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


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.

Ann Neurol ; 77(3): 478-86, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25557926


OBJECTIVE: Understanding how symptomatic intracranial atherosclerotic disease (ICAD) evolves with current medical therapy may inform secondary stroke prevention. METHODS: In a prospective academic-initiated study, we recruited 50 patients (mean age = 63.4 ± 9.0 years) with acute strokes attributed to high-grade (≥70%) intracranial atherosclerotic stenosis for 3-dimensional rotational angiograms before and after intensive medical therapy for 12 months. Treatment targets included low-density lipoprotein ≤ 70mg/dl, glycosylated hemoglobin (HbA1c) ≤ 6.5%, and systolic blood pressure ≤ 140 mmHg. We analyzed infarct topography and monitored microembolic signal in recurrent strokes. The reference group was a published cohort of 143 ICAD patients. RESULTS: Overall, the stenoses regressed from 79% at baseline (interquartile range [IQR] = 71-87%) to 63% (IQR = 54-74%) in 1 year (p < 0.001). Specifically, the qualifying lesions (n = 49) regressed (stenosis reduced >10%) in 24 patients (49%), remained quiescent (stenosis same or ±10%) in 21 patients (43%), and progressed (stenosis increased >10%) in 4 patients (8%). There was no difference in intensity of risk factor control between groups of diverging clinical or angiographic outcomes. Higher HbA1c at baseline predicted plaque regression at 1 year (odds ratio = 4.4, 95% confidence interval = 1.4-14.5, p = 0.006). Among the 6 patients with recurrent strokes pertaining to the qualifying stenosis, 5 patients had solitary or rosarylike acute infarcts along the internal or anterior border zones, and 2 patients showed microembolic signals in transcranial Doppler ultrasound. INTERPRETATION: A majority of symptomatic high-grade intracranial plaques had regressed or remained quiescent by 12 months under intensive medical therapy. Artery-to-artery thromboembolism with impaired washout at border zones was a common mechanism in stroke recurrence.

Constrição Patológica/tratamento farmacológico , Arteriosclerose Intracraniana/tratamento farmacológico , Placa Aterosclerótica/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Resultado do Tratamento , Idoso , Angiografia Cerebral , Constrição Patológica/complicações , Constrição Patológica/diagnóstico , Feminino , Humanos , Imagem Tridimensional , Arteriosclerose Intracraniana/complicações , Arteriosclerose Intracraniana/diagnóstico , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/diagnóstico , Recidiva , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/etiologia
PLoS One ; 9(5): e97531, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24818753


BACKGROUND: Patients with symptomatic intracranial atherosclerosis (ICAS) of ≥ 70% luminal stenosis are at high risk of stroke recurrence. We aimed to evaluate the relationships between hemodynamics of ICAS revealed by computational fluid dynamics (CFD) models and risk of stroke recurrence in this patient subset. METHODS: Patients with a symptomatic ICAS lesion of 70-99% luminal stenosis were screened and enrolled in this study. CFD models were reconstructed based on baseline computed tomographic angiography (CTA) source images, to reveal hemodynamics of the qualifying symptomatic ICAS lesions. Change of pressures across a lesion was represented by the ratio of post- and pre-stenotic pressures. Change of shear strain rates (SSR) across a lesion was represented by the ratio of SSRs at the stenotic throat and proximal normal vessel segment, similar for the change of flow velocities. Patients were followed up for 1 year. RESULTS: Overall, 32 patients (median age 65; 59.4% males) were recruited. The median pressure, SSR and velocity ratios for the ICAS lesions were 0.40 (-2.46-0.79), 4.5 (2.2-20.6), and 7.4 (5.2-12.5), respectively. SSR ratio (hazard ratio [HR] 1.027; 95% confidence interval [CI], 1.004-1.051; P = 0.023) and velocity ratio (HR 1.029; 95% CI, 1.002-1.056; P = 0.035) were significantly related to recurrent territorial ischemic stroke within 1 year by univariate Cox regression, respectively with the c-statistics of 0.776 (95% CI, 0.594-0.903; P = 0.014) and 0.776 (95% CI, 0.594-0.903; P = 0.002) in receiver operating characteristic analysis. CONCLUSIONS: Hemodynamics of ICAS on CFD models reconstructed from routinely obtained CTA images may predict subsequent stroke recurrence in patients with a symptomatic ICAS lesion of 70-99% luminal stenosis.

Simulação por Computador , Hidrodinâmica , Arteriosclerose Intracraniana/complicações , Arteriosclerose Intracraniana/fisiopatologia , Acidente Vascular Cerebral/complicações , Idoso , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Recidiva , Estudos Retrospectivos , Medição de Risco
Stroke ; 45(5): 1402-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24699055


BACKGROUND AND PURPOSE: We aimed to evaluate the procedural safety, clinical, and angiographic outcome of carotid angioplasty and stenting for high-grade (≥70%) radiation-induced carotid stenosis (RIS) using atherosclerotic stenosis (AS) as a control. METHODS: In this 6-year prospective nonrandomized study, we compared the carotid angioplasty and stenting outcome of 65 consecutive patients (84 vessels) with RIS with that of a control group of 129 consecutive patients (150 vessels) with AS. Study end points were 30-day periprocedural stroke or death, ipsilateral ischemic stroke, technical success, procedural characteristics, instent restenosis (ISR; ≥50%) and symptomatic ISR. RESULTS: The median follow-up was 47.3 months (95% confidence interval, 26.9-61.6). Imaging assessment was available in 74 vessels (RIS) and 120 vessels (AS) in 2 years. Comparing RIS group with AS group, the rates of periprocedural stroke or death were 1.5% (1/65) versus 1.6% (2/129; P=1); ipsilateral ischemic stroke rates were 4.6% (3/65) versus 4.7% (6/129; P=1); the annual risks of ipsilateral ischemic stroke were 1.2% (3 patient/254.7 patient year) versus 1.2% (6 patient/494.2 patient year; P=0.89); technical success rates were both 100%. Stenting of common carotid artery and the use of multiple stents was more common in the RIS group (P=0 in both cases); ISR rates were 25.7% (19/74) versus 4.2% (5/120; P<0.001); symptomatic ISR rates were 6.8% (5/74) versus 0.8% (1/120; P=0.031). CONCLUSIONS: The safety, effectiveness, and technical difficulty of carotid angioplasty and stenting for RIS are comparable with that for AS although it is associated with a higher rate of ISR. CLINICAL TRIAL REGISTRATION: This trial was not registered as enrollment started in 2006.

Angioplastia/métodos , Doenças das Artérias Carótidas/terapia , Estenose das Carótidas/terapia , Lesões por Radiação/etiologia , Lesões por Radiação/terapia , Stents , Idoso , Angioplastia/efeitos adversos , Angioplastia/instrumentação , Isquemia Encefálica/epidemiologia , Isquemia Encefálica/etiologia , Isquemia Encefálica/mortalidade , Doenças das Artérias Carótidas/complicações , Doenças das Artérias Carótidas/mortalidade , Estenose das Carótidas/etiologia , Estenose das Carótidas/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Lesões por Radiação/mortalidade , Índice de Gravidade de Doença , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/mortalidade , Fatores de Tempo , Resultado do Tratamento
J Neurol Sci ; 324(1-2): 38-9, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23040959


We evaluated the safety and efficacy of rituximab in seven Chinese patients with neuromyelitis optica (NMO) or neuromyelitis optica syndrome disorders (NMOSD) in a tertiary medical center in Hong Kong. After rituximab induction, five patients became relapse-free and two had 50% reduction of relapses over a median follow-up of 24 months. No further deterioration of functional status, measured by the Expanded Disability Status Scale, was observed in all patients. Infusions were well tolerated except in two patients who developed transient hypotension. Rituximab reduced clinical relapse and prevented neurological deterioration in a small cohort of Chinese patients with NMO or NMOSD.

Anticorpos Monoclonais Murinos/uso terapêutico , Antineoplásicos/uso terapêutico , Neuromielite Óptica/tratamento farmacológico , Adulto , Anticorpos Monoclonais Murinos/efeitos adversos , Antineoplásicos/efeitos adversos , Grupo com Ancestrais do Continente Asiático , Avaliação da Deficiência , Feminino , Hong Kong , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Infusões Intravenosas , Imagem por Ressonância Magnética , Masculino , Metilprednisolona/uso terapêutico , Pessoa de Meia-Idade , Recidiva , Rituximab , Adulto Jovem