Microbleeds Are Associated With Subsequent Hemorrhagic and Ischemic Stroke in Healthy Elderly Individuals

Management of Spontaneous Intracerebral Hematoma

The incidence of spontaneous intracerebral hematoma (SICH) is even now high worldwide, especially higher in Japan than in Western countries, despite the development of advances in blood pressure (BP) management and food/alcohol intake education. Although mortality and morbidity for SICH are high, some controversies remain regarding the appropriate acute phase of treatment. Recent studies have revealed that BP lowering treatment than 140 mmHg resulted in better outcomes. However the efficacy of surgical treatment for SICH has not been well established, with the exception of that for cerebellar SICH over 3 cm in diameter and life-saving procedures, although many randomized control studies and systematic reviews focused on surgical treatment have been reported. In this review, we summarize some issues and discuss strategies in development for the treatment of SICH.

Putative Cerebral Microbleeds in Dogs Undergoing Magnetic Resonance Imaging of the Head: A Retrospective Study of Demographics, Clinical Associations, and Relationship to Case Outcome

BACKGROUND

Cerebral microbleeds (CMBs) are focal intraparenchymal signal voids on gradient-echo magnetic resonance imaging (MRI), corresponding to regions of chronic hemorrhage. In humans, they are associated with systemic disease and shorter survival times. Although similar findings have been identified in dogs, their epidemiology and clinical correlations have not been investigated.

OBJECTIVE

To determine epidemiological features, clinical associations, and associations with outcome for putative CMB-like foci (putative microbleeds [pMBs]) identified by T2*-weighted MRI in dogs.

ANIMALS

Five hundred and eighty-two dogs undergoing 3T brain MRI between 2011 and 2016.

METHODS

Retrospective case-control study. Demographic, diagnostic, and clinicopathological data were obtained from medical records and phone follow-up. Demographic variables were compared between dogs with and without evidence of pMBs. For dogs with such evidence, and a subset of matched controls, associations with clinical presentation, concurrent disease, and survival times were evaluated.

RESULTS

Dogs with pMBs were older (P < .001) and smaller (P = .004) than unaffected dogs. Compared to matched controls, they presented more frequently for vestibular signs (P = .030). Cortical atrophy occurred concurrently with pMBs in 26% (14/54) of dogs. Diagnosed renal disease was not significantly associated with pMBs, but proteinuria was more common in dogs with pMBs than in matched controls (odds ratio = 3.01, P = .005). Dogs with pMBs had a shorter median survival time than did matched controls (P = .011).

CONCLUSIONS AND CLINICAL IMPORTANCE

Putative microbleeds occurred in 54 of 582 (9.3%) of dogs undergoing brain MRI, but may not be a normal consequence of aging. They were associated with shorter survival time and proteinuria in the study population.

Evolution of cerebral microbleeds after cranial irradiation in medulloblastoma patients

OBJECTIVE

To characterize the temporal and spatial pattern of cerebral microbleeds (CMBs) after cranial irradiation in patients with medulloblastoma.

METHODS

We retrospectively identified patients with medulloblastoma treated with craniospinal irradiation at the Massachusetts General Hospital between 1999 and 2015. Longitudinal MRI including T2*-weighted gradient-recalled echo (GRE) sequences were reviewed, and the prevalence, spatial pattern, and risk factors associated with CMBs were characterized.

RESULTS

We identified a total of 27 patients; 5 patients were children (median age 6.3 years) and 22 patients were adults (median age 28.8 years). CMBs were found in 67% (18/27) of patients, who were followed for a median of 4.1 years. Patients with CMBs had longer GRE follow-up time compared to those without CMBs (4.9 vs 1.7 years, p = 0.035). The median latency of the appearance of CMBs was 2.79 years (interquartile range 1.76-4.26). The prevalence of CMBs increased with each year from time of radiation therapy, and the cumulative prevalence was highest in patients age <20 years (100% cumulative prevalence, vs 59% in adult patients treated at age ≥20 years). CMBs were mostly found in lobar distribution and predominately in bilateral occipital lobes. Patients using antithrombotic medications developed CMBs at a significantly higher rate (p = 0.041).

CONCLUSIONS

Our data demonstrate a high prevalence of CMBs following cranial irradiation, progressively increasing with each year from time of radiation therapy.

Serum Lipid Fractions and Cerebral Microbleeds in a Healthy Japanese Population

Background: Cerebral microbleeds (CMBs) are associated with focal hemosiderin deposits and represent a form of cerebral small vessel disease. To date, indefinite and inconsistent reports are available regarding the association between serum lipid fractions and CMBs. In addition, these previous studies did not include Asian populations, who may have a higher risk of cerebral hemorrhage. The purpose of this study was to examine the associations between serum lipid fractions and CMBs in healthy Japanese subjects. Methods: We performed a cross-sectional study involving 4,024 neurologically normal Japanese subjects (mean age 61.6 years). All the participants underwent 1.5-Tesla magnetic resonance imaging scan, and CMBs were classified into 3 groups based on their locations. The concentrations of lipid fractions were categorized into quartiles and the association between the lipid fractions and CMBs were investigated using logistic regression analysis. Results: CMBs were observed in 164 (4.1%) of participants. Of these participants with CMBs, 33 (20.1%) had lobar CMBs and 91 (55.5%) had deep CMBs. Subjects with deep CMBs had lower total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels. After adjusting for confounding factors, lower TC and HDL-C levels were still associated with the presence of deep CMBs (OR for the highest vs. the lowest quartiles of TC and HDL-C was 2.28 [95% CI 1.05-4.94], and 1.93 [95% CI 1.02-3.65], respectively). The presence of subcortical infarcts and periventricular hyperintensities was more frequently observed in deep CMBs, whereas white matter hyperintensities were more frequently observed in lobar CMBs. Conclusions: Our results suggest that low serum TC and HDL-C levels are closely associated with deep CMBs.

Prevention of Stroke in Patients With Silent Cerebrovascular Disease: A Scientific Statement for Healthcare Professionals From the American Heart Association/American Stroke Association

Two decades of epidemiological research shows that silent cerebrovascular disease is common and is associated with future risk for stroke and dementia. It is the most common incidental finding on brain scans. To summarize evidence on the diagnosis and management of silent cerebrovascular disease to prevent stroke, the Stroke Council of the American Heart Association convened a writing committee to evaluate existing evidence, to discuss clinical considerations, and to offer suggestions for future research on stroke prevention in patients with 3 cardinal manifestations of silent cerebrovascular disease: silent brain infarcts, magnetic resonance imaging white matter hyperintensities of presumed vascular origin, and cerebral microbleeds. The writing committee found strong evidence that silent cerebrovascular disease is a common problem of aging and that silent brain infarcts and white matter hyperintensities are associated with future symptomatic stroke risk independently of other vascular risk factors. In patients with cerebral microbleeds, there was evidence of a modestly increased risk of symptomatic intracranial hemorrhage in patients treated with thrombolysis for acute ischemic stroke but little prospective evidence on the risk of symptomatic hemorrhage in patients on anticoagulation. There were no randomized controlled trials targeted specifically to participants with silent cerebrovascular disease to prevent stroke. Primary stroke prevention is indicated in patients with silent brain infarcts, white matter hyperintensities, or microbleeds. Adoption of standard terms and definitions for silent cerebrovascular disease, as provided by prior American Heart Association/American Stroke Association statements and by a consensus group, may facilitate diagnosis and communication of findings from radiologists to clinicians.

Oral Cnm-positive Streptococcus Mutans Expressing Collagen Binding Activity is a Risk Factor for Cerebral Microbleeds and Cognitive Impairment

Cerebral microbleeds (CMBs) are an important risk factor for stroke and dementia. We have shown that the collagen binding surface Cnm protein expressed on cnm-positive Streptococcus mutans is involved in the development of CMBs. However, whether the collagen binding activity of cnm-positive S. mutans is related to the nature of the CMBs or to cognitive impairment is unclear. Two-hundred seventy nine community residents (70.0 years) were examined for the presence or absence of cnm-positive S. mutans in the saliva by PCR and collagen binding activity, CMBs, and cognitive function were evaluated. Cnm-positive S. mutans was detected more often among subjects with CMBs (p < 0.01) than those without. The risk of CMBs was significantly higher (odds ratio = 14.3) in the group with S. mutans expressing collagen binding activity, as compared to the group without that finding. Deep CMBs were more frequent (67%) and cognitive function was lower among subjects with cnm-positive S. mutans expressing collagen binding activity. This work supports the role of oral health in stroke and dementia and proposes a molecular mechanism for the interaction.

Relationship between asymptomatic intra-cranial lesions and brachial-ankle pulse wave velocity in coronary artery disease patients without stroke

Little is known about the significance of asymptomatic intra-cranial lesions (ICL) identified by brain MRI in coronary artery disease (CAD) patients. Silent cerebral lesions are suggested to be associated with arterial stiffness in healthy subjects. We investigated whether subclinical ICL are associated with arterial stiffness and the prognosis in CAD patients without medical history of cerebrovascular diseases. We recruited CAD patients who required percutaneous coronary intervention (PCI), did not meet exclusion criteria, and agreed with MRI before PCI. Subjects were divided into two groups according to the presence of ICL of cerebral microbleeds or lacunar infarction. Arterial stiffness was evaluated by brachial-ankle pulse wave velocity (baPWV). Clinical outcome was defined as a composite of cardiovascular death, non-fatal myocardial infarction, stroke, unstable angina and heart failure. In total, 149 patients underwent brain MRI. Patients with ICL (n=55) had significantly higher baPWV than those without ICL (1591-2204 vs. 1450-1956 cm per sec; P=0.009). A multivariate analysis showed that male sex (odds ratio (OR), 3.15; 95% confidence interval (CI), 1.38-7.20; P=0.006) and baPWV (OR, 1.001; 95% CI, 1.000-1.002; P=0.023) were predictors of ICL. In total, 12 patients experienced a cardiovascular event. The Kaplan-Meier analysis indicated a significantly higher incidence of cardiovascular events in patients with ICL (log-rank test: P=0.018). Multivariate Cox proportional hazards analyses indicated that ICL finding was a significant predictor of clinical outcome (hazard ratio, 3.41; 95% CI, 1.02-11.5; P=0.047). Patients with subclinical ICL had a higher baPWV and worse prognoses than those without ICL.

A cohort study of relationship between serum calcium levels and cerebral microbleeds (CMBs) in ischemic stroke patients with AF and/or RHD

Calcium is an essential element for life and has cerebroprotective property in stroke patients. Low serum calcium levels were found to be related to large hematoma volumes in intracerebral hemorrhagic patients and hemorrhagic transformation in ischemic stroke patients after thrombolysis. However, their impact on hemorrhage-prone small vessel disease represented by cerebral microbleeds (CMBs) is uncertain. We aim to investigate whether low serum calcium levels are associated with presence and location of CMBs.Ischemic stroke patients with atrial fibrillation (AF) and/or rheumatic heart disease admitted to our hospital were consecutively and prospectively enrolled. Demographic and clinical information were collected and analyzed according to the occurrence and location of CMBs, and levels of serum calcium. We used logistic regression analysis to estimate the multivariable adjusted relationship between serum calcium levels and the presence or location of CMBs.Among the 67 patients (28 males; mean age, 67.3 years) in the final analysis, 39 (58.2%) were found to have CMBs. After adjustment for age, sex, smoking habits, drinking habits, and renal impairment, the presence of CMBs and deep CMBs was, respectively, 4.96- and 4.83-fold higher in patients with lower serum calcium levels (≤2.15 mmol/L) than in patients with higher serum calcium levels.Lower serum calcium levels (≤2.15 mmol/L) are independently associated with the presence of CMBs and deep CMBs in ischemic stroke patients with AF and/or rheumatic heart disease, which should be verified and extended in large cohorts, with other types of stroke patients and the general population.

Anticoagulation for Atrial Fibrillation in Patients with Cerebral Microbleeds

Intracranial haemorrhage (ICH) is the most feared and devastating complication of oral anticoagulation, with high mortality and disability in survivors. Oral anticoagulant-related ICH is increasing in incidence, most likely in part due to the increased use of anticoagulation for atrial fibrillation in the elderly populations with a high prevalence of bleeding-prone cerebral small vessel diseases. Risk scores have been developed to predict bleeding, including ICH, as well as the risk of ischaemic stroke. Recently, attention has turned to brain imaging, in particular, MRI detection of potential prognostic biomarkers, which may help better predict outcomes and individualize anticoagulant decisions. Cerebral microbleeds (CMBs)--small, round areas of signal loss on blood-sensitive MR sequences--have been hypothesized to be a marker for bleeding-prone small vessel pathology, and thus, future symptomatic ICH risk. In this review, we outline the prevalence and prognostic value of CMBs in populations affected by AF for whom anticoagulation decisions are relevant, including healthy older individuals and survivors of ischaemic stroke or ICH. We consider the limitations of currently available evidence, and discuss future research directions in relation to both prognostic markers and treatment options for atrial fibrillation.

Superficial temporal artery-to-middle cerebral artery bypass surgery for middle cerebral artery stenosis in a patient with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy is a rare hereditary small vessel disease. Ischemic events are the main clinical manifestation of this condition. Here, we present a case in which superficial temporal artery-to-middle cerebral artery anastomosis was performed in a patient with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy who developed cerebral infarctions caused by severe middle cerebral artery stenosis. Cerebral blood flow and cerebrovascular reactivity were effectively improved using double anastomoses. To our knowledge, surgical revascularization for patients with this condition has not yet been described in the literature. Superficial temporal artery-to-middle cerebral artery anastomosis is effective for patients with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy who show marked regional cerebral hypoperfusion.

Silent arteriovenous malformation hemorrhage and the recognition of "unruptured" arteriovenous malformation patients who benefit from surgical intervention

BACKGROUND

Arteriovenous malformation (AVM) patients present in 4 ways relative to hemorrhage: (1) unruptured, without a history or radiographic evidence of old hemorrhage (EOOH); (2) silent hemorrhage, without a bleeding history but with EOOH; (3) ruptured, with acute bleeding but without EOOH; and (4) reruptured, with acute bleeding and EOOH.

OBJECTIVE

We hypothesized that characteristics and outcomes in the unrecognized group of silent hemorrhage patients may differ from those of unruptured patients.

METHODS

Two hundred forty-two patients operated-on since 1997 were categorized by hemorrhage status and hemosiderin positivity in this cohort study: unruptured (group 1), silent hemorrhage (group 2), and ruptured/reruptured (group 3/4). Group 3/4 was combined because hemosiderin cannot distinguish acute hemorrhage from older silent hemorrhage.

RESULTS

Hemosiderin was found in 45% of specimens. Seventy-five patients (31.0%) had unruptured AVMs, 30 (12.4%) had silent hemorrhage, and 137 (56.6%) had ruptured/reruptured AVMs. Deep drainage, posterior fossa location, preoperative modified Rankin Scale (mRS) score, outcome, and macrophage score were different across groups. Only the macrophage score was different between the groups without clinical hemorrhage. Outcomes were better in silent hemorrhage patients than in those with frank rupture (mean mRS scores of 1.2 and 1.7, respectively).

CONCLUSION

One-third of patients present with silent AVM hemorrhage. No clinical or anatomic features differentiate these patients from unruptured patients, except the presence of hemosiderin and macrophages. Silent hemorrhage can be diagnosed using magnetic resonance imaging with iron-sensitive imaging. Silent hemorrhage portends an aggressive natural history, and surgery halts progression to rerupture. Good final mRS outcomes and better outcomes than in those with frank rupture support surgery for silent hemorrhage patients, despite the findings of ARUBA.

Relationship between Cnm-positive Streptococcus mutans and cerebral microbleeds in humans

OBJECTIVE

Cerebral hemorrhage has been shown to occur in animals experimentally infected with Streptococcus mutans carrying the collagen-binding Cnm gene. However, the relationship between cerebral microbleeds and oral hygiene, with a focus on Cnm gene-positive S. mutans infection, remains unclear.

MATERIAL AND METHODS

One hundred and thirty-nine subjects participated. The presence or absence of Cnm-positive S. mutans and its collagen-binding activity were investigated using saliva samples, and relationship with cerebral microbleeds detected on MRI investigated, including clinical information and oral parameters.

RESULTS

Fifty-one subjects were identified as Cnm-positive S. mutans carriers (36.7%), with cerebral microbleeds being detected in 43 (30.9%). A significantly larger number of subjects carried Cnm-positive S. mutans in the cerebral microbleeds (+) group. S. mutans with Cnm collagen-binding ability was detected in 39 (28.1%) of all subjects, and the adjusted odds ratio for cerebral microbleeds in the Cnm-positive group was 14.4. Regarding the presence of cerebral microbleeds, no significant differences were noted in the number of remaining teeth, dental caries, or in classic arteriosclerosis risk factors.

CONCLUSIONS

The occurrence of cerebral microbleeds was higher in subjects carrying Cnm-positive S. mutans, indicating that the presence of Cnm-positive S. mutans increases cerebral microbleeds, and is an independent risk for the development of cerebrovascular disorders.

[Small vessel disease associated with cranial irradiation]

We report two cases of young patients with lacunar stroke who demonstrated multiple microbleeds (MBs) a long period after cranial irradiation. Case 1: a 44-year-old man developed dysarthria and left hemiparesis from a day before admission. Magnetic resonance imaging showed an acute lacunar infract in the right corona radiata. Case 2: a 28-year-old woman was admitted due to dysarthria and right hemiparesis. An acute lacunar infract was detected in the left corona radiata. T2* WI revealed multiple MBs in the region corresponding to the irradiation in both patients. Since these patients had no vascular risk factors except for smoking habit in the former one and dyslipidemia in the latter one. We speculated that lacunar stroke and MBs had resulted from past cranial irradiation. In addition to accelerated atherosclerosis of the large vessels, small vessel disease should be noted as an important long-term complication after cranial irradiation.

The Clinical Relevance of Microbleeds in Stroke study (CROMIS-2): rationale, design, and methods

BACKGROUND AND RATIONALE

The increasing use of oral anticoagulants, mostly to prevent ischemic stroke due to atrial fibrillation in an ageing population, has been associated with a fivefold increased incidence of oral anticoagulant-associated intracerebral hemorrhage: a rare, serious, and unpredictable complication. We hypothesize that cerebral microbleeds and other markers of cerebral small vessel disease on magnetic resonance imaging, and genetic polymorphisms (e.g. influencing cerebral small vessel integrity or anticoagulation stability), are associated with an increased risk of oral anticoagulant-associated intracerebral hemorrhage, with potential to improve risk prediction.

AIMS

(1) To determine the incidence, clinical, radiological, and genetic associations of oral anticoagulant-associated intracerebral hemorrhage in a prospective, multicentre cohort study of patients with atrial fibrillation-related ischemic stroke or transient ischemic attack started on oral anticoagulants; (2) To investigate characteristics of oral anticoagulant-associated intracerebral hemorrhage compared with non-oral anticoagulants related intracerebral hemorrhage in a prospective study.

DESIGN AND METHODS

Study 1: Prospective, multicentre, inception cohort study of 1425 adults started on oral anticoagulants (including vitamin K antagonists and the nonvitamin K oral anticoagulants) after recent ischemic stroke and concurrent atrial fibrillation. Participants will have standardized brain magnetic resonance imaging (including a T2*-weighted gradient-recalled echo sequence) and DNA sample collection at baseline, with two-year follow-up by postal questionnaire and medical records surveillance for symptomatic intracranial hemorrhage, other serious vascular events, and death. We will compare the rates of symptomatic intracranial hemorrhage (primary outcome; subclassified as intracerebral, subdural, extradural, intraventricular), other vascular events, and death (secondary outcomes) in participants with one or more cerebral microbleeds to the rates in those without cerebral microbleeds.

STUDY

Prospective case-control study of oral anticoagulant-associated intracerebral hemorrhage compared with non-oral anticoagulant-associated intracerebral hemorrhage to investigate genetic, clinical, and radiological associations with oral anticoagulant-associated intracerebral hemorrhage. In participants with intracerebral hemorrhage (including at least 300 with oral anticoagulant-associated intracerebral hemorrhage), we will collect a DNA sample, standardized clinical data and routine brain imaging (magnetic resonance imaging or computed tomography), and information on functional outcome.

EXPECTED OUTCOMES

We will identify the factors associated with increased intracranial hemorrhage risk after oral anticoagulants for secondary prevention after ischemic stroke due to atrial fibrillation. We will determine clinical, radiological and genetic factors, and clinical outcomes associated with oral anticoagulant-associated intracerebral hemorrhage.

Endothelial depletion of murine SRF/MRTF provokes intracerebral hemorrhagic stroke

Intracerebral hemorrhagic stroke and vascular dementia are age- and hypertension-associated manifestations of human cerebral small vessel disease (SVD). Cerebral microvessels are formed by endothelial cells (ECs), which are connected through tight junctions, adherens junctions, and stabilizing basement membrane structures. These endothelial connections ensure both vessel stability and blood-brain barrier (BBB) functions, the latter enabling selective exchange of ions, bioactive molecules, and cells between the bloodstream and brain tissue. Srf(iECKO) mice, permitting conditional EC-specific depletion of the transcription factor Serum Response Factor (SRF), suffer from loss of BBB integrity and intracerebral hemorrhaging. Cerebral microbleeds and larger hemorrhages developed upon postnatal and adult depletion of either SRF or its cofactors Myocardin Related Transcription Factor (MRTF-A/-B), revealing essential requirements of ongoing SRF/MRTF activity for maintenance of cerebral small vessel integrity. In vivo magnetic resonance imaging allowed detection, localization, and time-resolved quantification of BBB permeability and hemorrhage formation in Srf(iECKO) brains. At the molecular level, direct and indirect SRF/MRTF target genes, encoding structural components of tight junctions (Claudins and ZO proteins), adherens junctions (VE-cadherin, α-Actinin), and the basement membrane (Collagen IV), were down-regulated upon SRF depletion. These results identify SRF and its MRTF cofactors as major transcriptional regulators of EC junctional stability, guaranteeing physiological functions of the cerebral microvasculature. We hypothesize that impairments in SRF/MRTF activity contribute to human SVD pathology.

Intracranial Hemorrhage After Ischemic Stroke: Incidence, Time Trends, and Predictors in a Swedish Nationwide Cohort of 196 765 Patients

BACKGROUND

Epidemiological data on the risk of intracranial hemorrhage (ICrH) after ischemic stroke are sparse. The aims of this study were to describe incidence, trends over time, and predictors of ICrH within 1 year after ischemic stroke.

METHODS AND RESULTS

All patients registered in the Swedish stroke register Riksstroke for 1998 to 2009 were included (n=196 765), and data were combined with the National Patient Register to identify ICrH occurrence. A matched reference population was obtained. Incidence rates and cumulative incidences were calculated. Multivariable regression analyses were used to identify predictors. Analyses were performed separately for the first 30 days and days 31 to 365 after ischemic stroke. The incidence rate was 1.97% per year at risk for the first year (0.13% in the reference population) and 0.85% excluding the first 30 days. Over time, the cumulative incidence increased the first 30 days but decreased over days 31 to 365. Thrombolysis, previous ICrH, atrial fibrillation, and male sex were associated with increased risk of ICrH during the first 30 days. Previous ICrH, increasing age, and male sex were associated with increased risk during days 31 to 365. Statins and antithrombotic treatment did not independently predict ICrH occurrence.

CONCLUSIONS

The incidence of ICrH within 1 year after ischemic stroke was ≈2% per year at risk, about 15 times higher compared with the reference population. Over the study period, ICrH risk increased within the first 30 days but decreased thereafter. Previous ICrH, thrombolysis, and male sex affected the risk, whereas an increased use of antithrombotic treatments and statins did not.

Cerebral Microbleeds Are Associated With an Increased Risk of Stroke: The Rotterdam Study

BACKGROUND

Cerebral microbleeds are highly prevalent in people with clinically manifest cerebrovascular disease and have been shown to increase the risk of stroke recurrence. Microbleeds are also frequently found in healthy elderly, a population in which the clinical implication of microbleeds is unknown.

METHODS AND RESULTS

In the population-based Rotterdam Study, the presence, number, and location of microbleeds were assessed at baseline on brain MRI of 4759 participants aged ≥45 years. Participants were followed for incident stroke throughout the study period (2005-2013). We used Cox proportional hazards to investigate if people with microbleeds were at increased risk of stroke in comparison with those without microbleeds, adjusting for demographic, genetic, and cardiovascular risk, and cerebrovascular imaging markers. Microbleed prevalence was 18.7% (median count 1 [1-111]). During mean follow-up of 4.9 years (standard deviation, 1.6) 93 strokes occurred (72 ischemic, 11 hemorrhagic, and 10 unspecified). Microbleed presence was associated with an increased risk of all strokes (hazard ratio, 1.93; 95% confidence interval, 1.25-2.99). The risk increased with greater microbleed count. In comparison with those without microbleeds, participants with microbleeds in locations suggestive of cerebral amyloid angiopathy (lobar with or without cerebellar microbleeds) were at increased risk of intracerebral hemorrhage (hazard ratio, 5.27; 95% confidence interval, 1.38-20.23). Microbleeds at other locations were associated with an increased risk of both ischemic stroke and intracerebral hemorrhage.

CONCLUSIONS

Microbleeds on MRI are associated with an increased risk of stroke in the general population. Our results strengthen the notion that microbleeds mark progression of cerebrovascular pathology and represent a precursor of stroke.

Aging exacerbates hypertension-induced cerebral microhemorrhages in mice: role of resveratrol treatment in vasoprotection

Recent studies demonstrate that aging exacerbates hypertension-induced cognitive decline, but the specific age-related mechanisms remain elusive. Cerebral microhemorrhages (CMHs) are associated with rupture of small intracerebral vessels and are thought to progressively impair neuronal function. To determine whether aging exacerbates hypertension-induced CMHs young (3 months) and aged (24 months) mice were treated with angiotensin II plus L-NAME. We found that the same level of hypertension leads to significantly earlier onset and increased incidence of CMHs in aged mice than in young mice, as shown by neurological examination, gait analysis, and histological assessment of CMHs in serial brain sections. Hypertension-induced cerebrovascular oxidative stress and redox-sensitive activation of matrix metalloproteinases (MMPs) were increased in aging. Treatment of aged mice with resveratrol significantly attenuated hypertension-induced oxidative stress, inhibited vascular MMP activation, significantly delayed the onset, and reduced the incidence of CMHs. Collectively, aging promotes CMHs in mice likely by exacerbating hypertension-induced oxidative stress and MMP activation. Therapeutic strategies that reduce microvascular oxidative stress and MMP activation may be useful for the prevention of CMHs, protecting neurocognitive function in high-risk elderly patients.

Contribution of Deep Microbleeds to Stroke Recurrence: Differences between Patients with Past Deep Intracerebral Hemorrhages and Lacunar Infarctions

BACKGROUND

This study investigated the contribution of deep cerebral microbleeds (MBs) to stroke recurrences in patients with histories of deep intracerebral hemorrhages (ICHs) or lacunar infarctions (LIs).

METHODS

We prospectively analyzed stroke recurrences in patients admitted to our hospital who were treated for deep ICHs or LIs between April 2004 and December 2011. The number of deep MBs was counted on admission. Stroke recurrence-free rate curves were generated with the Kaplan-Meier method using the log-rank test. The odds ratios (ORs) for recurrent strokes were derived using multivariate logistic regression models, based on deep MBs and risk factors.

RESULTS

We evaluated magnetic resonance images or the recurrences of 231 deep-ICH patients (92 women, 68.0 ± 12.0 years old) and 309 LI patients (140 women, 70.7 ± 11.7 years old). The incidences of deep ICHs (1.5%/year) and LIs (2.1%/year) presenting as stroke recurrences were significantly larger in LI patients with deep MBs than in those without (.01 [P = .0001] and .08%/year [P = .005], respectively). However, there was no significant difference between deep-ICH patients with and without MBs in terms of incidence of recurrences. Multivariate analyses revealed that deep MBs independently and significantly elevated the rate of deep ICHs (OR, 19.0; P = .007) or LIs (OR, 3.62; P = .008) presenting as recurrences in LI patients, but not in deep-ICH patients, when adjusted for stroke risk factors.

CONCLUSIONS

There may be differences between patients with deep ICHs and those with LIs in terms of the contribution of deep MBs to stroke recurrence.

Association of mild kidney dysfunction with silent brain lesions in neurologically normal subjects

Background

Chronic kidney disease (CKD) has been closely associated with stroke. Although a large number of studies reported the relationship between CKD and different types of asymptomatic brain lesions, few comprehensive analyses have been performed for all types of silent brain lesions.

Methods

We performed a cross-sectional study involving 1,937 neurologically normal subjects (mean age 59.4 years). Mild CKD was defined as an estimated glomerular filtration rate between 30 and 60 ml/min/1.73 m² or positive proteinuria.

Results

The prevalence of mild CKD was 8.7%. Univariate analysis revealed an association between CKD and all silent brain lesions, including silent brain infarction, periventricular hyperintensity, subcortical white matter lesion, and microbleeds, in addition to hypertension and diabetes mellitus after adjusting for age and sex. In binary logistic regression analysis, the presence of CKD was a significant risk factor for all types of silent brain lesions, independent of other risk factors.

Conclusions

These results suggest that mild CKD is independently associated with all types of silent brain lesions, even in neurologically normal subjects.

Cerebral microbleeds as a predictor of macrobleeds: what is the evidence?

Cerebral microbleeds on blood-sensitive magnetic resonance imaging sequences have emerged as a common and important marker of small vessel disease. Cerebral microbleeds differ from other imaging manifestations of small vessel disease (e.g. lacunes and leukoaraiosis), as they seem to provide more direct evidence of microvascular leakiness from bleeding-prone arteriopathies, namely hypertensive arteriopathy and cerebral amyloid angiopathy, the two leading causes of spontaneous intracerebral haemorrhage. Thus, cerebral microbleeds in specific sub-populations might provide evidence of an ongoing active small vessel arteriopathy with increased future risk of symptomatic intracerebral haemorrhage ('macrobleeding'). If this hypothesis is correct, it raises clinical dilemmas especially regarding the safety of antithrombotic drug use. Although data so far are limited, the relationship of microbleeds to future macrobleeding (and cerebral ischemia) seems to critically depend on the specific patient population and cerebral microbleeds location and burden, which may reflect the nature and severity of the underlying arteriopathies.

Pathogenesis and treatment of vascular cognitive impairment

SUMMARY 

Vascular cognitive impairment (VCI) defines a continuum of disorders ranging from mild cognitive impairment to full-blown dementia, attributable to cerebrovascular causes. Major morphological types – multi-infarct encephalopathy, strategic infarct type, subcortical arteriosclerotic leukoencephalopathy, multilacunar state, postischemic encephalopathy – result from systemic, cardiac and local large or small vessel disease. Cognitive decline is commonly caused by widespread small cerebrovascular lesions (CVLs) affecting regions/networks essential for cognition, memory and behavior. CVLs often coexist with Alzheimer-type and other pathologies, which interact in promoting dementia, but in many nondemented elderly individuals, mixed brain pathologies are also present. Due to the high variability of CVLs, no validated clinical and neuropathological criteria for VCI are available. Cholinesterase inhibitors and memantine produce small cognitive improvement but without essential effect. Antihypertensive treatment, cardiovascular control and lifestyle modifications reducing vascular risk factors are essential. Given its growing health, social and economic burden, prevention and treatment of VCI are a major challenge of neuroscience.

Hemorrhagic Transformation after Tissue Plasminogen Activator Reperfusion Therapy for Ischemic Stroke: Mechanisms, Models, and Biomarkers

Intracerebral hemorrhagic transformation (HT) is well recognized as a common cause of hemorrhage in patients with ischemic stroke. HT after acute ischemic stroke contributes to early mortality and adversely affects functional recovery. The risk of HT is especially high when patients receive thrombolytic reperfusion therapy with tissue plasminogen activator, the only available treatment for ischemic stroke. Although many important publications address preclinical models of ischemic stroke, there are no current recommendations regarding the conduct of research aimed at understanding the mechanisms and prediction of HT. In this review, we discuss the underlying mechanisms for HT after ischemic stroke, provide an overview of the models commonly used for the study of HT, and discuss biomarkers that might be used for the early detection of this challenging clinical problem.

Risk factors of cerebral microbleeds in strictly deep or lobar brain regions differed

BACKGROUND

T2*-weighted gradient echo magnetic resonance imaging is sensitive in detecting cerebral microbleeds (MBs), but there are few reports on the risk factors of MBs in different brain regions. Therefore, we aimed to investigate whether the risk factors associated with the presence of MBs in strictly deep or lobar brain regions were different.

METHODS

This study consisted of 696 consecutive acute ischemic stroke patients from 6 hospitals in the Chinese IntraCranial AtheroSclerosis Study. We evaluated the number and location of MBs, severity of lacune and leukoaraiosis (LA), and etiologic subtype of ischemic stroke. Multivariable logistic regression was used to analyze risk factors of MBs in different brain regions.

RESULTS

Among 696 acute ischemic stroke patients, 162 patients (23.3%) had MBs. Of them, 62 patients had strictly deep brain MBs, 49 patients had strictly lobar MBs. There was a significant correlation between the number of MBs, the number of lacune, and the severity of LA (P < .0001). In multivariable logistic regression analysis, both strictly deep and strictly lobar brain, MBs were significantly associated with history of cerebral hemorrhage (P = .037 and P = .026, respectively), presence of lacune (P = .004 and P = .032, respectively), and severe LA (P = .002 and P = .008, respectively). However, MBs in strictly deep regions were significantly associated with higher mean arterial pressure (P = .030), and those in strictly lobar brain regions were significantly associated with older age (P = .023).

CONCLUSIONS

The risk factors of MBs in strictly deep or lobar regions differ modestly, which may be related to heterogeneous vascular pathologic changes.

Progression of brain microbleeds in essential hypertensive patients: a 2-year follow-up study

BACKGROUND

Brain microbleeds (BMBs) are common in hypertensive patients and are associated with higher blood pressure (BP) levels. Little is known about risk factors for progression of BMBs, in particular the contribution of ambulatory BP levels. We aimed to determine BMB progression and the association with BP levels in a cohort of essential hypertensive patients.

METHODS

At baseline and after 2 years of follow-up, 193 participants underwent brain magnetic resonance imaging (MRI) and 24-hour ambulatory BP measurement in addition to office BP measurement. The relation between BMB progression and baseline untreated BP characteristics was tested in logistic regression analyses.

RESULTS

Progression of BMBs on follow-up MRI was seen in 12 (6%) participants. Patients with progression were significantly older, and the prevalence as well as total number of BMBs at baseline was greater. With correction for age and sex, baseline 24-hour systolic and diastolic BP and 24-hour pulse pressure significantly predicted progression. Similar results were seen for baseline awake and asleep BP. On additional adjustments for baseline presence of BMBs, the associations remained significant for 24-hour, awake, and asleep systolic BP, awake diastolic BP, and awake and asleep pulse pressure. Office systolic BP was also associated with progression of BMBs, whereas office diastolic BP was not.

CONCLUSIONS

High ambulatory BP levels are important and possibly modifiable predictors for progression of BMBs. This warrants further study, with an adequately long follow-up period and early adequate treatment of hypertension.

Characteristics of intracerebral hemorrhage during rivaroxaban treatment: comparison with those during warfarin

BACKGROUND AND PURPOSE

Neuroradiological characteristics and functional outcomes of patients with intracerebral hemorrhage (ICH) during novel oral anticoagulant treatment were not well defined. We examined these in comparison with those during warfarin treatment.

METHODS

The consecutive 585 patients with ICH admitted from April 2011 through October 2013 were retrospectively studied. Of all, 5 patients (1%) had ICH during rivaroxaban treatment, 56 (10%) during warfarin, and the other 524 (89%) during no anticoagulants. We focused on ICH during rivaroxaban and warfarin treatments and compared the clinical characteristics, neuroradiological findings, and functional outcomes.

RESULTS

Patients in the rivaroxaban group were all at high risk for major bleeding with hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly (HAS-BLED) score of 3 and higher rate of past history of ICH. Moreover, multiple cerebral microbleeds (≥4) were detected more frequently in rivaroxaban group than in warfarin (80% versus 29%; P=0.04). Hematoma volume in rivaroxaban group was markedly smaller than that in warfarin (median: 4 versus 11 mL; P=0.03). No patient in the rivaroxaban group had expansion of hematoma and surgical treatment. Rivaroxaban group showed lower modified Rankin Scale at discharge relative to warfarin, and the difference between modified Rankin Scale before admission and at discharge was smaller in rivaroxaban than in warfarin (median: 1 versus 3; P=0.047). No patient in the rivaroxaban group died during hospitalization, whereas 10 (18%) warfarin patients died.

CONCLUSIONS

Rivaroxaban-associated ICH occurs in patients at high risk for major bleeding. However, they had a relatively small hematoma, no expansion of hematoma, and favorable functional and vital outcomes compared with warfarin-associated ICH.

Comparative analysis of H&E and Prussian blue staining in a mouse model of cerebral microbleeds

Cerebral microbleeds are microscopic hemorrhages with deposits of blood products in the brain, which can be visualized with MRI and are implicated in cerebrovascular diseases. Hematoxylin and eosin (H&E) and Perl's Prussian blue are popular staining methods used to localize cerebral microbleeds in pathology. This paper compared these two staining techniques in a mouse model of cerebral microbleeds. We used lipopolysaccharide (LPS) to induce cerebral microhemorrhages. C57B6 mice were treated with LPS (5 mg/kg, i.p.) or vehicle at baseline and at 24 hr. The brains were extracted 48 hr after the first injection and adjacent coronal sections were stained with H&E and Prussian blue to compare the effectiveness of the two staining techniques. H&E-positive stains were increased with LPS treatment and were correlated with grossly visible microhemorrhages on the brain surface; Prussian blue-positive stains, by comparison, showed no significant increase with LPS treatment and did not correlate with either H&E-positive stains or surface microhemorrhages. H&E staining is thus a more reliable indicator of acute bleeding events induced by LPS in this model within a short time span.

Cerebral microbleeds: a review of clinical, genetic, and neuroimaging associations

Cerebral microbleeds (microbleeds) are small, punctuate hypointense lesions seen in T2* Gradient-Recall Echo (GRE) and Susceptibility-Weighted (SWI) Magnetic Resonance Imaging (MRI) sequences, corresponding to areas of hemosiderin breakdown products from prior microscopic hemorrhages. They occur in the setting of impaired small vessel integrity, commonly due to either hypertensive vasculopathy or cerebral amyloid angiopathy. Microbleeds are more prevalent in individuals with Alzheimer’s disease (AD) dementia and in those with both ischemic and hemorrhagic stroke. However they are also found in asymptomatic individuals, with increasing prevalence with age, particularly in carriers of the Apolipoprotein (APOE) ε4 allele. Other neuroimaging findings that have been linked with microbleeds include lacunar infarcts and white matter hyperintensities on MRI, and increased cerebral β-amyloid burden using ¹¹C-PiB Positron Emission Tomography. The presence of microbleeds has been suggested to confer increased risk of incident intracerebral hemorrhage – particularly in the setting of anticoagulation – and of complications of immunotherapy for AD. Prospective data regarding the natural history and sequelae of microbleeds are currently limited, however there is a growing evidence base that will serve to inform clinical decision-making in the future.

Spontaneous intracerebral hemorrhage in CADASIL

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary small vascular disease and its mainly clinical manifestations are ischemic events. Spontaneous intracerebral hemorrhage (ICH) involvement in patients with CADASIL is extremely uncommon.

CASE REPORT

A 46-year-old normotensive Chinese man developed a large hematoma in the left basal ganglia after he was diagnosed with CADASIL 2 months ago, the patient did not take any antithrombotics. Susceptibility weighted imaging at pre-ICH showed multiple cerebral microbleeds (CMBs) in the bilateral basal ganglia. He experienced migraine at about 10 months post-ICH. To our knowledge, this is the first report of ICH in CADASIL patients with Arg90Cys mutation in exon 3.

DISCUSSION AND CONCLUSIONS

ICH should be considered when evaluating new attacks in CADASIL patients. Thus, MRI screening for CMBs might be helpful in predicting the risk of ICH and guiding antithrombotic therapy. In addition, strict control of hypertension and cautious use of antithrombotics may be important in this context.

New Appearance of Extraischemic Microbleeds on T2*-Weighted Magnetic Resonance Imaging 24 Hours After Tissue-type Plasminogen Activator Administration

Background and Purpose—

It is unknown whether new-extraischemic microbleeds (new-EMBs) develop rapidly after tissue-type plasminogen activator (tPA) infusion. We hypothesized that new-EMBs may develop rapidly after tPA infusion using T2*-weighted MRI (T2*) and investigated the frequency and clinical factors associated with new-EMBs.

Methods—

Patients with acute stroke within 3 hours of onset who were treated with tissue-type plasminogen activator (tPA) were studied prospectively. T2* was performed before and 24 hours after tPA therapy. Independent clinical factors associated with new-EMBs development were examined using multivariate logistic regression analysis.

Results—

A total of 224 patients (121 men; mean age, 76.2±10.6 years) were enrolled in the present study. MBs before tPA infusion were observed in 72 (32.1%) patients. Within 24 hours after tPA infusion, 6 (2.7%) patients had symptomatic intracranial hemorrhage (extraischemic [n=4], and hemorrhagic transformation [n=2]). Follow-up T2* revealed asymptomatic new-EMBs in 11 (4.9%) patients and hemorrhagic transformation in the infarcted area in 65 (29.0%). The total and mean number of new-EMBs were 23 and 1.6±1.3, respectively. Patients with new-EMBs more frequently had symptomatic extraischemic hemorrhage than those without new-EMBs (27.3% [3/11] versus 0.5% [1/213]; P =0.0003). However, the frequency of hemorrhagic transformation was not different between patients with and without new-EMBs (27.3% versus 29.1%; P =0.9999). Multivariate logistic regression demonstrated that the presence of MBs before tPA infusion was the only independent factor associated with new-EMBs (odds ratio, 10.6; 95% confidence interval, 20.68–54.279; P =0.0046).

Conclusions—

New-EMBs occurred rapidly after tPA infusion in 4.9% of patients. The presence of MBs before tPA therapy was associated with new-EMBs. Patients with new-EMBs are likely to have symptomatic extraischemic hemorrhage.

Relationship between the phase value of ESWAN and fractional anisotropy of diffusion tensor imaging in patients with cerebral microbleeds: preliminary results

AIMS

The purpose of the present study was to measure phase values (PVs) and fractional anisotropy (FA) of cerebral microbleeds (CMBs) using phase and FA map, and to investigate the potential relationship between PVs and FAs in CMBs in vivo.

METHODS

We retrospectively analyzed 30 patients with CMBs using enhanced T2*-weighted angiography and diffusion tensor imaging. The PVs and FAs of CMBs were measured and documented, and the mean FAs were compared between CMBs and the corresponding normal brain tissue. The mean PVs were correlated with FAs in CMBs in seven different brain regions.

RESULTS

A total of 106 CMBs were defined, and the mean FA of the CMBs in white matter, EC/IC/CR, thalamus, and cerebellum were significantly lower than that of normal brain tissue in the control group (p<0.05). Positive correlations were observed between the PV and FA of CMBs in white matter, external capsule, internal capsule and corona radiata (r=0.70, 0.38).

CONCLUSION

Enhanced T2*-weighted angiography and diffusion tensor imaging sequence may be useful neuroimaging sequences that could reflect the severity of damage of white matter by measuring the FA of CMBs and provide useful reference data for the quantitative assessment of CMBs.