Asymptomatic Carotid Stenosis Is Associated With Circadian and Other Variability in Embolus Detection

Abbott, Anne L.; Merican, Julia S.; Pearce, Dora C; Jurić, Ana; Worsnop, Christopher; Foster, Emma; Chambers, Brian R.

doi:10.3389/fneur.2019.00322

Cited by 6 publications

(5 citation statements)

References 52 publications

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“…Therefore, these were actually studies of embolic signal detection in mixed samples of asymptomatic and symptomatic people with carotid stenosis. Further, embolic signal detection in relation to advanced ACS is labor intensive, not possible in up to 54% of older people owing to inadequate temporal bone TCD windows, 85 lacks specificity (being present in $62% of persons), 86 has not been tested in the context of current optimal medical intervention and no study has shown a procedural benefit if embolic signals are detected.…”

Section: Other Rebuttalsmentioning

confidence: 99%

Misconceptions regarding the adequacy of best medical intervention alone for asymptomatic carotid stenosis

Abbott

Brunser

Giannoukas

et al. 2020

Journal of Vascular Surgery

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Background: Medical intervention (risk factor identification, lifestyle coaching, and medication) for stroke prevention has improved significantly. It is likely that no more than 5.5% of persons with advanced asymptomatic carotid stenosis (ACS) will now benefit from a carotid procedure during their lifetime. However, some question the adequacy of medical intervention alone for such persons and propose using markers of high stroke risk to intervene with carotid endarterectomy (CEA) and/or carotid angioplasty/stenting (CAS). Our aim was to examine the scientific validity and implications of this proposal.Methods: We reviewed the evidence for using medical intervention alone or with additional CEA or CAS in persons with ACS. We also reviewed the evidence regarding the validity of using commonly cited makers of high stroke risk to select such persons for CEA or CAS, including markers proposed by the European Society for Vascular Surgery in 2017.Results: Randomized trials of medical intervention alone versus additional CEA showed a definite statistically significant CEA stroke prevention benefit for ACS only for selected average surgical risk men aged less than 75 to 80 years with 60% or greater stenosis using the North American Symptomatic Carotid Endarterectomy Trial criteria. However, the most recent measurements of stroke rate with ACS using medical intervention alone are overall lower than for those who had CEA or CAS in randomized trials. Randomized trials of CEA versus CAS in persons with ACS were underpowered. However, the trend was for higher stroke and death rates with CAS. There are no randomized trial results related to comparing current optimal medical intervention with CEA or CAS. Commonly cited markers of high stroke risk in relation to ACS lack specificity, have not been assessed in conjunction with current optimal medical intervention, and have not been shown in randomized trials to identify those who benefit from a carotid procedure in addition to current optimal medical intervention.Conclusions: Medical intervention has an established role in the current routine management of persons with ACS. Stroke risk stratification studies using current optimal medical intervention alone are the highest research priority for identifying persons likely to benefit from adding a carotid procedure. (

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Section: Other Rebuttalsmentioning

confidence: 99%

Misconceptions regarding the adequacy of best medical intervention alone for asymptomatic carotid stenosis

Abbott

Brunser

Giannoukas

et al. 2020

Journal of Vascular Surgery

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“…Problems related to the lack of specificity of proposed stroke risk markers are compounded by guideline writers not providing reproducible definitions (129)(130)(131). For example, ∼10% of asymptomatic carotid stenosis patients will have at least 1-2 ipsilateral middle cerebral artery ES detected after 1-2 h of TCD monitoring (133). However, this proportion increases to over 60% with more frequent monitoring (133).…”

Section: Limiting Carotid Procedures To "High Stroke Risk" Patients F...mentioning

confidence: 99%

“…This includes detection of embolic signals (ES) with transcranial Doppler (TCD). Of the three studies investigating the association of ES detection and risk of subsequent stroke in asymptomatic carotid stenosis patients, two were flawed because nearly half the strokes that occurred during follow-up were in patients who already had an ipsilateral TIA during follow-up ( 94 , 132 , 133 ). Therefore, these were studies of mixed asymptomatic and symptomatic patients with carotid stenosis.…”

Section: Common “Furphies” Regarding Carotid Artery Proceduresmentioning

confidence: 99%

“…For example, ~10% of asymptomatic carotid stenosis patients will have at least 1–2 ipsilateral middle cerebral artery ES detected after 1–2 h of TCD monitoring ( 133 ). However, this proportion increases to over 60% with more frequent monitoring ( 133 ). By way of another example, at least some degree of ultrasound echolucency is very common in 60–99% asymptomatic carotid stenosis plaques, reported in at least 63% of carotid duplex studies in the “ASED Study” ( 136 ).…”

Section: Common “Furphies” Regarding Carotid Artery Proceduresmentioning

confidence: 99%

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Extra-Cranial Carotid Artery Stenosis: An Objective Analysis of the Available Evidence

Abbott

2022

Front. Neurol.

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Background and PurposeCarotid stenosis is arterial disease narrowing of the origin of the internal carotid artery (main brain artery). Knowing how to best manage this is imperative because it is common in older people and an important cause of stroke. Inappropriately high expectations have grown regarding the value of carotid artery procedures, such as surgery (endarterectomy) and stenting, for lowering the stroke risk associated with carotid stenosis. Meanwhile, the improving and predominant value of medical intervention (lifestyle coaching and medication) continues to be underappreciated.Methods and ResultsThis article aims to be an objective presentation and discussion of the scientific literature critical for decision making when the primary goal is to optimize patient outcome. This compilation follows from many years of author scrutiny to separate fact from fiction. Common sense conclusions are drawn from factual statements backed by original citations. Detailed research methodology is given in cited papers. This article has been written in plain language given the importance of the general public understanding this topic. Issues covered include key terminology and the economic impact of carotid stenosis. There is a summary of the evidence-base regarding the efficacy and safety of procedural and medical (non-invasive) interventions for both asymptomatic and symptomatic patients. Conclusions are drawn with respect to current best management and research priorities. Several “furphies” (misconceptions) are exposed that are commonly used to make carotid stenting and endarterectomy outcomes appear similar. Ongoing randomized trials are mentioned and why they are unlikely to identify a routine practice indication for carotid artery procedures. There is a discussion of relevant worldwide guidelines regarding carotid artery procedures, including how they should be improved. There is an outline of systematic changes that are resulting in better application of the evidence-base.ConclusionThe cornerstone of stroke prevention is medical intervention given it is non-invasive and protects against all arterial disease complications in all at risk. The “big” question is, does a carotid artery procedure add patient benefit in the modern era and, if so, for whom?

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“…Abbott та співавт. (2019) [43]. За результатами двох 12-годинних сеансів ТКД-моніторингу в 10 суб'єктів виявлено, що емболія має циркадні коливання з найвищими показниками за 4-6 год до опівдня, що відповідає піковій циркадній частоті інсульту та інших судинних подій.…”

Section: реєстрація мікроемболічних сигналів при атеросклеротичних каunclassified

Ultrasound detection of cerebral microembolism in carotid stenoses: progress and perspective (A review of the literature)

Globa

2020

Endovasc. Neurorad.

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The review summarizes available information regarding the method of Transcranial doppler sonography (TCD) usage to record microembolism in patients with carotid artery stenosis, search for information was carried out in literature 1997–2020 (PUBMED, MEDLINE).History overview of TCD with embolodetection implementation is presented, as well as ways of its technical and methodological improvement. Evidence-based studies of the method clinical relevance in atherosclerotic carotid stenoses and their surgical treatment are outlined. Observation results of the intraoperative cerebral embolization during carotid endarterectomy and carotid artery stenting are presented along with comparison of TCD-embolodetection data, neuroimaging and clinical outcomes. Individual centres and multicenter study ACES data on prognostic value of registration of embolic signals in asymptomatic carotid stenosis, risk assessment of vascular events in diffe-rent groups of patients and in varying degrees of stenosis of the vessel lumen was analyzed. The role of embolodetection in predicting repeated cerebrovascular disorders in symptomatic carotid stenosis and its importance for monitoring antiplatelet therapy is set out (multicenter study CARESS). The evidence of the reliability of TCD embolodetection as tool for verificarion of at-risk patients with carotid stenosis who may benefit ftom surgical treatment is presented.Recent advances in ultrasound and other imaging techniques for assessing unstable plague are outlined along with prospects for the use of TCD monitoting for cerebrovascular disorders forecasting.

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Asymptomatic Carotid Stenosis Is Associated With Circadian and Other Variability in Embolus Detection

Cited by 6 publications

References 52 publications

Misconceptions regarding the adequacy of best medical intervention alone for asymptomatic carotid stenosis

Misconceptions regarding the adequacy of best medical intervention alone for asymptomatic carotid stenosis

Extra-Cranial Carotid Artery Stenosis: An Objective Analysis of the Available Evidence

Ultrasound detection of cerebral microembolism in carotid stenoses: progress and perspective (A review of the literature)

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