Association of pericardial fat accumulation rather than abdominal obesity with coronary atherosclerotic plaque formation in patients with suspected coronary artery disease

The Impact of Exercise Training Plus Dietary Interventions on Ectopic Fat in Population with Overweight/Obesity with and without Chronic Disease: A Systematic Review, Meta-analysis, and Metaregression of Randomized Clinical Trials

Background

The growing prevalence of obesity and related chronic diseases has led to increased interest in interventions targeting ectopic fat reduction to which its accumulation is linked to metabolic dysfunction.

Objectives

This study aimed to evaluate the effects of combined exercise training combined with dietary interventions compared with dietary interventions alone on ectopic fat [visceral fat area (VFA), liver fat, intramuscular fat (IMF), pancreatic fat, renal sinus fat, and pericardial and epicardial fats] in adults with overweight and obesity, both with and without chronic diseases.

Methods

Web of Science, Scopus, and PubMed were searched for original articles up to 1 March, 2024, that included exercise compared with control interventions on body weight and ectopic fat in adults with overweight or obesity. Weighted mean differences (WMD) for body weight, liver fat, pancreatic fat, and renal sinus fat and standardized mean differences (SMD) for VFA, IMF, pericardial and epicardial fats, and 95% confidence intervals were determined using random-effects models.

Results

Thirty-two studies, including 1488 participants and 38 intervention groups, met the inclusion criteria. The combined intervention of exercise and diet did not reduce body weight (WMD = -0.23 kg, P = 0.180), liver fat (WMD = 0.05%, P = 0.730), IMF (SMD = -0.08, P = 0.640), pericardial and epicardial fats (SMD = -0.12, P = 0.280), pancreatic fat (WMD = -0.24%, P = 0.370), and renal sinus fat (WMD = 0.01 cm2, P = 0.170) when compared with a diet-only group. Interestingly, exercise combined with diet significantly reduced VFA in participants with obesity (SMD = -0.12, P = 0.040) and healthy males (SMD = -0.33, P = 0.001) when compared with a diet-only group.

Conclusions

The findings suggest that combined exercise and dietary interventions did not lead to significant reductions in most ectopic fat depots when compared with diet alone. However, a modest reduction in VFA was observed in participants with obesity and healthy males. These results highlight the nuanced impact of exercise in combination with dietary interventions and the need to consider specific fat depots and participant characteristics in obesity management strategies.The trial was registered at PROSPERO as CRD42024546770.

Change in pericardial fat volume in postmenopausal women with papillary thyroid cancer undergoing thyrotropin suppressive therapy

BACKGROUND

Despite TSH suppressive therapy improve the prognosis for the patient with differentiated thyroid cancer (DTC), there is an increasing concern regarding the potentially harmful effects of lifelong TSH suppression. Therefore, we aimed to examine the changes in body composition under TSH suppression in postmenopausal women with DTC.

METHODS

The body composition was assessed by the volumes as following; fat tissues of the epicardium and abdominal visceral and subcutaneous areas; bilateral psoas muscle or thigh muscle. Each volumetric measurements were performed using computed tomography (CT) scans using baseline and follow-up fluorine-18 fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT)s for 2-year follow up period in Pusan National University Hospital, South Korea.

RESULTS

The 43 patients' median age was 50.0 years, and median body mass index (BMI) was 23.53 (interquartile range[IQR]: 22.19- 24.92) at the initial 18F-FDG PET/CT. The median follow-up period was 19.24 months (IQR: 17.24-21.79). No significant change in weight or BMI were observed during follow-up. Volumes of fat and muscles was not changed significantly except epicardial fat volume. The epicardial fat volume significantly increased during the follow-up period. The epicardial fat volumes were correlated with visceral fat volume, respectively, however, the changing ratio was only correlated with TSH suppression on multiple regression analysis.

CONCLUSION

Both skeletal muscle and abdominal fat volumes did not change, whereas epicardial fat volume increased over less than 2 years of observation under TSH suppressive therapy. Further research is needed for the harmonization of benefits or losses with the optimal TSH concentration in postmenopausal women.

Comparison of epicardial adipose tissue volume of normal and coronary artery disease patients during diastolic and systolic phases of retrospective electrocardiogram-gated volume scan

INTRODUCTION

The abundance of epicardial adipose tissue (EAT) correlates with the extent and severity of coronary artery disease (CAD). If the quantity of EAT varies between diastole and systole during an ECG-synchronized volume scan, it can potentially affect the diagnostic accuracy of CAD. The aim of this study was to compare the EAT volume between the diastolic and systolic phases during an ECG-gated volume scan of patients with or without CAD.

METHODS

In this study, 47 patients (11 with and 36 without CAD) underwent coronary computed tomography (CT) angiography between September 2022 and August 2023. All patients underwent a second-generation 320-row computed tomography (CT) scan with a retrospective ECG-triggered volume scan. The data volumes obtained at 5 % steps of the R-R interval were automatically analyzed on a Ziostation2 Plus workstation using a CT coronary artery analysis application. Myocardial fat components ranging from -160 to -70 in CT value were extracted to determine fat content. EAT volumes between R-R intervals were compared for 40 % diastolic and 75 % systolic phases in the scans of patients with and without CAD.

RESULTS

The median and interquartile range (IQR) of the EAT volumes were 130 (112-183) mL and 98 (67-129) mL for the groups with and without CAD, respectively, indicating a significant difference (p < 0.05). For the ECG-gated scan without CAD, the median and IQR of the EAT volumes were 98 (66-129) and 94 (68-134) mL in the diastolic and systolic phases (p = 0.82), respectively, and for CAD, 166 (129-191) and 158 (113-178) mL (p = 0.56), respectively. Thus, the differences in the EAT volume were not significant between diastolic and systolic phases (p > 0.05).

CONCLUSION

Differences in EAT volume between patients with and without CAD were significant. However, the EAT volume differences between the diastolic and systolic phases were not significant, irrespective of CAD, during the ECG-gated volume scans.

IMPLICATIONS FOR PRACTICE

The diastolic and systolic cardiac phases did not significantly influence EAT volume measurements.

Impact of epicardial fat on coronary vascular function, cardiac morphology, and cardiac function in women with suspected INOCA

AIMS

Epicardial fat is a metabolically active adipose tissue depot situated between the myocardium and visceral pericardium that covers ∼80% of the heart surface. While epicardial fat has been associated with the development of atherosclerotic coronary artery disease, less is known about the relationship between epicardial fat and coronary vascular function. Moreover, the relations between excess epicardial fat and cardiac morphology and function remain incompletely understood.

METHODS AND RESULTS

To address these knowledge gaps, we retrospectively analysed data from 294 individuals from our database of women with suspected ischaemia with no obstructive coronary disease (INOCA) who underwent both invasive coronary function testing and cardiac magnetic resonance imaging. Epicardial fat area, biventricular morphology, and function, as well as left atrial function, were assessed from cine images, per established protocols. The major novel findings were two-fold: first, epicardial fat area was not associated with coronary vascular dysfunction. Secondly, epicardial fat was associated with increased left ventricular concentricity (β = 0.15, P = 0.01), increased septal thickness (β = 0.17, P = 0.002), and reduced left atrial conduit fraction (β = -0.15, P = 0.02), even after accounting for age, BMI, and history of hypertension.

CONCLUSION

Taken together, these data do not support a measurable relationship between epicardial fat and coronary vascular dysfunction but do suggest that epicardial fat may be related to concentric remodelling and diastolic dysfunction in women with suspected INOCA. Prospective studies are needed to elucidate the long-term impact of epicardial fat in this patient population.

Higher epicardial adipose tissue volume is associated with higher coronary fatty plaque volume and is regulated by waist circumference but not EPA+DHA supplementation

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation lower triglyceride levels. The impact on epicardial adipose tissue volume (EATV), which is associated with cardiovascular events, is unclear.

OBJECTIVE

To determine if triglyceride reduction with EPA+DHA supplementation decreases EATV and whether EATV affects coronary plaque.

METHODS

139 subjects with coronary artery disease (CAD) on statins were randomized to 3.36 g EPA+DHA daily or none (control) for 30 months. EATV, coronary plaque volumes and coronary artery calcium score were measured with coronary computed tomographic angiography.

RESULTS

Change in triglyceride level correlated with change in EATV (r=0.236; p=0.006). Despite a 6.7% triglyceride reduction (p=0.021) with EPA+DHA supplementation compared to no change in control (between group p=0.034); both groups had similar reductions in EATV possibly due to statin treatment. EATV above the median (>115.6 cm3) was the only determinant of baseline coronary fatty plaque volume (β=2.4, p=0.010). After multivariate adjustment, waist circumference, a surrogate of abdominal visceral adiposity, was the only determinant of baseline EATV (odds ratio {OR]:1.093; 95% confidence interval [CI]:1.003-1.192, p=0.042). Moreover, increase in waist circumference was the only predictor of an increase in EATV at 30 months (β=0.320, p=0.018).

CONCLUSIONS

EATV is associated with higher coronary fatty plaque volume and is regulated by waist circumference but not EPA+DHA supplementation at 30-month follow-up in CAD patients on statin treatment. The direct correlation between waist circumference and EATV suggests that maintaining a healthy weight may limit EATV and coronary fatty plaque volume, potentially leading to a decrease in cardiovascular events.

Epicardial adipose tissue density predicts the presence of atrial fibrillation and its recurrence after catheter ablation: three-dimensional reconstructed image analysis

Epicardial adipose tissue (EAT) induces inflammation in the atria and is associated with atrial fibrillation (AF). Several studies have examined the relationship between EAT volume (EAT-V) and density (EAT-D) and the presence of AF after catheter ablation. However, conclusions have been inconsistent. This study included 43 consecutive patients who underwent catheter ablation for AF and 30 control patients. EAT-V and EAT-D around the entire heart, entire atrium, left atrium (LA), and right atrium (RA) were measured in detail using reconstructed three-dimensional (3D) EAT images from dual-source computed tomography (CT). None of the measurements of EAT-V differed significantly between patients with AF and controls or between patients with recurrent AF and those without. On the other hand, all measurements of EAT-D were higher in patients with AF than in controls (entire atrium, p < 0.001; RA, p < 0.001; LA, p = 0.002). All EAT-D measurements were associated with the presence of AF. Among patients with AF who underwent ablation, all EAT-D measurements were higher in patients with recurrent AF than in those without. The difference was significant for EATRA-D (p = 0.032). All atrial EAT-D values predicted recurrent AF (EATRA-D: hazard ratio [HR], 1.208; 95% confidence interval [95% CI], 1.053-1.387; p = 0.007; EATLA-D: HR, 1.108; 95% CI 1.001-1.225; p = 0.047; EATatrial-D: HR, 1.174; 95% CI 1.040-1.325; p = 0.010). The most sensitive cutoffs for predicting recurrent AF were highly accurate for EATRA-D (area under the curve [AUC], 0.76; p < 0.01) and EATatrial-D (AUC = 0.75, p < 0.05), while the cutoff for EATLA-D had low accuracy (AUC, 0.65; p = 0.209). For predicting the presence of AF and recurrent AF after catheter ablation, 3D analysis of atrial EAT-D, rather than EAT-V, is useful.

Sex differences in the association between epicardial adipose tissue volume and left atrial volume index

BACKGROUND

Sex disparities in the association between epicardial adipose tissue volume (EATV) and cardiovascular disease have been reported. The sex-dependent effects of EATV on left atrial (LA) size have not been elucidated.

METHODS

Consecutive 247 subjects (median 65 [interquartile range 57, 75] years; 67% of men) who underwent multi-detector computed tomography without significant coronary artery disease or moderate to severe valvular disease were divided into two groups: patients with sinus rhythm (SR) or atrial fibrillation (AF). Sex differences in the association between the EATV index (EATVI) (mL/m2) and LA volume index (LAVI) in 63 SR (28 men and 35 women) and 184 AF (137 men and 47 women) patients were evaluated using univariate and multivariate regression analyses.

RESULTS

In overall that includes both men and women, the relationship between EATVI and LAVI was not significantly correlated for patients with SR and AF. The relationship between EATVI and LAVI differed between men and women in both SR and AF groups. In SR patients, there was a positive relationship between EATVI and LAVI in men, but not in women. In contrast, in patients with AF, a negative relationship was found between EATVI and LAVI in women, whereas no association was found in men.

CONCLUSIONS

We evaluated sex differences in the association between EATVI and LAVI in patients with either SR or AF, and found a positive relationship in men with SR and a negative relationship in women with AF. This is the first report to evaluate sex differences in the relationship between EATVI and LAVI, suggesting that EAT may play a role, at least in part, in sex differences in the etiology of AF.

Epicardial Adipose Tissue in Patients with Coronary Artery Disease: A Meta-Analysis

Objective: The aim of this study is to assess the association between epicardial adipose tissue (EAT) and coronary artery disease (CAD) via meta−analysis. Methods: Specific searches of online databases from January 2000 to May 2022 were conducted. All observational studies evaluating the association between EAT and CAD in PubMed, Web of Science, and the Cochrane Library databases were screened. A meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta−Analyses guidelines (PRISMA). In total, 21 studies encompassing 4975 subjects met the inclusion criteria, including 2377 diagnosed and assigned as the CAD group, while the other 2598 were assigned as the non−CAD group. Subjects in the CAD group were further divided into the severe stenosis group (stenosis ≥ 50%, n = 846) and the mild/moderate stenosis group (stenosis < 50%, n = 577). Results: Both the volume and thickness of EAT in the CAD group were larger compared to the non−CAD group (p < 0.00001). In a subgroup analysis within the CAD group, the severe stenosis group had a larger volume and thickness with respect to EAT when compared to the mild/moderate group (p < 0.001). Conclusions: The enlargement of EAT presented in CAD patients with an association with CAD severity. Although limited by different CAD types and measuring methods for EAT, as well as a smaller sample size, our results suggest that EAT is a novel predictor and a potential therapeutic target for CAD.

Aortic arch calcification with pericardial fat mass detected on a single chest X-ray image is closely associated with the predictive variables of future cardiovascular disease

This study evaluated the associations between aortic arch calcification (AAC) with pericardial fat (PF) mass detected on a single chest X-ray image and predictive variables of future cardiovascular disease (CVD). The subjects were 353 patients treated with at least one of the hypertension, dyslipidemia or diabetes. All subjects were evaluated for AAC; divided into 3 groups with AAC grades of 0, 1, or 2; and examined for the presence of PF. Carotid intima-media thickness (IMT, n = 353), cardio-ankle vascular index (CAVI, n = 218), the Suita score (n = 353), and cardiovascular risk points defined in the Hisayama study (n = 353), an assessment of the risk of future cardiovascular disease, were measured. The relationship of AAC grades, with or without PF, and CVD risks was evaluated. The IMT (1.62 ± 0.74 mm, 2.33 ± 1.26, and 2.43 ± 0.89 in patients with AAC grade 0, 1 and 2, respectively, p < 0.001), CAVI (8.09 ± 1.32, 8.71 ± 1.32, and 9.37 ± 1.17, respectively, p < 0.001), the Suita score (46.6 ± 10.7, 51.8 ± 8.3, and 54.2 ± 8.2, respectively, p < 0.001), and cardiovascular risk points (8.5 ± 2.6, 10.6 ± 2.3, and 11.5 ± 2.3, respectively, p < 0.001) were significantly elevated with AAC progression. Multinomial logistic regression analysis adjusted for clinical characteristics showed that the relative risk ratios of the Suita score or cardiovascular risk points were elevated according to the progress of AAC grade with PF. Therefore, aortic arch calcification with pericardial mass detected on a single chest X-ray image is closely associated with the predictive variables of future CVD.

Automatic quantification of epicardial adipose tissue volume

PURPOSE

Epicardial fat is the adipose tissue between the serosal pericardial wall layer and the visceral layer. It is distributed mainly around the atrioventricular groove, atrial septum, ventricular septum and coronary arteries. Studies have shown that the density, thickness, volume and other characteristics of epicardial adipose tissue (EAT) are independently correlated with a variety of cardiovascular diseases. Given this association, the accurate determination of EAT volume is an essential aim of future research. Therefore, the purpose of this study was to establish a framework for fully automatic EAT segmentation and quantification in coronary computed tomography angiography (CCTA) scans.

METHODS

A set of 103 scans are randomly selected from our medical center. An automatic pipeline has been developed to segment and quantify the volume of EAT. First, a multi-slice deep neural network is used to simultaneously segment the pericardium in multiple adjacent slices. Then a deformable model is employed to reduce false positive and negative regions in the segmented binary pericardial images. Finally, the pericardium mask is used to define the region of interest (ROI) and the threshold method is utilized to extract the pixels ranging from -175 Hounsfield units (HU) to -15 HU for the segmentation of EAT.

RESULTS

The Dice indices of the pericardial segmentation using the proposed method with respect to the manual delineation results of two radiology experts were 97.1%  ±  0.7% and 96.9%  ±  0.6%, respectively. The inter-observer variability was also assessed, resulting in a Dice index of 97.0%  ±  0.7%. For the EAT segmentation results, the Dice indices between the proposed method and the two radiology experts were 93.4%  ±  1.5% and 93.3%  ±  1.3%, respectively, and the same measurement between the experts themselves was 93.6%  ±  1.9%. The Pearson's correlation coefficients between the EAT volumes computed from the results of the proposed method and the manual delineation by the two experts were 1.00 and 0.99 and the same coefficients between the experts was 0.99.

CONCLUSIONS

This work describes the development of a fully automatic EAT segmentation and quantification method from CCTA scans and the results compare favorably with the assessments of two independent experts. The proposed method is also packaged with a graphical user interface which can be found at https://github.com/MountainAndMorning/EATSeg.

Differences Between Patients with and without Atherosclerosis in Expression Levels of Inflammatory Mediators in the Adipose Tissue Around the Coronary Artery

Perivascular adipose tissue (PVAT) secretes large amounts of inflammatory mediators and plays a certain role in atherosclerosis formation from the exterior of the vessel. In the present study, we examined the expression level of inflammation-related mediators using adipose tissue samples harvested from patients with and without coronary artery disease (CAD). The subjects were 23 patients who underwent elective coronary bypass surgery (CAD group) and 17 patients who underwent elective mitral valve surgery (non-CAD group) between January 2017 and March 2018. The adipose tissue was harvested from three sites: the ascending aorta (AO), subcutaneous fat (SC), and pericoronary artery (CO) for the measurement of the expression levels of interleukin (IL) -1β, IL-6, IL-10, tumor necrosis factor (TNF) -α, interferon (INF) -γ, and arginase (Arg) -1. In both the non-CAD and CAD groups, the expression levels of all mediators, except Agr-1, which showed a tendency to have higher levels in the SC than in the AO and CO, tended to upregulate in the AO than in the SC and CO. The CAD group had higher values of almost all mediators, except Arg-1. Most importantly, the expression levels of IL-1β, IL-6, and IL-10 in the coronary artery were significantly higher in the CAD group. The expression levels of inflammatory mediators in the pericoronary adipose tissue were significantly higher in the CAD than in the non-CAD group. The adipose tissue appears to influence atherosclerosis formation from the exterior of the coronary artery.

Vascular-specific epicardial adipose tissue in predicting functional myocardial ischemia for patients with stable chest pain

The relationship between vascular-specific epicardial adipose tissue (vEAT) volume and myocardial ischemia measured by fractional flow reserve (FFR) was not well investigated. Patients with typical and atypical chest pain undergoing coronary computed tomographic angiography scan followed by invasive coronary angiography in combination with FFR examination within one month were retrospectively included. EAT volume and CT attenuation was calculated. The patient with FFR ≤ 0.8 in at least one vessel was referred to as functional ischemia. The mean age of all patients was 61.7 ± 8.9 years and 66.7% of patients were male. There was a significant difference for left anterior descending branch (LAD) vEAT volume between patients with and without functional myocardial ischemia (28.7 ± 10.6 cm³ vs. 23.9 ± 8.7 cm³, p = 0.005). After adjusted by cardiac risk factors and CAD-RADS categories in multivariable logistic regression analysis, LAD-vEAT volume ≥ 24.6 cm³ (OR 3.355, 95% CI 1.546-7.281, p = 0.002) remained an independent predictor of functional ischemia. After adding LAD-vEAT volume ≥ 24.6 cm³ to a prediction model composed with cardiac risk factors and CAD-RADS categories, receiver operating characteristic curve analysis showed significantly improved areas under curve (AUC) for the new model (AUC: 0.795, p = 0.0319) compared with the previous ones. Moreover, the new model revealed significance in net reclassification improvement (NRI: 0.186, p = 0.037). In conclusion, LAD-vEAT volume measurements have incremental predictive performance beyond cardiac risk factors and CAD-RADS categories in identifying significant flow-limit ischemia detected by FFR.

The role of ectopic adipose tissue: benefit or deleterious overflow?

Ectopic adipose tissues (EAT) are present adjacent to many organs and have predominantly been described in overweight and obesity. They have been suggested to be related to fatty acid overflow and to have harmful effects. The objective of this semi-comprehensive review is to explore whether EAT may play a supportive role rather than interfering with its function, when the adjacent organ is challenged metabolically and functionally. EAT are present adhered to different tissues or organs, including lymph nodes, heart, kidney, ovaries and joints. In this review, we only focused on epicardial, perinodal, and peritumoral fat since these locations have been studied in more detail. Evidence was found that EAT volume significantly increased, associated with chronic metabolic challenges of the corresponding tissue. In vitro evidence revealed transfer of fatty acids from peritumoral and perinodal fat to the adjacent tissue. Cytokine expression in these EAT is upregulated when the adjacent tissue is challenged. In these tissues, glycolysis is enhanced, whereas fatty acid oxidation is increased. Together with more direct evidence, this shows that glucose is oxidized to a lesser degree, but used to support anabolic metabolism of the adjacent tissue. In these situations, browning occurs, resulting from upregulation of anabolic metabolism, stimulated by uncoupling proteins 1 and 2 and possibly 3. In conclusion, the evidence found is fragmented but the available data support the view that accumulation and browning of adipocytes adjacent to the investigated organs or tissues may be a normal physiological response promoting healing and (patho)physiological growth.

Segmentation of cardiac fats based on Gabor filters and relationship of adipose volume with coronary artery disease using FP-Growth algorithm in CT scans

Heart mediastinal and epicardial fat tissues are related to several adverse metabolic effects and cardiovascular risk factors, especially coronary artery disease (CAD). The manual segmentation of those fats is that the high dependence on user intervention and time-consuming analyzes. As a result, the automated measurement of cardiac fats could be considered as one of the most important biomarkers for cardiovascular risks in imaging and medical visualization by physicians. In this paper, we validate an automatic approach for the cardiac fat segmentation in non-contrast CT images then investigate the correlation between cardiac fat volume and CAD using the association rule mining algorithm. The pre-processing step includes threshold and contrast enhancement, the feature extraction step includes Gabor filter bank based on GLCM, the cardiac fat segmentation step is predicated on pattern recognition classification algorithms, and eventually, the step of investigating the relationship between cardiac fat volume and CAD is using FP-Growth algorithm. Experimental validation using CT images of two databases points to a good performance in cardiac fat segmentation. Experiments showed that the accuracy of the designed algorithm using the ensemble classifier with the best performance over other classifiers for the cardiac fat segmentation was 99.2%, with a sensitivity of 96.3% and a specificity of 99.8%. The results of using the FP-Growth algorithm showed that the low volume of epicardial (Confidence = 0.6818, Lift = 1.0626) and mediastinal (Confidence = 0.6696, Lift = 1.0436) fat are associated with healthy individuals and the high volume of epicardial (Confidence = 0.8, Lift = 2.2326) and mediastinal (Confidence = 0.75, Lift = 2.093) fat are related to individuals of CAD. As a result, cardiac fats can be used as a reliable biomarker tool in predicting the extent of CAD stenosis.

Non-Systematic Review of Diet and Nutritional Risk Factors of Cardiovascular Disease in Obesity

Although cardiovascular disease and its risk factors have been widely studied and new methods of diagnosis and treatment have been developed and implemented, the morbidity and mortality levels are still rising-cardiovascular disease is responsible for more than four million deaths each year in Europe alone. Even though nutrition is classified as one of the main and changeable risk factors, the quality of the diet in the majority of people does not follow the recommendations essential for prevention of obesity and cardiovascular disease. It demonstrates the need for better nutritional education in cardiovascular disease prevention and treatment, and the need to emphasize dietary components most relevant in cardiovascular disease. In our non-systematic review, we summarize the most recent knowledge about nutritional risk and prevention in cardiovascular disease and obesity.

Relationship Between Ginsenoside Rg3 and Metabolic Syndrome

Metabolic syndrome is an important public health issue and is associated with a more affluent lifestyle. Many studies of metabolic syndrome have been reported, but its pathogenesis remains unclear and there is no effective treatment. The ability of natural compounds to ameliorate metabolic syndrome is currently under investigation. Unlike synthetic chemicals, such natural products have proven utility in various fields. Recently, ginsenoside extracted from ginseng and ginseng root are representative examples. For example, ginseng is used in dietary supplements and cosmetics. In addition, various studies have reported the effects of ginsenoside on metabolic syndromes such as obesity, diabetes, and hypertension. In this review, we describe the potential of ginsenoside Rg3, a component of ginseng, in the treatment of metabolic syndrome.

Association of Local Epicardial Adipose Tissue Depots and Left Ventricular Diastolic Performance in Patients With Preserved Left Ventricular Ejection Fraction

BACKGROUND

Although full-volume quantification of epicardial adipose tissue (EAT) is a predictor of LV diastolic dysfunction (LVDD), how localized EAT depots are linked to LVDD remains unclear. We evaluated the effect of local EAT depots on LV diastolic function parameters in patients with preserved LV ejection fraction (LVEF).

METHODS AND RESULTS

From 423 consecutive patients who underwent cardiac CT angiography, we recruited 252 with sinus rhythm and normal LVEF. The EAT volume index (EATV/body surface area) and the localized EAT thickness around the right coronary artery (EATRCA), left anterior descending artery (EATLAD), left circumflex artery (EATLCX), right ventricle (EATRV), left ventricle (EATLV), right atrium (EATRA), and left atrium (EATLA) were measured using cardiac CT. In the LVDD group (n=71), the EATV index (75±30 vs. 64±28 mL/m2, P=0.010), EATLCX(10.7±3.8 vs. 9.4±3.4 mm, P=0.008), and EATLV(2.6±1.6 vs. 2.1±1.4 mm, P=0.024) were greater than in the non-LVDD group (n=181). In contrast, EATLCXand EATLVwere markedly associated with decreased lateral e' and increased lateral E/e'. Multiple regression analysis indicated that EATLCXand EATLVwere strongly associated with LV diastolic function parameters.

CONCLUSIONS

Localized EAT depots are linked to altered mitral annular motion. Further study is warranted to clarify whether localized EAT depots are functionally linked to the clinical manifestations of LVDD.

Epicardial adipose tissue is a predictor of decreased kidney function and coronary artery calcification in youth- and early adult onset type 2 diabetes mellitus

PURPOSE

To examine the association of epicardial and pericardial fat volume (EFV, PFV) with cardiovascular risk factors and kidney function in Native Americans of southwestern heritage with youth and early adult onset type 2 diabetes mellitus (T2DM) versus healthy controls.

METHODS

Using computed tomography, we quantified EFV and PFV in 149 Native Americans (92 women, 57 men), 95 of which had T2DM (38 diagnosed prior to age 20 years). Duration of T2DM, mean carotid arterial mass (AM), coronary artery calcification (CAC), IL-6, and estimated glomerular filtration rate eGFR_cr(CKD-EPI) were measured.

RESULTS

EFV and PFV were associated with BMI (r = 0.37, p < 0.0001; r = 0.26, p = 0.001) and did not differ between onset age-groups and controls (p > 0.05). EFV was associated with AM only in controls (r = 0.51, p < 0.0001). After adjustment for BMI, T2DM duration, HbA1C, age, and sex, EFV was a predictor of CAC and IL-6 concentrations in early adult onset T2DM (β = 0.05 ± 0.02 cm³, p = 0.03; β = 0.05 ± 0.01 pg/ml/cm³, p = 0.002). EFV and PFV were independent predictors of reduced eGFR_cr(CKD-EPI) in the youth onset T2DM group (β = -0.3 ± 0.08 ml/min/cm³, p = 0.001; β = -0.25 ± 0.05 ml/min/cm³, p < 0.0001).

CONCLUSIONS

Epicardial fat volume may be a risk factor for heart disease in individuals with early adult onset T2DM and a predictor of decreased kidney function in individuals with youth onset T2DM.

Relationship between epicardial adipose tissue and coronary vascular function in patients with suspected coronary artery disease and normal myocardial perfusion imaging

Aims

We evaluated the relationship between epicardial adipose tissue (EAT) and coronary vascular function assessed by rubidium-82 (82Rb) positron emission tomography/computed tomography (PET/CT) in patients with suspected coronary artery disease (CAD).

Methods and results

The study population included 270 patients with suspected CAD and normal myocardial perfusion at stress–rest 82Rb PET/CT. Coronary artery calcium (CAC) score and EAT volume were measured. Absolute myocardial blood flow (MBF) was computed in mL/min/ from the dynamic rest and stress imaging. Myocardial perfusion reserve (MPR) was defined as the ratio of hyperaemic to baseline MBF and it was considered reduced when <2. MPR was normal in 177 (65%) patients and reduced in 93 (35%). Patients with impaired MPR were older (P < 0.001) and had higher CAC score values (P = 0.033), EAT thickness (P = 0.009), and EAT volume (P < 0.001). At univariable logistic regression analysis, age, heart rate reserve (HRR), CAC score, EAT thickness, and EAT volume resulted significant predictors of reduced MPR, but only age (P = 0.002), HRR (P = 0.021), and EAT volume (P = 0.043) were independently associated with reduced MPR, at multivariable analysis. In patients with CAC score 0 (n = 114), a significant relation between EAT volume and MPR (P = 0.014) was observed, while the relationship was not significant (P = 0.21) in patients with CAC score >0 (n = 156).

Conclusion

In patients with suspected CAD and normal myocardial perfusion, EAT volume predicts hyperaemic MBF and reduced MPR, confirming that visceral pericardium fat may influence coronary vascular function. Thus, EAT evaluation has a potential role in the early identification of coronary vascular dysfunction.

Quantification of epicardial fat with cardiac CT angiography and association with cardiovascular risk factors in symptomatic patients: from the ALTER-BIO (Alternative Cardiovascular Bio-Imaging markers) registry

PURPOSE

We aimed to assess the association between features of epicardial adipose tissue and demographic, morphometric and clinical data, in a large population of symptomatic patients with clinical indication to cardiac computed tomography (CT) angiography.

METHODS

Epicardial fat volume (EFV) and adipose CT density of 1379 patients undergoing cardiac CT angiography (918 men, 66.6%; age range, 18-93 years; median age, 64 years) were semi-automatically quantified. Clinical variables were compared between diabetic and nondiabetic patients to assess potential differences in EFV and adipose CT density. Multiple regression models were calculated to find the clinical variables with a significant association with EFV and adipose CT density.

RESULTS

The median EFV in diabetic patients (112.87 mL) was higher compared with nondiabetic patients (82.62 mL; P < 0.001). The explanatory model of the multivariable analysis showed the strongest associations between EFV and BMI (β=0.442) and age (β=0.365). Significant yet minor association was found with sex (β=0.203), arterial hypertension (β=0.072), active smoking (β=0.068), diabetes (β=0.068), hypercholesterolemia (β=0.046) and cardiac height (β=0.118). The mean density of epicardial adipose tissue was associated with BMI (β=0.384), age (β=0.105), smoking (β=0.088), and diabetes (β=0.085).

CONCLUSION

In a large population of symptomatic patients, EFV is higher in diabetic patients compared with nondiabetic patients. Clinical variables are associated with quantitative features of epicardial fat.

Cardiac Obesity and Cardiac Cachexia: Is There a Pathophysiological Link?

Obesity is a risk factor for cardiometabolic and vascular diseases like arterial hypertension, diabetes mellitus type 2, dyslipidaemia, and atherosclerosis. A special role in obesity-related syndromes is played by cardiac visceral obesity, which includes epicardial adipose tissue and intramyocardial fat, leading to cardiac steatosis; hypertensive heart disease; atherosclerosis of epicardial coronary artery disease; and ischemic cardiomyopathy, cardiac microcirculatory dysfunction, diabetic cardiomyopathy, and atrial fibrillation. Cardiac expression of these changes in any given patient is unique and multimodal, varying in clinical settings and level of expressed changes, with heart failure development depending on pathophysiological mechanisms with preserved, midrange, or reduced ejection fraction. Progressive heart failure with misbalanced metabolic and catabolic processes will change muscle, bone, and fat mass and function, with possible changes in the cardiac fat state from excessive accumulation to reduction and cardiac cachexia with a worse prognosis. The question we address is whether cardiac obesity or cardiac cachexia is to be more feared.

Roles of Perivascular Adipose Tissue in the Pathogenesis of Atherosclerosis

Traditionally, it is believed that white adipose tissues serve as energy storage, heat insulation, and mechanical cushion, whereas non-shivering thermogenesis occurs in brown adipose tissue. Recent evidence revealed that adipose tissue secretes many types of cytokines, called as adipocytokines, which modulate glucose metabolism, lipid profile, appetite, fibrinolysis, blood pressure, and inflammation. Most of the arteries are surrounded by perivascular adipose tissue (PVAT). PVAT has been thought to be simply a structurally supportive tissue for vasculature. However, recent studies showed that PVAT influences vasodilation and vasocontraction, suggesting that PVAT regulates vascular tone and diameter. Adipocytokines secreted from PVAT appear to have direct access to the adjacent arterial wall by diffusion or via vasa vasorum. In fact, PVAT around atherosclerotic lesions and mechanically-injured arteries displayed inflammatory cytokine profiles, suggesting that PVAT functions to promote vascular lesion formation. Many clinical studies revealed that increased accumulation of epicardial adipose tissue (EAT), which surrounds coronary arteries, is associated with coronary artery disease. In this review article, we will summarize recent findings about potential roles of PVAT in the pathogenesis of atherosclerosis, particularly focusing on a series of basic and clinical studies from our laboratory.

CT Attenuation of Pericoronary Adipose Tissue in Normal Versus Atherosclerotic Coronary Segments as Defined by Intravascular Ultrasound

BACKGROUND

The factors influencing genesis of atherosclerosis at specific regions within the coronary arterial system are currently uncertain. Local mechanical factors such as shear stress as well as metabolic factors, including inflammatory mediators released from epicardial fat, have been proposed. We analyzed computed tomographic (CT) attenuation of pericoronary adipose tissue in normal versus atherosclerotic coronary segments as defined by intravascular ultrasound (IVUS).

PATIENTS AND METHODS

We evaluated the data sets of 29 patients who were referred for invasive coronary angiography and in whom IVUS of 1 coronary vessel was performed for clinical reasons. Coronary CT angiography was performed within 24 hours from invasive coronary angiography. Computed tomographic angiography was performed using dual-source CT (Siemens Healthcare; Forchheim, Germany). A contrast-enhanced volume data set was acquired (120 kV, 400 mA/rot, collimation 2 × 64 × 0.6 mm, 60-80 mL intravenous contrast agent). Intravascular ultrasound was performed using a 40-MHz IVUS catheter (Atlantis; Boston Scientific Corporation, Natick, Mass) and motorized pullback at 0.5 mm/s. Sixty corresponding coronary artery segments within the coronary artery system were identified in both dual source computed tomography and IVUS using bifurcation points as fiducial markers. In dual source computed tomography data sets, 8 serial parallel cross sections (2-mm slice thickness) were rendered orthogonal to the center line of the coronary artery for each segment. For each cross section, pericoronary adipose tissue within a radius of 3 mm from the coronary artery and enclosed within the epicardium (excluding coronary veins and myocardium) was manually traced and mean CT attenuation values were obtained. Intravascular ultrasound was used to define coronary segments as follows: presence of predominantly fibrous atherosclerotic plaque (hyperechoic), presence of predominantly lipid-rich atherosclerotic plaque (hypoechoic), and absence of atherosclerotic plaque.

RESULTS

In IVUS, 20 coronary segments with fibrous plaque, 20 segments with lipid-rich plaque, and 20 coronary segments without plaque were identified. The mean CT attenuation of pericoronary adipose tissue for segments with any coronary atherosclerotic plaque was -34 ± 14 Hounsfield units (HU), as compared with -56 ± 16 HU for segments without plaque (P = 0.005). The density of pericoronary fat in segments with fibrous versus lipid-rich plaque as defined by IVUS was not significantly different (-35 ± 19 HU vs -36 ± 16 HU, P = 0.8).

CONCLUSIONS

Mean CT attenuation of pericoronary adipose tissue is significantly lower for normal versus atherosclerotic coronary segments. This supports a hypothesis of different types of pericoronary adipose tissue, the more metabolically active of which might exert local effects on the coronary vessels, thus contributing to atherogenesis.

Correlates of pericardial adipose tissue volume using multidetector CT scanning in cardiac patients in China

BACKGROUND

Pericardial adipose tissue (PAT) is an emerging cardiovascular risk factor, yet much less is understood about PAT volume in Chinese adults, especially in relation to physical activity. The study explores associations between demographic and clinical variables and PAT volume, using multidetector computed tomography (MDCT) scanning in China. We also examined the relationship between PAT volume and coronary artery disease (CAD).

METHODS

An observational, correlational study design was used. Chinese (n=163) attended a study visit and underwent MDCT scanning between September 2014 and December 2015.

RESULTS

Participants were 48.5% male and had a mean age of 60.6 (SD 9.4) years. PAT volume was higher (p=0.001) in males than in females. PAT volume was correlated with age (r=0.388, p=0.001), systolic blood pressure (r=0.205, p=0.009), body mass index (r=0.466, p=0.001), high-density cholesterol (r=-0.282, p=0.001), low-density cholesterol (r=0.177, p=0.024), and triglycerides (r=0.248, p=0.001). Both moderate intensity physical activity energy consumption (r=-0.363, p=0.001) and total physical activity (r=-0.290, p=0.001) had inverse relationships with PAT volume. Total sedentary energy consumption was positively related to PAT volume (r=0.266, p=0.001). Multiple regression revealed that age, male gender, BMI, LDL-C and total physical activity energy consumption were significant predictors of PAT volume (R²=0.465). The relationship between PAT volume and CAD was found to be significant in the adjusted models.

CONCLUSIONS

Age, male gender, BMI, LDL-C and total physical activity energy consumption were significant predictors of PAT volume, and PAT volume itself is a predictor of CAD.

Clinical importance of epicardial adipose tissue

Different visceral fat compartments have several systemic effects and may play a role in the development of both insulin resistance and cardiovascular diseases. In the last couple of years special attention has been paid to the epicardial adipose tissue (EAT), which can be quantified by non-invasive cardiac imaging techniques. The epicardial fat is a unique fat compartment between the myocardium and the visceral pericardium sharing a common embryologic origin with the visceral fat depot. Epicardial adipose tissue has several specific roles, and its local effects on cardiac function are incorporated in the complex pathomechanism of coronary artery disease. Importantly, EAT may produce several adipocytokines and chemokines that may influence - through paracrine and vasocrine effects - the development and progression of coronary atherosclerosis. Epicardial adipose tissue volume has a relatively strong genetic dependence, similarly to other visceral fat depots. In this article, the anatomical and physiological as well as pathophysiological characteristics of the epicardial fat compartment are reviewed.

Role of Adipose Tissue Endothelial ADAM17 in Age-Related Coronary Microvascular Dysfunction

OBJECTIVE

A disintegrin and metalloproteinase ADAM17 (tumor necrosis factor-α [TNF]-converting enzyme) regulates soluble TNF levels. We tested the hypothesis that aging-induced activation in adipose tissue (AT)-expressed ADAM17 contributes to the development of remote coronary microvascular dysfunction in obesity.

APPROACH AND RESULTS

Coronary arterioles (CAs, ≈90 µm) from right atrial appendages and mediastinal AT were examined in patients (aged: 69±11 years, BMI: 30.2±5.6 kg/m²) who underwent open heart surgery. CA and AT were also studied in 6-month and 24-month lean and obese mice fed a normal or high-fat diet. We found that obesity elicited impaired endothelium-dependent CA dilations only in older patients and in aged high-fat diet mice. Transplantation of AT from aged obese, but not from young or aged, mice increased serum cytokine levels, including TNF, and impaired CA dilation in the young recipient mice. In patients and mice, obesity was accompanied by age-related activation of ADAM17, which was attributed to vascular endothelium-expressed ADAM17. Excess, ADAM17-shed TNF from AT arteries in older obese patients was sufficient to impair CA dilation in a bioassay in which the AT artery was serially connected to a CA. Moreover, we found that the increased activity of endothelial ADAM17 is mediated by a diminished inhibitory interaction with caveolin-1, owing to age-related decline in caveolin-1 expression in obese patients and mice or to genetic deletion of caveolin-1.

CONCLUSIONS

The present study indicates that aging and obesity cooperatively reduce caveolin-1 expression and increase vascular endothelial ADAM17 activity and soluble TNF release in AT, which may contribute to the development of remote coronary microvascular dysfunction in older obese patients.

Ectopic Fat Depots and Coronary Artery Calcium in South Asians Compared With Other Racial/Ethnic Groups

Background

South Asians have a low body mass index and high prevalence of cardiovascular disease (CVD) relative to other racial/ethnic groups. Radiographically detected ectopic fat distribution is better associated with CVD than body mass index. We assessed whether differences in ectopic fat depots explained differences in the prevalence/severity of coronary artery calcium (CAC), a predictor of incident CVD events, among South Asians compared with other racial/ethnic groups.

Methods and Results

We examined the associations of radiographically detected visceral, intermuscular, intrahepatic, and pericardial fat with CAC among adults without baseline CVD. We compared 803 South Asians in the Mediators of Atherosclerosis in South Asians Living in America to 4 racial/ethnic groups in the Multi‐Ethnic Study of Atherosclerosis: 2622 whites, 1893 blacks, 1496 Latinos, and 803 Chinese Americans. We adjusted for body mass index and known CVD risk factors. South Asians had the highest intrahepatic fat and lowest pericardial fat volume (PFV). There was a positive graded association between ectopic fat and higher CAC scores in all the groups with the strongest associations observed with PFV. PFV was independently associated with CAC severity in South Asians (P=0.01) and blacks (P=0.05) and borderline in whites (P=0.06). PFV partially explained the higher CAC burden in South Asians compared with blacks, but not the other racial/ethnic groups.

Conclusions

Differences in PFV explain a small fraction of the higher CAC burden in South Asians. Our findings suggest that ectopic fat depots may not explain the elevated CAC risk in South Asians.

Automated pericardium delineation and epicardial fat volume quantification from noncontrast CT

PURPOSE

The authors aimed to develop and validate an automated algorithm for epicardial fat volume (EFV) quantification from noncontrast CT.

METHODS

The authors developed a hybrid algorithm based on initial segmentation with a multiple-patient CT atlas, followed by automated pericardium delineation using geodesic active contours. A coregistered segmented CT atlas was created from manually segmented CT data and stored offline. The heart and pericardium in test CT data are first initialized by image registration to the CT atlas. The pericardium is then detected by a knowledge-based algorithm, which extracts only the membrane representing the pericardium. From its initial atlas position, the pericardium is modeled by geodesic active contours, which iteratively deform and lock onto the detected pericardium. EFV is automatically computed using standard fat attenuation range.

RESULTS

The authors applied their algorithm on 50 patients undergoing routine coronary calcium assessment by CT. Measurement time was 60 s per-patient. EFV quantified by the algorithm (83.60 ± 32.89 cm(3)) and expert readers (81.85 ± 34.28 cm(3)) showed excellent correlation (r = 0.97, p < 0.0001), with no significant differences by comparison of individual data points (p = 0.15). Voxel overlap by Dice coefficient between the algorithm and expert readers was 0.92 (range 0.88-0.95). The mean surface distance and Hausdorff distance in millimeter between manually drawn contours and the automatically obtained contours were 0.6 ± 0.9 mm and 3.9 ± 1.7 mm, respectively. Mean difference between the algorithm and experts was 9.7% ± 7.4%, similar to interobserver variability between 2 readers (8.0% ± 5.3%, p = 0.3).

CONCLUSIONS

The authors' novel automated method based on atlas-initialized active contours accurately and rapidly quantifies EFV from noncontrast CT.

STAT4 contributes to adipose tissue inflammation and atherosclerosis

Adipose tissue (AT) inflammation is an emerging factor contributing to cardiovascular disease. STAT4 is a transcription factor expressed in adipocytes and in immune cells and contributes to AT inflammation and insulin resistance in obesity. The objective of this study was to determine the effect of STAT4 deficiency on visceral and peri-aortic AT inflammation in a model of atherosclerosis without obesity. Stat4(-/-)Apoe(-/-) mice and Apoe(-/-) controls were kept either on chow or Western diet for 12 weeks. Visceral and peri-aortic AT were collected and analyzed for immune composition by flow cytometry and for cytokine/chemokine expression by real-time PCR. Stat4(-/-)Apoe(-/-) and Apoe(-/-) mice had similar body weight, plasma glucose, and lipids. Western diet significantly increased macrophage, CD4+, CD8+, and NK cells in peri-aortic and visceral fat in Apoe(-/-) mice. In contrast, in Stat4(-/-)Apoe(-/-) mice, a Western diet failed to increase the percentage of immune cells infiltrating the AT. Also, IL12p40, TNFa, CCL5, CXCL10, and CX3CL1 were significantly reduced in the peri-aortic fat in Stat4(-/-)Apoe(-/-) mice. Importantly, Stat4(-/-)Apoe(-/-) mice on a Western diet had significantly reduced plaque burden vs Apoe(-/-) controls. In conclusion, STAT4 deletion reduces inflammation in peri-vascular and visceral AT and this may contribute via direct or indirect effects to reduced atheroma formation.

Relationship between epicardial fat and quantitative coronary artery plaque progression: insights from computer tomography coronary angiography

Epicardial fat volume (EFV) has been suggested to promote atherosclerotic plaque development in coronary arteries, and has been correlated with both coronary stenosis and acute coronary events. Although associated with progression of coronary calcification burden, a relationship with progression of coronary atheroma volume has not been previously tested. We studied patients who had clinically indicated serial 320-row multi-detector computer tomography coronary angiography with a median 25-month interval. EFV was measured at baseline and follow-up. In vessels with coronary stenosis, quantitative analysis was performed to measure atherosclerotic plaque burden, volume and aggregate plaque volume at baseline and follow-up. The study comprised 64 patients (58.4 ± 12.2 years, 27 males, 192 vessels, 193 coronary segments). 79 (41 %) coronary segments had stenosis at baseline. Stenotic segments were associated with greater baseline EFV than those without coronary stenosis (117.4 ± 45.1 vs. 102.3 ± 51.6 cm(3), P = 0.046). 46 (24 %) coronary segments displayed either new plaque formation or progression of adjusted plaque burden at follow-up. These were associated with higher baseline EFV than segments without stenosis or those segments that had stenoses that did not progress (128.7 vs. 101.0 vs. 106.7 cm(3) respectively, P = 0.006). On multivariate analysis, baseline EFV was the only independent predictor of coronary atherosclerotic plaque progression or new development (P = 0.014). High baseline EFV is associated with the presence of coronary artery stenosis and plaque volume progression. Accumulation of EFV may be implicated in the evolution and progression of coronary atheroma.

Thoracic fat volume is independently associated with coronary vasomotion

PURPOSE

Thoracic fat has been associated with an increased risk of coronary artery disease (CAD). As endothelium-dependent vasoreactivity is a surrogate of cardiovascular events and is impaired early in atherosclerosis, we aimed at assessing the possible relationship between thoracic fat volume (TFV) and endothelium-dependent coronary vasomotion.

METHODS

Fifty healthy volunteers without known CAD or major cardiovascular risk factors (CRFs) prospectively underwent a (82)Rb cardiac PET/CT to quantify myocardial blood flow (MBF) at rest, and MBF response to cold pressor testing (CPT-MBF) and adenosine (i.e., stress-MBF). TFV was measured by a 2D volumetric CT method and common laboratory blood tests (glucose and insulin levels, HOMA-IR, cholesterol, triglyceride, hsCRP) were performed. Relationships between CPT-MBF, TFV and other CRFs were assessed using non-parametric Spearman rank correlation testing and multivariate linear regression analysis.

RESULTS

All of the 50 participants (58 ± 10y) had normal stress-MBF (2.7 ± 0.6 mL/min/g; 95 % CI: 2.6-2.9) and myocardial flow reserve (2.8 ± 0.8; 95 % CI: 2.6-3.0) excluding underlying CAD. Univariate analysis revealed a significant inverse relation between absolute CPT-MBF and sex (ρ = -0.47, p = 0.0006), triglyceride (ρ = -0.32, p = 0.024) and insulin levels (ρ = -0.43, p = 0.0024), HOMA-IR (ρ = -0.39, p = 0.007), BMI (ρ = -0.51, p = 0.0002) and TFV (ρ = -0.52, p = 0.0001). MBF response to adenosine was also correlated with TFV (ρ = -0.32, p = 0.026). On multivariate analysis, TFV emerged as the only significant predictor of MBF response to CPT (p = 0.014).

CONCLUSIONS

TFV is significantly correlated with endothelium-dependent and -independent coronary vasomotion. High TF burden might negatively influence MBF response to CPT and to adenosine stress, even in persons without CAD, suggesting a link between thoracic fat and future cardiovascular events.

Implications of Pericardial, Visceral and Subcutaneous Adipose Tissue on Vascular Inflammation Measured Using 18FDG-PET/CT

Objective

Pericardial adipose tissue (PAT) is associated with adverse cardiometabolic risk factors and cardiovascular disease (CVD). However, the relative implications of PAT, abdominal visceral and subcutaneous adipose tissue on vascular inflammation have not been explored.

Method and Results

We compared the association of PAT, abdominal visceral fat area (VFA), and subcutaneous fat area (SFA) with vascular inflammation, represented as the target-to-background ratio (TBR), the blood-normalized standardized uptake value measured using ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography (¹⁸FDG-PET) in 93 men and women without diabetes or CVD. Age- and sex-adjusted correlation analysis showed that PAT, VFA, and SFA were positively associated with most cardiometabolic risk factors, including systolic blood pressure, LDL-cholesterol, triglycerides, glucose, insulin resistance and high sensitive C-reactive proteins (hsCRP), whereas they were negatively associated with HDL-cholesterol. In particular, the maximum TBR (maxTBR) values were positively correlated with PAT and VFA (r = 0.48 and r = 0.45, respectively; both P <0.001), whereas SFA showed a relatively weak positive relationship with maxTBR level (r = 0.31, P = 0.003).

Conclusion

This study demonstrated that both PAT and VFA are significantly and similarly associated with vascular inflammation and various cardiometabolic risk profiles.

Relationship of pericardial fat with lipoprotein distribution: The Multi-Ethnic study of atherosclerosis

OBJECTIVE

Pericardial fat and lipoprotein abnormalities contribute to increased risk of cardiovascular disease (CVD). We investigated the relationship between pericardial fat volume and lipoprotein distribution, and whether the association of pericardial fat volume with subclinical atherosclerosis and incident CVD events differs according to lipoprotein distribution.

METHODS

We analyzed data from 5407 participants from the Multi-Ethnic Study of Atherosclerosis who had measurements of pericardial fat volume, lipoprotein distribution, carotid intima-media thickness (IMT), and coronary artery calcium (CAC). All participants were free of clinically apparent CVD at baseline. Incident CVD was defined as any adjudicated CVD event.

RESULTS

After adjusting for demographic factors, traditional risk factors, and biomarkers of inflammation and hemostasis, a larger pericardial fat volume was associated with higher large VLDL particle (VLDL-P) concentration and small HDL particle (HDL-P) concentration, and smaller HDL-P size (regression coefficients = 0.585 nmol/L, 0.366 μmol/L, and -0.025 nm per SD increase in pericardial fat volume respectively, all P < 0.05). The association of pericardial fat volume with large VLDL-P concentration and HDL-P size, but not small HDL-P concentration, remained significant after further adjusting for each other as well as LDL cholesterol, HDL cholesterol, and triglycerides. The relationship of pericardial fat volume with incident CVD events, carotid IMT, and prevalence and severity of CAC did not differ by quartiles of large VLDL-P concentration, small HDL-P concentration, or HDL-P size (P for interaction>0.05).

CONCLUSION

Pericardial fat is associated with atherogenic lipoprotein abnormalities. However, its relationship with subclinical atherosclerosis and incident CVD events does not differ according to lipoprotein distribution.

Flow mediated dilation with photoplethysmography as a substitute for ultrasonic imaging

Flow mediated dilation (FMD) is a non-invasive method for endothelial function assessment providing an index extracted from ultrasonic B-mode images. Although utilized in the research community, the difficulty of its application and high cost of ultrasonic devices prevent it from being widely used in clinical settings. In this study we show that substituting the ultrasonic device with more easily handled and low cost photoplethysmography and electrocardiography is possible. We introduce new indices based on the photoplethysmogram (PPG) and electrocardiogram (ECG) and show that they are correlated with the ultrasound-based FMD Index. To this end, a conventional ultrasound FMD test was carried out whereas PPG and ECG were simultaneously recorded from 20 healthy volunteers (13 M, 7 F) in the age range of 23-32 years. Our results show a significant correlation between our proposed index and ultrasound FMD when using the ECG in conjunction with the PPG (R = 0.77, p < 0.000 01). Using the PPG alone produces a lower correlation (R = 0.72, p < 0.0001). Compared to conventional FMD, the proposed method is low cost and does not require any special operator skills. Hence it may be easily utilized as a screening tool in locations deprived of high-end ultrasound imaging devices.

Relationship of pericardial fat with biomarkers of inflammation and hemostasis, and cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Pericardial fat may increase the risk of cardiovascular disease (CVD) by increasing circulating levels of inflammation and hemostasis biomarkers. We investigated the associations of pericardial fat with inflammation and hemostasis biomarkers, as well as incident CVD events, and whether there are any ethnic differences in these associations.

METHODS

We analyzed results from 6415 participants from the Multi-Ethnic Study of Atherosclerosis who had measurements of pericardial fat volume and circulating levels of C-reactive protein (CRP), fibrinogen, interleukin (IL)-6, factor VIII, D-dimer and plasmin-antiplasmin complex (PAP), and had a mean follow-up period of 9.5 years. Incident CVD event was defined as any adjudicated CVD event.

RESULTS

After adjusting for confounding factors, pericardial fat volume was positively associated with natural log (ln) of IL-6 levels, but inversely associated with ln D-dimer and ln PAP levels (β = 0.067, -0.032, and -0.105 respectively, all P < 0.05). Although a larger pericardial fat volume was associated with a higher risk of incident CVD, the association was attenuated to borderline significance after adjusting for traditional cardiovascular risk factors (P = 0.050). There was a borderline significant ethnicity interaction (P = 0.080), whereby the association between pericardial fat volume and incident CVD was significant in Hispanic Americans, even after further adjusting for biomarkers of inflammation and hemostasis (hazard ratio = 1.31 per SD increase, 95% confidence interval 1.09-1.57, P = 0.004).

CONCLUSION

Pericardial fat was associated with several inflammation and hemostasis biomarkers. The association of pericardial fat with incident CVD events was independent of these biomarkers only among Hispanic Americans.

Association of epicardial and abdominal visceral adipose tissue with coronary atherosclerosis in patients with a coronary artery calcium score of zero

BACKGROUND

We sought to examine whether epicardial and abdominal visceral adipose tissue distribution is associated with coronary atherosclerosis in patients with a coronary artery calcium (CAC) score of zero, assessed by coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

We studied 352 patients with suspected coronary artery disease (mean age 61±11 years, 57% male) with a CAC score of zero who had undergone CCTA. Non-calcified coronary plaques (NCPs) were detected in 102 patients (29%); those causing ≥50% stenosis were found in 15 patients (4%). Patients were divided into 4 groups on the basis of CT-based epicardial adipose tissue (EAT) volume and abdominal visceral adipose tissue (VAT) area using the sex-specific median value. Multivariate analysis showed that the adjusted odds ratios for the presence of NCPs in the high VAT area/low EAT volume group, and the high VAT area/high EAT volume group were 2.80 (95% confidence interval [95% CI]: 1.25-6.35, P=0.01) and 2.68 (95% CI: 1.36-5.45, P=0.004), respectively. Interestingly, the low VAT area/high EAT volume group showed an equivalent adjusted odds ratio of 3.02 (95% CI: 1.33-6.90, P=0.008).

CONCLUSIONS

EAT volume is eligible as a marker to be evaluated in addition to VAT area in patients with a CAC score of zero.

Epicardial adipose tissue: far more than a fat depot

Epicardial adipose tissue (EAT) refers to the fat depot that exists on the surface of the myocardium and is contained entirely beneath the pericardium, thus surrounding and in direct contact with the major coronary arteries and their branches. EAT is a biologically active organ that may play a role in the association between obesity and coronary artery disease (CAD). Given recent advances in non-invasive imaging modalities such a multidetector computed tomography (MDCT), EAT can be accurately measured and quantified. In this review, we focus on the evidence suggesting a role for EAT as a quantifiable risk marker in CAD, as well as describe the role EAT may play in the development and vulnerability of coronary artery plaque.

Adipokines, vascular wall, and cardiovascular disease: a focused overview of the role of adipokines in the pathophysiology of cardiovascular disease

Epidemiological evidence has shown that abdominal obesity is closely associated with the development of cardiovascular (CV) disease, suggesting that it might be considered as an independent CV risk factor. However, the pathophysiological mechanisms responsible for the association between these 2 clinical entities remain largely unknown. Adipocytes are considered able to produce and secrete chemical mediators known as "adipokines" that may exert several biological actions, including those on heart and vessels. Of interest, a different adipokine profile can be observed in the plasma of patients with obesity or metabolic syndrome compared with healthy controls. We consider the main adipokines, focusing on their effects on the vascular wall and analyzing their role in CV pathophysiology.

The relationship between coronary artery disease and pericoronary epicardial adipose tissue thickness

OBJECTIVES

A retrospective study to investigate the relationship between epicardial adipose tissue thickness (EATT) and presence of coronary artery plaque, coronary artery disease (CAD) and CAD risk factors.

METHODS

Multidetector computed tomography (MDCT) coronary angiography images were reviewed. Left anterior decending artery, right coronary artery and left circumflex artery pericoronary EATT were measured. Demographic, clinical and CAD risk factor data were obtained from medical records.

RESULTS

Patients with CAD (n = 49) had significantly larger mean EATT than those without CAD (n = 101). Pericoronary EATT was significantly correlated with body mass index, total cholesterol level, coronary artery calcium score, hypertension and diabetes mellitus history.

CONCLUSIONS

There is an association between pericoronary EATT and CAD, as well as CAD risk factors. Pericoronary EATT measurement may become a widely used, easy-to-perform method for determining CAD risk.

Associations of physical activity and sedentary behavior with regional fat deposition

INTRODUCTION

Increased sedentary behavior predicts greater cardiovascular morbidity and mortality and does so independently of physical activity (PA). This association is only partially explained by body mass index (BMI) and overall body fat, suggesting mechanisms besides general increased adiposity. The purpose of this study was to explore associations of self-reported leisure PA and sitting time with regional fat depositions and abdominal muscle among community-dwelling older adults.

METHODS

Participants were 539 diverse adults (mean age = 65 yr) who completed a study visit in 2001-2002. Areas of pericardial, intrathoracic, subcutaneous, visceral, and intermuscular fat, as well as abdominal muscle, were measured using computed tomography. Leisure PA and sitting hours were entered simultaneously into multivariate regression models to determine associations with muscle and fat areas.

RESULTS

After adjusting for demographics, smoking, diabetes, hypertension, triglycerides, and cholesterol, greater PA was associated with less intrathoracic, visceral, subcutaneous, and intermuscular fat (for all P < 0.05), while greater sedentary time was associated with greater pericardial and intrathoracic fat (for both P < 0.05). After further adjusting for BMI, each hour of weekly PA was associated with 1.85 cm less visceral fat (P < 0.01) but was not associated with other fat depositions. Conversely, each hour of daily sitting was associated with 2.39 cm more pericardial fat (P < 0.05) but was not associated with any other fat depositions. There were no associations with abdominal muscle area. Adjusting for common inflammatory markers had little effect. Associations between fat and PA were stronger for men.

CONCLUSIONS

Sitting and PA have distinct associations with regional fat deposition in older adults. The association between sitting and pericardial fat could partially explain the link between sitting and coronary heart disease.

Impact of abdominal and epicardial fat on the association between plasma adipocytokine levels and coronary atherosclerosis in non-obese patients

OBJECTIVE

Ectopic fat accumulation is associated with coronary artery disease. Visceral adipose tissue has paracrine and systemic effects and is a source of adipocytokines. It has been implicated in the pathogenesis of coronary atherosclerosis; however, nothing is known about whether increases in epicardial fat have the same effect on coronary atherosclerosis as increases in abdominal visceral fat.

METHODS

We examined 216 consecutive patients suspected to have coronary artery disease. Individuals with acute coronary syndrome and inadequate computed tomography (CT) imaging were excluded. We enrolled 164 patients (65 ± 10 years old; 70% men; body mass index [BMI], 23.8 ± 3.6 kg/m(2)). The plasma concentrations of adiponectin, interleukin-6 (IL-6), plasminogen activator inhibitor-1, and vascular endothelial growth factor were measured. The characteristics of coronary plaque, abdominal visceral fat area, and epicardial fat volume (EFV) were determined by 64-slice CT imaging.

RESULTS

EFV was greater in subjects with noncalcified plaque than in those with no plaque or with calcified plaque (126 ± 39 mL vs. 98 ± 34 mL and 97 ± 45 mL, respectively; P = 0.010). EFV was significantly correlated with BMI, triglycerides, and the triglyceride/high-density lipoprotein cholesterol ratio (r = 0.51, 0.19, and 0.20, respectively) but not with plasma levels of adipocytokines. The plasma adiponectin and IL-6 concentration was significantly correlated with abdominal visceral fat area in coronary plaque patients (r = -0.49 and 0.20).

CONCLUSIONS

In non-obese Japanese patients, epicardial fat may have unique mechanisms affecting the development of coronary atherosclerosis, which is different from abdominal visceral fat.