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1.
Lancet Neurol ; 18(4): 394-405, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30878104

RESUMO

With over 2 million new cases annually, stroke is associated with the highest disability-adjusted life-years lost of any disease in China. The burden is expected to increase further as a result of population ageing, an ongoing high prevalence of risk factors (eg, hypertension), and inadequate management. Despite improved access to overall health services, the availability of specialist stroke care is variable across the country, and especially uneven in rural areas. In-hospital outcomes have improved because of a greater availability of reperfusion therapies and supportive care, but adherence to secondary prevention strategies and long-term care are inadequate. Thrombolysis and stroke units are accepted as standards of care across the world, including in China, but bleeding-risk concerns and organisational challenges hamper widespread adoption of this care in China. Despite little supporting evidence, Chinese herbal products and neuroprotective drugs are widely used, and the increased availability of neuroimaging techniques also results in overdiagnosis and overtreatment of so-called silent stroke. Future efforts should focus on providing more balanced availability of specialised stroke services across the country, enhancing evidence-based practice, and encouraging greater translational research to improve outcome of patients with stroke.

2.
Ann Neurol ; 85(5): 752-764, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30840312

RESUMO

OBJECTIVE: To investigate whether hemodynamic features of symptomatic intracranial atherosclerotic stenosis (sICAS) might correlate with the risk of stroke relapse, using a computational fluid dynamics (CFD) model. METHODS: In a cohort study, we recruited patients with acute ischemic stroke attributed to 50 to 99% ICAS confirmed by computed tomographic angiography (CTA). With CTA-based CFD models, translesional pressure ratio (PR = pressurepoststenotic /pressureprestenotic ) and translesional wall shear stress ratio (WSSR = WSSstenotic - throat /WSSprestenotic ) were obtained in each sICAS lesion. Translesional PR ≤ median was defined as low PR and WSSR ≥4th quartile as high WSSR. All patients received standard medical treatment. The primary outcome was recurrent ischemic stroke in the same territory (SIT) within 1 year. RESULTS: Overall, 245 patients (median age = 61 years, 63.7% males) were analyzed. Median translesional PR was 0.94 (interquartile range [IQR] = 0.87-0.97); median translesional WSSR was 13.3 (IQR = 7.0-26.7). SIT occurred in 20 (8.2%) patients, mostly with multiple infarcts in the border zone and/or cortical regions. In multivariate Cox regression, low PR (adjusted hazard ratio [HR] = 3.16, p = 0.026) and high WSSR (adjusted HR = 3.05, p = 0.014) were independently associated with SIT. Patients with both low PR and high WSSR had significantly higher risk of SIT than those with normal PR and WSSR (risk = 17.5% vs 3.0%, adjusted HR = 7.52, p = 0.004). INTERPRETATION: This work represents a step forward in utilizing computational flow simulation techniques in studying intracranial atherosclerotic disease. It reveals a hemodynamic pattern of sICAS that is more prone to stroke relapse, and supports hypoperfusion and artery-to-artery embolism as common mechanisms of ischemic stroke in such patients. Ann Neurol 2019;85:752-764.

4.
J Neurol Neurosurg Psychiatry ; 90(4): 428-435, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30554138

RESUMO

BACKGROUND AND PURPOSE: Cerebral microbleeds (CMBs), which predict future intracerebral haemorrhage (ICH), may guide anticoagulant decisions for atrial fibrillation (AF). We aimed to evaluate the risk of warfarin-associated ICH in Chinese patients with AF with CMBs. METHODS: In this prospective, observational, multicentre study, we recruited Chinese patients with AF who were on or intended to start anticoagulation with warfarin from six hospitals in Hong Kong. CMBs were evaluated with 3T MRI brain at baseline. Primary outcome was clinical ICH at 2-year follow-up. Secondary outcomes were ischaemic stroke, systemic embolism, mortality of all causes and modified Rankin Scale ≥3. Outcome events were compared between patients with and without CMBs. RESULTS: A total of 290 patients were recruited; 53 patients were excluded by predefined criteria. Among the 237 patients included in the final analysis, CMBs were observed in 84 (35.4%) patients, and 11 had ≥5 CMBs. The mean follow-up period was 22.4±10.3 months. Compared with patients without CMBs, patients with CMBs had numerically higher rate of ICH (3.6% vs 0.7%, p=0.129). The rate of ICH was lower than ischaemic stroke for patients with 0 to 4 CMBs, but higher for those with ≥5 CMBs. CMB count (C-index 0.82) was more sensitive than HAS-BLED (C-index 0.55) and CHA2DS2-VASc (C-index 0.63) scores in predicting ICH. CONCLUSIONS: In Chinese patients with AF on warfarin, presence of multiple CMBs may be associated with higher rate of ICH than ischaemic stroke. Larger studies through international collaboration are needed to determine the risk:benefit ratio of oral anticoagulants in patients with AF of different ethnic origins.

5.
Conf Proc IEEE Eng Med Biol Soc ; 2018: 1037-1040, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440568

RESUMO

Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation technique that serves as treatment tool to neurological disorders. However, the mechanism of how the stimulation modulates ongoing brain activity and connectivity is still not fully understood. Simultaneous acquisition of neuroimaging data together with brain stimulation could allow a noninvasive examination of the brain dynamic changes during the process. In this pilot study, concurrent tDCS and fMRI was conducted in a healthy subject. Dynamic functional connectivity and effective connectivity were used to reveal the information flow. The results demonstrated that tDCS duration has important effects on the brain connectivity and the causal relationships among the brain regions. These results might reflect the fundamental mechanism of brain processing under the external stimulation.

6.
J Cereb Blood Flow Metab ; : 271678X18805209, 2018 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-30351176

RESUMO

We aimed to investigate the roles of antegrade residual flow and leptomeningeal collateral flow in sustaining cerebral perfusion distal to an intracranial atherosclerotic stenosis (ICAS). Patients with apparently normal cerebral perfusion distal to a symptomatic middle cerebral artery (MCA)-M1 stenosis were enrolled. Computational fluid dynamics models were built based on CT angiography to obtain a translesional pressure ratio (PR) to gauge the residual antegrade flow. Leptomeningeal collaterals (LMCs) were scaled on CT angiography. Cerebral perfusion metrics were obtained in CT perfusion maps. Among 83 patients, linear regression analyses revealed that both translesional PR and LMC scale were independently associated with relative ipsilesional mean transit time (rMTT). Subgroup analyses showed that ipsilesional rMTT was significantly associated with translesional PR ( p < 0.001) rather than LMC scale in those with a moderate (50-69%) MCA stenosis, which, however, was only significantly associated with LMC scale ( p = 0.051) in those with a severe (70-99%) stenosis. Antegrade residual flow and leptomeningeal collateral flow have complementary effects in sustaining cerebral perfusion distal to an ICAS, while cerebral perfusion may rely more on the collateral circulation in those with a severe stenosis.

7.
J Stroke ; 20(3): 342-349, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30309229

RESUMO

BACKGROUND AND PURPOSE: Vasa vasorum (VV) have been believed to be rare or non-existent in small-caliber intracranial arteries. In a series of human cerebral artery specimens, we identified and examined the distribution of VV in association with co-existing intracranial atherosclerosis. METHODS: We obtained cerebral artery specimens from 32 consecutive autopsies of subjects aged 45 years or above. We scrutinized middle cerebral artery (MCA), vertebral artery (VA), and basilar artery (BA) for the presence of adventitial VV. We described the distribution of VV, and the characteristics of co-existing atherosclerotic lesions. RESULTS: Among 157 intracranial arteries, adventitial VV were present in 74 of the 157 specimens (47%), involving MCA (n=13, 18%), BA (n=14, 19%), and VA (n=47, 64%). Although qualitatively these 74 adventitial VV distributed similarly in arteries with or without atherosclerotic lesions (disease-free arteries n=4/8; arteries of pre-atherosclerosis n=17/42; and arteries of progressive atherosclerosis n=53/107), the presence of adventitial VV in intracranial VA was associated with a heavier plaque load (1.72±1.66 mm2 vs. 0.40±0.32 mm2, P<0.001), severer luminal stenosis (25%±21% vs. 12%±9%, P=0.002), higher rate of concentric lesions (79% vs. 36%, P=0.002), and denser intraplaque calcification (44% vs. 0%, P=0.003). Histologically, intracranial VA with VV had a larger diameter (3.40±0.79 mm vs. 2.34±0.58 mm, P<0.001), thicker arterial wall (0.31±0.13 mm vs. 0.23±0.06 mm, P=0.002), and a larger intima-media (0.19±0.09 mm vs. 0.13± 0.04 mm, P=0.003) than VA without VV. CONCLUSION: s Our study demonstrated the distribution of adventitial VV within brain vasculature and association between vertebral VV and progressive atherosclerotic lesions with a heavier plaque load and denser intraplaque calcification.

8.
Stroke Vasc Neurol ; 3(3): 117-130, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30294467

RESUMO

Collateral circulation plays a vital role in sustaining blood flow to the ischaemic areas in acute, subacute or chronic phases after an ischaemic stroke or transient ischaemic attack. Good collateral circulation has shown protective effects towards a favourable functional outcome and a lower risk of recurrence in stroke attributed to different aetiologies or undergoing medical or endovascular treatment. Over the past decade, the importance of collateral circulation has attracted more attention and is becoming a hot spot for research. However, the diversity in imaging methods and criteria to evaluate collateral circulation has hindered comparisons of findings from different cohorts and further studies in exploring the clinical relevance of collateral circulation and possible methods to enhance collateral flow. The statement is aimed to update currently available evidence and provide evidence-based recommendations regarding grading methods for collateral circulation, its significance in patients with stroke and methods under investigation to improve collateral flow.

9.
Cerebrovasc Dis ; 46(1-2): 82-88, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30184553

RESUMO

BACKGROUND AND PURPOSE: MLC601 has been shown in preclinical studies to enhance neurorestorative mechanisms after stroke. The aim of this post hoc analysis was to assess whether combining MLC601 and rehabilitation has an effect on improving functional outcomes after stroke. METHODS: Data from the CHInese Medicine NeuroAiD Efficacy on Stroke (CHIMES) and CHIMES-Extension (CHIMES-E) studies were analyzed. CHIMES-E was a 24-month follow-up study of subjects included in CHIMES, a multi-centre, double-blind placebo-controlled trial which randomized subjects with acute ischemic stroke, to either MLC601 or placebo for 3 months in addition to standard stroke treatment and rehabilitation. Subjects were stratified according to whether they received or did not receive persistent rehabilitation up to month (M)3 (non- randomized allocation) and by treatment group. The modified Rankin Scale (mRS) and Barthel Index were assessed at month (M) 3, M6, M12, M18, and M24. RESULTS: Of 880 subjects in CHIMES-E, data on rehabilitation at M3 were available in 807 (91.7%, mean age 61.8 ± 11.3 years, 36% female). After adjusting for prognostic factors of poor outcome (age, sex, pre-stroke mRS, baseline National Institute of Health Stroke Scale, and stroke onset-to-study-treatment time), subjects who received persistent rehabilitation showed consistently higher treatment effect in favor of MLC601 for all time points on mRS 0-1 dichotomy analysis (ORs 1.85 at M3, 2.18 at M6, 2.42 at M12, 1.94 at M18, 1.87 at M24), mRS ordinal analysis (ORs 1.37 at M3, 1.40 at M6, 1.53 at M12, 1.50 at M18, 1.38 at M24), and BI ≥95 dichotomy analysis (ORs 1.39 at M3, 1.95 at M6, 1.56 at M12, 1.56 at M18, 1.46 at M24) compared to those who did not receive persistent rehabilitation. CONCLUSIONS: More subjects on MLC601 improved to functional independence compared to placebo among subjects receiving persistent rehabilitation up to M3. The larger treatment effect of MLC601 was sustained over 2 years which supports the hypothesis that MLC601 combined with rehabilitation might have beneficial and sustained effects on neuro-repair processes after stroke. There is a need for more data on the effect of combining rehabilitation programs with stroke recovery treatments.

12.
Neurologist ; 23(2): 47-50, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29494434

RESUMO

OBJECTIVES: Stenosis of the intracranial large arteries, especially the middle cerebral artery (MCA), is common in the Chinese population. We conducted a case-control study to investigate clinical and apolipoprotein E (ApoE) gene polymorphism of MCA atherosclerosis in the Chinese population. MATERIALS AND METHODS: Polymerase chain reaction-based protocols were used to identify the genotypes of polymorphisms in ApoE genes. Clinical parameters and the genotypes of polymorphisms in the ApoE genes were compared in patients with and without MCA stenosis. The ApoE exon ε4 genotypes with risk factors were compared in the patients with and without MCA stenosis. RESULTS: In total, 337 ischemic stroke patients were recruited, 156 cases with and 181 without MCA stenosis. Univariate analysis showed that the levels of systolic blood pressure and pulse pressure were higher in the MCA-stenosis group. There were no significant differences in the genotype and allele frequencies of the ApoE polymorphism observed between patients with and without MCA stenosis. However, there was a trend that the MCA-stenosis group tended to have more of genotype ε4/ε4 (3.8% vs. 0.6%, P=0.052) than the non-MCA-stenosis group. There was no effect of ApoE genotype and genotype-by-environment interactions on ischemic stroke susceptibility. CONCLUSIONS: This present study indicated that the hypertension (ie, systolic blood pressure and pulse pressure) and the ApoEε4/ε4 genotype may be associated with the occurrence of MCA stenosis in the ischemic stroke Chinese patients.


Assuntos
Apolipoproteínas E/genética , Aterosclerose/genética , Isquemia Encefálica/genética , Doenças Arteriais Cerebrais/genética , Artéria Cerebral Média/patologia , Acidente Vascular Cerebral/genética , Idoso , Estudos de Casos e Controles , China , Constrição Patológica/patologia , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Fatores de Risco
13.
Neuroradiology ; 60(4): 357-363, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29426978

RESUMO

PURPOSE: Intracranial artery calcification (IAC) has been demonstrated to be correlated with ischemic stroke, cognitive decline, and other vascular events by accumulating evidences from both Western and Asian populations. The proposed study aimed to investigate its potential mechanisms by evaluating the blood flow velocity and pulsatility index (PI) of cerebral arteries. METHODS: Consecutive ischemic stroke patients admitted to the Prince of Wales Hospital were recruited after excluding those with atrial fibrillation or poor temporal window. Quantitative measurements of IAC severity were assessed on brain CT scans. Transcranial Doppler (TCD) ultrasonography was performed to evaluate the blood flow velocity of the middle cerebral artery (MCA) and vertebral-basilar artery (VBA). RESULTS: In total, 318 patients were analyzed. Spearman's correlation analysis demonstrated both high MCA systolic flow velocity and high MCA PI were correlated with IAC Agatston score, p < 0.001 individually. Similar correlation was also found between IAC Agatston score and high VBA velocity/high VBA PI, p ≤ 0.001 individually. Multiple logistic regression analysis showed IAC Agatston score was an independent risk factor for high MCA velocity (OR 1.533; 95% CI 1.235-1.903), high VBA velocity (OR 1.964; 95% CI 1.381-2.794), and high VBA PI (OR 1.200; 95% CI 1.016-1.418), respectively. CONCLUSION: Heavier IAC might cause generalized artery flow velocity changes and increased pulsatility index, which may indicate high resistance within cerebrovasculature.


Assuntos
Artéria Basilar/diagnóstico por imagem , Artéria Basilar/fisiopatologia , Hemodinâmica/fisiologia , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia , Ultrassonografia Doppler Transcraniana , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/fisiopatologia , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/fisiopatologia , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Humanos , Masculino , Estudos Prospectivos , Fluxo Pulsátil/fisiologia , Fatores de Risco
14.
J Stroke Cerebrovasc Dis ; 27(1): 44-52, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29107636

RESUMO

BACKGROUND: Computational fluid dynamics (CFD) allows noninvasive fractional flow (FF) computation in intracranial arterial stenosis. Removal of small artery branches is necessary in CFD simulation. The consequent effects on FF value needs to be judged. METHODS: An idealized vascular model was built with 70% focal luminal stenosis. A branch with one third or one half of the radius of the parent vessel was added at a distance of 5, 10, 15 and 20 mm to the lesion. With pressure and flow rate applied as inlet and outlet boundary conditions, CFD simulations were performed. Flow distribution at bifurcations followed Murray's law. By including or removing side branches, five patient-specific intracranial artery models were simulated. Transient simulation was performed on a patient-specific model, with a larger branch for validation. Branching effect was considered trivial if the FF difference between paired models (branches included or removed) was within 5%. RESULTS: Compared with the control model without a branch, in all idealized models the relative differences of FF was within 2%. In five pairs of cerebral arteries (branches included/removed), FFs were 0.876 and 0.877, 0.853 and 0.858, 0.874 and 0.869, 0.865 and 0.858, 0.952 and 0.948. The relative difference in each pair was less than 1%. In transient model, the relative difference of FF was 3.5%. CONCLUSION: The impact of removing side branches with radius less than 50% of the parent vessel on FF measurement accuracy is negligible in static CFD simulations, and minor in transient CFD simulation.


Assuntos
Artérias Cerebrais/fisiopatologia , Circulação Cerebrovascular , Doenças Arteriais Intracranianas/fisiopatologia , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Velocidade do Fluxo Sanguíneo , Angiografia Cerebral/métodos , Artérias Cerebrais/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Constrição Patológica , Humanos , Hidrodinâmica , Doenças Arteriais Intracranianas/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador , Fluxo Sanguíneo Regional
15.
Stroke ; 49(1): 215-218, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29203690

RESUMO

BACKGROUND AND PURPOSE: Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome. METHODS: In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6). RESULTS: Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group (P=0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P=0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P=0.027). CONCLUSIONS: Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke.


Assuntos
Doenças do Sistema Nervoso Autônomo , Sistema Nervoso Autônomo/fisiopatologia , Isquemia Encefálica , Acidente Vascular Cerebral , Idoso , Doenças do Sistema Nervoso Autônomo/etiologia , Doenças do Sistema Nervoso Autônomo/mortalidade , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Isquemia Encefálica/complicações , Isquemia Encefálica/mortalidade , Isquemia Encefálica/fisiopatologia , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/fisiopatologia , Taxa de Sobrevida
16.
Front Neurol ; 8: 488, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28993752

RESUMO

BACKGROUND: Anterior and posterior circulation atherosclerosis differ in vascular risk factors and stroke mechanisms. However, few studies have compared the pathological features between these lesions. Using a series of intracranial artery specimens, we characterized the intracranial atherosclerotic lesions and compared pathological features among different arteries of the intracranial vasculature. METHODS: Intracranial large arteries of 32 consecutively recruited autopsy cases of Chinese adults aged 45 years or older were examined pathologically using routine histology and immunostaining, to characterize the pathological features of the atherosclerotic lesions. We analyzed middle cerebral arteries (MCAs) (both left and right), vertebral arteries (VAs) (side more affected), and basilar arteries (BAs). RESULTS: Progressive atherosclerotic lesions were present in 91(71%) of the 128 arteries examined. Features of complicated plaques were infrequently detected: plaque hemorrhage was encountered in 12%, neovasculature in 12%, lumen thrombi in 13%, macrophage infiltration in 20%, and calcification in 25% of arteries. Luminal narrowing of MCA was the most severe, followed by VA; the BA least stenotic (37 ± 25 vs. 30 ± 24 vs. 20 ± 20%, all p < 0.05). MCA had more eccentric (vs. concentric) plaques than VA (69 vs. 25%, p = 0.003) and BA (69 vs. 38%; p = 0.03). Lumen thrombi were more frequent in BA, and calcification most commonly occurred in VA atherosclerotic lesions. CONCLUSION: Intracranial atherosclerotic plaques were commonly present in this sample, but the lesions generally lacked features of complicated plaques. MCA lesions had demonstrable differences compared with VA and BA lesions. Further studies are needed to determine whether these characteristics indicate a distinctive atherosclerotic phenotype for the intracranial vasculature.

17.
World J Stem Cells ; 9(8): 133-143, 2017 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-28928910

RESUMO

AIM: To examine the safety and efficacy of mesenchymal stem cell (MSC) therapy for intracerebral haemorrhage with neurological dysfunctions for a year. METHODS: MSC were ex vivo expanded from 29 mL (17-42 mL) autologous bone marrow. Patients were randomized to have two intravenous injections of autologous MSC or placebos in four weeks apart. Neurological functions and clinical outcomes were monitored before treatment and at 12th, 16th, 24th, 36th and 60th week upon completion of the treatment. RESULTS: A mean of 4.57 × 107 (range: 1.43 × 107-8.40 × 107) MSC per infusion was administered accounting to 8.54 × 105 (2.65 × 105-1.45 × 106) per kilogram body weight in two occasions. There was neither adverse event at time of administration nor sign of de novo tumour development among patients after monitoring for a year post MSC therapy. Neuro-restoration and clinical improvement in terms of modified Barthel index, functional independence measure and extended Glasgow Outcome Scale were evident among patients having MSC therapy compared to patients receiving placebos. CONCLUSION: Intravenous administration of autologous bone marrow-derived MSC is safe and has the potential of improving neurological functions in chronic stroke patients with severe disability.

18.
J Stroke ; 19(3): 249-260, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28877564

RESUMO

Intracranial atherosclerosis is one of the leading causes of ischemic stroke and occurs more commonly in patients of Asian, African or Hispanic origin than in Caucasians. Although the histopathology of intracranial atherosclerotic disease resembles extracranial atherosclerosis, there are some notable differences in the onset and severity of atherosclerosis. Current understanding of intracranial atherosclerotic disease has been advanced by the high-resolution magnetic resonance imaging (HRMRI), a novel emerging imaging technique that can directly visualize the vessel wall pathology. However, the pathological validation of HRMRI signal characteristics remains a key step to depict the plaque components and vulnerability in intracranial atherosclerotic lesions. The purpose of this review is to describe the histological features of intracranial atherosclerosis and to state current evidences regarding the validation of MR vessel wall imaging with histopathology.

19.
Stroke ; 48(7): 1835-1841, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28626054

RESUMO

BACKGROUND AND PURPOSE: Posterior circulation ischemic stroke (IS) is generally considered an illness with a poor prognosis. However, there are no effective rating scales to predict recurrent stroke following it. Therefore, our aim was to identify clinical or radiological measures that could assist in predicting recurrent cerebral ischemic episodes. METHODS: We prospectively enrolled 723 noncardiogenic posterior circulation IS patients with onset of symptoms <7 days. Stroke risk factors, admission symptoms and signs, topographical distribution and responsible cerebral artery of acute infarcts, and any recurrent IS or transient ischemic attack (TIA) within 1 year were assessed. Cox regression was used to identify risk factors associated with recurrent IS or TIA within the year after posterior circulation IS. RESULTS: A total of 40 patients (5.5%) had recurrent IS or TIA within 1 year of posterior circulation IS. Multivariate Cox regression identified chief complaint with dysphagia (hazard ratio [HR], 4.16; 95% confidence interval [CI], 1.69-10.2; P=0.002), repeated TIAs within 3 months before the stroke (HR, 15.4; 95% CI, 5.55-42.5; P<0.0001), responsible artery stenosis ≥70% (HR, 7.91; 95% CI, 1.00-62.6; P=0.05), multisector infarcts (HR, 5.38; 95% CI, 1.25-23.3; P=0.02), and not on antithrombotics treatment at discharge (HR, 3.06; 95% CI, 1.09-8.58; P=0.03) as independent predictors of recurrent IS or TIA. CONCLUSIONS: Some posterior circulation IS patients are at higher risk for recurrent IS or TIA. Urgent assessment and preventive treatment should be offered to these patients as soon as possible.


Assuntos
Ataque Isquêmico Transitório/diagnóstico , Ataque Isquêmico Transitório/epidemiologia , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Ataque Isquêmico Transitório/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Recidiva , Fatores de Risco , Acidente Vascular Cerebral/fisiopatologia
20.
J Neurol Neurosurg Psychiatry ; 88(6): 520-531, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28536207

RESUMO

Cerebral autoregulation (CA) is a protective mechanism that maintains cerebral blood flow at a relatively constant level despite fluctuations of cerebral perfusion pressure or arterial blood pressure. It is a universal physiological mechanism that may involve myogenic, neural control as well as metabolic regulations of cerebral vasculature in response to changes in pressure or cerebral blood flow. Traditionally, CA has been represented by a sigmoid curve with a wide plateau between about 50 mm Hg and 170 mm Hg of steady-state changes in mean arterial pressure, defined as static CA. With the advent of transcranial Doppler, measurement of cerebral blood flow in response to transient changes in arterial pressure has been used to assess dynamic CA. However, a gold standard for measuring CA is not currently available. Stroke has been the leading cause of long-term adult disability throughout the world. A better understanding of CA and its response to pathological derangements can help assess the severity of stroke, guide management decisions, assess response to interventions and provide prognostic information. The objective of this review is to provide a comprehensive insight about physiology of autoregulation, measurement methodologies and clinical applications in stroke to help build a consensus for what should be included in an internationally agreed protocol for CA testing and monitoring, and to promote its translation into clinical bedside practice for stroke management.


Assuntos
Encéfalo/irrigação sanguínea , Circulação Cerebrovascular/fisiologia , Homeostase/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Pressão Sanguínea/fisiologia , Dióxido de Carbono/sangue , Estenose das Carótidas/fisiopatologia , Humanos , Oxigênio/sangue , Prognóstico , Ultrassonografia Doppler Transcraniana
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