Assessment of Carotid Plaque Vulnerability Using Structural and Geometrical Determinants

Abstract

upture of atheromatous plaque in the carotid artery often leads to thrombosis and subsequent stroke. 1 This is potentially preventable by carotid revascularization techniques, and the degree of luminal stenosis is commonly used in clinical practice as an indicator for carotid endarterectomy or carotid artery angioplasty/stenting. Carotid endarterectomy has been shown to be beneficial in patients with symptomatic high-grade (70-99%) stenosis, 2,3 but it is more difficult to draw conclusions about possible benefits for patients with moderate carotid stenosis. Moreover, the debate continues about whether or not asymptomatic patients with a moderate stenosis should undergo endarterectomy, despite the findings of the recent Asymptomatic Carotid Surgery Trial (ACST). 4 Previous studies have shown that vulnerable plaque (ie, prone to rupture with thromboembolic complications) has a thin fibrous cap, a large lipid core and a high inflammatory cell burden. 5,6 Therefore, investigating plaque structure and morphology may aid in the risk stratification of patients with a moderate luminal stenosis.Although the original concept of vulnerable plaque was derived from the coronary circulation, there are compelling reasons why it also applies to the carotid circulation. [7][8][9][10][11][12] The mechanism of plaque rupture is not entirely clear, but is thought to be a multifactorial process involving thinning and weakening of the fibrous cap by enzymes secreted by activated macrophages, and biomechanical stress as the trigger leading to plaque rupture. [13][14][15] From the point of view of structural analysis, plaque rupture is structural failure when the plaque cannot resist the hemodynamic blood pressure and shear stress exerted on it. In the process of plaque rupture, an excessive concentration of stress at a weak site on the plaque surface is considered to be an important factor. [16][17][18] The mechanism of plaque rupture has been widely studied using computational simulations. 17,19,20 Hung et al used histology-based 2-dimensional (D) solid models for arterial plaque and found that a thin fibrous cap and a large lipid core are important determinants of increased plaque stress. 21 Cheng et al used a finite element model based on histology to analyze coronary lesions, and their data suggested that the concentration of circumferential tensile stress in the lesion may play an important role in plaque rupture and myocardial infarction. 17 Tang et al used an ex vivo magnetic resonance imaging (MRI)-based flow-structure interaction model to study the interaction between flow and plaque, and suggested that large cyclic stress -strain variations in the plaque under pulsatile flow pressure may lead to plaque fatigue and possible rupture. 22 Imoto et al used longitudinal structural analysis of plaque rupture and revealed that plaque shape, size and remodeling may be associated with plaque rupture. 23 We previously used a blood flow and plaque interaction model to demonstrate Assessment of Carotid Plaque Vulnerability Using Structu...

Advances in MRI for the evaluation of carotid atherosclerosis

“…The result obtained from 30 patients using 2D structure-only modelling indicated that the stress level in symptomatic individuals was about twice as high as that of the asymptomatic cohort. This observation was further confirmed by a study with a slightly larger patient cohort 55 (n 5 40). Sadat et al 56,57 and Zhu et al 58 found that stress level right after the onset of symptom was much higher than that of recently symptomatic and asymptomatic patients.…”

Diagonal Ear-Lobe Crease is Correlated With Atherosclerotic Changes in Carotid Arteries

“…28 Li et al have demonstrated the importance of the detection of the vulnerable plaques. 29 These and many other studies highlight the importance of the simple and reliable predictors of atherosclerosis like ELC for the detection of the atherosclerotic changes as early as possible. Identification of the persons at risk of such major outcomes in the earlier stages would lower the burden of morbidities and mortalities associated with these disorders.…”

Metabolic Syndrome and Carotid Artery Parameter in Koreans Aged 50 Years and Older

“…[41][42][43] Plaque is formed by inflammation, oxidation, and endothelial dysfunction as a late response compared with thickening of the intimamedia. [44][45][46][47][48] When the entire study population (4,088), including subjects with hypertension, diabetes, and dyslipidemia, were included in the analysis, the relationship between MetS and carotid plaques was significant in both men (OR 1.45, 95%CI 1.16-1.81) and women (OR 1.65, 95%CI 1.36-1.99). Additional prospective investigations are needed to further examine the sex differences in the relationship between MetS and subclinical atherosclerosis.…”