Differences in Lesion Severity and Cellular Composition between in vivo Assessed Upstream and Downstream Sides of Human Symptomatic Carotid Atherosclerotic Plaques

Abstract

Background: The heterogeneous structure of carotid atherosclerotic plaques may be better understood if it is related to blood flow variations, influencing gene expression and cellular functions. Upstream of the maximum stenosis there is laminar blood flow and high shear stress, downstream there is turbulence and low shear stress. We studied if these variations were associated with differences in plaque morphology and composition between sites located up- and downstream of the maximum stenosis in symptomatic carotid plaques. Methods: Patients with symptomatic carotid stenosis were examined with magnetic resonance angiography to localize the maximum stenosis in-vivo, prior to endarterectomy. In 41 endarterectomized specimens, transverse tissue sections prepared up- and downstream of the maximum stenosis were compared using histopathology and immunohistochemistry. Results: The location of maximum stenosis relative the carotid bifurcation varied considerably between plaques. Compared with the downstream side, the upstream side of the stenosis had higher incidence of severe lesions with cap rupture and intraplaque hemorrhage, more macrophages, less smooth muscle cells and more collagen. Conclusions: The up- and downstream sides of symptomatic carotid plaques differed in plaque morphology and composition. This implies that the intraplaque location of sampling sites may be a confounding factor in studies of atherosclerotic plaques.

Very Urgent Carotid Endarterectomy Confers Increased Procedural Risk

“…It is not clear why there should be an increased risk with very early CEA, but potential explanations are that the brain is more vulnerable to ischemia so soon after a neurological event or that the carotid plaques are more vulnerable at early time points and thus hazardous to remove without complications. 34,35 Prompt medical therapy has been shown to be beneficial in the acute phase, perhaps due to a plaque-stabilizing effect. 28 …”

Human oral, gut, and plaque microbiota in patients with atherosclerosis

“…The patient samples were obtained from the Göteborg Atheroma Study Group biobank, which includes carotid endarterectomies from patients who were operated for minor ischemic stroke, transient ischemic attack, or amaurosis fugax as previously described in detail (44). The patients were consecutively included, and completed questionnaires covering previous and current diseases, lifestyle factors, and medication.…”

Contrast-Enhanced 3T High-Resolution MR Imaging in Symptomatic Atherosclerotic Basilar Artery Stenosis

“…In a study on coronary atherosclerosis, plaque rupture was more frequently observed at the proximal, upstream side of the site of maximal stenosis, which is exposed to higher wall shear stress. [16][17][18] In patients with symptomatic extracranial carotid atherosclerotic plaques, the upstream side of the stenosis had higher incidence of cap rupture and intraplaque hemorrhage with more macrophages, fewer smooth muscle cells, and more collagen compared with the downstream side. 18 This study had some limitations.…”