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Patterns of cerebrovascular symptomatology associated with carotid atheroma
T J Tegos1, M M Sabetai, A N Nicolaides
1Irvine Laboratory for Cardiovascular Investigation and Research, Department of Vascular Surgery, St. Mary's Hospital, Imperial College of Science, Technology and Medicine, Praed St, Paddington, London, UK. t.tegos@ic.ac.uk
Insights
Amaurosis fugax is linked to unstable carotid plaques with low grey scale median and severe stenosis. Hemispheric transient ischemic attack and stroke involve plaques plus other factors.
Area of Science:
- Vascular Neurology
- Medical Imaging
- Cardiology
Background:
- Carotid artery stenosis is a major cause of stroke.
- Understanding plaque characteristics is crucial for predicting cerebrovascular events.
- Symptomatic carotid plaques require detailed analysis for risk stratification.
Purpose of the Study:
- To correlate specific ultrasonic tissue characteristics and stenosis severity of carotid plaques with clinical events.
- To differentiate the plaque features associated with amaurosis fugax, hemispheric transient ischemic attack (TIA), and stroke.
- To investigate the role of plaque echogenicity (grey scale median) in event prediction.
Main Methods:
- 146 symptomatic carotid plaques (50-99% stenosis) from 136 patients were analyzed.
- Duplex ultrasound imaging was used to assess stenosis and capture plaque images.
- Plaque echogenicity was quantified by evaluating the grey scale median to classify plaques as 'dark' or 'bright'.
Main Results:
- Carotid plaques associated with amaurosis fugax exhibited a low grey scale median (dark plaques) and severe stenosis.
- These features differed significantly (P < 0.05) from plaques causing hemispheric TIA and stroke.
- Plaque instability appears to be the primary driver for amaurosis fugax.
Conclusions:
- Amaurosis fugax is primarily associated with unstable, echolucent carotid plaques.
- Hemispheric TIA and stroke involve carotid plaque characteristics alongside other contributing pathogenetic factors.
- Ultrasonic plaque characterization aids in distinguishing the mechanisms of different cerebrovascular events.
Abstract:
The aim of this study was to identify ultrasonic tissue characteristics and stenosis of carotid plaques that correspond to amaurosis fugax, hemispheric transient ischaemic attack, and stroke. At total of 146 symptomatic carotid plaques (136 patients) associated with amaurosis fugax, hemispheric transient ischaemic attack, stroke, and having 50-99% stenosis on duplex, were studied. These plaques were imaged on duplex, captured in a computer and their grey scale median was evaluated to distinguish the dark (low grey scale median) from the bright (high grey scale median) plaques. Stenosis was assessed on duplex. The amaurosis fugax group corresponded to carotid plaques with low grey scale median and severe stenosis, as contrasted with the other two groups (hemispheric transient ischaemic attack and stroke) (P < 0.05). These results suggested that amaurosis fugax was dependent only on the instability of carotid plaques, whereas hemispheric transient ischaemic attack and stroke were both dependent on carotid plaques and other pathogenetic factors.