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Kussman BD, Imaduddin SM, Gharedaghi MH, Heldt T, LaRovere K. Cerebral Emboli Monitoring Using Transcranial Doppler Ultrasonography in Adults and Children: A Review of the Current Technology and Clinical Applications in the Perioperative and Intensive Care Setting. Anesth Analg 2021; 133:379-392. [PMID: 33764341 DOI: 10.1213/ane.0000000000005417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Transcranial Doppler (TCD) ultrasonography is the only noninvasive bedside technology for the detection and monitoring of cerebral embolism. TCD may identify patients at risk of acute and chronic neurologic injury from gaseous or solid emboli. Importantly, a window of opportunity for intervention-to eliminate the source of the emboli and thereby prevent subsequent development of a clinical or subclinical stroke-may be identified using TCD. In this review, we discuss the application of TCD sonography in the perioperative and intensive care setting in adults and children known to be at increased risk of cerebral embolism. The major challenge for evaluation of emboli, especially in children, is the need to establish the ground truth and define true emboli identified by TCD. This requires the development and validation of a predictive TCD emboli monitoring technique so that appropriately designed clinical studies intended to identify specific modifiable factors and develop potential strategies to reduce pathologic cerebral embolic burden can be performed.
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Affiliation(s)
- Barry D Kussman
- From the Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts
| | - Syed M Imaduddin
- Department of Electrical Engineering and Computer Science, the Institute for Medical Engineering and Science, and the Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Mohammad Hadi Gharedaghi
- From the Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts
| | - Thomas Heldt
- Department of Electrical Engineering and Computer Science, the Institute for Medical Engineering and Science, and the Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Kerri LaRovere
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts
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Das AS, Regenhardt RW, LaRose S, Monk AD, Castro PM, Sheriff FG, Sorond FA, Vaitkevicius H. Microembolic Signals Detected by Transcranial Doppler Predict Future Stroke and Poor Outcomes. J Neuroimaging 2020; 30:882-889. [PMID: 32648610 DOI: 10.1111/jon.12749] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Although transcranial Doppler detects microembolic signals (MES) in numerous settings, the practical significance of such findings remains unclear. METHODS Clinical information from ischemic stroke or transient ischemic attack patients (n = 248) who underwent embolic monitoring from January 2015 to December 2018 was obtained. RESULTS MES were found in 15% of studies and ischemic recurrence was seen in 11% of patients (over 7 ± 6 days). Patients with MES had more lacunes than those without MES (1 ± 3 vs. 1 ± 2, P = .016), were more likely to have ischemic recurrence (37% vs. 6%, P < .001), undergo a future revascularization procedure (26% vs. 10%, P = .005), have a longer length of stay (9 vs. 4 days, P = .043), and have worse functional disability at discharge (modified Rankin Scale 3-6, 66% vs. 34%, P < .001). After controlling for several relevant cofactors, patients with MES were more likely to have ischemic recurrence (HR 4.90, 95% CI 2.16-11.09, P < .001), worse functional disability (OR 3.31, 95% CI 1.22-8.99, P = .019), and longer length of stays (β = .202, P < .001). CONCLUSIONS MES may help to risk stratify patients as their presence is associated with ischemic recurrence and worse outcomes.
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Affiliation(s)
- Alvin S Das
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Robert W Regenhardt
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Sarah LaRose
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Andrew D Monk
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Pedro M Castro
- Department of Neurology, Centro Hospital Universitário São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Faheem G Sheriff
- Department of Neurosurgery, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX
| | - Farzaneh A Sorond
- Department of Neurology, Northwestern Memorial Hospital, Feinberg School of Medicine, Chicago, IL
| | - Henrikas Vaitkevicius
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
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Cerebral Microembolization in Left Ventricular Assist Device Associated Ischemic Events. J Stroke Cerebrovasc Dis 2020; 29:104660. [PMID: 32044219 DOI: 10.1016/j.jstrokecerebrovasdis.2020.104660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION The significance of microembolic signals (MES) detected by transcranial Doppler ultrasound emboli monitoring (TCD-e) in patients supported with left ventricular assist devices (LVAD) remains unclear. We aimed to investigate the relationship between cerebral microembolization detected by TCD-e and acute ischemic events in LVAD patients. METHODS We reviewed consecutive patients with acute ischemic stroke or transient ischemic attack (TIA) in a prospectively collected database of LVAD patients. TCD-e exams consisted of monitoring the middle cerebral arteries for microembolic signals (MES) over 30 minutes. RESULTS Of 515 persons with LVAD, 41 TCD-e studies were performed in 35 patients with acute ischemic stroke or transient ischemic attack (TIA) in a median of 1 day (Interquartile range [IQR]: 0-2) after the event. MES were present in 15 (44%) TCD-e studies with a median MES count of 4 (IQR: 2-15.5). Bloodstream infections were more common in patients with MES (38% versus 8%, P = .039). There were trends for lower international normalized ratio (1.39 versus 1.69, P = .214), lower activated partial thromboplastin (33.2 versus 36.6, P = .577), higher lactate dehydrogenase (531 versus 409, P = .323) and a higher frequency of pump thrombosis (13% versus 8%, P = .637) in patients with MES compared with those without MES. CONCLUSIONS LVAD patients with acute ischemic stroke or TIA have a high prevalence of MES on TCD-e, which may serve as a marker for a prothrombotic state. Further study of MES in LVAD patients is warranted.
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Antiplatelet Drugs in the Management of Cerebral Ischemia. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00057-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Saedon M, Saratzis A, Lee RWS, Hutchinson CE, Imray CHE, Singer DRJ. Registry report on prediction by Pocock cardiovascular score of cerebral microemboli acutely following carotid endarterectomy. Stroke Vasc Neurol 2018; 3:147-152. [PMID: 30294470 PMCID: PMC6169612 DOI: 10.1136/svn-2017-000116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/10/2017] [Accepted: 11/12/2017] [Indexed: 11/26/2022] Open
Abstract
Background Cerebral microemboli may lead to ischaemic neurological complications after carotid endarterectomy (CEA). The association between classical cardiovascular risk factors and acute cerebral microemboli following carotid surgery has not been studied. The aim of this study was to explore whether an established cardiovascular risk score (Pocock score) predicts the presence of cerebral microemboli acutely after CEA. Subjects and methods Pocock scores were assessed for the 670 patients from the Carotid Surgery Registry (age 71±1 (SEM) years, 474 (71%) male, 652 (97%) Caucasian) managed from January 2002 to December 2012 in the Regional Vascular Centre at University Hospitals Coventry and Warwickshire NHS Trust, which serves a population of 950 000. CEA was undertaken in 474 (71%) patients for symptomatic carotid stenosis and in 196 (25%) asymptomatic patients during the same period. 74% of patients were hypertensive, 71% were smokers and 49% had hypercholesterolaemia. Results A high Pocock score (≥2.3%) was significantly associated with evidence of cerebral microemboli acutely following CEA (P=0.039, Mann-Whitney (MW) test). A Pocock score (≥2.3%) did not predict patients who required additional antiplatelet therapy (microemboli signal (MES) rate >50 hour-1: P=0.164, MW test). Receiver operating characteristic analysis also showed that the Pocock score predicts acute postoperative microemboli (area under the curve (AUC) 0.546, 95% CI 0.502 to 0.590, P=0.039) but not a high rate of postoperative microemboli (MES >50 hour−1: AUC 0.546, 95% CI 0.482 to 0.610, P=0.164). A Pocock score ≥2.3% showed a sensitivity of 74% for the presence of acute postoperative cerebral microemboli. A Pocock score ≥2.3% also showed a sensitivity of 77% and a negative predictive value of 90% for patients who developed a high microembolic rate >50 hour−1 after carotid surgery. Conclusion These findings demonstrate that the Pocock score could be used as a clinical tool to identify patients at high risk of developing acute postoperative microemboli.
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Affiliation(s)
- Mahmud Saedon
- Nottingham University Hospitals NHS Trust, Nottingham, UK.,University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK
| | | | - Rachel W S Lee
- University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK
| | | | | | - Donald R J Singer
- Yale School of Medicine, New Haven, Connecticut, USA.,Fellowship of Postgraduate Medicine, London, UK
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Chen X, Liu K, Wu X, Wang S, Li T, Xing Y. Microembolic Signals Predict Recurrence of Ischemic Events in Symptomatic Patients with Middle Cerebral Artery Stenosis. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:747-755. [PMID: 29395677 DOI: 10.1016/j.ultrasmedbio.2017.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Middle cerebral artery (MCA) stenosis is a common cause of ischemic stroke in Asian populations. We sought to determine whether microembolic signals (MESs) can predict the occurrence or recurrence of ischemia in symptomatic and asymptomatic patients with MCA stenosis. The symptomatic group had a significantly higher incidence of MES (30% vs. 16.2%, p < 0.05), as well as higher incidences of cerebral infarction and transient ischemic attack (TIA) (infarction, 13.0% vs. 4.4%, OR 3.123 [95% CI, 1.049-9.294], p < 0.05; TIA, 21.0% vs. 2.9%, OR = 7.108 [95% CI, 1.808-27.949], p < 0.001) than the asymptomatic group. After a follow-up period of 0.5-4.5 y, the subgroup of MES-positive (MES+) symptomatic patients had a significantly higher incidence of TIA (36.7% vs. 14.3%, OR = 1.623 [95% CI, 1.166-2.258]; p < 0.001) than the subgroup of MES-negative (MES-) symptomatic patients. The likelihood of the early occurrence of an endpoint event was also higher in the subgroup of MES+ symptomatic patients. In the group of asymptomatic patients with MCA stenosis, no significant differences were identified between the MES+ and MES- subgroups.
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Affiliation(s)
- Xiaomin Chen
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Kangding Liu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Xiujuan Wu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Sibo Wang
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Ting Li
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Yingqi Xing
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China.
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Safouris A, Krogias C, Sharma VK, Katsanos AH, Faissner S, Roussopoulou A, Zompola C, Kneiphof J, Kargiotis O, Deftereos S, Giannopoulos G, Triantafyllou N, Voumvourakis K, Vadikolias K, Tsivgoulis G. Statin Pretreatment and Microembolic Signals in Large Artery Atherosclerosis. Arterioscler Thromb Vasc Biol 2017; 37:1415-1422. [PMID: 28450295 DOI: 10.1161/atvbaha.117.309292] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/17/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Although statin pretreatment (SP) is associated with better outcomes in patients with acute cerebral ischemia after an ischemic stroke/transient ischemic attack, data on the underlying mechanism of this beneficial effect are limited. APPROACH AND RESULTS We sought to evaluate the potential association between SP and microembolic signal (MES) burden in acute cerebral ischemia because of large artery atherosclerosis (LAA). We prospectively evaluated consecutive patients with first-ever acute cerebral ischemia because of LAA in 3 tertiary stroke centers over a 2-year period. All patients underwent continuous 1-hour transcranial Doppler monitoring of the relevant vessel at baseline (≤24 hours). SP was recorded and dichotomized as high dose or low-to-moderate dose. SP was documented in 43 (41%) of 106 LAA patients (mean age, 65.4±10.3 years; 72% men; low-to-moderate dose, 32%; high dose, 8%). There was a significant (P=0.022) dose-dependent effect between SP and MES prevalence: no SP (37%), SP with low-to-moderate dose (18%), and SP with high dose (0%). Similarly, a significant (P=0.045) dose-dependent effect was documented between SP and MES burden: no SP (1.1±1.8), SP with low-to-moderate dose (0.7±1.6), and SP with high dose (0±0). In multivariable logistic regression analysis adjusting for demographics, vascular risk factors, location of LAA, stroke severity, and other prevention therapies, SP was associated with lower likelihood of MES presence (odds ratio, 0.29; 95% confidence interval, 0.09-0.92; P=0.036). In addition, SP was found also to be independently related to higher odds of functional improvement (common odds ratio, 3.33; 95% confidence interval, 1.07-10.0; P=0.037). CONCLUSIONS We found that SP in patients with acute LAA is related with reduced MES presence and lower MES burden with an apparently dose-dependent association.
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Affiliation(s)
- Apostolos Safouris
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Christos Krogias
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Vijay K Sharma
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Aristeidis H Katsanos
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Simon Faissner
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Andromachi Roussopoulou
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Christina Zompola
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Janina Kneiphof
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Odysseas Kargiotis
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Spyridon Deftereos
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Georgios Giannopoulos
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Nikos Triantafyllou
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Konstantinos Voumvourakis
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Konstantinos Vadikolias
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.)
| | - Georgios Tsivgoulis
- From the Second Department of Neurology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece (A.S., A.H.K., A.R., C.Z., K.V., G.T.); Acute Stroke Unit, Metropolitan Hospital, Pireus, Greece (A.S., O.K.); Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany (C.K., S.F., J.K.); Yong Loo Lin School of Medicine, National University of Singapore (V.K.S.); Division of Neurology, National University Hospital, Singapore (V.K.S.); Department of Neurology, University Hospital of Ioannina, School of Medicine, University of Ioannina, Greece (A.H.K.); Second Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Greece (S.D., G.G.); First Department of Neurology, University of Athens, School of Medicine, Eginition University Hospital, Greece (N.T.); and Department of Neurology, Alexandroupolis University Hospital, School of Medicine, Democritus University of Thrace, Greece (K.V.).
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Saedon M, Hutchinson CE, Imray CHE, Singer DRJ. ABCD 2 risk score does not predict the presence of cerebral microemboli in patients with hyper-acute symptomatic critical carotid artery stenosis. Stroke Vasc Neurol 2017; 2:41-46. [PMID: 28959490 PMCID: PMC5600015 DOI: 10.1136/svn-2017-000073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 02/02/2017] [Indexed: 11/23/2022] Open
Abstract
Introduction ABCD2 risk score and cerebral microemboli detected by transcranial Doppler (TCD) have been separately shown to the predict risk of recurrent acute stroke. We studied whether ABCD2 risk score predicts cerebral microemboli in patients with hyper-acute symptomatic carotid artery stenosis. Participants and methods We studied 206 patients presenting within 2 weeks of transient ischaemic attack or minor stroke and found to have critical carotid artery stenosis (≥50%). 86 patients (age 70±1 (SEM: years), 58 men, 83 Caucasian) had evidence of microemboli; 72 (84%) of these underwent carotid endarterectomy (CEA). 120 patients (age 72±1 years, 91 men, 113 Caucasian) did not have microemboli detected; 102 (85%) of these underwent CEA. Data were analysed using X2 and Mann–Whitney U tests and receiver operating characteristic (ROC) curves. Results 140/206 (68%: 95% CI 61.63 to 74.37) patients with hyper-acute symptomatic critical carotid stenosis had an ABCD2 risk score ≥4. There was no significant difference in the NICE red flag criterion for early assessment (ABCD2 risk score ≥4) for patients with cerebral microemboli versus those without microemboli (59/86 vs 81/120 patients: OR 1.05 ABCD2 risk score ≥4 (95% CI 0.58 to 1.90, p=0.867)). The ABCD2 risk score was <4 in 27 of 86 (31%: 95% CI 21 to 41) embolising patients and in 39 of 120 (31%: 95% CI 23 to 39) without cerebral microemboli. After adjusting for pre-neurological event antiplatelet treatment (APT), area under the curve (AUC) of ROC for ABCD2 risk score showed no prediction of cerebral microemboli (no pre-event APT, n=57: AUC 0.45 (95% CI 0.29 to 0.60, p=0.531); pre-event APT, n=147: AUC 0.51 (95% CI 0.42 to 0.60, p=0.804)). Conclusions The ABCD2 score did not predict the presence of cerebral microemboli or carotid disease in over one-quarter of patients with symptomatic critical carotid artery stenosis. On the basis of NICE guidelines (refer early if ABCD2 ≥4), assessment of high stroke risk based on ABCD2 scoring may lead to inappropriate delay in urgent treatment in many patients.
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Affiliation(s)
- Mahmud Saedon
- Warwick Medical School, University of Warwick, Coventry, UK
| | | | - Christopher H E Imray
- Warwick Medical School, University of Warwick, Coventry, UK.,University Hospitals Coventry Warwickshire NHS Trust, Coventry, UK
| | - Donald R J Singer
- Warwick Medical School, University of Warwick, Coventry, UK.,Fellowship of Postgraduate Medicine, London, UK.,Yale School of Medicine, New Haven, Connecticut, USA
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9
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LaRovere KL, Kapur K, McElhinney DB, Razumovsky A, Kussman BD. Cerebral High-Intensity Transient Signals during Pediatric Cardiac Catheterization: A Pilot Study Using Transcranial Doppler Ultrasonography. J Neuroimaging 2017; 27:381-387. [DOI: 10.1111/jon.12426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 12/30/2016] [Indexed: 11/29/2022] Open
Affiliation(s)
- Kerri L. LaRovere
- Department of Neurology; Boston Children's Hospital and Harvard Medical School; Boston MA
| | - Kush Kapur
- Department of Neurology; Boston Children's Hospital and Harvard Medical School; Boston MA
| | - Doff B. McElhinney
- Department of Cardiothoracic Surgery; Boston Children's Hospital and Harvard Medical School; Boston MA
| | - Alexander Razumovsky
- Sentient NeuroCare Services, Inc.; Boston Children's Hospital and Harvard Medical School; Boston MA
| | - Barry D. Kussman
- Department of Anesthesiology; Perioperative and Pain Medicine, Boston Children's Hospital and Harvard Medical School; Boston MA
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10
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Hingwala DR, Chandrasekhakan K, Thomas B, Sylaja PN, Unnikrishnan M, Kapilamoorthy TR. Atherosclerotic Carotid Plaques: Multimodality Imaging with Contrast-enhanced Ultrasound, Computed Tomography, and Magnetic Resonance Imaging. Ann Indian Acad Neurol 2017; 20:378-386. [PMID: 29184341 PMCID: PMC5682742 DOI: 10.4103/aian.aian_122_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Introduction The imaging of carotid plaques has undergone a paradigm shift increasing importance being given to plaque characterization. Patients with "vulnerable" plaques are more prone to develop future neurovascular events. Purpose The purpose of this study is to analyze the role of multimodality imaging techniques in the assessment of carotid atherosclerotic plaques. Materials and Methods Twenty-six patients were prospectively enrolled in the study. Patients underwent multidetector computed tomography (CT) angiography, ultrasound, contrast-enhanced ultrasound, and high-resolution magnetic resonance imaging (MRI) of the carotid arteries with special emphasis on the carotid bifurcation. Results The mean age of patients was 65.41 years. Twenty-one were males. Plaque neovascularization was seen in 10 of the 18 plaques studied (55.56%). Based on the predominant components of the plaque, plaques were characterized as lipid (3), lipid with recent hemorrhage (1), fibrous (7), fibrofatty (4), fibrofatty with some hemorrhagic components (3), and recent hemorrhage (2). Conclusions Together, contrast-enhanced ultrasound, CT, and MRI provide complete information about the plaque characteristics.
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Affiliation(s)
- Divyata R Hingwala
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - Kesavadas Chandrasekhakan
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - Bejoy Thomas
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - P N Sylaja
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - M Unnikrishnan
- Department of Cardiovascular and Thoracic Surgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - T R Kapilamoorthy
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
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11
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Saedon M, Dilshad A, Tiivas C, Virdee D, Hutchinson CE, Singer DRJ, Imray CHE. Prospective validation study of transorbital Doppler ultrasound imaging for the detection of transient cerebral microemboli. Br J Surg 2014; 101:1551-5. [PMID: 25224848 DOI: 10.1002/bjs.9634] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/06/2014] [Accepted: 07/25/2014] [Indexed: 11/08/2022]
Abstract
BACKGROUND Transient cerebral microemboli are independent biomarkers of early risk of ischaemic stroke in acute carotid syndromes. Transcranial Doppler imaging (TCD) through the temporal bone is the standard method for detection of cerebral microemboli, but an acoustic temporal bone window for TCD is not available in around one in seven patients. Transorbital Doppler imaging (TOD) has been used when TCD is not possible. The aim of this study was to validate the use of TOD against TCD for detecting cerebral microemboli. METHODS The study included patients undergoing elective carotid endarterectomy; all had confirmed temporal and orbital acoustic windows. Subjects gave written informed consent to postoperative TCD and TOD monitoring, which was performed simultaneously for 30 min by two vascular scientists. RESULTS The study included 100 patients (mean(s.e.m.) age 72(1) years; 65 men). Microemboli were detected by one or both methods in 40·0 per cent of patients: by TOD and TCD in 24 patients, by TOD alone in ten and by TCD alone in six. For detecting microemboli, TOD had a sensitivity of 80·0 per cent, specificity of 86·1 per cent, positive predictive value of 71·6 per cent and negative predictive value of 91·2 per cent. Bland-Altman analysis revealed no significant bias (bias 0·11 (95 per cent c.i. -0·52 to 0·74) microemboli; P = 0·810) with upper and lower limits of agreement of +6 and -6 microemboli. CONCLUSION TOD appears a valid alternative to TCD for detecting microembolic signals in patients with no suitable temporal acoustic window.
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Affiliation(s)
- M Saedon
- University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK; Warwick Medical School, University of Warwick, Coventry, UK
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12
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Warsz-Wianecka A, Lasek-Bal A, Kazibutowska Z. Cerebral microembolism in patients with segmental left ventricular wall motion abnormalities. Neurol Neurochir Pol 2014; 48:98-104. [PMID: 24821634 DOI: 10.1016/j.pjnns.2013.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 12/23/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND PURPOSE The significance of segmental heart wall motion abnormalities for stroke is unknown. The aims of the study included (1) comparison of the frequency and type of embolic signals in the middle cerebral artery in patients with segmental left ventricular wall hypokinesis due to coronary heart disease with and without stroke, and (2) determination of the relationship between inflammatory parameters, fibrinogen level, dyslipidemia and microembolic signals in the middle cerebral artery in patients with segmental heart hypokinesis. MATERIAL AND METHODS The study included 68 patients with segmental heart hypokinesis (33 without stroke [group I] and 35 with stroke [group II]), as well as 37 healthy volunteers and a reference group of 30 patients. Echocardiography and carotid/transcranial Doppler with detection of microembolic signals were performed. Patients from group I and II had erythrocyte sedimentation rate, leucocyte count, triglycerides, total cholesterol, HDL, and LDL examined. RESULTS Embolic signals were detected in patients with segmental heart hypokinesis significantly more frequently than in the control and reference groups. The high number of embolic signals, signals of high intensity, hypokinesis of the distal part of the intraventricular septum, increased cholesterol levels, LDL and triglycerides were all found more frequently in patients from group II than in group I. Embolic signals were detected more frequently in patients with high fibrinogen levels and leukocytosis. CONCLUSIONS Embolic signals in the middle cerebral artery in patients with segmental left ventricular hypokinesis have to be considered as a risk factor of stroke. The following changes are observed in patients with cardiogenic stroke: hypokinetic intraventricular septum, high intensity embolic signals, increased serum fibrinogen levels and leucocyte count. It may indicate the importance of these factors in the aetiology of stroke.
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Affiliation(s)
- Aldona Warsz-Wianecka
- Dept. of Neurology, Medical University of Silesia Hospital No. 7, Professor Leszek Giec Upper Silesian Medical Centre, Katowice, Poland
| | - Anetta Lasek-Bal
- Dept. of Neurology, Medical University of Silesia Hospital No. 7, Professor Leszek Giec Upper Silesian Medical Centre, Katowice, Poland.
| | - Zofia Kazibutowska
- Dept. of Neurology, Medical University of Silesia Hospital No. 7, Professor Leszek Giec Upper Silesian Medical Centre, Katowice, Poland
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Kerasnoudis A, Meves SH, Gold R, Krogias C. Correlation between frequency of microembolic signals and efficacy of antiplatelet therapy in symptomatic carotid disease. J Neuroimaging 2013; 23:484-8. [PMID: 23317001 DOI: 10.1111/j.1552-6569.2012.00770.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/04/2012] [Accepted: 08/26/2012] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The detection of microembolic signals in transcranial-Doppler monitoring is associated with a higher stroke risk. We investigated the correlation between the frequency of microembolic signals and the efficacy of the antiplatelet therapy in patients with a recent symptomatic carotid-artery stenosis. SUBJECTS AND METHODS Thirty-two patients (mean age: 70 years, 22 men) with a recent symptomatic carotid-artery stenosis underwent 30-minute TCD-monitoring. Twenty-three patients received acetylsalicylic-acid and 9 patients clopidogrel as antiplatelet-therapy. At the same day, the antiplatelet effect was measured with multiple-electrode-impedance aggregometry. RESULTS In 20 cases, the qualifying event was a stroke and in 12 cases, a TIA. Twenty-six of the patients had a >50% degree of stenosis. More than one microembolic signals were detected in 13 (40.6%) of the subjects, while multiple-electrode-impedance aggregometry revealed eight low responders (6 acetylsalicylic-acid, 2 clopidogrel). More than one microembolic signals were detected in 6 of the 8 (75.0%) patients with low response, but in only 7 of the 24 subjects (29.2%) with an effective antiplatelet treatment (sensitivity 75%, specificity 70.8%; Fisher's exact test: P = .038). CONCLUSIONS Our study suggests that in patients with recent symptomatic carotid-artery stenosis the detection of more than one microembolic signals might serve as a useful marker for the effectiveness of the antiplatelet treatment.
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14
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del Zoppo GJ. Central Nervous System Ischemia. Platelets 2013. [DOI: 10.1016/b978-0-12-387837-3.00033-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Boulon C, Baud JM, Kercret G, Pichot O, Poggi JN, Saby JC, Sprynger M. [Detection of micro-embolic signals: a review of the literature]. JOURNAL DES MALADIES VASCULAIRES 2012; 37:311-319. [PMID: 23146344 DOI: 10.1016/j.jmv.2012.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 09/28/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND The detection of micro-embolic signals (MES), by transcranial Doppler sonography might be useful for risk stratification in patients with symptomatic and asymptomatic carotid or cerebral artery stenosis, dissections, aortic atheroma, interventional procedures, and right to left cardiac shunts. AIM Review of the technique and clinical situations of MES detection. METHODS PubMed search from 1990 to 2012. RESULTS MES were found in 0,19, 48% versus 0,3, and 12% of patients with symptomatic and asymptomatic inferior than 30, 30 to 69, and 70 to 99% carotid stenosis, respectively. MES were related to the risk of recurrent stroke or transient ischemic attack (TIA). In the ACES study, the absolute annual risk of stroke or TIA after 2 years was 7% with vs 3% without MES. In patients with intracranial stenosis, the risk of stroke recurrence was 48% with vs 7% without MES at 13.6 months follow-up. MES were reported in 25% of the symptomatic versus none of the asymptomatic patients with intracranial stenosis. CONCLUSION Detection of MES is feasible and reproducible for multicenter studies, using rigourous methodology and long lasting recordings. It may contribute to risk stratification, especially in patients with extra- or intracranial stenosis.
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Affiliation(s)
- C Boulon
- Service de Médecine Vasculaire, Hôpital St-André, 1, rue Jean-Burguet, 33075 Bordeaux, France.
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16
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Cerebral embolization in asymptomatic versus symptomatic patients after carotid stenting. J Vasc Surg 2012; 56:1579-84; discussion 1584. [DOI: 10.1016/j.jvs.2012.06.074] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/27/2012] [Accepted: 06/01/2012] [Indexed: 11/24/2022]
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Generation, detection and prevention of gaseous microemboli during cardiopulmonary bypass procedure. Int J Artif Organs 2012; 34:1039-51. [PMID: 22183517 DOI: 10.5301/ijao.5000010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2011] [Indexed: 11/20/2022]
Abstract
Neuropsychological injury after cardiopulmonary bypass (CPB) is one of the most serious and costly complications arising from the procedure. Gaseous microemboli (GME) have long been implicated as one of the principal causes. There are two major sources of GME: surgical and manual manipulation of the heart and arteries; and the components of the extracorporeal circuit, including the type of pump, different perfusion modes, the design of the oxygenator and reservoir, and the use of vacuum assisted venous drainage (VAVD), all of which have a great impact on the delivery of existing GME to the patients. Transcranial cranial Doppler (TCD) has been used for more than two decades to assess and monitor the quality of extracorporeal perfusion with regard to the blood flow velocity of the middle cerebral arteries (MCA) and emboli detection, contributing to the achievement of better perfusion results. The Emboli Detection and Classification (EDAC) Quantifier has been able to detect and track microemboli in CPB circuits up to 1,000 microemboli per second at flow rates ranging from 0.2 L/min to 6.0 L/min. The deleterious effects of GME are multiple, including damage to the cerebral vascular endothelium, disruption of the blood-brain barrier, complement activation, leukocyte aggregation, increased platelet adherence, and fibrin deposition in the micro-vasculature. Improvements in perfusion equipment and in perfusion and surgical techniques have led to a dramatic reduction in the occurrence of GME during cardiac surgery. Although the clinical relevance of cerebral air embolization in causing neurological damage is unclear, every single person involved in perfusion and surgical technology should be aware of the risk of embolization and strictly regulate clinical behavior. Related research should also be done to improve the design of circuit components and clinical practice with a view to eliminating air bubbles during CPB procedure.
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Jayasooriya G, Thapar A, Shalhoub J, Davies AH. Silent cerebral events in asymptomatic carotid stenosis. J Vasc Surg 2011; 54:227-36. [PMID: 21722830 DOI: 10.1016/j.jvs.2011.01.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 01/12/2011] [Accepted: 01/17/2011] [Indexed: 01/20/2023]
Abstract
BACKGROUND Approximately 20% of strokes are attributable to carotid stenosis. However, the number of asymptomatic patients needed to prevent one stroke or death with endarterectomy is high at 17 to 32. There is a clear need to identify asymptomatic individuals at high risk of developing future ischemic events to improve the cost-effectiveness of surgery. Our aim was to examine the evidence for subclinical microembolization and silent brain infarction in the prediction of stroke in asymptomatic carotid stenosis using transcranial Doppler (TCD), computed tomography (CT), and magnetic resonance imaging (MRI). METHODS The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Articles regarding humans between 1966 and 2010 were identified through systematic searches of Pubmed, MEDLINE, and EMBASE electronic databases using a predetermined search algorithm. RESULTS Fifty-eight full text articles met the inclusion criteria. A median of 28% of microemboli positive patients experienced a stroke or transient ischemic attack during follow-up compared with 2% of microemboli negative patients (P = .001). The same was true for the end point of stroke alone with a median of 10% of microemboli positive patients experiencing a stroke vs 1% of microemboli negative patients (P = .004). A specific pattern of silent CT infarctions was related to future stroke risk (odds ratio [OR] = 4.6; confidence interval [CI] = 3.0-7.2; P < .0001). There are no prospective MRI studies linking silent infarction and stroke risk. CONCLUSIONS There is level 1 evidence for the use of TCD to detect microembolization as a risk stratification tool. However, this technique requires further investigation as a stroke prevention tool and would be complemented by improvements in carotid plaque imaging.
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Affiliation(s)
- Gayani Jayasooriya
- Academic Section of Vascular Surgery, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
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Srivastava P. Optimization of antiplatelet/antithrombotic therapy for secondary stroke prevention. Ann Indian Acad Neurol 2011; 13:6-13. [PMID: 20436740 PMCID: PMC2859581 DOI: 10.4103/0972-2327.61270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 07/30/2009] [Accepted: 11/14/2009] [Indexed: 11/04/2022] Open
Abstract
Role of antiplatelet therapy in secondary stroke prevention is of major significance. Antiplatelet agents predominantly in use are aspirin, clopidogrel, and combination regimes. The review focuses on the optimization of antiplatelet regimen based on evidence obtained from randomized-controlled trials, on different antiplatelet regimes and the risk assessment that may be unique to each patient.
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Affiliation(s)
- Padma Srivastava
- Department of Neurology, CN Center, AIIMS, Ansari Nagar, New Delhi, India
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Mitsuoka H, Shintani T, Furuya H, Nakao Y, Higashi S. Ultrasonographic character of carotid plaque and postprocedural brain embolisms in carotid artery stenting and carotid endarterectomy. Ann Vasc Dis 2011; 4:106-9. [PMID: 23555438 DOI: 10.3400/avd.oa.11.00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 03/28/2011] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To investigate ultrasonographic character of carotid plaques, and incidences of brain embolism in carotid angioplasty and stenting (CAS) and carotid endarterectomy (CEA). MATERIALS AND METHODS CEA (22/25 symptomatic lesions) and CAS (17/20 symptomatic lesions) between 2007 and 2010. Embolic protection devices (15 occlusion and 5 filtering devices) were used during CAS. Carotid plaques were classified into three categories (I: calcificated, II: intermediately echogenic, III: echolucent). Magnetic resonance imaging (MRI) was used to investigate brain emboli. RESULTS Ultrasonographic character of the plaques in CEA cases (I: 4%, II: 88%, III: 8%) was different from the one in CAS cases (I: 10%, II: 90%, III: 0%). The incidence of brain embolism in the CAS cases was 52.6% while 0% in the CEA cases (p = 0.00037). CAS had high incidences of brain embolism in any plaques (I: 100%, II: 43.8%). In the most recent 9 procedures of CAS using occlusion devices, averaged number of embolic lesion was 1.0 (0 post operative day; 0 POD). The number increased as 1.4 (1 POD) and 2.0 (7 POD). CONCLUSION CEA should be currently the first choice for most patients with a high-grade and symptomatic carotid artery stenosis.
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Affiliation(s)
- Hiroshi Mitsuoka
- Department of Vascular Surgery, Shizuoka Red Cross Hospital, Shizuoka, Shizuoka, Japan
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21
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Forteza AM, Koch S, Campo-Bustillo I, Gutierrez J, Haussen DC, Rabinstein AA, Romano J, Zych GA, Duncan R. Transcranial Doppler detection of cerebral fat emboli and relation to paradoxical embolism: a pilot study. Circulation 2011; 123:1947-52. [PMID: 21518982 DOI: 10.1161/circulationaha.110.950634] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The fat embolism syndrome is clinically characterized by dyspnea, skin petechiae, and neurological dysfunction. It is associated mainly with long bone fracture and bone marrow fat passage to the systemic circulation. An intracardiac right-to-left shunt (RLS) could allow larger fat particles to reach the systemic circulation. Transcranial Doppler can be a useful tool to detect both RLS and the fat particles reaching the brain. METHODS AND RESULTS We prospectively studied patients with femur shaft fracture with RLS evaluation, daily transcranial Doppler with embolus detection studies, and neurological examinations to evaluate the relation of RLS and microembolic signals to the development of fat embolism syndrome. Forty-two patients were included; 14 had an RLS detected. Seven patients developed neurological symptoms; all of them had a positive RLS (P=<0.001). The patients with an RLS showed higher counts and higher intensities of microembolic signals (P=<0.05 and P=<0.01, respectively) compared with those who did not have an RLS identified. The presence of high microembolic signal counts and intensities in patients with RLS was strongly predictive of the occurrence of neurological symptoms (odds ratio, 204; 95% confidence interval, 11 to 3724; P<0.001) with a positive predictive value of 86% and negative predictive value of 97%. CONCLUSIONS In patients with long bone fractures, the presence of an RLS is associated with larger and more frequent microembolic signals to the brain detected by transcranial Doppler study and can predict the development of neurological symptoms.
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Affiliation(s)
- Alejandro M Forteza
- Cardiac and Stroke Institute, Jackson Memorial Hospital, University of Miami Miller School of Medicine, FL, USA.
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Dawson J, Quinn T, Lees KR, Walters MR. Microembolic Signals and Aspirin Resistance in Patients with Carotid Stenosis. Cardiovasc Ther 2011; 30:234-9. [DOI: 10.1111/j.1755-5922.2010.00259.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Acharya RU, Faust O, Alvin APC, Sree SV, Molinari F, Saba L, Nicolaides A, Suri JS. Symptomatic vs. Asymptomatic Plaque Classification in Carotid Ultrasound. J Med Syst 2011; 36:1861-71. [DOI: 10.1007/s10916-010-9645-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 12/20/2010] [Indexed: 12/01/2022]
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24
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Meairs S, Hennerici M, Mohr J. Ultrasonography. Stroke 2011. [DOI: 10.1016/b978-1-4160-5478-8.10044-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Paraskevas KI, Mikhailidis DP, Veith FJ. Mechanisms to explain the poor results of carotid artery stenting (CAS) in symptomatic patients to date and options to improve CAS outcomes. J Vasc Surg 2010; 52:1367-75. [DOI: 10.1016/j.jvs.2010.04.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 03/30/2010] [Accepted: 04/07/2010] [Indexed: 11/25/2022]
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Lam CK, Yoo T, Hiner B, Liu Z, Grutzendler J. Embolus extravasation is an alternative mechanism for cerebral microvascular recanalization. Nature 2010; 465:478-82. [PMID: 20505729 PMCID: PMC2879083 DOI: 10.1038/nature09001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 03/09/2010] [Indexed: 12/31/2022]
Abstract
Cerebral microvascular occlusion is a common phenomenon throughout life1,2 that could be an underappreciated mechanism of brain pathology. Failure to promptly recanalize microvessels may lead to disruption of brain circuits and significant functional deficits3. Hemodynamic forces and the fibrinolytic system4 are considered the principal mechanisms responsible for recanalization of occluded cerebral capillaries and terminal arterioles. However, using high resolution fixed tissue microscopy and two photon imaging in living mice we found that a large fraction of occluding microemboli failed to be lysed and washed out within 48 hours after internal carotid infusion. Surprisingly, emboli were instead found to translocate outside the vessel lumen within 2-7 days leading to complete re-establishment of blood flow and sparing of the vessel. Recanalization occurred by a previously unknown mechanism of microvascular plasticity involving the rapid envelopment of emboli by endothelial membrane projections which subsequently form a new vessel wall. This was followed by the formation of an endothelial opening through which emboli translocated into the perivascular parenchyma. The rate of embolus extravasation was significantly reduced by pharmacological inhibition of matrix metalloproteinase 2/9 activity. In aged mice, extravasation was markedly delayed, resulting in persistent tissue hypoxia, synaptic damage and cell death. Our study identifies a novel cellular mechanism that may be critical for recanalization of occluded microvessels. Alterations in the efficiency of this protective mechanism may have important implications in microvascular pathology, stroke recovery, and age-related cognitive decline.
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Affiliation(s)
- Carson K Lam
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Ilinois 60611 USA
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Meseguer E, Labreuche J, Durdilly C, Echeverría A, Lavallee PC, Ducrocq G, Touboul PJ, Steg PG, Amarenco P. Prevalence of Embolic Signals in Acute Coronary Syndromes. Stroke 2010; 41:261-6. [DOI: 10.1161/strokeaha.109.566380] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
The purpose of this study was to assess the prevalence of embolic signals (ES) in acute coronary syndromes (ACS) and their association with stroke.
Methods—
From December 2004 to October 2006, 209 consecutive patients with ACS (without prosthetic heart valves or previous stroke) were studied within 72 hours of symptom onset. Patients underwent ES monitoring in both middle cerebral arteries by transcranial Doppler for 30 minutes. Median follow-up was 14 months after discharge.
Results—
Patients were treated according to current European Society Cardiology guidelines. Specifically, 92% of patients received heparin(s), 100% aspirin, 92% clopidogrel, 67% intravenous glycoprotein IIb/IIIa inhibitors, 9% fibrinolysis, and 67% underwent angioplasty. ES were detected in 7 patients (prevalence 3.4%; 95% CI, 1.4 to 6.8). Except for a higher prevalence of ES in patients with unstable angina versus other ACS categories (8.5% versus 1.9%,
P
=0.047), none of the factors among baseline characteristics, clinical features, ACS treatment, and cardiac findings were associated with the presence of ES. During hospitalization, 3 patients without ES had cerebrovascular events (one stroke and 2 transient ischemic attacks), whereas no cerebrovascular events occurred in patients with ES.
Conclusions—
The prevalence of ES among hospitalized patients with ACS is currently low, possibly because of improvement in ACS treatment. In this ACS sample, ES did not appear associated with short-term risk of cerebrovascular events.
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Affiliation(s)
- Elena Meseguer
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Julien Labreuche
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Cloe Durdilly
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Amaya Echeverría
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Philippa C. Lavallee
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Gregory Ducrocq
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Pierre-Jean Touboul
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Philippe Gabriel Steg
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Pierre Amarenco
- From INSERM U-698 and Paris-Diderot University (E.M., J.L., P.C.L., P.-J.T., P.G.S., P.A.), the Department of Neurology and Stroke Center (E.M., J.L., C.D., A.E., P.C.L., P.-J.T., P.A.), and the Department of Cardiology (G.D., P.G.S.), Bichat Hospital, Assistance Publique-Hopitaux de Paris, Paris, France
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King A, Markus HS. Doppler Embolic Signals in Cerebrovascular Disease and Prediction of Stroke Risk. Stroke 2009; 40:3711-7. [DOI: 10.1161/strokeaha.109.563056] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Alice King
- From Clinical Neuroscience, St. George’s University of London, London UK
| | - Hugh S. Markus
- From Clinical Neuroscience, St. George’s University of London, London UK
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30
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Whitaker D, Motallebzadeh R. Intraoperative cerebral high-intensity transient signals and postoperative cognitive function: a systematic review. Am J Surg 2009; 198:295-7; author reply 254-5. [DOI: 10.1016/j.amjsurg.2008.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Accepted: 11/17/2008] [Indexed: 12/01/2022]
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31
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Carotid endarterectomy, stenting, and other prophylactic interventions. HANDBOOK OF CLINICAL NEUROLOGY 2008. [PMID: 18793902 DOI: 10.1016/s0072-9752(08)94065-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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32
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Purandare N. Role of cerebral microemboli in the causation of Alzheimer’s disease and vascular dementia. FUTURE NEUROLOGY 2008. [DOI: 10.2217/14796708.3.4.391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vascular risk factors are involved in the causation of both vascular dementia (VaD) and Alzheimer’s disease (AD), which together account for up to 80% of all dementias. Asymptomatic spontaneous cerebral emboli (SCE) have been shown to predict future risk of cerebrovascular accidents and silent strokes on MRI. Over a period of years, SCE could potentially cause progressive brain damage and dementia. Our research has shown that SCE occur more frequently in both AD and VaD compared with controls without dementia. SCE are associated with depressive symptoms and predict a more rapid progression of dementia. SCE may be a common mechanism of vascular brain damage that explains the AD, VaD and mixtures of the two. SCE may be a potentially treatable target to slow progression and possibly prevent these dementias.
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Affiliation(s)
- Nitin Purandare
- The University of Manchester, Room 3.316, Psychiatry Research Group, School of Community Based Medicine, University Place (3rd Floor East), Oxford Road, Manchester, M13 9PL, UK
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33
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Ritter MA, Dittrich R, Thoenissen N, Ringelstein EB, Nabavi DG. Prevalence and prognostic impact of microembolic signals in arterial sources of embolism. J Neurol 2008; 255:953-61. [PMID: 18458865 DOI: 10.1007/s00415-008-0638-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 04/06/2007] [Accepted: 04/30/2007] [Indexed: 11/27/2022]
Affiliation(s)
- Martin A Ritter
- Dept. of Neurology, University of Münster, Albert-Schweitzer-Str. 33, 48129 Münster, Germany.
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34
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35
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Sharma VK, Tsivgoulis G, Lao AY, Alexandrov AV. Role of transcranial Doppler ultrasonography in evaluation of patients with cerebrovascular disease. Curr Neurol Neurosci Rep 2007; 7:8-20. [PMID: 17217849 DOI: 10.1007/s11910-007-0016-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Transcranial Doppler ultrasonography (TCD) is the only noninvasive examination method that enables the reliable evaluation of blood flow from the basal intracerebral vessels, adding physiologic information to the anatomic images. TCD is relatively inexpensive, can be performed at bedside, and allows monitoring in acute emergency settings and for prolonged periods with a high temporal resolution, making it ideal for studying dynamic cerebrovascular responses. In acute stroke, TCD is capable of providing rapid information about the hemodynamic status of the cerebral circulation and monitoring recanalization in real-time, with a potential for enhancing tissue plasminogen activator-induced thrombolysis. Extended applications such as emboli monitoring, right-to-left shunt detection, and vasomotor reactivity make TCD an important and valuable tool for evaluating stroke mechanisms, planning and monitoring treatment, and determining prognosis.
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Affiliation(s)
- Vijay K Sharma
- Division of Neurology, National University Hospital, Singapore.
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36
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Dunmore BJ, McCarthy MJ, Naylor AR, Brindle NPJ. Carotid plaque instability and ischemic symptoms are linked to immaturity of microvessels within plaques. J Vasc Surg 2007; 45:155-9. [PMID: 17210401 DOI: 10.1016/j.jvs.2006.08.072] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 08/27/2006] [Indexed: 01/09/2023]
Abstract
BACKGROUND Instability and rupture of carotid atherosclerotic plaques leads to thromboemboli and ischemic symptoms. Angiogenesis occurs within atherosclerotic plaques, and plaque vulnerability and symptomatic carotid disease have been associated with increased numbers of microvessels. In addition to microvessel number, it is possible that the phenotypes of intraplaque vessels could influence plaque stability. To test this, the morphology and maturity of vessels within plaques from symptomatic and asymptomatic patients was determined. METHODS Carotid plaques were collected after endarterectomy from a cohort of 13 asymptomatic patients and 30 symptomatic patients. Plaques were sectioned and immunostained for the presence of endothelial cells, vascular smooth muscle cells, macrophages, and vascular endothelial growth factor. Sections were assessed for microvessel morphology, maturity as judged by smooth muscle cell cover, and the presence of vascular endothelial growth factor and macrophages. RESULTS Two types of vascular structure were observed within plaques, microvessels and dilated, highly irregular multilobular vessels. These irregular dysmorphic vessels were found almost exclusively in plaques from symptomatic patients. The dysmorphic vessels lacked smooth muscle cells and were highly immature. Plaques also contained vascular endothelial growth factor, and this was observed adjacent to the dysmorphic vessels. This growth factor was found colocalized with macrophages. CONCLUSIONS Symptomatic carotid plaques contain abnormal, immature microvessels similar to those found in tumors and healing wounds. Such vessels could contribute to plaque instability by acting as sites of vascular leakage by inflammatory cell recruitment. The immature vessels within plaques may be therapeutic targets for promoting plaque stabilization.
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Affiliation(s)
- Benjamin J Dunmore
- Department of Obstetrics and Gynaecology, University of Cambridge, Cambridge, UK
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37
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Central Nervous System Ischemia. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50798-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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38
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Masdeu JC, Irimia P, Asenbaum S, Bogousslavsky J, Brainin M, Chabriat H, Herholz K, Markus HS, Martínez-Vila E, Niederkorn K, Schellinger PD, Seitz RJ. EFNS guideline on neuroimaging in acute stroke. Report of an EFNS task force. Eur J Neurol 2006; 13:1271-83. [PMID: 17116208 DOI: 10.1111/j.1468-1331.2006.01507.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965-2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient.
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Affiliation(s)
- J C Masdeu
- Department of Neurology and Neurosurgery, University of Navarra, Pamplona, Spain.
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Azarpazhooh MR, Chambers BR. Clinical application of transcranial Doppler monitoring for embolic signals. J Clin Neurosci 2006; 13:799-810. [PMID: 16908159 DOI: 10.1016/j.jocn.2005.12.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 12/20/2005] [Indexed: 12/12/2022]
Abstract
A major advantage of transcranial ultrasound is its suitability for continuous monitoring. Microembolic signals (MES) are brief, high-intensity transients that occur when particulate microemboli or gaseous microbubbles pass through the ultrasound beam. These MES have been detected in several clinical scenarios, but rarely in age-matched controls. The detection of MES provides important pathophysiological information in a variety of disorders, but their clinical importance and possible therapeutic implications are still under debate. The present article summarizes the significance of MES in different clinical settings and outlines some of the problems to be resolved so that transcranial ultrasound can be applied in clinical practice.
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Affiliation(s)
- M R Azarpazhooh
- National Stroke Research Institute, University of Melbourne, Austin Health, Heidelberg Heights, Victoria, Australia
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40
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Poppert H, Sadikovic S, Sander K, Wolf O, Sander D. Embolic signals in unselected stroke patients: prevalence and diagnostic benefit. Stroke 2006; 37:2039-43. [PMID: 16794197 DOI: 10.1161/01.str.0000231644.47325.aa] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The present study investigated the prevalence of cerebral microemboli detected by transcranial Doppler sonography in unselected stroke and transient ischemic attack (TIA) patients under standard clinical conditions. We aimed to evaluate the feasibility and the value of the method for clinical use. METHODS The records of 937 consecutive patients who were investigated between October 1995 and August 2004 at our institution were reviewed. Stroke or TIA were subtyped using the TOAST classification criteria. RESULTS Two hundred and eighty-four subjects were excluded because there was an interval of >14 days between onset of symptoms and examination, no definite diagnosis of stroke or TIA at discharge, or an artificial heart valve. Embolic signals (ES) were detected in 37 (5.7%) of the remaining 653 patients. In subjects with positive ES detection the mean interval between symptom onset and ES detection was 4.9 (SD 4.0) days compared with 5.4 (SD 3.5) days in the remaining patients (P=0.01). ES were more common in patients with large-artery atherosclerosis compared with other subtype groups (P<0.001). The proportion of detected signals was influenced by the antihemostatic treatment: ES were found more often in anticoagulated patients than in patients receiving antiplatelet medication (P<0.001). CONCLUSIONS The study shows a high clinical significance of ES in patients with recent stroke attributable to arterio-arterial embolism or of cardiac embolic origin and the high specificity of the technique. Given the low sensitivity shown, ES detection cannot generally be recommended for routine diagnostics in stroke patients.
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Affiliation(s)
- Holger Poppert
- Department of Neurology, Klinikum Rechts der Isar, Munich University of Technology, Moehlstr. 28, 81675 Muenchen, Germany.
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Dittrich R, Ritter MA, Kaps M, Siebler M, Lees K, Larrue V, Nabavi DG, Ringelstein EB, Markus HS, Droste DW. The Use of Embolic Signal Detection in Multicenter Trials to Evaluate Antiplatelet Efficacy. Stroke 2006; 37:1065-9. [PMID: 16514091 DOI: 10.1161/01.str.0000209331.39894.3d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotid Stenosis) trial proved the effectiveness of the combination of clopidogrel and aspirin compared with aspirin alone in reducing presence and number of microembolic signals (MES) in patients with recently symptomatic carotid stenosis. The present study aimed at installing primary and secondary quality control measures in CARESS because MES evaluation relies on subjective judgment by human experts. METHODS As primary quality control, centers participating in CARESS evaluated a reference digital audio tape (DAT) before the study containing both MES and artifacts. Interobserver agreement of classifying signals as MES was expressed as proportions of specific agreement of positive ratings (ps+/-values). For all DATs included in CARESS (n=300), online number of MES and off-line number of MES read by the central reader were compared using correlation coefficients. As secondary control, a sample of 16 of 300 DATs was cross-validated by another independent reader (post-trial validator). RESULTS For the reference tape, the cumulative ps+/-value was 0.894 based on 12 of 14 observers. Two observers with very different results improved after a training procedure. Agreement between post-trial validator and central reader was ps+=0.805, indicating very good agreement. Correlation between online evaluation and off-line evaluation of DATs was very good overall (cumulative rho=0.84; P<0.001). CONCLUSIONS Multicenter studies using MES as outcome parameter are feasible. However, primary and secondary quality control procedures are important.
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Affiliation(s)
- Ralf Dittrich
- Department of Neurology, University Hospital of Münster, Germany
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42
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Rodriguez RA, Rubens F, Rodriguez CD, Nathan HJ. Sources of Variability in the Detection of Cerebral Emboli with Transcranial Doppler During Cardiac Surgery. J Neuroimaging 2006; 16:126-32. [PMID: 16629734 DOI: 10.1111/j.1552-6569.2006.00035.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE The application of intensity thresholds for embolus detection with transcranial Doppler (TCD) can exclude from analysis an unrecognized proportion of high-intensity transient signals (HITS))whose intensities are below the threshold. The lack of consistent threshold criteria between clinical trials may explain part of the discrepancy in the reported HITS counts. We investigated the effect of choosing different thresholds on the sensitivity and specificity of detecting HITS during cardiopulmonary bypass (CPB). METHODS Two observers independently analyzed TCD recordings from 8 patients under CPB. Doppler signals were classified as true HITS, equivocal HITS, artifacts, and Doppler speckles according to preestablished criteria. The relative intensity of Doppler signals was measured by two different methods (TCD software vs manual). Receiver Operating Characteristic curves determined the optimal threshold for each of the two intensity methods. RESULTS Reviewers achieved agreement in 96% of 2190 Doppler signals (kappa = 0.90). Relative intensities calculated with the TCD-software method were 3 dB (95% CI: 3.0-3.4) higher than the manual method. The optimal threshold was found at 10 dB (sensitivity: 99%; specificity: 90.8%) with the software method and at 7 dB with the manual method (sensitivity: 96%; specificity: 83%). The use of an intensity threshold 2 dB higher than the optimal increased the rejection of true HITS by 8% and 14%, respectively. CONCLUSIONS Using intensity thresholds higher than the optimal for embolus detection decreases HITS counts. Choosing a threshold depends on the type of method used for measuring the signal intensity. Uniform threshold criteria and comparative studies between different Doppler devices are necessary for making clinical trials more comparable.
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Affiliation(s)
- Rosendo A Rodriguez
- Department of Surgery, Division of Cardiac Surgery, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario K1Y 4W7, Canada.
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43
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Caplan LR, Wong KS, Gao S, Hennerici MG. Is Hypoperfusion an Important Cause of Strokes? If So, How? Cerebrovasc Dis 2006; 21:145-53. [PMID: 16401883 DOI: 10.1159/000090791] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Accepted: 09/13/2005] [Indexed: 01/13/2023] Open
Abstract
Traditionally hypoperfusion and embolism are considered separate important causes of stroke in patients with arterial occlusive disease. However, although hypoperfusion and embolism differ in mechanisms and location, they generally coincide in severe obstructive lesions and cause washout disturbances of embolism in low perfusion territories distal to stenosis. Unless the collateral blood supply is sufficient to prevent ischemia, multiple remote spot-like infarctions occur within the hypoperfused brain territory. In border-zone distributed infarction - long suspected to result from hemodynamic compromise alone - complementary interaction of embolisation and hypoperfusion territories has to be considered. Thus hypoperfusion with embolism or embolism alone are the most common explanations for stroke, the former often associated with less severe clinical deficits than the latter.
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Affiliation(s)
- Louis R Caplan
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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44
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Sztajzel R, Momjian-Mayor I, Comelli M, Momjian S. Correlation of cerebrovascular symptoms and microembolic signals with the stratified gray-scale median analysis and color mapping of the carotid plaque. Stroke 2006; 37:824-9. [PMID: 16456117 DOI: 10.1161/01.str.0000204277.86466.f0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE To determine whether a stratified gray-scale median (GSM) analysis of the carotid plaque combined with color mapping correlated better with the presence of neurological symptoms and microembolic signals (MES) than a whole plaque measurement. METHODS A total of 131 patients presenting 167 carotid stenoses between 30% and 99% were analyzed by ultrasound. Emboli detection was performed by transcranial Doppler. For each plaque, the GSM values at depth 0 mm (surface) and at one third (30) and one half (50) of the plaque thickness were compared with the values obtained for the whole plaque. The plaque pixels were mapped into 3 colors: red, yellow and green, depending on their GSM value. RESULTS Mean GSM values were lower among symptomatic plaques, but a statistically significant difference between values of the whole plaque and those of the surface was obtained only for MES+ stenoses (P<0.01). In a proportional odds logistic regression model based on 4 subgroups with an increasing clinical risk (MES-/symptoms-; MES-/symptoms+; MES+/symptoms-; +; MES+/symptoms+), low mean GSM values and the predominant red color at the surface were independent factors associated with the presence of symptoms or MES (P<0.0005). Furthermore, compared with a whole plaque measurement, analysis of the surface values predicted systematically with a greater sensitivity and specificity (receiver operating characteristic curves) each one of these 4 subgroups. CONCLUSIONS Low mean GSM values and predominance of the red color at the surface correlated with most of the symptomatic or MES+ stenoses. This combined approach should be further investigated in a longitudinal study.
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Affiliation(s)
- Roman Sztajzel
- Department of Neurology, University Hospital Geneva and Medical School, Switzerland.
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Hudorović N. Clinical significance of microembolus detection by transcranial Doppler sonography in cardiovascular clinical conditions. Int J Surg 2006; 4:232-41. [PMID: 17462357 DOI: 10.1016/j.ijsu.2005.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 12/11/2005] [Accepted: 12/13/2005] [Indexed: 11/30/2022]
Abstract
Transcranial Doppler can detect microembolic signals, which are characterized by unidirectional high intensity increase, short duration, and random occurrence, producing a "whistling" sound. Microembolic signals have been proven to represent solid or gaseous particles within the blood flow. Microemboli have been detected in a number of clinical cardiovascular settings: carotid artery stenosis, aortic arch plaques, atrial fibrillation, myocardial infarction, prosthetic heart valves, patent foramen ovale, valvular stenosis, during invasive procedures (angiography, percutaneous transluminal angioplasty) and surgery (carotid, cardiopulmonary bypass). Despite numerous studies performed so far, clinical significance of microembolic signals is still unclear. This article provides an overview of the development and current state of technical and clinical aspects of microembolus detection.
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Affiliation(s)
- Narcis Hudorović
- University Department of Vascular and Endovascular Surgery, University Hospital Sestre Milosrdnice, 10000 Zagreb, Vinogradska 29, Croatia.
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Thoennissen NH, Allroggen A, Dittrich R, Ritter M, Schmid C, Scheld HH, Ringelstein EB, Nabavi DG. Can Doppler time domain analysis of microembolic signals discriminate between gaseous and solid microemboli in patients with left ventricular assist device? Neurol Res 2005; 27:780-4. [PMID: 16197817 DOI: 10.1179/016164105x39950] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Microembolic signals (MES) can be detected by transcranial Doppler sonography (TCD). To identify gaseous microemboli the inhalation of oxygen is an established method in patients with prosthetic heart valves. Time domain analysis of sample volume length (SVL) and of frequency modulation showed promising results in the discrimination between solid and gaseous microemboli. We investigated whether these time domain analyses allow the discrimination of different types of microemboli in patients with the non-pulsatile DeBakey left ventricular assist device (LVAD). MATERIALS AND METHODS Repeated unilateral detection of MES was performed by TCD in 20 patients supported with DeBakey LVAD. Each monitoring session consisted of 20 minutes without and 20 minutes with inhalation of 100% oxygen (6 l/min). A total of 500 MES, detected with (n=250) or without (n=250) the supply of oxygen, were randomly chosen for offline analysis. The SVL (in cm) was calculated by duration and velocity of the MES measured in the time domain mode. Additionally, frequency modulation of MES was classified into three main types: Without modulation (type I), with gradual changes (type II) and with rapid changes (type III). RESULTS With oxygen supply, both prevalence (26.4% versus 36.2%, p<0.01) and mean counts of MES per hour (49+/-293 versus 108+/-550, p<0.001) significantly declined compared with the MES load while breathing room air. There was no significant difference in the SVL of MES under oxygen (0.85+/-0.38 cm) compared with those without oxygen delivery (0.92+/-0.37 cm, p=0.6). Furthermore, no significant differences were noted for the MES frequency modulation types in time domain analysis with regard to oxygen supply. CONCLUSIONS The reduction of MES under oxygen delivery confirms the gaseous nature in a substantial number of circulating microemboli produced by the DeBakey LVAD. However, SVL and frequency modulation of MES did not appear to provide valuable information regarding the structural nature of the underlying microembolic material.
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Thoennissen NH, Schneider M, Allroggen A, Ritter M, Dittrich R, Schmid C, Scheld HH, Ringelstein EB, Nabavi DG. High level of cerebral microembolization in patients supported with the DeBakey left ventricular assist device. J Thorac Cardiovasc Surg 2005; 130:1159-66. [PMID: 16214534 DOI: 10.1016/j.jtcvs.2005.02.068] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 02/16/2005] [Accepted: 02/22/2005] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Microembolic signals detected by transcranial Doppler ultrasonography have been demonstrated to be clinically relevant in patients supported with pulsatile left ventricular assist devices. We prospectively investigated the quantity of microembolic signals in patients supported with the continuous-flow DeBakey left ventricular assist device (MicroMed DeBakey VAD; MicroMed Technology, Inc, Houston, Tex) including the refined Carmeda BioActive Surface system (Carmeda AB, Stockholm, Sweden). METHODS Twenty-three patients (20 male) aged 14 to 62 years supported with DeBakey left ventricular assist devices (n = 6 with Carmeda) were enrolled in this study. Microembolic signal monitorings were performed twice weekly by insonating the middle cerebral artery for 20 minutes without and 20 minutes with oronasal application of oxygen (6 L/min). Evidence of clinically manifest thromboembolic events was based on regular questionnaires, clinical examinations, and results of diagnostic procedures. RESULTS Despite a low incidence of thromboembolic complications (0.24 per 100 left ventricular assist device days), 20 patients (87%) showed circulating microemboli. Overall, microembolic signals were found in 175 of 499 transcranial Doppler ultrasonographic examinations (35.1%), with mean counts of 81.2 +/- 443 (range 0-5042 signals/h). Both microembolic signal prevalence (25% vs 34%, P = .01) and absolute signal counts (46.5 vs 104, P < .01) significantly declined with oxygen delivery. There was no significant correlation between the individual microembolic signal activity and the incidence of clinical thromboembolism or the intensity of antihemostatic treatment. Patients supported with the Carmeda device did not show reduced rates of clinical thromboembolization or cerebral microemboli. CONCLUSION In patients with DeBakey left ventricular assist devices, a high load of clinically silent microemboli can be detected within the cerebral arteries despite a low incidence of embolic complications. It needs to be investigated whether such continuous, presumably gaseous microembolization causes cognitive or neuropsychologic deficits.
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Affiliation(s)
- Issam Moussa
- Columbia University Medical Center (CUMC), Endovascular Services Center for Interventional Vascular Therapy, CUMC New York, NY, USA
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Mackinnon AD, Aaslid R, Markus HS. Ambulatory Transcranial Doppler Cerebral Embolic Signal Detection in Symptomatic and Asymptomatic Carotid Stenosis. Stroke 2005; 36:1726-30. [PMID: 16040594 DOI: 10.1161/01.str.0000173402.88560.ae] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Transcranial Doppler (TCD) ultrasound can detect asymptomatic emboli in carotid stenosis. Current systems are nonportable and can only record for short durations. A novel ambulatory TCD system allows prolonged recording. We applied this to patients with symptomatic and asymptomatic carotid stenosis to determine patterns of embolization in the 2 conditions and optimal recording protocols.
Methods—
Ambulatory TCD recordings were performed in 12 symptomatic and 15 asymptomatic carotid stenosis (≥50%) patients for 8 hours and then repeated on a second occasion.
Results—
Nine (75%) of symptomatic subjects had embolic signals during the first recording. In this group, repeating the recording did not increase the proportion of positive patients. In asymptomatic patients, 4 (26.7%) had embolic signals on 1 recording, and this proportion increased to 46.7% after 2 recordings. There was significant clustering of embolic signals demonstrating that the process was nonrandom.
Conclusions—
Ambulatory TCD is possible in patients with carotid artery stenosis. By increasing the duration of recording, additional information is provided, particularly in asymptomatic patients. Our results also demonstrate clustering of embolic signals. Our study provides baseline data to allow studies in both asymptomatic and symptomatic carotid stenosis to be planned.
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Affiliation(s)
- Andrew D Mackinnon
- Department of Clinical Neurosciences, St Georges Hospital Medical School, London SW17 0RE, United Kingdom
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Abbott AL, Chambers BR, Stork JL, Levi CR, Bladin CF, Donnan GA. Embolic Signals And Prediction of Ipsilateral Stroke or Transient Ischemic Attack in Asymptomatic Carotid Stenosis. Stroke 2005; 36:1128-33. [PMID: 15879327 DOI: 10.1161/01.str.0000166059.30464.0a] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
We tested the hypothesis that transcranial Doppler embolic signal (ES) detection identifies an increased risk of ipsilateral carotid stroke or transient ischemic attack (TIA) in subjects with asymptomatic severe carotid stenosis.
Methods—
Subjects with duplex-determined 60% to 99% carotid stenosis, without other apparent cerebroembolic sources, underwent 6-monthly neurological assessment and 60-minute ES monitoring. ES positivity was defined as ≥1 ES detected in ≥1 study, ES negativity as no ES in any study, and consistent ES negativity as no ES in any study where ≥6 studies were performed. Rates of ipsilateral carotid stroke/TIA were calculated using Kaplan–Meier analysis and correlated with ES status using odds ratios (ORs) and Cox proportional hazards regression analysis.
Results—
A total of 202 subjects (138 male; mean age 74 years; mean follow-up 34 months) were recruited. The average annual rate of ipsilateral carotid stroke/TIA was 3.1%. A total of 231 arteries were monitored at least once (mean 4.3 studies/artery). Six of 60 (10.0%) ES-positive arteries had an ipsilateral carotid stroke/TIA compared with 12 of 171 (7.0%) ES-negative arteries (OR, 1.47; 95% CI, 0.43, 4.48;
P
=0.624) and 2 of 41 (4.9%) consistently ES-negative arteries (OR, 2.17; 95% CI, 0.36, 22.90;
P
=0.59). Differences in survival free of ipsilateral carotid stroke/TIA according to ES status were not statistically significant.
Conclusions—
Although there were more ipsilateral carotid cerebrovascular events among ES-positive arteries, this was not statistically significant. Less labor-intensive techniques are required to make further study and clinical application practical.
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Affiliation(s)
- Anne L Abbott
- National Stroke Research Institute, Austin Health, Melbourne, Australia.
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