Atherosclerotic Plaque in the Left Carotid Artery Is More Vulnerable Than in the Right

Study Questions:

Is there a difference in the prevalence and vulnerability of atherosclerotic plaque in the left versus the right carotid artery?


The authors used magnetic resonance imaging (MRI)-based scanning data from a population-based cohort of 1,414 stroke-free participants (≥45 years). The prevalence, stenosis, and thickness of the plaque and its predominant component (i.e., lipid core, intraplaque hemorrhage, calcification, or fibrous tissue in each carotid artery) were assessed.


Bilateral plaque was present in 85% of the participants. Among the rest, left-sided plaque was almost twice as prevalent as on the right side (67% vs. 33%; p < 0.001). Plaque thickness was greater on the left (3.1 ± 1.2 vs. 2.9 ± 1.3 mm; p < 0.001), but no difference in degree of stenosis was noted. Intraplaque hemorrhage (9.1 vs. 5.9%; p < 0.001) and fibrous tissue (45.0 vs. 38.5%; p < 0.001) were more prevalent on the left, whereas calcification occurred more often on the right (37.4 vs. 31.6% at the left; p < 0.001). Lipid distribution was similar.


The authors concluded that left-sided plaques are more prevalent and more likely to demonstrate features of vulnerability.


Ischemic strokes more commonly impact the left hemisphere, and this study suggests that this may be related in part to differences in plaque prevalence and morphology, rather than better recognition of left-sided versus right-sided stroke. This study does not have obvious immediate implications for clinical practice. Presence of carotid plaque (irrespective of the side it is on) should automatically trigger optimization of primary prevention therapy.

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