Correlating Ex Vivo Carotid Calcification Measurements With Cerebrovascular Symptoms

Background and Purpose: The purpose of this study is to examine the ability of ex vivo derived Agatston, Volume, and Density-Volume calcium scores or calcium density measurements to differentiate between carotid plaques based on preoperative cerebrovascular symptomatology. Methods: Thirty-eight carotid plaques were acquired from standard endarterectomy. Micro-computed tomography was performed on the ex vivo samples. Image series were downsampled to represent the resolution of clinical multidetector computed tomography. Agatston, Volume, and Density-Volume carotid calcium scores were then calculated using coronary methodologies. The fractions of low- and high-density calcification were also determined. Results: The coronary calcium scores could not differentiate between carotid plaques from asymptomatic versus symptomatic patients. However, plaques from asymptomatic patients contained significantly lower fractions of low-density calcification and higher fractions of high-density calcification. Conclusions: Screening for carotid calcium density in noncontrast computed tomography could reflect plaque stability.

Clinical value of MRI T2-mapping quantitative assessment of carotid plaque

Background Stroke is a severe health problem, and magnetic resonance imaging (MRI) plays a significant role in stroke. Purpose To investigate the clinical value of MRI T2-mapping in carotid artery plaque. Material and Methods To locate the plaque in the carotid artery, 25 patients with carotid atherosclerosis were examined by 3.0-T MRI with three-dimensional (3D) time-of-flight and 3D fast spin-echo (FSE) T1-weighted scanning. The original images were obtained after T2-mapping (multi-spin-echo sequence) scanning. The T2 values of the plaque in the narrowest lumen were measured on T2 maps after postprocessing of the original images. Based on the symptoms, the patients were divided into two sub-groups; independent sample t-test was employed to compare the difference between the T2 values of the plaque in the two groups. We evaluated the optimal threshold and diagnostic efficacy of T2 values in predicting cerebrovascular symptoms by the receiver operating characteristic (ROC) curve. Results The T2 values of the carotid artery plaque in symptomatic and asymptomatic patients were 111.43 ± 46.54 ms and 59.25 ± 39.77 ms, respectively (t = −3.421, P < 0.01). ROC analysis showed that the T2 value of 65.38 ms was the optimal threshold to predict cerebrovascular symptoms. The specificity, sensitivity, and accuracy attained were 94.1% (16/17), 93.3% (14/15), and 93.8% (30/32), respectively. Conclusion We quantitatively assessed carotid plaque components by MRI T2-mapping technology. The T2 values of the carotid plaque were associated with cerebrovascular symptoms. The T2 values of the symptomatic plaque group were significantly higher than those of the asymptomatic group.

Physiological motion of the carotid atherosclerotic plaque quantified using ultrasound B-Mode image analysis

BackgroundPhysical motion throughout the cardiac cycle may contribute to the rupture of the atherosclerotic carotid plaque, resulting in ischaemic stroke. The purpose of this study was to quantify the physiological motion of the atherosclerotic carotid plaque and to investigate any relationship between the quantified motion parameters and the degree of stenosis, greyscale plaque characteristics, and the presence of cerebrovascular symptoms.MethodsDisplacement, velocity and acceleration of 81 plaques (51% symptomatic, stenosis range 10%-95%) from 51 patients were measured using an automated system employing a block matching algorithm relative to the ultrasound probe and relative to the periadventitial tissues, over a mean duration of 5 cardiac cycles.ResultsAveraged across all plaques, the displacement amplitude was 1.2 mm relative to the probe, and 0.35 mm relative to the periadventitial tissues. Maximum and mean plaque velocities were 4.7 and 1.3 mm/s relative to the ultrasound probe, and 2.4 and 0.70 mm/s relative to the periadventitial tissues. The corresponding acceleration magnitudes were 69 and 22 mm/s2 relative to the probe, and 57 and 18 mm/s2 relative to the periadventitial tissues. There were no significant differences in any of the motion parameters, with respect to the presence of cerebrovascular symptoms, and none of the parameters showed a statistically significant relationship to the degree of stenosis, and the greyscale plaque characteristics (p≤0.05). The technique used was able to detect plaque motion amplitudes above 50μm.ConclusionsThis study provides quantitative data on the physiological motion of the atherosclerotic carotid plaque in-vivo. No significant relationship was found between the measured motion parameters and the presence of cerebrovascular symptoms, the degree of stenosis, and the greyscale plaque characteristics.

Spotty Carotid Plaques Are Associated with Inflammation and the Occurrence of Cerebrovascular Symptoms

Background: Echolucent carotid plaques have been related to an increased risk of ischemic cerebrovascular events. The aim of the present study was to evaluate whether a new objective ultrasonographic parameter, the statistical geometric feature (SGF), reflecting spottiness of carotid plaques, can be associated with cerebrovascular symptoms and with a rupture-prone plaque phenotype. Methods: The plaques of 144 patients who underwent carotid endarterectomy were included in this study. SGF and plaque area were estimated by outlining the plaque on ultrasound (US) images. The correlation coefficient for inter- and intraobserver variability was 0.69 and 0.93, respectively. The SGF values were normalized to the degree of stenosis (SGF/DS). The plaques collected at surgery 1 day after the US were analyzed histologically, and inflammatory markers and matrix metalloproteinases (MMPs) were measured. Results: Patients with ipsilateral hemispheric symptoms had higher SGF/DS compared to patients without symptoms (0.82 [0.59–1.16] vs. 0.70 [0.56–0.89], p = 0.01). Analysis of plaque components revealed a positive correlation between SGF/DS and the percentage of the plaque area stained for lipids, macrophages, and hemorrhage. A correlation was also found between SGF/DS and plaque expression of interleukin-6, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, vascular endothelial growth factor A, C-C motif chemokine 3 and 20, and MMP-9. An inverse correlation was found with plaque levels of osteoprotegerin. Conclusions: The present study supports the concept that spottiness is a feature of the carotid plaques rich in inflammation and can be associated with the typical phenotype of high-risk plaques.

Abstract 323: Utilization and Outcomes of Carotid Artery Stenting vs. Carotid Endarterectomy

Introduction: Carotid artery stenting is an alternative to carotid endarterectomy in average surgical-risk symptomatic patients and asymptomatic patients with ≥60% stenosis. We wanted to compare utilization and peri-procedural mortality between these procedures. Methods: The 2000-2013 National Inpatient Sample (NIS) was analyzed for admissions when procedures for carotid artery stenting (CAS) or carotid endarterectomy (CEA) were performed. Admissions when both procedures were performed were excluded. Trend of procedures and death during index admission was compared depending on prior cerebrovascular symptoms. Results: During the study period, 1991941 patients underwent CEA of which 9.12% were symptomatic and 343,741 patients underwent CAS of which 10.8% were symptomatic. Mean age for CAS vs CEA group was lower among both symptomatic (68.6 vs 69.6 yrs, p<0.001) and asymptomatic patients (70.7 vs 71.2 yrs, p<0.001). More males than females underwent CAS (57% vs 43%) and CEA (58% vs 42%). Both CAS and CEA during same admission was carried out in 20,875 (0.89%) patients. There was a rising trend of both CEA and CAS procedures in symptomatic and asymptomatic patients (ptrend < 0.001)(Figure A1 & B1). Trend of mortality has not changed significantly in all groups except for CEA in asymptomatic patients wherein mortality rate has decreased (ptrend <0.001)(Figure A2 & B2). On multivariable logistic regression analysis, associated conditions significant for mortality in symptomatic patients were atrial fibrillation (OR 2.05, p<0.001), myocardial infarction (OR 1.61, p=0.001) heart failure (OR 1.39, p=0.021) and malnutrition (OR 3.58, p<0.001). Adjusted likelihood of mortality after CAS vs CEA was higher in symptomatic (OR 3.78, p<0.001, C statistic 0.74) and asymptomatic patients (OR 2.00, p<0.001, C statistic 0.80). Conclusion: Utilization of CAS and CEA has increased over time. Mortality after CAS vs. CEA during index admission, remains high.