans.

Vitamin D and subclinical cerebrovascular disease: the Atherosclerosis Risk in Communities brain magnetic resonance imaging study

IMPORTANCE

Vitamin D deficiency has been associated with hypertension, diabetes mellitus, and incident stroke. Little is known about the association between vitamin D and subclinical cerebrovascular disease.

OBJECTIVE

To examine the relationship of 25-hydroxyvitamin D (25[OH]D) levels with cerebrovascular abnormalities as assessed on brain magnetic resonance imaging (MRI) among participants of the Atherosclerosis Risk in Communities (ARIC) Brain MRI study.

DESIGN, SETTING, AND PARTICIPANTS

Participants were white and black adults aged 55 to 72 years with no history of clinical stroke who underwent a cerebral MRI at ARIC visit 3 (n = 1622) and a second cerebral MRI approximately 10 years later (n = 888).

EXPOSURES

The 25(OH)D level was measured by mass spectrometry at visit 3, with levels adjusted for calendar month and categorized using race-specific quartiles.

MAIN OUTCOMES AND MEASURES

The cross-sectional and prospective associations of 25(OH)D levels with white matter hyperintensities (WMHs) and MRI-defined infarcts were investigated using multivariable regression models.

RESULTS

The mean age of the participants was 62 years, 59.6% were women, and 48.6% were black. Lower 25(OH)D levels were not significantly associated with WMH score of severity, prevalent high-grade WMH score (≥3), or prevalent infarcts in cross-sectional, multivariable-adjusted models (all P > .05). Similarly, no significant prospective associations were found for lower 25(OH)D levels with change in WMH volume, incident high WMH score (≥3), or incident infarcts on the follow-up MRI, which occurred approximately 10 years later.

CONCLUSIONS AND RELEVANCE

A single measure of 25(OH)D was not cross-sectionally associated with WMH grade or prevalent subclinical infarcts and was not prospectively associated with WMH progression or subclinical brain infarcts seen on serial cerebral MRIs obtained approximately 10 years apart. These findings do not support optimizing vitamin D levels for brain health.

Neuroimaging standards for research into small vessel disease and its contribution to ageing and neurodegeneration

Cerebral small vessel disease (SVD) is a common accompaniment of ageing. Features seen on neuroimaging include recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy. SVD can present as a stroke or cognitive decline, or can have few or no symptoms. SVD frequently coexists with neurodegenerative disease, and can exacerbate cognitive deficits, physical disabilities, and other symptoms of neurodegeneration. Terminology and definitions for imaging the features of SVD vary widely, which is also true for protocols for image acquisition and image analysis. This lack of consistency hampers progress in identifying the contribution of SVD to the pathophysiology and clinical features of common neurodegenerative diseases. We are an international working group from the Centres of Excellence in Neurodegeneration. We completed a structured process to develop definitions and imaging standards for markers and consequences of SVD. We aimed to achieve the following: first, to provide a common advisory about terms and definitions for features visible on MRI; second, to suggest minimum standards for image acquisition and analysis; third, to agree on standards for scientific reporting of changes related to SVD on neuroimaging; and fourth, to review emerging imaging methods for detection and quantification of preclinical manifestations of SVD. Our findings and recommendations apply to research studies, and can be used in the clinical setting to standardise image interpretation, acquisition, and reporting. This Position Paper summarises the main outcomes of this international effort to provide the STandards for ReportIng Vascular changes on nEuroimaging (STRIVE).

Immunology primer for neurosurgeons and neurologists part 2: Innate brain immunity

Over the past several decades we have learned a great deal about microglia and innate brain immunity. While microglia are the principle innate immune cells, other cell types also play a role, including invading macrophages, astrocytes, neurons, and endothelial cells. The fastest reacting cell is the microglia and despite its name, resting microglia (also called ramified microglia) are in fact quite active. Motion photomicrographs demonstrate a constant movement of ramified microglial foot processes, which appear to be testing the microenvironment for dangerous alteration in extracellular fluid content. These foot processes, in particular, interact with synapses and play a role in synaptic function. In event of excitatory overactivity, these foot processes can strip selected synapses, thus reducing activation states as a neuroprotective mechanism. They can also clear extracellular glutamate so as to reduce the risk of excitotoxicity. Microglia also appear to have a number of activation phenotypes, such as: (1) phagocytic, (2) neuroprotective and growth promoting, or (3) primarily neurodestructive. These innate immune cells can migrate a great distance under pathological conditions and appear to have anatomic specificity, meaning they can accumulate in specifically selected areas of the brain. There is some evidence that there are several types of microglia. Macrophage infiltration into the embryonic brain is the source of resident microglia and in adulthood macrophages can infiltrate the brain and are for the most part pathologically indistinguishable from resident microglia, but may react differently. Activation itself does not imply a destructive phenotype and can be mostly neuroprotective via phagocytosis of debris, neuron parts and dying cells and by the release of neurotrophins such as nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF). Evidence is accumulating that microglia undergo dynamic fluctuations in phenotype as the neuropathology evolves. For example, in the early stages of neurotrauma and stroke, microglia play a mostly neuroprotective role and only later switch to a neurodestructive mode. A great number of biological systems alter microglia function, including neurohormones, cannabinoids, other neurotransmitters, adenosine triphosphate (ATP), adenosine, and corticosteroids. One can appreciate that with aging many of these systems are altered by the aging process itself or by disease thus changing the sensitivity of the innate immune system.

Blood-brain barrier permeability and long-term clinical and imaging outcomes in cerebral small vessel disease

BACKGROUND AND PURPOSE

Increased blood-brain barrier (BBB) permeability occurs in cerebral small vessel disease. It is not known if BBB changes predate progression of small vessel disease.

METHODS

We followed-up patients with nondisabling lacunar or cortical stroke and BBB permeability magnetic resonance imaging after their original stroke. Approximately 3 years later, we assessed functional outcome (Oxford Handicap Score, poor outcome defined as 3-6), recurrent neurological events, and white matter hyperintensity (WMH) progression on magnetic resonance imaging.

RESULTS

Among 70 patients with mean age of 68 (SD ± 11) years, median time to clinical follow-up was 39 months (interquartile range, 30-45) and median Oxford Handicap Score was 2 (interquartile range, 1-3); poor functional outcome was associated with higher baseline WMH score (P<0.001) and increased basal ganglia BBB permeability (P=0.046). Among 48 patients with follow-up magnetic resonance imaging, WMH progression at follow-up was associated with baseline WMH (ANCOVA P<0.0001) and age (ANCOVA P=0.032).

CONCLUSIONS

Further long-term studies to evaluate the role of BBB dysfunction in progression of small vessel disease are required in studies that are large enough to account for key prognostic influences such as baseline WMH and age.