SPARKLE (Subtypes of Ischaemic Stroke Classification System), incorporating measurement of carotid plaque burden: a new validated tool for the classification of ischemic stroke subtypes

Carotid stenosis and cryptogenic stroke

OBJECTIVES

Cryptogenic stroke represents a type of ischemic stroke with an unknown origin, presenting a significant challenge in both stroke management and prevention. According to the Trial of Org 10,172 in Acute Stroke Treatment criteria, a stroke is categorized as being caused by large artery atherosclerosis only when there is >50% luminal narrowing of the ipsilateral internal carotid artery. However, nonstenosing carotid artery plaques can be an underlying cause of ischemic stroke. Indeed, emerging evidence documents that some features of plaque vulnerability may act as an independent risk factor, regardless of the degree of stenosis, in precipitating cerebrovascular events. This review, drawing from an array of imaging-based studies, explores the predictive values of carotid imaging modalities in the detection of nonstenosing carotid plaque (<50%), that could be the cause of a cerebrovascular event when some features of vulnerability are present.

METHODS

Google Scholar, Scopus, and PubMed were searched for articles on cryptogenic stroke and those reporting the association between cryptogenic stroke and imaging features of carotid plaque vulnerability.

RESULTS

Despite extensive diagnostic evaluations, the etiology of a considerable proportion of strokes remains undetermined, contributing to the recurrence rate and persistent morbidity in affected individuals. Advances in imaging modalities, such as magnetic resonance imaging, computed tomography scans, and ultrasound examination, facilitate more accurate detection of nonstenosing carotid artery plaque and allow better stratification of stroke risk, leading to a more tailored treatment strategy.

CONCLUSIONS

Early detection of nonstenosing carotid plaque with features of vulnerability through carotid imaging techniques impacts the clinical management of cryptogenic stroke, resulting in refined stroke subtype classification and improved patient management. Additional research is required to validate these findings and recommend the integration of these state-of-the-art imaging methodologies into standard diagnostic protocols to improve stroke management and prevention.

Atrial fibrillation and stroke: State-of-the-art and future directions

Atrial fibrillation (AF) and stroke remain a major cause of morbidity and mortality. The two conditions shared common co-morbidities and risk factors. AF-related strokes are associated with worse clinical outcomes and higher mortality compared to non-AF-related. Early detection of AF is vital for prevention. While various scores have been developed to predict AF in such a high-risk group, they are yet to incorporated into clinical guidelines. Novel markers and predictors of AF including coronary and intracranial arterial calcification have also been studied. There are also ongoing debates on the management of acute stroke in patients with AF, and those who experienced breakthrough stroke while on oral anticoagulants. We provided an overview of the complex interplay between AF and stroke, as well as the treatment and secondary prevention of stroke in AF. We also comprehensively discussed the current evidence and the ongoing conundrums, and highlighted the future directions on the topic.

Hospital-Level Variability in Reporting of Ischemic Stroke Subtypes and Supporting Diagnostic Evaluation in GWTG-Stroke Registry

BACKGROUND

Secondary prevention of ischemic stroke (IS) requires adequate diagnostic evaluation to identify the likely etiologic subtype. We describe hospital-level variability in diagnostic testing and IS subtyping in a large nationwide registry.

METHODS AND RESULTS

We used the GWTG-Stroke (Get With The Guidelines-Stroke) registry to identify patients hospitalized with a diagnosis of acute IS at 1906 hospitals between January 1, 2016, and September 30, 2017. We compared the documentation rates and presence of risk factors, diagnostic testing, achievement/quality measures, and outcomes between patients with and without reported IS subtype. Recording of diagnostic evaluation was optional in all IS subtypes except cryptogenic, where it was required. Of 607 563 patients with IS, etiologic IS subtype was documented in 57.4% and missing in 42.6%. Both the rate of missing stroke pathogenesis and the proportion of cryptogenic strokes were highly variable across hospitals. Patients missing stroke pathogenesis less frequently had documentation of risk factors, evidence-based interventions, or discharge to home. The reported rates of major diagnostic testing, including echocardiography, carotid and intracranial vascular imaging, and short-term cardiac monitoring were <50% in patients with documented IS pathogenesis, although these variables were missing in >40% of patients. Long-term cardiac rhythm monitoring was rarely reported, even in cryptogenic stroke.

CONCLUSIONS

Reporting of IS etiologic subtype and supporting diagnostic testing was low overall, with high rates of missing optional data. Improvement in the capture of these data elements is needed to identify opportunities for quality improvement in the diagnostic evaluation and secondary prevention of stroke.

Subcortical infarcts in patients with nonstenotic cervical atherosclerotic disease

BACKGROUND

Prior studies have elucidated a relationship between nonstenotic plaque in patients with cryptogenic embolic infarcts with a largely cortical topology, however, it is unclear if nonstenotic cervical internal carotid artery (ICA) plaque is relevant in subcortical cryptogenic infarct patterns.

METHODS

A nested cohort of consecutive patients with anterior, unilateral, and subcortical infarcts without an identifiable embolic source were identified from a prospective stroke registry (September 2019 - June 2021). Patients with extracranial stenosis >50% or cardiac sources of embolism were excluded. Patients with computed tomography angiography were included and comparisons were made according to the infarct pattern being lacunar versus non-lacunar. Prevalence estimates for cervical internal carotid artery (ICA) plaque presence were estimated with 95% confidence intervals (CI), and differences in plaque thickness and features were compared between sides.

RESULTS

Of the 1684 who were screened, 141 met inclusion criteria (n=80 due to small vessel disease, n=61 cryptogenic). The median age was 66y (interquartile range, IQR 58-73) and the National Institutes of Health Stroke Scale score was 3 (IQR 1-5). There was a higher probability of finding excess plaque ipsilateral to the stroke (41.1%, 95% CI 33.3-49.3%) than finding excess contralateral plaque (29.1%, 95% CI 22.2-37.1%; p=0.03), but this was driven by patients with non-lacunar infarcts (excess ipsilateral vs. contralateral plaque frequency of 49.2% vs. 14.8%, p<0.001) rather than lacunar infarcts (35.0% vs. 40.0%, p=0.51).

CONCLUSIONS

The probability of finding ipsilateral, nonstenotic carotid plaque in patients with subcortical cryptogenic strokes exceeds the probability of contralateral plaque and is driven by larger subcortical infarcts, classically defined as being cryptogenic. Approximately 1 in 3 unilateral anterior subcortical infarcts may be due to nonstenotic ICA plaque.

Why do guidelines recommend screening for abdominal aortic aneurysms, but not for asymptomatic carotid stenosis? A plea for a randomized controlled trial

BACKGROUND

Current guidelines do not recommend screening for asymptomatic carotid artery stenosis (AsxCS). The rationale behind this recommendation is that detection of AsxCS may lead to an unnecessary carotid intervention. In contrast, screening for abdominal aortic aneurysms is strongly recommended.

METHODS

A critical analysis of the literature was performed to evaluate the implications of detecting AsxCS.

RESULTS

Patients with AsxCS are at high risk for future stroke, myocardial infarction and vascular death. Population-wide screening for AsxCS should not be recommended. Additionally, screening of high-risk individuals for AsxCS with the purpose of identifying candidates for a carotid intervention is inappropriate. Instead, selective screening for AsxCS should be considered and should be viewed as an opportunity to identify individuals at high risk for atherosclerotic cardiovascular disease and future cardiovascular events for the timely initiation of intensive medical therapy and risk factor modification.

CONCLUSIONS

Although mass screening should not be recommended, there are several arguments suggesting that selective screening for AsxCS should be considered. The rationale supporting such selective screening is to optimize risk factor control and to initiate intensive medical therapy for prevention of future cardiovascular events, rather than to identify candidates for an intervention.

Carotid total plaque area as an independent predictor of short-term subclinical polyvascular atherosclerosis progression and major adverse cardiac and cerebrovascular events

BACKGROUND

The use of ultrasound-based methods for imaging of subclinical atherosclerosis, including measurement of carotid plaque burden (cPB), is a promising direction for further improvement of major adverse cardiac and cerebrovascular events (MACCE) prediction.

OBJECTIVES

The aim of the study was to research the prognostic values' significance of cPB indicators with regard to the short-term progression of polyvascular subclinical atherosclerosis and the long-term onset of MACCE.

DESIGN

Single-center prospective cohort study.

METHODS

The study included patients 40-64 years of age. All patients underwent duplex scanning (DS) of the carotid and lower limb arteries. The following cPB indicators were determined: carotid plaque score (cPS), maximum carotid plaque thickness (cPTmax), and carotid total plaque area (cTPA). The combined endpoint included the following components: cardiovascular death; nonfatal myocardial infarction; nonfatal stroke or transient ischemic attack (TIA); revascularization of the coronary and/or peripheral arteries.

RESULTS

The study included 387 patients, among whom 142 (36.7%) patients underwent repeated DS after 12-24 months. The median follow-up time was 20.0 (13.0; 36.5) months. MACCE were recorded in 33 (8.52%) of patients. cTPA and cPTmax, but not cPS, were independently associated with the progression of subclinical polyvascular atherosclerosis over a period of 13.9 months of follow-up. cTPA, but not cPTmax and cPS, was independently associated with the development of MACCE over a period of 20.0 months of follow-up. Only a cTPA > 42.0 mm2 proved to be an independent predictor of both the progression of subclinical polyvascular atherosclerosis and MACCE.

CONCLUSION

In patients from 40 to 64 years of age with various cardiovascular risks, among the indicators of the cPB, only an increase in cTPA > 42.0 mm2 was shown to be independently associated with an increase in the relative risk (RR) of progression of subclinical polyvascular atherosclerosis by 2.38 (1.08-5.25) times, as well as with the development of MACCE by 3.10 (1.54-6.26) times.

The role of non-stenosing carotid artery plaques in embolic stroke of undetermined source, is it a silent offender? A review of literature

PURPOSE

Atherosclerotic cervical internal carotid artery disease is one of the major causes of ischemic stroke and transient ischemic attacks. The risk of stroke from mild to moderate stenoses (i.e. <50% stenosis) might be underestimated. There is increasing evidence that plaque morphological features reflect plaque instability that may harbor high risk for embolization. In this narrative review, we will review the literature on plaque features that predict vulnerability beyond the degree of stenosis, discuss the clinical association with stroke, and evaluate the evidence that these lesions serve as a source for embolic stroke of unknown source (ESUS).

METHODS

We performed a literature search using PubMed, EMBASE, and Web of Science. The terms "embolic stroke of undetermined source" and "plaque morphology" were used either alone or in combination with "non-flow limiting stenosis," "non-stenosing plaques," "high-risk plaque features" or "internal carotid artery plaque." Data on plaque morphology and ESUS were mainly taken from review articles, observational studies including retrospective cohort and cross-sectional studies, meta-analyses, and systematic reviews.

CONCLUSION

Nonstenosing carotid artery plaques with high-risk features carry a remarkable risk for stroke occurrence and randomized clinical trials are warranted for further evaluation of using carotid artery stenting or carotid endarterectomy to mitigate the risk of stroke.

Effects of Cervical Rotatory Manipulation on Hemodynamics and Plaque Stability of Atherosclerotic Internal Carotid Artery in Rabbits

OBJECTIVE

The purpose of this study was to investigate the effects of cervical rotatory manipulation (CRM) on hemodynamics and plaque stability of atherosclerotic internal carotid artery (ICA) in rabbits.

METHODS

Forty rabbits were randomly divided into 4 groups: (1) internal carotid atherosclerosis (ICAS) rabbits treated with CRM (ICAS-CRM group); (2) ICAS rabbits treated without CRM (ICAS group), (3) Normal-CRM group (normal rabbits treated with CRM), and (4) blank control group. In the ICAS-CRM group and ICAS group, the ICAS model was induced by ICA balloon injury combined with a high-fat diet for 12 weeks. CRM was applied to rabbits in the ICAS-CRM and the Normal-CRM groups. During the study, an ultrasonography examination was performed for detecting plaque and hemodynamics on the ICAs. At the end of the study, all atherosclerotic ICAs were removed for histological and immunohistochemical detection.

RESULTS

The hemodynamics (especially end-diastolic velocity, resistance index, and pulsatility index) through the ICAs were adversely affected by atherosclerosis while not adversely affected by CRM. Compared with the ICAS group, the micro-vessel density and average integrated optical densities of macrophages in the ICAS-CRM group were significantly increased. Compared to the ICAS group, in the ICAS-CRM group, the atherosclerosis was more serious, and the tunica intima was more unstable.

CONCLUSIONS

Although CRM did not affect the hemodynamic index of ICA, it was observed to decrease the stability of severe ICAS plaques in rabbits, which may increase the plaque vulnerability.

Management of Patients with Embolic Stroke of Unknown Source: Interpreting the Evidence in the Light of Clinical Judgement

PURPOSE OF REVIEW

To assess the validity of the belief that anticoagulation is not beneficial in patients with embolic stroke of unknown source (ESUS), and to asssess the benefits and safety of direct-acting oral anticoagulants (DOACs).

RECENT FINDINGS

The failure of randomized trials to show benefit of anticoagulation in ESUS is probably due to misclassification of large artery atherosclerosis (LAA) as ESUS, as defined by a stenosis ≥ 50%. There are important differences among DOACs. There are a number of problems with dabigatran, and rivaroxaban and edoxaban are not suitable for once-daily dosing. Recent evidence from real-world practice indicates that apixaban is more effective and safer than rivaroxaban. Plaque burden should be included in the definition of LAA. Patients in whom a cardioembolic source is strongly suspected should be anticoagulated; antiplatelet agents are not significantly safer than DOACs, and are not effective in cardioembolic stroke.

Increased level of FAM19A5 is associated with cerebral small vessel disease and leads to a better outcome

Objective

FAM19A5 plays an essential role in the development and acute or chronic inflammation of the central nervous system. The present study aimed to explore the association between FAM19A5 and cerebral small vessel disease (cSVD).

Methods

A total of 344 recent small subcortical infarct (RSSI) patients and 265 healthy controls were included in this study. The difference in the FAM19A5 level between the two groups was compared and the correlation between FAM19A5 and cerebral infarction volume was analyzed. Also, the association between FAM19A5 and the total magnetic resonance imaging (MRI) burden with its imaging characteristics was explored. Moreover, the correspondence of FAM19A5 with the outcome was assessed via Δ National Institutes of Health Stroke Scale score (NIHSS) and the percentage of NIHSS improvement.

Results

FAM19A5 was highly expressed in the RSSI group (P = 0.023), showing a positive correlation with cerebral infarction volume (P < 0.01). It was positively correlated with total MRI cSVD burden (P < 0.001) and reflected the severity of white matter hyperintensity (WMH) (P < 0.01) and enlarged perivascular space (EPVS) (P < 0.01), but did not show any association with cerebral microbleed (CMB) and lacune. Moreover, FAM19A5 suggested a larger Δ NIHSS (P = 0.021) and NIHSS improvement percentage (P = 0.007).

Conclusion

Serum FAM19A5 was increased in RSSI and positively correlated with the infarct volume. It also reflects the total MRI burden of cSVD, of which the imaging characteristics are positively correlated with WMH and EPVS. In addition, higher FAM19A5 levels reflect better outcomes in RSSI patients.

Endarterectomy for symptomatic non-stenotic carotids: a systematic review and descriptive analysis

OBJECTIVE

To systematically analyse prior reports of carotid endarterectomy (CEA) performed in cases of ≤50% carotid stenosis in order to understand patient tolerance and potential benefit.

METHODS

A systematic review and descriptive analysis was performed in concordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An English-language search was performed of online databases using librarian-selected search terms. Abstracts were reviewed for relevance which included mention of carotid endarterectomy and stenosis. Prospective or retrospective observational cohort studies that reported series of patients who underwent endarterectomy for minimal (≤50%) luminal stenosis with reported outcomes were included.

RESULTS

Six studies (which included our institutional series) with a total of 143 patients met the inclusion criteria. The weighted mean age at the time of CEA was 72.3 years; 113 (79.0%) were male. 55.8% of patients with available data had recurrent ipsilateral ischaemic events despite medical therapy. Two patients out of 129 with available perioperative data (1.6%) had perioperative MRI findings of acute ischaemic stroke, both within the hemisphere contralateral to the side of CEA. Of the 138 patients with available follow-up (mean, 36 months), none had recurrent ipsilateral ischaemic events.

CONCLUSIONS

Endarterectomy for symptomatic carotid disease causing ≤50% stenosis may be a potentially beneficial strategy to prevent stroke recurrence. Studies with robust methodology are needed to draw more definitive conclusions in terms of the safety and efficacy of endarterectomy for minimal stenosis with vulnerable features relative to intensive medical therapy.

Vascular Dementia and Crosstalk Between the Complement and Coagulation Systems

Vascular Dementia (VaD) is a neurocognitive disorder caused by reduced blood flow to the brain tissue, resulting in infarction, and is the second most common type of dementia. The complement and coagulation systems are evolutionary host defence mechanisms activated by acute tissue injury to induce inflammation, clot formation and lysis; recent studies have revealed that these systems are closely interlinked. Overactivation of these systems has been recognised to play a key role in the pathogenesis of neurological disorders such as Alzheimer's disease and multiple sclerosis, however their role in VaD has not yet been extensively reviewed. This review aims to bridge the gap in knowledge by collating current understanding of VaD to enable identification of complement and coagulation components involved in the pathogenesis of this disorder that may have their effects amplified or supressed by crosstalk. Exploration of these mechanisms may unveil novel therapeutic targets or biomarkers that would improve current treatment strategies for VaD.

Plaque Length Predicts the Incidence of Microembolic Signals in Acute Anterior Circulation Stroke

Microembolic signals (MES) of the carotid artery are associated with plaque destabilization and reoccurrence of stroke. Previous studies have focused primarily on the degree of carotid artery stenosis and plaque components, and the relationship between plaque length and microembolic sign has received little attention. We aimed to find the association between carotid plaque length (CPL) and the presence of MES. We conducted a retrospective observational cross-sectional study. A total of 84 acute anterior-circulation ischemic stroke/transient ischemic attack (TIA) patients with carotid artery atherosclerosis were classified into an MES-positive (MES+) group and MES-negative (MES−) group. We measured multiple parameters of carotid plaque size (length, thickness) in each patient and evaluated the relationship between different plaque parameters and occurrence of MES. We found that male, carotid artery stenosis (CAS), CPL, carotid plaque thickness (CPT), and intima-media thickness (IMT) of the carotid artery were each significantly different between two groups (all P < 0.05). The multivariate analysis showed CPL (odds ratio (OR), 1.109; 95% CI, 1.044–1.177; P = 0.001) to be independently associated with the presence of MES. The areas under the ROC curves (AUCs) for CPL for predicting MES were 0.777 (95% CI, 0.640–0.914; P < 0.001). The cutoff value of CPL for predicting MES was 16.7 mm, with a sensitivity of 88.2% and a specificity of 77.6%. We found that CPL was a meaningful independent predictor of MES. Therefore, CPL may be useful for risk stratification of long and nonstenotic plaques in anterior circulation stroke.

Stroke Prevention: Little-Known and Neglected Aspects

Combining available therapies has the potential to reduce the risk of stroke by 80% or more. A comprehensive review of all aspects of stroke prevention would be very lengthy; in this narrative review, we focus on some aspects of stroke prevention that are little-known and/or neglected. These include the following: (1) implementation of a Mediterranean diet; (2) B vitamins to lower homocysteine; (3) coordinated approaches to smoking cessation; (4) intensive lipid-lowering therapy; (5) lipid lowering in the elderly; (6) physiologically individualized therapy for hypertension based on renin/aldosterone phenotyping; (7) avoiding excessive blood pressure reduction in patients with stiff arteries; (8) treatment of insulin resistance with pioglitazone in stroke patients with prediabetes and diabetes; (9) impaired activation of clopidogrel in patients with variants of CYP2C19; (10) aspirin pseudoresistance due to enteric coating; (11) rationale for anticoagulation in patients with embolic stroke of unknown source; (12) pharmacologic properties of direct-acting oral anticoagulants that should be considered when choosing among them; (13) the identification of which patients with asymptomatic carotid stenosis are at a high enough risk to benefit from carotid endarterectomy or stenting; and (14) the importance of age in choosing between endarterectomy and stenting. Stroke prevention could be improved by better recognition of these issues and by implementation of the principles derived from them.

Contemporary approach to diagnosis of ischemic stroke pathogenetic variants in patients with atherosclerosis and arterial hypertension

The angio- and neurovisualization methods vigorously developing in recent decades determine the relevance of improvement of etiopathogenetic ischemic stroke classification used for the treatment tactics selection and for secondary prevention of the disorder. The study was aimed to clarify the capabilities of clinical diagnosis for pathogenetic variants of ischemic stroke. For that, in 125 postmortem cases, the macro and microscopic examination of brain and cardiovascular system was carried out in order to verify the stroke pathogenesis established as a result of the previous patients’ examination. The study demonstrates the great potential of the major pathogenetic stroke subtypes (large-artery atherosclerosis, cardioembolism, small-artery occlusion) diagnosis using the complex of contemporary clinical and instrumental methods and the main morphological criteria of these subtypes in accordance with the TOAST classification. Moreover, the clinical and pathomorphological assessment allowed us to differentiate stroke resulting from various alterations of single cerebral artery, the atherothrombotic occlusion (44% of cases for the subtype), arterio-arterial embolism (13%) and critical stenosis (10%), as well as stroke resulting from cerebrovascular insufficiency (33%), within the “large-artery atherosclerosis” subtype. Thus, the high informativity of the existing examination methods allows for a more differentiated understanding of the cause of ischemic stroke, which is fully in line with modern personalized medicine.

[Cerebrovascular diseases: matching ICD-10 and ICD-11 codes]

A comparison of the codes and wording of the ICD-11 with the previous version of the classification was carried out. It seems necessary to develop a new revision of the domestic classification of cerebrovascular pathology, consistent with the ICD-11 codes.

Prevalence of Non-Stenotic (<50%) Carotid Plaques in Acute Ischemic Stroke and Transient Ischemic Attack: A Systematic Review and Meta-Analysis

INTRODUCTION

Non-stenotic (<50%) carotid plaques have recently been recognized as a potential source of stroke. This meta-analysis aims to summarize the prevalence of non-stenotic carotid plaques in stroke patients in general and in patients with embolic stroke of undetermined source in particular.

METHODS

We performed a comprehensive systematic review of the literature and meta-analysis on acute ischemic stroke patients in whom carotid imaging was performed using the MEDLINE, Embase and Cochrane database, including studies published up to December 2019. Keywords were "stroke", "transient ischemic attack", "carotid", "plaque", "atherosclerosis" and "disease". Included studies had ≥10 patients with acute ischemic stroke and reported the prevalence of non-stenotic (<50%%stenosis) carotid plaques detected on any imaging modality.

RESULTS

We included forty-five studies (n = 18304 patients, 48.4% males, mean age 63.6 years) in our meta-analysis. Imaging modalities used were ultrasound (n = 26 studies), CT-angiography (n = 7), magnetic resonance-imaging (n = 8) and catheter angiography (n = 4). The overall prevalence of non-stenotic carotid plaques was 51% (95% CI: 43 - 59). 10 studies included mainly patients with embolic stroke of undetermined source (>50% of all patients). The pooled prevalence of non-stenotic carotid plaques in these studies was 55% (95% CI: 42 - 68). 23 studies explicitly reported ipsilateral non-stenotic carotid plaques, the pooled prevalence of which was 51% (95% CI: 45 - 59).

CONCLUSIONS

In this meta-analysis, non-stenotic carotid plaques were present in more than 50% of all acute ischemic stroke patients, with a slightly higher prevalence in ESUS patients. Given the potential role of non-stenotic carotid plaques in stroke etiology, particularly in ESUS, further research should aim to identify criteria that predict the stroke risk associated with non-stenotic carotid plaques.

Recent advances in preventing recurrent stroke

Since a 2017 update, there have been important advances in stroke prevention. These include new evidence about nutrition, antiplatelet therapy, anticoagulation, lipid-lowering therapy, hypertension control, pioglitazone, and carotid endarterectomy and stenting. Evidence regarding toxic metabolites produced by the intestinal microbiome from egg yolk and red meat has important dietary implications, particularly for patients with impaired renal function, including the elderly. They should avoid egg yolk and red meat and limit the intake of animal flesh. Higher doses of folic acid may be needed for patients with the T allele of MTHFR, so it may not be sufficient to give vitamin B12 (methylcobalamin) alone, even in countries with folate fortification. There is now good evidence that lipid-lowering therapy is even more beneficial in the elderly than in younger patients; we should be using lipid-lowering therapy more intensively, often/usually combining statins with ezetimibe. There is new evidence that lower systolic blood pressure targets are better for most patients, but a subgroup with stiff arteries, a wide pulse pressure, and a diastolic pressure of <60 would be more likely to be harmed than helped by aiming for a systolic target of <120 mmHg. There is a better understanding of how the pharmacological properties of direct-acting oral anticoagulants and the metabolism of antiplatelet agents should inform decisions about the use of these agents. Pioglitazone markedly reduces the risk of stroke, both in diabetics and prediabetics; it should be used more widely. It is now clear that carotid endarterectomy is safer than stenting and that the difference is strongly affected by age. Most patients, and in particular older patients, would be better served by endarterectomy than stenting.

A Narrative and Critical Review of Randomized-Controlled Clinical Trials on Patent Foramen Ovale Closure for Reducing the Risk of Stroke Recurrence

Patent foramen ovale (PFO) is a common cardiac anatomic variant that has been increasingly found in young (<60 years) cryptogenic stroke patients. Despite initial neutral randomized-controlled clinical trials (RCTs), there have been four recent RCTs providing consistent data in favor of the efficacy and safety of PFO closure compared to medical therapy for secondary stroke prevention. However, taking into consideration the high prevalence of PFO, the low risk of stroke recurrence under medical treatment and the uncommon yet severe adverse events of the intervention, patient selection is crucial for attaining meaningful clinical benefits. Thorough workup to exclude alternative causes of stroke and identification of high-risk PFOs through clinical, neuroimaging and echocardiographic criteria are essential. Cost effectiveness of the procedure cannot be proven for the time being, since there are no robust data on clinical outcome after PFO-associated stroke but only limited anecdotal data suggesting low risk for long-term disability.

Validation of Risk Prediction Models to Detect Asymptomatic Carotid Stenosis

Background Significant asymptomatic carotid stenosis (ACS) is associated with higher risk of strokes. While the prevalence of moderate and severe ACS is low in the general population, prediction models may allow identification of individuals at increased risk, thereby enabling targeted screening. We identified established prediction models for ACS and externally validated them in a large screening population. Methods and Results Prediction models for prevalent cases with ≥50% ACS were identified in a systematic review (975 studies reviewed and 6 prediction models identified [3 for moderate and 3 for severe ACS]) and then validated using data from 596 469 individuals who attended commercial vascular screening clinics in the United States and United Kingdom. We assessed discrimination and calibration. In the validation cohort, 11 178 (1.87%) participants had ≥50% ACS and 2033 (0.34%) had ≥70% ACS. The best model included age, sex, smoking, hypertension, hypercholesterolemia, diabetes mellitus, vascular and cerebrovascular disease, measured blood pressure, and blood lipids. The area under the receiver operating characteristic curve for this model was 0.75 (95% CI, 0.74-0.75) for ≥50% ACS and 0.78 (95% CI, 0.77-0.79) for ≥70% ACS. The prevalence of ≥50% ACS in the highest decile of risk was 6.51%, and 1.42% for ≥70% ACS. Targeted screening of the 10% highest risk identified 35% of cases with ≥50% ACS and 42% of cases with ≥70% ACS. Conclusions Individuals at high risk of significant ACS can be selected reliably using a prediction model. The best-performing prediction models identified over one third of all cases by targeted screening of individuals in the highest decile of risk only.

Polygenic Risk Scores for Subtyping of Schizophrenia

Schizophrenia is a complex disorder with many comorbid conditions. In this study, we used polygenic risk scores (PRSs) from schizophrenia and comorbid traits to explore consistent cluster structure in schizophrenia patients. With 10 comorbid traits, we found a stable 4-cluster structure in two datasets (MGS and SSCCS). When the same traits and parameters were applied for the patients in a clinical trial of antipsychotics, the CATIE study, a 5-cluster structure was observed. One of the 4 clusters found in the MGS and SSCCS was further split into two clusters in CATIE, while the other 3 clusters remained unchanged. For the 5 CATIE clusters, we evaluated their association with the changes of clinical symptoms, neurocognitive functions, and laboratory tests between the enrollment baseline and the end of Phase I trial. Class I was found responsive to treatment, with significant reduction for the total, positive, and negative symptoms (p = 0.0001, 0.0099, and 0.0028, respectively), and improvement for cognitive functions (VIGILANCE, p = 0.0099; PROCESSING SPEED, p = 0.0006; WORKING MEMORY, p = 0.0023; and REASONING, p = 0.0015). Class II had modest reduction of positive symptoms (p = 0.0492) and better PROCESSING SPEED (p = 0.0071). Class IV had a specific reduction of negative symptoms (p = 0.0111) and modest cognitive improvement for all tested domains. Interestingly, Class IV was also associated with decreased lymphocyte counts and increased neutrophil counts, an indication of ongoing inflammation or immune dysfunction. In contrast, Classes III and V showed no symptom reduction but a higher level of phosphorus. Overall, our results suggest that PRSs from schizophrenia and comorbid traits can be utilized to classify patients into subtypes with distinctive clinical features. This genetic susceptibility based subtyping may be useful to facilitate more effective treatment and outcome prediction.

Ischaemic stroke etiological classification system: the agreement analysis of CISS, SPARKLE and TOAST

Background and purpose

The ideal stroke classification system needs to have validity, high reliability and applicability among different stroke research settings. The Chinese Ischemic Stroke Subclassification (CISS) and the Subtypes of Ischemic Stroke Classification System (SPARKLE) have emerged recently but have not been tested using agreement analysis. As a result, the objective of this study is to investigate the level of agreement among stroke subtype classifications using CISS, SPARKLE and Trial of Org 10172 in Acute Stroke Treatment (TOAST). We also analyse the inter-rater reliability of CISS.

Methods

The data include 623 inpatients who have had an ischaemic stroke, accrued from Beijing Tiantan Hospital between 1 October 2015 and 19 April 2016. According to the diagnostic standards of the three subtype classification systems, 299 inpatients who satisfied the requirements of our study were independently classified with etiological subtypes, and we compared the three subclassifications.

Results

There was substantial overall agreement among the three classification systems: CISS versus SPARKLE (kappa value=0.684, p<0.001), CISS versus TOAST (kappa value=0.615, p<0.001) and SPARKLE versus TOAST (kappa value=0.675, p<0.001). The inter-rater reliability of CISS was excellent (kappa value=0.857, p<0.001). Furthermore, among the three subtype classification systems, the variance analysis results of the etiological subtypes were not uniform.

Conclusion

There were generally substantial agreements among three ischaemic stroke etiological classification systems. CISS is a valid and reliable classification system, with which different stroke research centres can apply and compare data.

Vitamin B 12 deficiency and hyperhomocysteinaemia in outpatients with stroke or transient ischaemic attack: a cohort study at an academic medical centre

OBJECTIVE

We sought to assess the current magnitude of the opportunity for secondary stroke prevention with B vitamins.

DESIGN

A cohort study.

SETTING

The Urgent TIA (Transient Ischaemic Attack) Clinic at an academic medical centre.

MAIN OUTCOME MEASURES

We assessed the prevalence of biochemical vitamin B12 deficiency (B12Def, serum B12 <156 pmol/L), hyperhomocysteinaemia (HHcy; plasma total homocysteine [tHcy] >14 µmol/L) and metabolic B12 deficiency (MetB12Def, serum B12 <258 pmol/L and HHcy) between 2002 and 2017, by age group and by stroke subtype.

RESULTS

Data were available in 4055 patients. B12Def was present in 8.2% of patients overall; it declined from 10.9% of patients referred before 2009 to 5.4% thereafter (p=0.0001). MetB12Def was present in 10.6% of patients, and HHcy was present in 19.1% of patients. Among the patients aged ≥80 years, MetB12Def was present in 18.1% and HHcy in 35%. Among the 3410 patients whose stroke subtype was determined, HHcy was present in 18.4% of patients: 23.3% of large artery atherosclerosis, 18.1% of cardioembolic, 16.3% of small vessel disease, 10.8% of other unusual aetiologies and 13.6% of undetermined subtypes (p=0.0001).

CONCLUSIONS

Despite a decline in our referral area since 2009, B12Def, MetB12Def and HHcy remain common in patients with stroke/TIA. Because these conditions are easily treated and have serious consequences, all patients with stroke/TIA should have their serum B12 and tHcy measured.

Anticoagulation in patients with Embolic Stroke of Unknown Source

When warfarin was the mainstay of anticoagulation for the prevention of cardioembolic stroke, the paradigm was essentially "we mustn't anticoagulate anyone unless we prove that the stroke was cardioembolic." Now that direct-acting oral anticoagulants are available, the paradigm should change. The risk of stroke is highest soon after the initial event, particularly in patients with more than one infarction. Direct-acting oral anticoagulants are not significantly more likely than aspirin to cause severe hemorrhage, and it is now clear that patients with paradoxical embolism are better treated with anticoagulant than aspirin. Percutaneous closure of a patent foramen ovale is better than aspirin, but not better than anticoagulant, and some patients with paradoxical embolism may be better treated with anticoagulant than with percutaneous closure, which cannot prevent pulmonary embolism. Patients in whom cardioembolic stroke is strongly suspected should probably be anticoagulated pending the results of investigations such as echocardiography and prolonged cardiac monitoring for atrial fibrillation, and some of them, in whom the suspicion of a cardioembolic source is very strong, should probably be anticoagulated long term, even if such investigations do not confirm a cardiac source.

Consensus statement on current and emerging methods for the diagnosis and evaluation of cerebrovascular disease

Cerebrovascular disease (CVD) remains a leading cause of death and the leading cause of adult disability in most developed countries. This work summarizes state-of-the-art, and possible future, diagnostic and evaluation approaches in multiple stages of CVD, including (i) visualization of sub-clinical disease processes, (ii) acute stroke theranostics, and (iii) characterization of post-stroke recovery mechanisms. Underlying pathophysiology as it relates to large vessel steno-occlusive disease and the impact of this macrovascular disease on tissue-level viability, hemodynamics (cerebral blood flow, cerebral blood volume, and mean transit time), and metabolism (cerebral metabolic rate of oxygen consumption and pH) are also discussed in the context of emerging neuroimaging protocols with sensitivity to these factors. The overall purpose is to highlight advancements in stroke care and diagnostics and to provide a general overview of emerging research topics that have potential for reducing morbidity in multiple areas of CVD.

Risk factors of pure leukoaraiosis and the association with preclinical carotid atherosclerosis

BACKGROUND AND AIMS

The risk factors of cerebral large artery disease (carotid atherosclerosis) have been well recognized, but not of small artery disease, especially leukoaraiosis. In this study, we investigated the risk factors of pure leukoaraiosis (without stroke), and the association with preclinical carotid atherosclerosis.

METHODS

Data from 384 subjects with leukoaraiosis and 379 controls with normal cerebral parenchyma were collected at the Beijing Tiantan Hospital from 1 January, 2009 to 31 December, 2015. Entry criteria: 1) age over 40 years; 2) not taking lipid lowering drugs and vitamin B; 3) normal cerebral parenchyma or leukoaraiosis on brain MRI scan; 4) intra- and extra-cranial large artery stenosis less than 50%.

EXCLUSION CRITERIA

1) any brain lesions except cerebral leukoaraiosis; 2) severe systemic diseases. Age, gender, well-known vascular risk factors, serum lipid profile, levels of total homocysteine, vitamin B12, folic acid were analyzed with multivariable logistic regression model.

RESULTS

Age and hypertension, but not serum homocysteine, vitamin B12, folic acid, or serum lipid profile, were independently associated with leukoaraiosis. Furthermore, there was no significant association between pure leukoaraiosis and preclinical carotid atherosclerosis after adjusting for age.

CONCLUSIONS

Only age and hypertension are independently related to pure leukoaraiosis, and there is no association between pure leukoaraiosis and preclinical carotid atherosclerosis.

Cardioembolic stroke: everything has changed

Historically, because of the difficulty of using warfarin safely and effectively, many patients with cardioembolic stroke who should have been anticoagulated were instead given ineffective antiplatelet therapy (or no antithrombotic therapy). With the arrival of new oral anticoagulants that are not significantly more likely than aspirin to cause severe haemorrhage, everything has changed. Because antiplatelet agents are much less effective in preventing cardioembolic stroke, it is now more prudent to anticoagulate patients in whom cardioembolic stroke is strongly suspected. Recent advances include the recognition that intermittent atrial fibrillation is better detected with more prolonged monitoring of the cardiac rhythm, and that percutaneous closure of patent foramen ovale (PFO) may reduce the risk of stroke. However, because in most patients with stroke and PFO the PFO is incidental, this should be reserved for patients in whom paradoxical embolism is likely. A high shunt grade on transcranial Doppler saline studies, and clinical clues to paradoxical embolism, can help in appropriate selection of patients for percutaneous closure. For patients with atrial fibrillation who cannot be anticoagulated, ablation of the left atrial appendage is an emerging option. It is also increasingly recognised that high levels of homocysteine, often due to undiagnosed metabolic deficiency of vitamin B12, markedly increase the risk of stroke in atrial fibrillation, and that B vitamins (folic acid and B12) do prevent stroke by lowering homocysteine. However, with regard to B12, methylcobalamin should probably be used instead of cyanocobalamin. Many important considerations for judicious application of therapies to prevent cardioembolic stroke are discussed.

Stroke, cerebrovascular diseases and vascular cognitive impairment in Africa

With increased numbers of older people a higher burden of neurological disorders worldwide is predicted. Stroke and other cerebrovascular diseases do not necessarily present with different phenotypes in Africa but their incidence is rising in tandem with the demographic change in the population. Age remains the strongest irreversible risk factor for stroke and cognitive impairment. Modifiable factors relating to vascular disease risk, diet, lifestyle, physical activity and psychosocial status play a key role in shaping the current spate of stroke related diseases in Africa. Hypertension is the strongest modifiable risk factor for stroke but is also likely associated with co-inheritance of genetic traits among Africans. Somewhat different from high-income countries, strokes attributed to cerebral small vessel disease (SVD) are higher >30% among sub-Saharan Africans. Raised blood pressure may explain most of the incidence of SVD-related strokes but there are likely other contributing factors including dyslipidaemia and diabetes in some sectors of Africa. However, atherosclerotic and cardioembolic diseases combined also appear to be common subtypes as causes of strokes. Significant proportions of cerebrovascular diseases are ascribed to various forms of infectious disease including complications of human immunodeficiency virus. Cerebral SVD leads to several clinical manifestations including gait disturbance, autonomic dysfunction and depression. Pathological processes are characterized by arteriolosclerosis, lacunar infarcts, perivascular spaces, microinfarcts and diffuse white matter changes, which can now all be detected on neuroimaging. Except for isolated cases of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy or CADASIL, hereditary arteriopathies have so far not been reported in Africa. Prevalence estimates of vascular dementia (2-3%), delayed dementia after stroke (10-20%) and vascular cognitive impairment (30-40%) do not appear to be vastly different from those in other parts of the world. However, given the current demographic transition in both urban and rural settings these figures will likely rise. Wider application of neuroimaging modalities and implementation of stroke care in Africa will enable better estimates of SVD and other subtypes of stroke. Stroke survivors with SVD type pathology are likely to have low mortality and therefore portend increased incidence of dementia.

Recent Advances in Primary and Secondary Prevention of Atherosclerotic Stroke

Atherosclerosis is a major cause of ischemic stroke that can be effectively prevented with appropriate lifestyle modifications and control of cardiovascular risk factors. Medical advances in recent years along with aggressive cardiovascular risk factor modifications have resulted in decreased recurrence rates of atherosclerotic stroke. Non-statin lipid-lowering molecules have recently shown clinical benefit and are recommended for very high-risk patients to reduce their risk of stroke. Aggressive hypertension treatment is crucial to reduce atherosclerotic stroke risk. Advances in antithrombotic treatments include combinations of antiplatelets and new antiplatelet agents in the acute phase post-stroke, which carries a high risk of recurrence. Intensive medical treatment has also limited the indications for carotid interventions, especially for asymptomatic disease. Intracranial atherosclerotic disease may provoke stroke through various mechanisms; it is increasingly recognized as a cause of ischemic stroke with advanced imaging and is best managed with lifestyle modifications and medical therapy. The diagnostic search for the vulnerable culprit atherosclerotic plaque is an area of intense research, from the level of the intracranial arteries to that of the aortic arch. Ultrasonography and novel magnetic resonance imaging techniques (high-resolution vessel-wall imaging) may assist in the identification of vulnerable atherosclerotic plaques as the underlying cause in cryptogenic or misdiagnosed non-atherosclerotic ischemic stroke. Vertebrobasilar atherosclerotic disease is less common than carotid artery disease; thus, high-quality data on effective prevention strategies are scarcer. However, aggressive medical treatment is also the gold standard to reduce cerebrovascular disease located in posterior circulation.

The pathology and pathophysiology of vascular dementia

Vascular dementia (VaD) is widely recognised as the second most common type of dementia. Consensus and accurate diagnosis of clinically suspected VaD relies on wide-ranging clinical, neuropsychological and neuroimaging measures in life but more importantly pathological confirmation. Factors defining subtypes of VaD include the nature and extent of vascular pathologies, degree of involvement of extra and intracranial vessels and the anatomical location of tissue changes as well as time after the initial vascular event. Atherosclerotic and cardioembolic diseases combined appear the most common subtypes of vascular brain injury. In recent years, cerebral small vessel disease (SVD) has gained prominence worldwide as an important substrate of cognitive impairment. SVD is characterised by arteriolosclerosis, lacunar infarcts and cortical and subcortical microinfarcts and diffuse white matter changes, which involve myelin loss and axonal abnormalities. Global brain atrophy and focal degeneration of the cerebrum including medial temporal lobe atrophy are also features of VaD similar to Alzheimer's disease. Hereditary arteriopathies have provided insights into the mechanisms of dementia particularly how arteriolosclerosis, a major contributor of SVD promotes cognitive impairment. Recently developed and validated neuropathology guidelines indicated that the best predictors of vascular cognitive impairment were small or lacunar infarcts, microinfarcts, perivascular space dilation, myelin loss, arteriolosclerosis and leptomeningeal cerebral amyloid angiopathy. While these substrates do not suggest high specificity, VaD is likely defined by key neuronal and dendro-synaptic changes resulting in executive dysfunction and related cognitive deficits. Greater understanding of the molecular pathology is needed to clearly define microvascular disease and vascular substrates of dementia. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

Etiologic classification of ischemic stroke: Where do we stand?

Despite major technological advances in ischemic stroke diagnostic techniques, our current understanding of stroke mechanisms and etiology continues to remain unclear in a significant percent of patients. As a result, several etiological ischemic stroke classifications have emerged during the last two decades but their reliability and validity is far from perfect and further world-wide research is needed in order to achieve the so much needed "standard reference language". An ideal ischemic stroke classification should both comprise all underlying pathologies that could potentially concur to an index event and emphasize the most likely etiological and pathophysiological mechanism. Currently available approaches to ischemic stroke classification are either phenotypic or causative in nature, a multitude of criteria being published by different authors. Phenotypic classifications are targeted towards describing the concurring underlying pathologies, without highlighting the most probable ischemic stroke etiology, while causative classifications focus on establishing the most likely cause, neglecting other associated diseases. A judicious use of this two different concepts might improve clinical research as well as daily clinical practice.

Secondary Stroke Prevention: Improving Diagnosis and Management with Newer Technologies

Treatment of hypertension, diabetes, high cholesterol, smoking cessation, and healthy lifestyle have all contributed to the decline in the incidence of vascular disease over the last several decades. Patients who suffer an acute stroke are at a high risk for recurrence. Introduction of newer technologies and their wider use allows for better identification of patients in whom the risk of recurrence following an acute stroke may be very high. Traditionally, the major focus for diagnosis and management has focused on patient history, examination, imaging for carotid stenosis/occlusion, and detection of AF and paroxysmal AF (PAF) with 24-48 h cardiac monitoring. This review focuses on the usefulness of three newer investigative tools that are becoming widely available and lead to better prevention. Continuous ambulatory blood pressure measurements for 24 h or longer and 3D Doppler measures of the carotid arteries provide key useful information on the state of vascular health and enhance our ability to monitor the response to preventive therapies. Furthermore, the detection of PAF can be significantly improved with prolonged cardiac monitoring for 3 weeks or longer, enabling the initiation of appropriate prevention therapy. This review will focus on the potential impact and importance of these emerging technologies on the prevention of recurrent stroke in high-risk patients.

Secular trends in ischemic stroke subtypes and stroke risk factors

BACKGROUND AND PURPOSE

Early diagnosis and treatment of a stroke improves patient outcomes, and knowledge of the cause of the initial event is crucial to identification of the appropriate therapy to maximally reduce risk of recurrence. Assumptions based on historical frequency of ischemic subtypes may need revision if stroke subtypes are changing as a result of recent changes in therapy, such as increased use of statins.

METHODS

We analyzed secular trends in stroke risk factors and ischemic stroke subtypes among patients with transient ischemic attack or minor or moderate stroke referred to an urgent transient ischemic attack clinic from 2002 to 2012.

RESULTS

There was a significant decline in low-density lipoprotein cholesterol and blood pressure, associated with a significant decline in large artery stroke and small vessel stroke. The proportion of cardioembolic stroke increased from 26% in 2002 to 56% in 2012 (P<0.05 for trend). Trends remained significant after adjusting for population change.

CONCLUSIONS

With more intensive medical management in the community, a significant decrease in atherosclerotic risk factors was observed, with a significant decline in stroke/transient ischemic attack caused by large artery atherosclerosis and small vessel disease. As a result, cardioembolic stroke/transient ischemic attack has increased significantly. Our findings suggest that more intensive investigation for cardiac sources of embolism and greater use of anticoagulation may be warranted.