Carotid Extra-media Thickness Research Articles

Carotid extra-media thickness in obesity and metabolic syndrome: A novel index of perivascular adipose tissue: Extra-media thickness in obesity and metabolic syndrome

ObjectivesWe aimed to evaluate the association between a novel ultrasound index extra-media thickness (EMT), obesity, and metabolic syndrome (MS) using several measures of adiposity. MethodsFour hundred patients were included in the study (age: 60.95 ± 7.3 years, F/M: 35/65%). Both common carotid arteries (CCA) indexes (EMT and intima-media thickness), anthropometric parameters, body fat percentage and ultrasound measures of different fat depots were obtained in all patients. MS was identified using three alternative definitions: International Diabetes Federation 2005 (IDF), National Cholesterol Education Program Adult Treatment Panel III 2001 (NCEP ATP III) and World Health Organization 1998 (WHO). ResultsThe study group included patients with very high (80.2%) or high (19.8%) CV risk (IDF MS: 59.5%). Carotid EMT measures averaged from both sides (±SD) were as follows: mean EMT: 791 ± 126 μm, mean minimum EMT: 731 ± 115 μm and mean maximum EMT: 885 ± 210 μm. Patients with MS, irrespective of its definition and measures of obesity, displayed significantly thicker mean EMT compared to non-MS individuals: 819 ± 129 μm vs 747 ± 113 μm (p < 0.001; IDF), 824 ± 131 μm vs 751 ± 112 μm (p < 0.001; NCEP ATP III) and 825 ± 137 μm vs 773 ± 120 μm (p < 0.001; WHO). Moreover, EMT was related to all major parameters of general obesity, abdominal fat distribution, regional neck subcutaneous fat with weaker association between EMT and epicardial fat thickness. Finally, EMT is associated with an increasing number of CV risk factors. ConclusionsThis is the first study providing novel findings on the relationship between EMT, MS, and adiposity indexes. Our results suggest that EMT may be a new non-invasive index of perivascular adipose tissue corresponding to cardiometabolic risk.

Abstract P338: Carotid Extra Media Thickness: An Indicator of Fat, Arterial Stiffness, Inflammation or Thickness?

Introduction: Epicardial fat is an emerging risk factor for cardiovascular (CV) disease. The importance of perivascular fat as a CV risk factor, which can be measured by ultrasound as Extra Medial Thickness (EMT), is less well described. Hypothesis: We hypothesized that EMT would be related to obesity and EMT may influence carotid stiffness. Methods: EMT defines the interface between the distal common carotid near wall to the jugular vein intima and includes arterial adventitia, interstitial tissue, perivascular fat, and vein intima. Mean of the maximum for right and left carotid EMT was measured at follow-up (5.9 years) with ultrasound (GE Vivid 7, Bothell, Wash.) in 112 subjects (34% male, 68% Non-Caucasian, mean age 22.9 ∓ 3.6 years) in a group of lean (L), obese (O), and T2DM (T) youth from a longitudinal study of CV Risk Factors. Anthropometrics, BP, fasting labs, and vascular measures for CIMT and arterial stiffness (Beta stiffness and Peterson’s elastic modulus) were obtained at baseline and follow-up. Variance stabilizing transformations were performed as appropriate. ANOVA was performed to compare means between the 3 study groups. ANCOVA was used to further delineate determinants of EMT. CV risk factors were regressed on EMT and other covariates in general linear models. Results: Mean EMT was lower in L (0.86±.28) compared to the O (0.98±.24) and T (1.00±.28) subjects, p&lt;0.05. Age and BMIz at baseline and change in glucose were determinants of EMT, while differences between study groups were no longer significant. EMT predicted higher CRP, but, significance was lost after adjustment for follow-up BMIz. EMT predicted higher Beta and Peterson’s which persisted after adjustment for BMI, glucose, and CRP. Conclusion: Adiposity and poor glucose control may lead to increased perivascular fat. Thicker EMT may lead to increased carotid stiffness, a risk factor for CV events. Public health measures to reduce obesity and glycemic-related arterial changes are needed to prevent future heart attack and stroke.

Weight gain in infancy is associated with carotid extra-medial thickness in later childhood

ObjectiveEarly life is an important period for determining future risk of cardiovascular disease. Carotid extra-medial thickness is a novel noninvasive measure that estimates arterial adventitial thickness, information concerning vascular health not captured by assessment of arterial intima-media thickness alone. We sought to determine whether fetal growth and early postnatal growth are associated with carotid extra-medial thickness in 8 year old children. MethodsCarotid extra-medial thickness was assessed by high-resolution ultrasound in 379 non-diabetic children aged 8-years, with complete data for birth weight, gestational age, early postnatal weight gain and carotid extra-medial thickness. ResultsWeight gain during infancy, from birth to 18 months of age, was significantly and positively associated with carotid EMT (11 μm per kg length-adjusted weight gain [95% CI 3, 18], P = 0.007). This association was significantly stronger in boys than girls (Pheterogeneity = 0.005). By contrast, there was no significant association between birth weight and carotid EMT (6 μm/kg birth weight [95% CI −12, 24], P = 0.51). ConclusionExcessive weight gain during infancy is associated with increased carotid extra-medial thickness, indicating that the alterations to the vasculature associated with excessive early postnatal growth likely include arterial adventitial thickening.

Carotid extra-medial thickness in childhood: Early life effects on the arterial adventitia

ObjectiveStructural modification of the arterial adventitia may be an early event in atherosclerosis. Carotid extra-medial thickness is a new measure of arterial adventitial thickness. We examined the association of cardiovascular risk factors with extra-medial thickness, in childhood. MethodsCarotid extra-medial thickness was assessed by high-resolution ultrasound in 389 non-diabetic children aged 8-years. A non-fasting blood sample was collected from 314 participants. Associations of gender, age, lipoproteins, blood pressure, BMI z-score, waist:height ratio and parental history of early vascular disease, with extra-medial thickness were examined. ResultsCarotid extra-medial thickness was lower in girls (r=−.163, P=.001) and directly associated with systolic (r=.128, P=.009), diastolic blood pressure (r=.130, P=.009), and height (r=.170, P=.0006). These associations remained after adjustment for carotid intima-media thickness. In multivariable analysis including carotid intima-media thickness, only gender and height were significantly associated with carotid extra-medial thickness. In gender-stratified analysis, the strongest associations with extra-medial thickness were BMI z-score (r=.181, P=.01), height (r=.210, P=.003) and diastolic blood pressure (r=.167, P=.02) for boys; and systolic blood pressure (r=.153, P=.03) and parental history of premature cardiovascular disease (r=.139, P=.05) for girls. The association of BMI z-score with extra-medial thickness differed by gender (P-interaction=.04). ConclusionsCarotid extra-medial thickness is independently associated with gender and height in childhood. Extra-medial thickness may provide important information concerning early arterial health, particularly related to the arterial adventitia.

Carotid intima–media and adventitial thickening: Comparison of new and established ultrasound and magnetic resonance imaging techniques

ObjectiveCarotid intima–media thickness is a well established non-invasive surrogate marker of cardiovascular disease, however there is evidence that structural modification of the arterial adventitia also accompanies cardiovascular risk factors and might be involved causally in atherosclerosis. We sought to determine the relative contributions of the intima–media and adventitia to variation in ultrasound and magnetic resonance derived measures of carotid wall thickness. MethodsCarotid ultrasound and magnetic resonance imaging were undertaken in 20 participants. Carotid intima–media thickness, carotid extra–media thickness (which incorporates the arterial adventitia) and total wall thickness (a combined near-wall intima–media thickness and carotid extra–media thickness) using high-resolution ultrasound, and wall thickness using magnetic resonance imaging, were obtained. ResultsAll ultrasound-derived measures of the arterial wall thickness were highly correlated with wall thickness by magnetic resonance imaging (all P<0.001); as expected the total wall thickness by ultrasound measure was most tightly correlated (correlation coefficient=0.814, P<0.0001). In multivariable models, there was evidence that both carotid intima–media thickness and carotid extra–media thickness contributed independently to the variance in wall thickness by magnetic resonance imaging, especially for the most severe focal thickening. Measures of carotid wall thickness that incorporated all three layers of the arterial wall were more closely correlated with the number of cardiovascular risk factors than carotid intima–media thickness alone. ConclusionsThese results indicate that the arterial adventitia is an important contributor to the wall thickness measure derived by magnetic resonance imaging, and that carotid extra–media thickness likely provides additional information concerning arterial structure than that obtained from carotid intima–media thickness alone.

Noninvasive Measurement of Carotid Extra-Media Thickness: Associations With Cardiovascular Risk Factors and Intima-Media Thickness

We sought to develop a noninvasive technique to quantify the thickness of a segment of the carotid artery wall that incorporates the adventitia and to identify whether differences in this measure are associated with cardiovascular risk factors. There is increasing evidence that the arterial adventitia undergoes extensive structural alteration, including thickening, in response to arterial injury. However, there is currently no widely accepted noninvasive technique for studying the thickness of the arterial adventitia in humans. The carotid artery and jugular vein were imaged simultaneously in longitudinal section with the use of high-resolution ultrasound. The distance from the jugular intima-lumen interface to the carotid media-adventitia margin was denominated as the carotid extra-media thickness (EMT). This measure includes the arterial adventitia but not the arterial intima or media. We measured the carotid EMT and intima-media thickness (IMT) in 175 subjects, including 54 with diabetes, 43 with dyslipidemia, 26 with other cardiovascular risk factors, and 52 healthy control subjects. When compared with control subjects, the EMT was increased in both the diabetes (p < 0.0001) and dyslipidemia (p = 0.04) groups. Multivariate linear regression analyses revealed that diabetes, high-density lipoprotein cholesterol (inverse association), and systolic blood pressure (J-shaped association) were the factors most strongly associated with EMT. These associations appear to be independent of carotid IMT. Carotid EMT can be assessed by ultrasonography. It is physically distinct from IMT and provides additional information concerning the vascular changes associated with cardiovascular risk factors. As such, the measurement of EMT, in addition to IMT, may provide a more complete indication of the structural modification of the vasculature associated with cardiovascular risk factors than that obtained by the measurement of carotid IMT alone.