Histological features of carotid plaque in patients with ocular ischemia versus cerebral events
Dominic P J Howard1, Guus W van Lammeren, Jessica N Redgrave
1John Radcliffe Hospital Headington, Oxford, UK.
Insights
Patients with ocular ischemic events have less vulnerable carotid plaque than those with cerebral events, potentially explaining lower stroke risk. This finding impacts understanding of carotid artery stenosis prognosis.
Area of Science:
- Vascular pathology
- Cerebrovascular disease
- Neurology
Background:
- Patients with carotid artery stenosis and ocular ischemic events have a lower risk of future ipsilateral ischemic stroke compared to those with cerebral ischemic events.
- This difference in prognosis is not fully understood but may relate to carotid plaque pathology.
Purpose of the Study:
- To compare carotid plaque histology in patients with cerebral versus ocular ischemic events.
- To investigate potential reasons for differing stroke risks between these patient groups.
Main Methods:
- Compared carotid plaque histology using validated semiquantitative scales.
- Analyzed data from consecutive patients undergoing carotid endarterectomy for symptomatic stenosis.
- Included 1317 patients with cerebral events and 323 patients with ocular events.
Main Results:
- Plaques from patients with cerebral events showed significantly more lipid core, inflammation, and overall instability.
- Plaques from patients with cerebral events had less fibrous content and calcification.
- Patients with cerebral events had a higher overall number of vulnerable plaque features (P=0.002).
Conclusions:
- Carotid plaques associated with ocular ischemic events exhibit fewer vulnerable features than those linked to cerebral events.
- These histological differences may explain the observed disparities in stroke risk between the two groups.
Background And Purpose:
Patients with carotid artery stenosis and ocular ischemic events have a much lower risk of future ipsilateral ischemic stroke on medical treatment and lower procedural risks for endarterectomy and stenting than patients with cerebral ischemic events, and are closer in risk to patients with asymptomatic stenosis. The reasons for this difference in prognosis are not fully understood, but may reflect differences in carotid plaque pathology.
Methods:
In consecutive patients undergoing carotid endarterectomy for recently symptomatic stenosis (Oxford Plaque Study, Athero-Express Study), we compared carotid plaque histology (using validated semiquantitative scales) in those who had cerebral events within the last 6 months (n=1317) versus those with ocular events only (n=323).
Results:
Compared with plaques from patients with ocular events only, those from patients with cerebral events had significantly more large lipid core (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.05-1.82; P=0.02), inflammation (OR, 1.32; 95% CI, 1.02-1.72; P=0.04) and overall plaque instability (OR, 1.37; 95% CI, 1.05-1.80; P=0.02), and less fibrous content (OR, 0.71; 95% CI, 0.54-0.92; P=0.01), and calcification (OR, 0.70; 95% CI, 0.54-0.91; P=0.008). The overall number of histological features known to be associated with vulnerable plaque was greater in patients with cerebral events than in those with ocular events (P=0.002).
Conclusions:
Carotid plaques from patients undergoing endarterectomy for previous ocular ischemic events have fewer vulnerable plaque features than those from patients with recent cerebral ischemic events, possibly explaining some of the differences in risk of stroke between these groups.
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