microembolic signal

  • 文章类型: Journal Article
    经颅多普勒(TCD)和脑MRI可能有助于评估APS患者,有助于对该人群的脑血管缺血事件的风险进行分层。本研究旨在评估原发性抗磷脂综合征患者脑MRI异常的频率。继发性抗磷脂综合征和SLE,并与TCD发现相关。
    这项研究,在两个自身免疫性疾病转诊中心进行了四年,包括22例原发性抗磷脂综合征患者,24例继发性抗磷脂综合征患者,27例无APS的SLE患者和21例健康对照。所有参与者都接受了TCD以评估脑血流动力学,检测微栓子信号并评估从右到左分流,其次是脑部MRI和磁共振血管造影。对急性微栓塞的MRI扫描进行了回顾,局部皮质梗死,边界梗塞,腔隙性梗塞,缺血性病变,白质高强度,微小和大出血和动脉狭窄≥颈部颈动脉的50%,两名神经放射学家对临床数据视而不见。
    两组的脑部MRI检查结果相似,除了腔隙性脑梗死,继发性抗磷脂综合征患者更常见(P=0.022)。TCD发现颅内狭窄的患者有较高的区域梗死频率(40%vs7.5%,P=0.02),腔隙(40%对11.3%,P=0.075)和边界区梗死(20%vs1.9%,P=0.034)。
    颅内狭窄的患者出现较高的区域频率,腔隙和边界区梗塞,提示在APS和卒中患者中不应该忽视颅内血管的评估。
    UNASSIGNED: Transcranial Doppler (TCD) and brain MRI may be useful in evaluating patients with APS, helping to stratify the risk of cerebrovascular ischaemic events in this population. This study aimed to assess the frequency of brain MRI abnormalities in patients with primary antiphospholipid syndrome, secondary antiphospholipid syndrome and SLE and correlate to TCD findings.
    UNASSIGNED: The study, conducted over four years at two autoimmune disease referral centres, included 22 primary antiphospholipid syndrome patients, 24 secondary antiphospholipid syndrome patients, 27 SLE patients without APS and 21 healthy controls. All participants underwent TCD to assess cerebral haemodynamics, detect microembolic signals and evaluate right-to-left shunts, followed by brain MRI and magnetic resonance angiography. MRI scans were reviewed for acute microembolism, localized cortical infarctions, border infarctions, lacunar infarctions, ischaemic lesions, white matter hyperintensity, micro and macro haemorrhages and arterial stenosis ≥50% of the cervical carotid artery, by two neuroradiologists blinded to the clinical data.
    UNASSIGNED: Brain MRI findings were similar between the groups, except for lacunar infarction, more frequent in patients with secondary antiphospholipid syndrome (P = 0.022). Patients with intracranial stenosis detected by TCD had a higher frequency of territorial infarction (40% vs 7.5%, P = 0.02), lacunar (40% vs 11.3%, P = 0.075) and border zone infarcts (20% vs 1.9%, P = 0.034).
    UNASSIGNED: Patients with intracranial stenosis presented a higher frequency of territorial, lacunar and border zone infarcts, suggesting that evaluating the intracranial vasculature should not be neglected in patients with APS and stroke.
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  • 文章类型: Journal Article
    栓塞性卒中占急性脑血管意外的很大比例。通过微血流检测进行多普勒血流监测可以提示脑梗死的栓塞性质。这项研究的目的是确定与缺血性卒中患者微栓子信号存在相关的因素。这项研究包括515名患者,其中48例(9.3%)检测到微栓子信号.根据多层螺旋CT血管造影,有无微栓子信号的患者颈总动脉和左颈内动脉的壁厚存在显著差异(p<0.05).因子分析揭示了一个变量,反映了左颈动脉粥样硬化的严重程度,这是微栓子信号记录的重要预测因子(p=0.016)。
    Embolic strokes make up a significant proportion of acute cerebrovascular accidents. Doppler blood flow monitoring with microembolodetection allows suggesting the embolic nature of cerebral infarction. The aim of this study was to identify factors associated with the presence of microembolic signals in patients with ischemic stroke. The study included 515 patients, microembolic signals were detected in 48 (9.3%) of them. According to multispiral CT angiography, significant differences in patients with and without microembolic signals were found for wall thickness of both common carotid arteries and for left internal carotid artery (p<0.05). Factor analysis revealed a variable that reflects the severity of left carotid arteries atherosclerosis, which was a significant predictor of registration of the microembolic signals (p=0.016).
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  • 文章类型: Journal Article
    Background An increased risk of acute ischemic stroke is recognized among patients with cancer. However, the mechanism behind cancer-related stroke is unclear. In this study, we determined the presence of associated venous thromboembolism and arterial thromboembolism and their clinical impact on patients with cancer-related stroke. Methods and Results Patients with embolic stroke of undetermined source with or without cancer were evaluated for venous thromboembolism (deep vein thrombosis [DVT] and/or pulmonary embolism) and arterial thromboembolism by using Doppler sonography to determine the presence of lower-extremity DVT and the microembolic signal of the symptomatic cerebral circulation, respectively. Infarct volume was determined by diffusion-weighted magnetic resonance imaging. The multivariable linear regression and Cox proportional hazard analysis were used to investigate the effect of DVT and microembolic signal on infarct volume and 1-year survival, respectively. Of 142 screened patients, 118 were included (37 with, 81 without cancer). Those with cancer had a higher prevalence of DVT or microembolic signal than did the noncancer group (62.2% versus 19.8%; P<0.001). Among patients with cancer-related stroke, DVT was associated with a greater infarct volume in magnetic resonance imaging (beta, 13.14; 95% CI, 1.62-24.66; P=0.028). Presence of DVT (hazard ratio, 16.79; 95% CI, 2.05-137.75; P=0.009) and microembolic signal (hazard ratio, 8.16; 95% CI, 1.36-48.85; P=0.022) were independent predictors of poor 1-year survival. Conclusions Patients with cancer-associated embolic stroke of undetermined source have an elevated risk of associated venous thromboembolism and arterial thromboembolism, both of which have a significant negative impact on 1-year survival. The results of this study may enhance our understanding of cancer-associated stroke and improve risk stratification of patients with this disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov/.Unique identifier: NCT02212496.
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  • 文章类型: Journal Article
    Background and Purpose- Hemodynamic compromise has been implicated in moyamoya disease (MMD) with transient ischemic attacks or ischemic stroke. However, increasing evidence supports the notion that artery-to-artery embolism may also contribute to ischemic events based on microembolic signal (MES) monitoring. Methods- A total of 48 patients aged between 20 and 60 years with newly diagnosed MMD were enrolled and angiographically classified according to the Suzuki staging system. For detection of MESs, transcranial Doppler was performed at the middle cerebral artery bilaterally for a 30-minute period. Mean flow velocities in the middle cerebral artery were also evaluated and categorized into low (<40 cm/s), normal (40-80 cm/s), and high (>80 cm/s). Clinical characteristics, cerebral angiography findings, recent ischemic events within 3 months, and antiplatelet medication were correlated with transcranial Doppler findings. Results- MESs were detected in 11 of the 48 patients (23%), with a frequency of 11 of 89 (12%) examined hemispheres. The mean number of MESs was 2 (range, 1-6). Six of the 11 hemispheres (55%) presented with ischemic strokes or transient ischemic attacks, and 2 (18%) presented with hemorrhagic strokes. The presence of MESs was associated with recent ischemic events ( P=0.024) and high mean flow velocities ( P=0.016), which was usually observed in Suzuki stage I and II (early-stage MMD). After controlling for age, sex, and antiplatelet medication, both recent ischemic events (odds ratio, 6.294; 95% CI, 1.345-29.457; P=0.019) and high mean flow velocities (odds ratio, 6.172; 95% CI, 1.235-31.25; P=0.027) were found to be independent predictors of MESs. Conclusions- MESs were observed in patients with high mean flow velocities, particularly early-stage MMD, and clinically associated with recent ischemic events. A randomized controlled study is necessary to determine the efficacy of antiplatelet agents in the treatment of MES-positive MMD.
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  • 文章类型: Journal Article
    BACKGROUND: Microembolic signals (MES) and insulin resistance (IR) is common in patients with acute ischemic stroke (AIS). Patients with active MES tend to be more seriously ill and prone to aggravating disease progression. IR is an important risk factor for stroke which has been found to be associated with the severity of stroke. This study aims to investigate the clinical correlation between intracranial MES and IR in AIS patients.
    METHODS: A total of 119 patients with AIS were enrolled in this study. The IR index (HOMA-IR) was calculated according to the homeostasis model and divided into 4 levels, where IR was defined by HOMA-IR index in the top quartile (Q4). Transcranial Doppler Sonography was performed in all patients within 72 hours after the stroke onset to monitor arterial MES in the lesion side of the brain for 30 minutes.
    RESULTS: It is found that the positive rate of MES increased with the increase of IR level. The positive rate of MES in IR group was 55.2% (16/29), and that in non-IR group was 32.2% (29/90). In addition, HOMA-IR in patients with MES- were significantly lower than those in patients with MES+ (1.6 [Interquartile range: 0.9-2.5] compared with 2.2 [Interquartile range: 1.3-4.1], P < .05).In multiple logistic regression analysis, we calculated the OR of MES as compared with the HOMA-IR. The result of OR value is 1.38 (95% confidence interval: 1.05-1.82, P = .02).
    CONCLUSIONS: IR is positively related to MES in patients with AIS. Higher level of IR might contribute to plaque destabilization and the formation of MES, which finally leading to the occurrence of stroke.
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  • 文章类型: Journal Article
    Right-to-left shunt (RLS) through a patent foramen ovale (PFO) is likely associated with ischemic stroke. Many studies have attempted to demonstrate the association between RLS and ischemic stroke. However, information on the association between the degree of RLS and the subtypes of ischemic stroke categorized by the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification is lacking.
    This was a retrospective study involving 508 patients with ischemic stroke who underwent a transcranial Doppler (TCD) microbubble test between 2013 and 2015. The degree of RLS was divided into 4 grades according to the microbubble signal (MBS) as follows: no MBS, grade 1; MBS < 20, grade 2; MBS > 20, grade 3; curtain sign, grade 4. The degree of RLS and the type of ischemic stroke as classified by TOAST were analyzed and compared with other clinical information and laboratory findings.
    The higher RLS grade was associated with the cardioembolism (CE) and stroke of undetermined etiology (SUE), and the microbubble signals were inversely related with small vessel disease (SVD). An MBS higher than grade 3 showed a 2.95-fold higher association with SUE than large artery atherosclerosis (LAA), while grade 4 MBS revealed an approximately 8-fold higher association with SUE than LAA.
    RLS identified by the TCD microbubble test was significantly and independently associated with cryptogenic ischemic stroke (negative evaluation). Subsequent studies are needed to determine the biologic relationship between RLS and ischemic stroke, particularly the cryptogenic subtype of ischemic stroke.
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  • 文章类型: Journal Article
    OBJECTIVE: Carotid artery stenosis can result in the brain tissue injury related to the intracranial aterial flow disturbances as well as microembolic complications. The choice of the proper therapy in patients with carotid artery stenosis, especially asymptomatic, remains still a significant clinical problem. The study aim was an assessment of the cerebral embolism and brain vascular reserve parameters in patients with carotid artery stenosis regarding the occurrence of the clinical symptoms, the degree of stenosis as well as plaque morphology.
    METHODS: The study included 60 patients, with internal carotid artery stenosis. The degree of stenosis, the atherosclerotic plaque surface and morphology were assessed by the means of Duplex Doppler ultrasound. Cerebrovascular reactivity (vasomotor reactivity reserve test and Breath Holding Index) and monitoring of the microembolic signals (MES) were assessed with transcranial Doppler ultrasound examination (TCD).
    RESULTS: The vasoreactivity parameters were significantly lower in the group of patients with stenosis ≥70% and in patients with ulcerations on the plaque surface. Microembolic signals were recorded significantly more often in symptomatic patients; in patients with stenosis ≥70%; in patients with ulcerations on the plaque surface and those with hypoechogenic plaque structure.
    CONCLUSIONS: Microembolic signals in patients with symptomatic carotid stenosis are one of the ultrasound features of unstable carotid stenosis. Worse reactivity parameters of the cerebral arteries are associated with the presence of a large degree of carotid artery stenosis.
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  • 文章类型: Comparative Study
    OBJECTIVE: To assess the incidence of silent cerebral embolization when using the transradial approach for diagnostic coronary angiography (DCA).
    BACKGROUND: Compared to other vascular access sites, the right transradial approach (RTA) could reduce the amount of brain emboli by avoiding mechanical trauma to the aortic wall caused by catheters and wire, whereas it increases manipulation of catheters in the ascending aorta and has a higher risk of direct embolization into the right common carotid artery. A recent study showed an increased incidence of microembolic signals (MES) in RTA compared to femoral. However, left transradial approach (LTA) has never been assessed.
    METHODS: 40 patients with suspected coronary artery disease were randomized to DCA via RTA (n=20) or LTA (n=20) with contemporaneous bilateral transcranial Doppler monitoring.
    RESULTS: MES were detected in all patients, with a significantly higher rate in the RTA group (median 61, interquartile range (IQR) 47-105, vs 48, IQR 31-60, p=0.035). MES generated during procedures needing >2 catheters (n=8), are higher than those detected during procedures performed with 2 catheters (n=32, 102, IQR 70-108, vs 48, IQR 33-60, p=0.001). At multivariate analysis increasing number of catheters was the only independent predictor of high incidence of MES (OR 16.4, 95% CI 1.23-219.9, p=0.034, -2LL=26.7).
    CONCLUSIONS: LTA has a lower risk of brain embolization because of the lower number of catheter exchange maneuvers. Since the degree of brain embolism depends on the magnitude of mechanical manipulation, catheter changes should be minimized to reduce the risk of cerebral embolization.
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  • 文章类型: Journal Article
    BACKGROUND: Dual antiplatelet therapy with clopidogrel and aspirin reduces the presence and number of microembolic signals in patients with large artery disease. However, whether it is effective in patients with intracranial disease alone remains uncertain. We performed a subgroup analysis of the The CLopidogrel plus Aspirin for Infarction Reduction (CLAIR in acute stroke or transient ischemic attack patients with large artery stenosis and microembolic signals) study of only patients with intracranial occlusive disease, excluding those with extra cranial disease.
    METHODS: CLAIR was a randomized-controlled, open-label, multicenter clinical trial with blinded outcome evaluation, which recruited patients with symptoms of ischemic stroke or transient ischemic attack within seven-days of onset, with large artery stenosis verified by transcranial Doppler and carotid ultrasound, and with microembolic signals detected by transcranial Doppler recording. All patients were randomized to receive clopidogrel plus aspirin daily for seven-days (dual treatment), or aspirin alone for seven-days (monotherapy). Repeated transcranial Doppler recordings for microembolic signals were made on day one, two, and seven. This subgroup study only analyzed the patients with purely intracranial large artery disease and excluded those with extra cranial stenosis.
    RESULTS: There were 70 patients recruited with purely intracranial stenosis, 34 in the dual treatment group and 36 in the monotherapy group. The proportion of the patients with positive emboli at day seven in the dual treatment group was significantly lower than that in the monotherapy group (relative risk reduction 56·5%, 95% confidence interval 2·5-80·6; P = 0·029). The number of emboli in the dual treatment group decreased significantly at day two (P = 0·043) and day seven (P = 0·018) compared with the monotherapy group. After adjustment for the number of emboli at day one, the effect of dual treatment was still significant for the reduction of presence (relative risk reduction 56·0%; 95% confidence interval 5·4-79·6; P = 0·036) and number (adjusted mean difference -0·9; 95% confidence interval -1·5 to -0·3; P = 0·004) of positive emboli at day seven.
    CONCLUSIONS: Dual treatment with clopidogrel and aspirin for seven-days is more effective than aspirin alone to reduce microembolic signals in patients with intracranial arterial stenosis.
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