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Complicated Carotid Artery Plaques as a Cause of Stroke
Quick Takes
- Complicated carotid artery plaque (CAP) may be an under-recognized cause of ischemic stroke.
- In this observational study, investigators found that in stroke patients with complicated CAP, the CAP was more likely to be present on the side of the infarct than on the contralateral side.
- In addition, complicated CAP was more likely in patients with cryptogenic stroke than in patients with cardioembolic or small vessel stroke.
- These findings suggest a potential causal role for complicated CAP in ischemic stroke.
Study Questions:
In patients with ischemic stroke, is complicated carotid artery plaque (CAP) associated with ipsilateral cerebral ischemia and a cryptogenic stroke etiology, two findings which would suggest a causal role for complicated CAP in stroke?
Methods:
This is a prospective observational study of patients with acute ischemic stroke (within the prior 7 days), aged ≥49 years, at four sites in Germany. Patients had infarcts limited to a single carotid territory on magnetic resonance imaging (MRI) and unilateral or bilateral carotid artery plaque ≥2 mm. Patients with ≥70% carotid stenosis were excluded. Plaques were characterized using high-resolution MRI. A plaque was defined as complicated if it had intralesional hemorrhage, a ruptured fibrous cap, or associated mural thrombus. Each patient underwent a workup to identify stroke etiology, and stroke etiology was assigned by investigators blinded to plaque imaging data. Stroke etiology could be: 1) cryptogenic, 2) cardioembolic or small vessel (combined for purposes of analysis), or 3) large artery (related to moderate [50-69%] carotid stenosis). The two primary comparisons were: 1) the prevalence of ipsilateral as compared to contralateral complicated CAP in patients with cryptogenic stroke, and 2) the prevalence of ipsilateral complicated CAP in patients with cryptogenic as compared to cardioembolic/small vessel stroke.
Results:
A total of 196 patients were included in the analysis. Of this group, 104 (53%) had cryptogenic stroke, 73 (37%) had cardioembolic or small vessel stroke, and 19 (10%) had large artery stroke. In the 104 patients with cryptogenic stroke, complicated CAPs were more likely in carotid arteries ipsilateral to the infarct (31%) compared to contralateral to the infarct (12%) (p = 0.0005). Ipsilateral complicated CAPs were more frequent in cryptogenic stroke (31%) than in cardioembolic/small vessel stroke (15%) (p = 0.02).
Conclusions:
In this observational study of patients with ischemic stroke, complicated CAP was associated with ipsilateral (as opposed to contralateral) cerebral ischemia and was associated with a cryptogenic (rather than known) stroke etiology. These two findings suggest a causal role for complicated CAP in ischemic stroke.
Perspective:
In up to one third of ischemic stroke patients, the cause of stroke is uncertain. The causal role of carotid artery plaques (as opposed to carotid artery stenosis) has not been extensively studied. The results of this study suggest that complicated CAP in a carotid artery that is <50% stenosed—a finding which is often ignored when determining stroke etiology in clinical practice—may be an important cause of ischemic stroke. The best management of complicated CAPs (e.g., medical versus surgical versus endovascular) remains uncertain and is an area for future study.
Clinical Topics: Noninvasive Imaging, Prevention, Vascular Medicine, Magnetic Resonance Imaging
Keywords: Brain Ischemia, Carotid Stenosis, Cerebral Infarction, Diagnostic Imaging, Embolism, Hemorrhage, Magnetic Resonance Imaging, Plaque, Atherosclerotic, Secondary Prevention, Stroke, Thrombosis, Vascular Diseases
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