Simultaneous assessment of plaque morphology, cerebral micro-embolic signal status and platelet biomarkers in patients with recently symptomatic and asymptomatic carotid stenosis (original) (raw)
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Journal of the neurological sciences, 2017
The relationship between on-treatment platelet reactivity and cerebral micro-embolic signals (MES) is unknown, and has not been previously simultaneously assessed in asymptomatic and symptomatic carotid stenosis patients. Consecutive eligible patients with ≥50% asymptomatic or recently symptomatic carotid stenosis (≤4weeks following TIA/ischaemic stroke) were recruited to this pilot study. Symptomatic patients were followed up to the 'late' phase (≥3months) following symptom onset or carotid intervention; longitudinal data were analysed from symptomatic patients with data available at both time-points. Platelet function/reactivity was assessed with the PFA-100® to measure collagen-ADP (C-ADP) and collagen-epinephrine (C-EPI) closure times in citrate-anticoagulated whole blood. Bilateral simultaneous 1-hour transcranial Doppler ultrasound (TCD) monitoring of the middle cerebral arteries was performed to classify patients as MES +ve or MES -ve. 31 patients with ≥50% asymptomat...
Neurological Research, 2009
Background: The in vivo correlates of microembolic signals (MES) are still unknown. Platelet-associates (PA) with monocytes or granulocytes or platelet aggregates only may represent these correlates. Methods: Thirty patients with asymptomatic carotid stenosis .50% and 16 patients with acute (,4 days) atherothrombotic stroke were investigated. PA, P-selectin and thrombospondin expressions on platelets were assessed by flow cytometry. Soluble P-selectin (sPS) levels were assessed. MES detections were performed by transcranial Doppler sonography for 1 hour. PA, Pselectin and thrombospondin expressions on platelets and sPS levels were compared between MES-positive (MESz) and MES-negative (MES2) patients. Results: Eight patients (27%) with asymptomatic carotid stenosis had 1-26 MES/h. Degree of stenosis was 78 ¡ 10% in MES2 and 88 ¡ 8% in the MESz (p50.01). There were no differences in percentages of PA. P-selectin and thrombospondin surface expression was lower in MESz, but this was not significant. sPS levels were higher in MESz (122 ¡ 27 ng/ml versus 80 ¡ 25 ng/ml in MES2, p50.01). Seven (44%) patients with stroke had 1-39 MES/h. There were no differences in percentages of PA. MESz had higher sPS levels (178 ¡ 43 versus 121 ¡ 44 ng/ml, p50.02) and less P-selectin surface expression than MES2 (9.0 ¡ 3.4 versus 4.5 ¡ 1.6%, p50.004). Conclusion: High levels of sPS in MESz and lower expression of platelet activation markers on platelets' surface suggest shedding of activation markers from the platelets' surface and thus enhanced activation of platelets of MESz compared with MES2. PA are probably not the clinical correlates of MES, but platelets seem to be the main cellular element of solid cerebral microemboli.
Source of Microembolic Signals in Patients With High-Grade Carotid Stenosis
Stroke, 2002
Background and Purpose-In patients with both symptomatic and asymptomatic carotid artery stenoses, the relationship between carotid plaque characteristics and transcranial Doppler (TCD)-detected microembolic signals (MES) is unclear. The purpose of this study was to examine the relationship between macroscopically described plaque characteristics and MES in patients undergoing carotid endarterectomy. Methods-Sequential patients scheduled for carotid endarterectomy underwent preoperative 30-minute TCD monitoring of the ipsilateral middle cerebral artery to detect MES. TCD signal analysis, by researchers who were blinded to patient information, was performed offline. Clinical variables of patients and macroscopic carotid plaque features seen at surgery were documented prospectively. Results-Of the 109 patients (74 male, 35 female; mean age, 68.8Ϯ8.7 years) enrolled, 71 had ipsilateral carotid territory symptoms. MES were detected in 27 of all patients (25%). Twenty-two of 71 symptomatic patients (31%) compared with 5 of 38 asymptomatic patients (13%) had MES (Pϭ0.046). Also, symptomatic patients had more emboli (total MES counts) than asymptomatic patients (Pϭ0.010). The presence or absence of MES was not associated with plaque characteristics. Conclusions-Our data do not confirm previous reports of an association between MES and macroscopic plaque characteristics. We hypothesize that smaller platelet aggregates and fibrin clots, which are not detected macroscopically, are the most likely sources of TCD-detected MES.
Stroke; a journal of cerebral circulation, 2014
In patients with mild to moderate symptomatic carotid artery stenosis, intraplaque hemorrhage (IPH) and a thin/ruptured fibrous cap (FC) as evaluated with MRI, and the presence of microembolic signals (MESs) as detected with transcranial Doppler, are associated with an increased risk of a (recurrent) stroke. The objective of the present study is to determine whether the prevalence of MES differs in patients with and without IPH and thin/ruptured FC, and patients with only a thin/ruptured FC without IPH. In this multicenter, diagnostic cohort study, patients with recent transient ischemic attack or minor stroke in the carotid territory and an ipsilateral mild to moderate carotid artery plaque were included. IPH and FC status were dichotomously scored. Analysis of transcranial Doppler data was done blinded for the MRI results. Differences between groups were analyzed with Fisher exact test. A total of 113 patients were included. Transcranial Doppler measurements were feasible in 105 p...
Stroke, 2014
Background and Purpose— Although symptomatic carotid stenosis is associated with 3-fold increased risk of early stroke recurrence, the pathophysiologic mechanisms of high early stroke risk have not been established. We aimed to investigate the relationship between early stroke recurrence after initial symptoms and histological features of plaque inflammation and instability in resected carotid plaque. Methods— Carotid endarterectomy tissue from consecutive patients with ipsilateral stenosis ≥50% and recent symptoms were analyzed using a validated histopathologic algorithm (Oxford Plaque Study [OPS] system). Nonprocedural stroke recurrence before carotid endarterectomy was ascertained at 7, 28, and 90 days after initial symptoms. Results— Among 44 patients meeting eligibility criteria, 27.3% (12/44) had stroke recurrence after initial stroke/transient ischemic attack but before carotid endarterectomy. Compared with patients without recurrence, stroke recurrence was associated with de...
Vojnosanitetski pregled, 2013
Background/Aim. A certain percentage of patients with asymptomatic carotid stenosis have an unstable carotid plaque. For these patients it is possible to register by modern imaging methods the existence of lesions of the brain parenchyma - the silent brain infarction. These patients have a greater risk of ischemic stroke. The aim of this study was to analyze the connection between the morphology of atherosclerotic carotid plaque in patients with asymptomatic carotid stenosis and the manifestation of silent brain infarction, and to analyze the influence of risk factors for cardiovascular diseases on the occurrence of silent brain infarction and the morphology of carotid plaque. Methods. This retrospective study included patients who had been operated for high grade (> 70%) extracranial atherosclerotic carotid stenosis at the Clinic for Vascular and Transplantation Surgery of the Clinical Center of Vojvodina over a period of 5 years. The patients analyzed had no clinical manifestat...
Plaque Features Associated With Increased Cerebral Infarction After Minor Stroke and TIA
JACC: Cardiovascular Imaging, 2012
The goal of this study was to determine whether a 3-T magnetic resonance imaging (MRI) protocol combining carotid atherosclerotic plaque and brain imaging can identify features of high-risk acutely symptomatic plaque that correlate with brain injury. B A C K G R O U N D It has previously been demonstrated that, in asymptomatic patients, MRI can identify features of carotid plaque that are associated with stroke, such as the presence of a large lipid core. We hypothesized that the early phase (Ͻ7 days) after a cerebrovascular event, when risk of recurrence is highest, may be associated with particular plaque characteristics that associate with cerebral injury. M E T H O D S Eighty-one patients (41 presenting acutely with transient ischemic attack [TIA] or minor stroke and 40 asymptomatic controls) underwent multicontrast carotid artery MRI on 2 separate occasions, each accompanied by diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) imaging of the brain. R E S U L T S Complex (American Heart Association [AHA] type VI) plaques were seen in 22 of 41 patients (54%) in the symptomatic group versus 8 of 40 (20%) in the asymptomatic group (p Ͻ 0.05). They were caused by intraplaque hemorrhage (34% vs. 18%; p ϭ 0.08), surface rupture (24% vs. 5%; p ϭ 0.03), or luminal thrombus (7% vs. 0%; p ϭ 0.24). Noticeably, 17 of 30 (57%) cases of AHA type VI plaque were in vessels with Ͻ70% stenosis. At follow-up scanning (Ͼ6 weeks later), only 2 cases of symptomatic AHA type VI plaque showed evidence of full healing. The presence of fibrous cap rupture was associated with higher DWI brain injury at presentation and higher total cerebral FLAIR signal at follow-up (p Ͻ 0.05). C O N C L U S I O N S Early carotid wall MRI in patients experiencing minor stroke or TIA showed a higher proportion of "complex" plaques compared with asymptomatic controls; a majority were in arteries of Ͻ70% stenosis. Fibrous cap rupture was associated with increases in DWI and FLAIR lesions in the brain. Combined carotid plaque and brain MRI may aid risk stratification and treatment selection in acute stroke and