Underlying Small Vessel Disease Associated With Mixed Cerebral Microbleeds

Cognitive impairment in cerebral small vessel disease induced by hypertension

ABSTRACT

Hypertension is a primary risk factor for the progression of cognitive impairment caused by cerebral small vessel disease, the most common cerebrovascular disease. However, the causal relationship between hypertension and cerebral small vessel disease remains unclear. Hypertension has substantial negative impacts on brain health and is recognized as a risk factor for cerebrovascular disease. Chronic hypertension and lifestyle factors are associated with risks for stroke and dementia, and cerebral small vessel disease can cause dementia and stroke. Hypertension is the main driver of cerebral small vessel disease, which changes the structure and function of cerebral vessels via various mechanisms and leads to lacunar infarction, leukoaraiosis, white matter lesions, and intracerebral hemorrhage, ultimately resulting in cognitive decline and demonstrating that the brain is the target organ of hypertension. This review updates our understanding of the pathogenesis of hypertension-induced cerebral small vessel disease and the resulting changes in brain structure and function and declines in cognitive ability. We also discuss drugs to treat cerebral small vessel disease and cognitive impairment.

Novel inflammatory and insulin resistance indices provide a clue in cerebral amyloid angiopathy

This study investigated the correlation of newly identified inflammatory and insulin resistance indices with cerebral amyloid angiopathy (CAA), and explored their potential to differentiate CAA from hypertensive arteriopathy (HA). We retrospectively analyzed 514 consecutive patients with cerebral small vessel disease (CSVD)-related haemorrhage, comparing the differences in novel inflammatory and insulin resistance indices between patients with CAA and HA. Univariate regression, LASSO and multivariate regression were used to screen variables and construct a classification diagnosis nomogram. Additionally, these biomarkers were explored in patients with mixed haemorrhagic CSVD. Inflammatory indices were higher in CAA patients, whereas insulin resistance indices were higher in HA patients. Further analysis identified neutrophil-to-lymphocyte ratio (NLR, OR 1.17, 95% CI 1.07-1.30, P < 0.001), and triglyceride-glucose index (TyG, OR = 0.56, 95% CI 0.36-0.83, P = 0.005) as independent factors for CAA. Therefore, we constructed a CAA prediction nomogram without haemorrhagic imaging markers. The nomogram yielded an area under the curve (AUC) of 0.811 (95% CI 0.764-0.865) in the training set and 0.830 (95% CI 0.718-0.887) in the test set, indicating an ability to identify high-risk CAA patients. These results show that CSVD patients can be phenotyped using novel inflammatory and insulin resistance indices, potentially allowing identification of high-risk CAA patients without haemorrhagic imaging markers.

Aldosteronism is associated with more severe cerebral small vessel disease in hypertensive intracerebral hemorrhage

Primary aldosteronism is associated with various types of cardiovascular and cerebrovascular damage independently of hypertension. Although chronic hypertension and related cerebral arteriosclerosis are the main risk factors for intracerebral hemorrhage, the effects of aldosteronism remain poorly understood. We enrolled 90 survivors of hypertensive intracerebral hemorrhage, 21 of them with aldosteronism and 69 with essential hypertension as controls in this study. Clinical parameters and neuroimaging markers of cerebral small vessel disease were recorded, and its correlations with aldosteronism were investigated. Our results showed that the aldosteronism group (55.2 ± 9.7 years, male 47.6%) had similar hypertension severity but exhibited a higher cerebral microbleed count (interquartile range) (8.5 [2.0‒25.8] vs 3 [1.0‒6.0], P = 0.005) and higher severity of dilated perivascular space in the basal ganglia (severe perivascular space [number >20], 52.4% vs. 24.6%, P = 0.029; large perivascular space [>3 mm], 52.4% vs. 20.3%, P = 0.010), compared to those with essential hypertension (53.8 ± 11.7 years, male 73.9%). In multivariate models, aldosteronism remained an independent predictor of a higher (>10) microbleed count (odds ratio = 8.60, P = 0.004), severe perivascular space (odds ratio = 4.00, P = 0.038); the aldosterone-to-renin ratio was associated with dilated perivascular space (P = 0.043) and large perivascular space (P = 0.008). In conclusions, survivors of intracerebral hemorrhage with aldosteronism showed a tendency towards more severe hypertensive arteriopathy than the essential hypertension counterparts independently of blood pressure; aldosteronism may contribute to dilated perivascular space around the deep perforating arteries. Aldosteronism is associated with more severe cerebral small vessel disease in hypertensive intracerebral hemorrhage.

In-vivo diagnosis of cerebral amyloid angiopathy: an updated review

PURPOSE OF REVIEW

Sporadic cerebral amyloid angiopathy (CAA) is a highly prevalent small vessel disease in ageing population with potential severe complications including lobar intracerebral hemorrhage (ICH), cognitive impairment, and dementia. Although diagnosis of CAA was made only with postmortem neuropathological examination a few decades ago, diagnosing CAA without pathological proof is now allowed in living patients. This review focuses on recently identified biomarkers of CAA and current diagnostic criteria.

RECENT FINDINGS

Over the past few years, clinicians and researchers have shown increased interest for CAA, and important advances have been made. Thanks to recent insights into mechanisms involved in CAA and advances in structural and functional neuroimaging, PET amyloid tracers, cerebrospinal fluid and plasma biomarkers analysis, a growing number of biomarkers of CAA have been identified. Imaging-based diagnostic criteria including emerging biomarkers have been recently developed or updated, enabling accurate and earlier diagnosis of CAA in living patients.

SUMMARY

Recent advances in neuroimaging allow diagnosing CAA in the absence of pathological examination. Current imaging-based criteria have high diagnostic performance in patients presenting with ICH, but is more limited in other clinical context such as cognitively impaired patients or asymptomatic individuals. Further research is still needed to improve diagnostic accuracy.

CADMUS: A Novel MRI-Based Classification of Spontaneous Intracerebral Hemorrhage Associated With Cerebral Small Vessel Disease

BACKGROUND AND OBJECTIVES

Cerebral small vessel disease (SVD) is the major cause of intracerebral hemorrhage (ICH). There is no comprehensive, easily applicable classification of ICH subtypes according to the presumed underlying SVD using MRI. We developed an MRI-based classification for SVD-related ICH.

METHODS

We performed a retrospective study in the prospectively collected Swiss Stroke Registry (SSR, 2013-2019) and the Stroke InvestiGation in North And central London (SIGNAL) cohort. Patients with nontraumatic, SVD-related ICH and available MRI within 3 months were classified as Cerebral Amyloid angiopathy (CAA), Deep perforator arteriopathy (DPA), Mixed CAA-DPA, or Undetermined SVD using hemorrhagic and nonhemorrhagic MRI markers (CADMUS classification). The primary outcome was inter-rater reliability using Gwet's AC1. Secondary outcomes were recurrent ICH/ischemic stroke at 3 months according to the CADMUS phenotype. We performed Firth penalized logistic regressions and competing risk analyses.

RESULTS

The SSR cohort included 1,180 patients (median age [interquartile range] 73 [62-80] years, baseline NIH Stroke Scale 6 [2-12], 45.6% lobar hematoma, systolic blood pressure on admission 166 [145-185] mm Hg). The CADMUS phenotypes were as follows: mixed CAA-DPA (n = 751 patients, 63.6%), undetermined SVD (n = 203, 17.2%), CAA (n = 154, 13.1%), and DPA (n = 72, 6.3%), with a similar distribution in the SIGNAL cohort (n = 313). Inter-rater reliability was good (Gwet's AC1 for SSR/SIGNAL 0.69/0.74). During follow-up, 56 patients had 57 events (28 ICH, 29 ischemic strokes). Three-month event rates were comparable between the CADMUS phenotypes.

DISCUSSION

CADMUS, a novel MRI-based classification for SVD-associated ICH, is feasible and reproducible and may improve the classification of ICH subtypes in clinical practice and research.

A bibliometric analysis of cerebral microbleeds and cognitive impairment

BACKGROUND AND OBJECTIVES

Cerebral microbleeds (CMBs) are imaging markers for small cerebral vascular diseases, which can accumulate and impact the corresponding brain networks. CMBs can affect cognitive function, including executive function, information processing speed, and visuospatial memory. Bibliometrics is a scientific and innovative method that can analyze and visualize the scientific field quantitatively. In this study, we aimed to use bibliometric analysis to demonstrate the relationship and mechanisms between CMBs and cognitive impairment. Furthermore, we reviewed the relationship between CMBs and different cognitive disorders. The use of bibliometrics can help further clarify this relationship.

METHODS

We retrieved articles on CMBs and cognitive impairment from the Web of Science Core Collection. The keywords (such as stroke, dementia, and cerebral amyloid angiopathy), authors, countries, institutions and journals, in the field were visually analyzed using VOSviewer software and bibliometric websites.

RESULTS

This bibliometric analysis reveals the related trends of CMBs in the field of cognitive impairment. CMBs, along with other small vascular lesions, constitute the basis of cognitive impairment, and studying CMBs is essential to understand the mechanisms underlying cognitive impairment.

CONCLUSION

This bibliometric analysis reveals a strong link between CMBs and cognitive impairment-related diseases and that specific brain networks were affected by CMBs. This provides further insights into the possible mechanisms and causes of CMBs and cognitive impairment. The direct and indirect damage (such as oxidative stress and neuroinflammation) to the brain caused by CMBs, destruction of the frontal-subcortical circuits, elevated Cystatin C levels, and iron deposition are involved in the occurrence and development of cognitive impairment. CMBs may be a potential marker for detecting, quantifying, and predicting cognitive impairment.

A Causal Classification System for Intracerebral Hemorrhage Subtypes

OBJECTIVE

Determining the underlying causes of intracerebral hemorrhage (ICH) is of major importance, because risk factors, prognosis, and management differ by ICH subtype. We developed a new causal CLASsification system for ICH Subtypes, termed CLAS-ICH, based on recent advances in neuroimaging.

METHODS

CLAS-ICH defines 5 ICH subtypes: arteriolosclerosis, cerebral amyloid angiopathy, mixed small vessel disease (SVD), other rare forms of SVD (genetic SVD and others), and secondary causes (macrovascular causes, tumor, and other rare causes). Every patient is scored in each category according to the level of diagnostic evidence: (1) well-defined ICH subtype; (2) possible underlying disease; and (0) no evidence of the disease. We evaluated CLAS-ICH in a derivation cohort of 113 patients with ICH from Massachusetts General Hospital, Boston, USA, and in a derivation cohort of 203 patients from Inselspital, Bern, Switzerland.

RESULTS

In the derivation cohort, a well-defined ICH subtype could be identified in 74 (65.5%) patients, including 24 (21.2%) with arteriolosclerosis, 23 (20.4%) with cerebral amyloid angiopathy, 18 (15.9%) with mixed SVD, and 9 (8.0%) with a secondary cause. One or more possible causes were identified in 42 (37.2%) patients. Interobserver agreement was excellent for each category (kappa value ranging from 0.86 to 1.00). Despite substantial differences in imaging modalities, we obtained similar results in the validation cohort.

INTERPRETATION

CLAS-ICH is a simple and reliable classification system for ICH subtyping, that captures overlap between causes and the level of diagnostic evidence. CLAS-ICH may guide clinicians to identify ICH causes, and improve ICH classification in multicenter studies. ANN NEUROL 2023;93:16-28.

Frequency of deep-seated cerebral microbleeds in patients with lobar hemorrhages and histopathological evidence for cerebral amyloid angiopathy

Background

Cerebral amyloid angiopathy (CAA) is a common disease and the most common cause of lobar hemorrhages in the elderly. Usually, deep-seated microhemorrhages preclude the diagnosis of CAA. In this study, we sought to estimate the frequency of deep-seated microbleeds on MRI in patients with lobar hemorrhages and histopathological evidence for cerebral amyloid angiopathy. In addition, we describe a cohort of patients with cortical and deep-seated microbleeds on MRI and a histopathological specimen available from lobar hematoma evacuation.

Methods

Retrospective database search for histopathological specimens from lobar hematoma evacuation and review of imaging findings (CT and MRI) and patient charts was performed.

Results

Between 1 January 2012 and 31 December 2020, 88 specimens from 88 patients were available. A total of 56 specimens were excluded (no brain tissue in the specimen n = 4, other diagnosis n = 8, no MRI n = 43, and no BOLD-based sequence n = 1). Of the remaining 32 patients, 25 patients (78%) did not harbor deep-seated lesions on MRI, of which 17 patients had histopathological features of CAA. A total of seven patients harbored deep-seated CMB. Of these seven patients, three (3/20, 15%) had histopathological features of CAA.

Conclusion

Approximately 15% of patients with histopathologically diagnosed CAA harbor deep-seated microbleeds. This finding may add to the discussion on how to identify patients with CAA and deep-seated CMB.

Prevalence and characterization of cerebral small vessel disease in young adults with intracerebral hemorrhage

BACKGROUND AND AIMS

Cerebral small vessel disease (CSVD) is the main cause of intracerebral hemorrhage (ICH) in older individuals but has not been systematically studied in younger people. We aimed to evaluate the prevalence and characteristics of CSVD in young adults with symptomatic ICH.

METHODS

We conducted a cohort study of consecutive adults aged 18-50 years with non-traumatic ICH. All patients were evaluated with brain and vascular imaging. Using validated imaging markers (cerebral microbleeds (CMBs), white matter hyperintensities and/or lacunes), patients were categorized as having CSVD-related ICH or non-CSVD-related ICH. Factors associated with CSVD were evaluated using multivariable analyses. CSVD subtypes were characterized using pre-specified criteria.

RESULTS

Of 146 young adults with ICH (mean age = 37.7), CSVD was present in 41 patients (28.1%; 95% confidence interval (CI) = 21.0-36.1). In multivariable analysis, older age, male sex, and hypertension were independently associated with the presence of CSVD. Deep perforator arteriopathy (48.8%) and mixed CSVD (31.7%) were the most common CSVD subtypes.

CONCLUSION

Our results suggest that CSVD is a frequent cause of ICH in young adults and provide new insights into the characterization of the disease. These findings may have important implications since the treatment and management differ from other causes of ICH.

Circle of Willis Morphology in Primary Intracerebral Hemorrhage

We aimed to study the distribution of Circle of Willis (CoW) morphology and its association with intracerebral hemorrhage (ICH) etiology and cerebral small vessel disease (CSVD) burden. Patients with primary ICH who had brain MRIs were consecutively enrolled between March 2012 and January 2021. CoW morphology, CSVD features and the combined CSVD burden (including global CSVD burden, total hypertensive arteriopathy [HA] burden, and total cerebral amyloid angiopathy [CAA] burden) were assessed. CoW morphology included poor CoW (defined as CoW score 0-2), incomplete CoW, and complete fetal-variant of the posterior communicating artery (CFPcoA). Among 296 patients enrolled, 215 were included in the analysis. There was no significant difference among HA-, CAA-, and mixed-ICH in each CoW morphology. Exploratory subgroup analyses suggested that poor CoW was associated with a greater incidence of HA-ICH and low incidence of mixed ICH in patients aged < 60 years, while mixed ICH occurred more frequently in patients with CFPcoA, especially in those without hypertension history (all p < 0.050). Additionally, incomplete CoW was correlated with a larger incidence of lacunes (adjusted OR [adOR] 2.114, 95% CI 1.062-4.207), microbleeds ≥ 5 (adOR 2.437, 95% CI 1.187-5.002), and therefore the combined CSVD burden (adOR 1.194, 95% CI 1.004-1.419 for global CSVD burden, adOR 1.343, 95% CI 1.056-1.707 for total CAA burden), independent of modifiable vascular risk factors, but not age and sex. The CoW might therefore have a potential impact on ICH etiology and is associated with a greater CSVD burden. Our findings are novel, and need to be verified in future studies.

Clinical neuroimaging in intracerebral haemorrhage related to cerebral small vessel disease: contemporary practice and emerging concepts

INTRODUCTION

About 80% of all non-traumatic intracerebral haemorrhage (ICH) are caused by the sporadic cerebral small vessel diseases deep perforator arteriopathy (DPA, also termed hypertensive arteriopathy or arteriolosclerosis) and cerebral amyloid angiopathy (CAA), though these frequently co-exist in older people. Contemporary neuroimaging (MRI and CT) detects an increasing spectrum of haemorrhagic and non-haemorrhagic imaging biomarkers of small vessel disease which may identify the underlying arteriopathies.

AREAS COVERED

We discuss biomarkers for cerebral small vessel disease subtypes in ICH, and explore their implications for clinical practice and research.

EXPERT OPINION

ICH is not a single disease, but results from a defined range of vascular pathologies with important implications for prognosis and treatment. The terms "primary" and "hypertensive" ICH are poorly defined and should be avoided, as they encourage incomplete investigation and classification. Imaging-based criteria for CAA will show improved diagnostic accuracy, but specific imaging biomarkers of DPA are needed. Ultra-high-field 7T-MRI using structural and quantitative MRI may provide further insights into mechanisms and pathophysiology of small vessel disease. We expect neuroimaging biomarkers and classifications to allow personalized treatments (e.g. antithrombotic drugs) in clinical practice and to improve patient selection and monitoring in trials of targeted therapies directed at the underlying arteriopathies.

Comparison of clinical and neuroimaging features between NOTCH3 mutations and nongenetic spontaneous intracerebral haemorrhage

BACKGROUND

The NOTCH3 mutation is a common cause of hereditary cerebral small vessel disease (CSVD) and may be a cause of spontaneous intracerebral haemorrhage (ICH). We aimed to investigate the clinical/imaging features for identifying the NOTCH3 mutations related ICH.

METHODS

The study was based on a cohort of 749 CSVD patients in Taiwan who received next-generation sequencing of CSVD genes including NOTCH3. Patients with history of ICH (n=206) were included for analysis. The CSVD neuroimaging markers were compared between the patients with NOTCH3 and without known genetic mutations.

RESULTS

After excluding the patients with other causes of ICH (structural lesions, systemic/medication-related, or amyloid angiopathy) and those without neuroimaging, 45 NOTCH3 mutation patients and 109 nongenetic ICH patients were included. The NOTCH3 mutation patients were more likely to have thalamic haemorrhage, a family history of stroke, and more severe CSVD neuroimaging markers. A five-point NOTCH3-ICH score was constructed and consisted of: history of stroke in siblings, thalamic haemorrhage, any deep nuclei lacunae, any hippocampal cerebral microbleed (CMB), and a thalamic CMB >5 (one point for each). A score ≥2 had a sensitivity of 88.9% and a specificity of 64.2% in identifying the NOTCH3 mutation. The NOTCH3 mutation patients had a higher risk of recurrent stroke (9.1 vs. 4.5 per 100 person-years; log-rank p = 0.03) during follow-up.

CONCLUSION

The patients with NOTCH3 mutation-related ICH had a higher burden of CMB in the hippocampus/thalamus and a higher recurrent stroke risk. The NOTCH3-ICH score may assist identifying genetic causes of ICH.

Inflammation and the Link to Vascular Brain Health: Timing Is Brain

Inflammation and its myriad pathways are now recognized to play both causal and consequential roles in vascular brain health. From acting as a trigger for vascular brain injury, as evidenced by the coronavirus disease 2019 (COVID-19) pandemic, to steadily increasing the risk for chronic cerebrovascular disease, distinct inflammatory cascades play differential roles in varying states of cerebrovascular injury. New evidence is regularly emerging that characterizes the role of specific inflammatory pathways in these varying states including those at risk for stroke and chronic cerebrovascular injury as well as during the acute, subacute, and repair phases of stroke. Here, we aim to highlight recent basic science and clinical evidence for many distinct inflammatory cascades active in these varying states of cerebrovascular injury. The role of cerebrovascular infections, spotlighted by the severe acute respiratory syndrome coronavirus 2 pandemic, and its association with increased stroke risk is also reviewed. Rather than converging on a shared mechanism, these emerging studies implicate varied and distinct inflammatory processes in vascular brain injury and repair. Recognition of the phasic nature of inflammatory cascades on varying states of cerebrovascular disease is likely essential to the development and implementation of an anti-inflammatory strategy in the prevention, treatment, and repair of vascular brain injury. Although advances in revascularization have taught us that time is brain, targeting inflammation for the treatment of cerebrovascular disease will undoubtedly show us that timing is brain.

Disrupted White Matter Integrity and Cognitive Functions in Amyloid-β Positive Alzheimer's Disease with Concomitant Lobar Cerebral Microbleeds

BACKGROUND

Lobar cerebral microbleeds (CMBs), which can impair white matter (WM), are often concomitant with definite Alzheimer's disease (AD).

OBJECTIVE

To explore the features of cognitive impairments and WM disruptions due to lobar CMBs in patients with AD.

METHODS

There were 310 participants who underwent Florbetapir F18 (AV45) amyloid PET and susceptibility-weighted imaging. Participants with cognitive impairment and amyloid-β positive (ADCI) were included into three groups: ADCI without CMBs, with strictly lobar CMBs (SL-CMBs), and with mixed CMBs (M-CMBs). Tract-based spatial statistics were performed to detect the group differences in WM integrity.

RESULTS

There were 82 patients and 29 healthy controls finally included. A decreasing tendency in memory and executive performance can be found among HCs > no CMBs (n = 16) >SL-CMBs (n = 41) >M-CMBs (n = 25) group. Compared to no CMBs, M-CMBs group had significantly decreased fractional anisotropy in left anterior thalamic radiation (ATR), forceps major, forceps minor and inferior longitudinal fasciculus, bilateral inferior fronto-occipital fasciculus (IFOF), and superior longitudinal fasciculus. M-CMBs group also had lower fractional anisotropy in left ATR, IFOF, uncinate fasciculus, and forceps minor compared with SL-CMBs. Furthermore, analysis of Pearson correlation indicated damages in discrepant WMs were positively associated with impairment of memory, executive function, and attention.

CONCLUSION

This study showed lobar CMBs had intensively aggravated cognitive impairments associated with extensive WM damages in definite AD. These findings highlight that lobar CMBs play an important role in AD progression and need to be taken into consideration for the early detection of AD.

Prevalence of cerebral amyloid angiopathy: A systematic review and meta-analysis

Reported prevalence estimates of sporadic cerebral amyloid angiopathy (CAA) vary widely. CAA is associated with cognitive dysfunction and intracerebral hemorrhage, and linked to immunotherapy‐related side‐effects in Alzheimer's disease (AD). Given ongoing efforts to develop AD immunotherapy, accurate estimates of CAA prevalence are important. CAA can be diagnosed neuropathologically or during life using MRI markers including strictly lobar microbleeds. In this meta‐analysis of 170 studies including over 73,000 subjects, we show that in patients with AD, CAA prevalence based on pathology (48%) is twice that based on presence of strictly lobar cerebral microbleeds (22%); in the general population this difference is three‐fold (23% vs 7%). Both methods yield similar estimated prevalences of CAA in cognitively normal elderly (5% to 7%), in patients with intracerebral hemorrhage (19% to 24%), and in patients with lobar intracerebral hemorrhage (50% to 57%). However, we observed large heterogeneity among neuropathology and MRI protocols, which calls for standardized assessment and reporting of CAA.

Cerebral microbleeds: from depiction to interpretation

Cerebral microbleeds (CMBs) are defined as hypointense foci visible on T2*-weighted and susceptible-weighted MRI sequences. CMBs are increasingly recognised with the widespread use of MRI in healthy individuals as well as in the context of cerebrovascular disease or dementia. They can also be encountered in major critical medical conditions such as in patients requiring extracorporeal mechanical oxygenation. The advent of MRI-guided postmortem neuropathological examinations confirmed that, in the context of cerebrovascular disease, the vast majority of CMBs correspond to recent or old microhaemorrhages. Detection of CMBs is highly influenced by MRI parameters, in particular field strength, postprocessing methods used to enhance T2* contrast and three dimensional sequences. Despite recent progress, harmonising imaging parameters across research studies remains necessary to improve cross-study comparisons. CMBs are helpful markers to identify the nature and the severity of the underlying chronic small vessel disease. In daily clinical practice, presence and numbers of CMBs often trigger uncertainty for clinicians especially when antithrombotic treatments and acute reperfusion therapies are discussed. In the present review, we discuss those clinical dilemmas and address the value of CMBs as diagnostic and prognostic markers for future vascular events.

Role of neuroimaging before reperfusion therapy. Part 1 - IV thrombolysis - Review

This review paper summarises the yield of the different imaging modalities in the evaluation of patients for IV thrombolysis. Non-contrast CT and CTA or brain MRI combined with MRA are the recommended sequences for the evaluation of patients within the 4.5 hours time window. Multimodal MRI (DWI/PWI), and more recently, CT perfusion, offer reliable surrogate of salvageable penumbra, the target mismatch, which is now currently used as selection criteria for revascularisation treatment in an extended time window. Those sequences may also help the physician for the management of other limited cases when the diagnosis of acute ischemic stroke is difficult. Another approach the DWI/FLAIR mismatch has been proposed to identify among wake-up stroke patients those who have been experiencing an acute ischemic stroke evolving from less than 4.5hrs. Other biomarkers, such as the clot imaging on MRI and CT, help to predict the recanalisation rate after IVT, while the impact of the presence microbleeds on MRI remains to be determined.

Long-Term Vascular Outcomes in Patients With Mixed Location Intracerebral Hemorrhage and Microbleeds

OBJECTIVE

To determine whether mixed location intracerebral hemorrhages/microbleeds (mixed ICH) is a risk factor for vascular unfavorable outcome compared to cerebral amyloid angiopathy-related ICH (CAA-ICH) or strictly deep hypertensive ICH/microbleeds (HTN-ICH).

METHODS

A total of 300 patients with spontaneous ICH were included. Clinical data, neuroimaging markers, and follow-up outcomes (recurrent ICH, ischemic stroke, and vascular death) were compared among mixed ICH (n = 148), CAA-ICH (n = 32), and HTN-ICH (n = 120). The association between follow-up events and neuroimaging markers was explored using multivariable Cox regression models.

RESULTS

Patients with mixed ICH were older (65.6 ± 12.1 years vs 58.1 ± 13.3 years, p < 0.001) than patients with HTN-ICH, but younger than patients with CAA-ICH (73.3 ± 13.8 years, p = 0.001). Compared to CAA-ICH, mixed ICH had similar incidence of vascular events (all p > 0.05). Compared to HTN-ICH, mixed ICH is associated with higher ICH recurrence (hazard ratio [HR] 3.0, 95% confidence interval [CI] 1.2-7.7), more ischemic stroke (HR 8.2, 95% CI 1.0-65.8), and vascular composite outcome (HR 3.5, 95% CI 1.5-8.2) after adjustment for age and sex. In patients with mixed ICH, the presence of cortical superficial siderosis (cSS) is associated the development of ICH recurrence (HR 4.8, 95% CI 1.0-23.2), ischemic stroke (HR 8.8, 95% CI 1.7-45.5), and vascular composite outcome (HR 6.2, 95% CI 1.9-20.2). The association between cSS and ischemic stroke (p = 0.01) or vascular composite outcome (p = 0.003) remained significant after further adjustment for other radiologic markers.

CONCLUSIONS

Mixed ICH harbors higher risk of unfavorable vascular outcome than HTN-ICH. Presence of cSS in mixed ICH independently predicts vascular event, suggesting the contribution of detrimental effect due to coexisting CAA.

Intracerebral haemorrhage, microbleeds and antithrombotic drugs

Antithrombotic therapy is a cornerstone for secondary prevention of ischaemic events, cerebral and extra-cerebral. A number of clinical questions remain unanswered concerning the impact of antithrombotic drugs on the risk of first-ever and recurrent macro or micro cerebral haemorrhages, raising the clinical dilemma on the risk/benefit balance of giving antiplatelets and anticoagulants in patients with potential high risk of brain bleeds. High field magnetic resonance imaging (MRI) blood-weighted sequences, including susceptibility weighted imaging (SWI), have expanded the spectrum of these clinical questions, because of their increasing sensitivity in detecting radiological markers of small vessel disease. This review will summarise the literature, focusing on four main clinical questions: how do cerebral microbleeds impact the risk of cerebrovascular events in healthy patients, in patients with previous ischaemic stroke or transient ischaemic attack, and in patients with intracerebral haemorrhage? Is the risk/benefit balance of oral anticoagulants shifted by the presence of microbleeds in patients with atrial fibrillation after recent ischaemic stroke or transient ischaemic attack? Should we restart antiplatelet drugs after symptomatic intracerebral haemorrhage or not? Are oral anticoagulants allowed in patients with a history of atrial fibrillation and previous intracerebral haemorrhage?

Clinical and radiological differences between patients with probable cerebral amyloid angiopathy and mixed cerebral microbleeds

BACKGROUND

The key imaging features of cerebral amyloid angiopathy (CAA) are lobar, cortical, or cortico-subcortical microbleeds, macrohaemorrhages and cortical superficial siderosis (cSS). In contrast, hypertensive angiopathy is characterized by (micro) haemorrhages in the basal ganglia, thalami, periventricular white matter or the brain stem. Another distinct form of haemorrhagic microangiopathy is mixed cerebral microbleeds (mixed CMB) with features of both CAA and hypertensive angiopathy. The distinction between the two entities (CAA and mixed CMB) is clinically relevant because the risk of haemorrhage and stroke should be well balanced if oral anticoagulation is indicated in CAA patients. We aimed to comprehensively compare these two entities.

METHODS

Patients with probable CAA according to the modified Boston criteria and mixed CMB without macrohaemorrhage were retrospectively identified from our database. Comprehensive comparison regarding clinical and radiological parameters was performed between the two cohorts.

RESULTS

Patients with CAA were older (78 ± 8 vs. 74 ± 9 years, p = 0.036) and had a higher prevalence of cSS (19% vs. 4%, p = 0.027) but a lower prevalence of lacunes (73% vs. 50%, p = 0.018) and deep lacunes (23% vs. 51%, p = 0.0003) compared to patients with mixed CMB. Logistic regression revealed an association between the presence of deep lacunes and mixed CMB. The other collected parameters did not reveal a significant difference between the two groups.

CONCLUSIONS

CAA and mixed CMB demonstrate radiological differences in the absence of macrohaemorrhages. However, more clinically available biomarkers are needed to elucidate the contribution of CAA and hypertensive angiopathy in mixed CMB patients.