Different "weight" of cardiac and general adiposity in predicting left ventricle morphology

Epicardial adipose tissue and cardiac lipotoxicity: A review

Epicardial adipose tissue (EAT) has morphological and physiological contiguity with the myocardium and coronary arteries, making it a visceral fat deposit with some unique properties. Under normal circumstances, EAT exhibits biochemical, mechanical, and thermogenic cardioprotective characteristics. Under clinical processes, epicardial fat can directly impact the heart and coronary arteries by secreting proinflammatory cytokines via vasocrine or paracrine mechanisms. It is still not apparent what factors affect this equilibrium. Returning epicardial fat to its physiological purpose may be possible by enhanced local vascularization, weight loss, and focused pharmacological therapies. This review centers on EAT's developing physiological and pathophysiological dimensions and its various and pioneering clinical utilities.

Epicardial fat links obesity to cardiovascular diseases

Patients with obesity have been historically associated with higher risk to develop cardiovascular diseases (CVD). However, regional, visceral, organ specific adiposity seems to play a stronger role in the development of those cardiovascular diseases than obesity by itself. Epicardial adipose tissue is the visceral fat depot of the heart with peculiar anatomy, regional differences, genetic profile and functions. Due to its unobstructed contiguity with heart and intense pro inflammatory and pro arrhythmogenic activities, epicardial fat is directly involved in major obesity-related CVD complications, such as coronary artery disease (CAD), atrial fibrillation (AF) and heart failure (HF). Current and developing imaging techniques can measure epicardial fat thickness, volume, density and inflammatory status for the prediction and stratification of the cardiovascular risk in both symptomatic and asymptomatic obese individuals. Pharmacological modulation of the epicardial fat with glucagon like peptide-1 receptor (GLP1R) analogs, sodium glucose transporter-2 inhibitors, and potentially dual (glucose-dependent insulinotropic polypeptide -GLP1R) agonists, can reduce epicardial fat mass, resume its original cardio-protective functions and therefore reduce the cardiovascular risk. Epicardial fat assessment is poised to change the traditional paradigm that links obesity to the heart.

Cardiac Computed Tomography Evaluation of Association of Left Ventricle Disfunction and Epicardial Adipose Tissue Density in Patients with Low to Intermediate Cardiovascular Risk

Background and objectives: Epicardial adipose tissue density (EAD) has been associated with coronary arteries calcium score, a higher load of coronary artery disease (CAD) and plaque vulnerability. This effect can be related to endocrine and paracrine effect of molecules produced by epicardial adipose tissue (EAT), that may influence myocardial contractility. Using coronary computed tomography angiography (CCT) the evaluation of EAD is possible in basal scans. The aim of the study is to investigate possible associations between EAD and cardiac function. Material and Methods: 93 consecutive patients undergoing CCT without and with contrast medium for known or suspected coronary CAD were evaluated. EAD was measured on basal scans, at the level of the coronary ostia, the lateral free wall of the left ventricle, at the level of the cardiac apex, and at the origin of the posterior interventricular artery. Cardiac function was evaluated in post-contrast CT scans in order to calculate ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV). Results: A statistically significant positive correlation between EAD and ejection fraction (r = 0.29, p-value < 0.01) was found. Additionally, a statistically significant negative correlation between EAD and ESV (r = -0.25, p-value < 0.01) was present. Conclusion: EAD could be considered a new risk factor associated with reduced cardiac function. The evaluation of this parameter with cardiac CT in patients with low to intermediate cardiovascular risk is possible.

Pathogenic gene expression of epicardial adipose tissue in patients with coronary artery disease

Background & objectives:

Coronary artery disease (CAD), a leading cause of mortality and morbidity worldwide has multifactorial origin. Epicardial adipose tissue (EAT) has complex mechanical and thermogenic functions and paracrine actions via various cytokines released by it, which can have both pro- and anti-inflammatory actions on myocardium and adjacent coronaries. The alteration of EAT gene expression in CAD is speculated, but poorly understood. This study was undertaken to find out the difference in gene expression of epicardial fat in CAD and non-CAD patients.

Methods:

Twenty seven patients undergoing coronary artery bypass graft (CABG) and 16 controls (non-CAD patients undergoing valvular heart surgeries) were included in the study and their EAT samples were obtained. Gene expressions of uncoupling protein-1, monocyte chemoattractant protein-1 (MCP-1), adiponectin, adenosine A1 receptor (ADORA-1), vascular cell adhesion molecule-1 (VCAM-1) and tumour necrosis factor-alpha (TNF-α) were studied by real-time reverse transcription-polymerase chain reaction. Glucose, insulin, lipid profile, high-sensitivity C-reactive protein, homocysteine, vitamin D, TNF-α and leptin levels were estimated in fasting blood samples and analyzed.

Results:

Leptin levels were significantly higher in CABG group as compared to controls (P<0.05), whereas other metabolic parameters were not significantly different between the two groups. MCP-1, VCAM-1 and TNF-α were upregulated in the CABG group as compared to controls. Further, multivariate analysis showed significantly reduced adjusted odds ratio for MCP-1 [0.27; 95% confidence interval: 0.08-0.91] in the CABG group as compared to controls (P<0.05).

Interpretation & conclusions:

Our findings showed an alteration in EAT gene expression in CAD patients with significant upregulation of MCP-1. Further studies with a large sample need to be done to confirm these findings.

Left ventricular myocardial deformation: a study on diastolic function in the Chinese male population and its relationship with fat distribution

Background

Obesity has become an epidemic in China with its increased prevalence, especially in the male population. Disparities in fat distribution rather than increasing body mass index (BMI) confer the risk of different diseases, including cardiac abnormalities. Therefore, early detection of cardiac abnormalities is important for treatment to reverse the progression to heart failure. Nowadays, strain analysis based on cardiac magnetic resonance (CMR) imaging has been established to assess myocardial function in diverse cardiac diseases. We aimed to assess the relationship between fat distribution and subclinical diastolic dysfunction in obese Chinese men assessed by deformation registration algorithm (DRA)-based myocardial strain rate (SR) analysis.

Methods

A total of 115 male participants with different BMI underwent CMR scanning using a 1.5T MAGNETOM Aera (Siemens Healthcare, Erlangen, Germany) and computed tomography (CT) scan. All the participants were enrolled from September 2017 to April 2018. They were classified into 3 groups according to their BMIs with 23 and 27.5 kg/m² being the cutoff values. A Trufi-Strain prototype software (version 2.0, Siemens Healthcare, Erlangen, Germany) was used to quantify SR in both early and late diastole from CMR cine images. Ratios of early and late SRs were calculated. Areas of epicardial and pericardial adipose tissue (EAT and PAT) were measured on a single 4-chamber-view slice of cine images. Volumes of visceral and subcutaneous adipose tissue (VAT and SAT) were acquired semi-automatically from CT images using the dedicated software Cardiac Risk2.0 (Siemens Healthcare). Waist and hip circumferences were manually measured (WC and HC). Analysis of variance or nonparametric tests, along with correlation and stepwise multivariate regression analysis models, was applied for statistical analysis.

Results

Peak late diastolic SRs were higher in obese men compared with their lean counterparts [-36.25±10.46 vs. -29.46±8.17, 66.97±18.58 vs. 45.62 (42.44, 55.96), and 56.81±15.07 vs. 41.40±6.41 for radial, circumferential, and longitudinal SRs, respectively; P<0.05]. All SR ratios in the obese subgroups were lower than those of lean men (3.12±1.14 vs. 4.63±1.24, 2.12±0.58 vs. 2.96±0.62 and 1.63±0.50 vs. 2.20±0.63 for radial, circumferential, and longitudinal directions, respectively; P<0.05). EAT was a significant predictor of diastolic function assessed by radial and circumferential SR ratios (β=-0.439 and -0.337 respectively; all P<0.001), while VAT was a significant predictor of circumferential and longitudinal SR ratios (β=-0.216 and -0.355, respectively, P<0.05).

Conclusions

Decreased LV diastolic function assessed by DRA-based SR analysis in obesity is associated with fat distribution. Furthermore, EAT and VAT might be better predictors of a decrease of diastolic function in obese Chinese men than BMI.

Effect of bariatric surgery on heart failure

INTRODUCTION

Obesity increases the risk of heart failure (HF), which continues to be a significant proportion of all cardiovascular diseases and affects increasingly younger populations. The cross-talk between adipose and the heart involves insulin resistance, adipokine signaling and inflammation, with the capacity of adipose tissue to mediate hemodynamic signals, promoting progressive cardiomyopathy. Areas covered: From a therapeutic perspective, there is not yet a single obesity-related pathway that when addressed, can ameliorate cardiomyopathy in obese patients and this is a matter of ongoing research. There is poor evidence of the beneficial long-term effect of small nonsurgical intentional weight loss on HF outcomes, in contrast to the field of HF accompanying severe obesity where observational studies have shown that bariatric surgery is associated with improved cardiac structure/function in severely obese patients with HF and preserved ejection fraction (HFpEF) as well as with improved cardiac structure/function in those with HF and reduced ejection fraction (HFrEF). Few studies report positive outcomes in subjects with obesity and HF, both severe, who underwent bariatric surgery as a rescue treatment, including bridge to heart transplantation. Expert commentary: The fast growing prevalence of obesity will continue to require the development of appropriate interventions directed at controlling or slowing pathways of cardiac damage in these patients, but at present, bariatric surgery should be considered an option to try to decrease morbidity associated with HF in severely obese adults.

Role of Epicardial Adipose Tissue in Health and Disease: A Matter of Fat?

Epicardial adipose tissue (EAT) is a small but very biologically active ectopic fat depot that surrounds the heart. Given its rapid metabolism, thermogenic capacity, unique transcriptome, secretory profile, and simply measurability, epicardial fat has drawn increasing attention among researchers attempting to elucidate its putative role in health and cardiovascular diseases. The cellular crosstalk between epicardial adipocytes and cells of the vascular wall or myocytes is high and suggests a local role for this tissue. The balance between protective and proinflammatory/profibrotic cytokines, chemokines, and adipokines released by EAT seem to be a key element in atherogenesis and could represent a future therapeutic target. EAT amount has been found to predict clinical coronary outcomes. EAT can also modulate cardiac structure and function. Its amount has been associated with atrial fibrillation, coronary artery disease, and sleep apnea syndrome. Conversely, a beiging fat profile of EAT has been identified. In this review, we describe the current state of knowledge regarding the anatomy, physiology and pathophysiological role of EAT, and the factors more globally leading to ectopic fat development. We will also highlight the most recent findings on the origin of this ectopic tissue, and its association with cardiac diseases. © 2017 American Physiological Society. Compr Physiol 7:1051-1082, 2017.

Epicardial adipose tissue and signs of metabolic syndrome in children

PURPOSE

The aim of this study was to investigate the possible correlation between epicardial adipose tissue (EAT) thickness and predictive parameters for metabolic syndrome (MS) in overweight/obese prepubertal children.

METHODS

73 prepubertal children, average age of 8.22 years, with no endocrine or syndromic causes of obesity or under drug therapy for chronic disease were enrolled. Weight, height, body circumferences and skinfolds' thickness were measured. BMI, BMI z score (z-BMI) and waist-to-height ratio (WtHR) were calculated. Standard MS-related laboratory parameters were assessed. Finally, all children underwent echocardiographic measurement of EAT.

RESULTS

A positive correlation between EAT and z-BMI was found only among overweight/obese children (r = 0.43, p = 0.001). In particular, data showed that 89 % of our sample had a waist (W) >90th percentile. Statistical differences in diastolic blood pressure (DBP; p < 0.01) and EAT (p = 0.02) were observed on comparing W <90th percentile vs W >90th percentile patients. Besides, in patients with W >90th percentile and family history of risk factors for MS, the value of EAT correlated positively with z-BMI, W, WtHR, triglycerides (Tg), insulin and homeostatic model assessment of insulin resistance and negatively with HDL.

CONCLUSIONS

The EAT and the markers of MS probably share the same pathogenetic factors. Further studies might elucidate whether EAT deserves to be included among the diagnostic factors of MS.

Frequency of Massive Cardiac Adiposity (Floating Heart) at Necropsy and Comparison of Clinical and Morphologic Variables With Cases With Nonmassive Cardiac Adiposity at a Single Texas Hospital, 2013 to 2014

Body weight continues to increase worldwide primarily because of the increase in body fat. This study analyzes the frequency of massive adiposity at autopsy determined by the ability of the heart to float in a container of 10% formaldehyde (because adipose tissue is lighter than myocardium) and compares certain findings in the patients with floating to those with nonfloating hearts. The hearts studied at necropsy during a 2-year period (2013 to 2014) at Baylor University Medical Center were carefully "cleaned" and weighed by the same person and tested as to their ability to float in a container of formaldehyde, an indication of severe cardiac adiposity. Of the 146 hearts studied, 76 (52%) floated in a container of formaldehyde and 70 (48%) did not. Comparison of the 76 patients with floating hearts with the 70 with nonfloating hearts showed significant differences in ages (62 ± 13 vs 58 ± 14 years). No significant differences between the 2 groups were found in gender, body mass index, frequency of systemic hypertension or diabetes mellitus, either acute or healed myocardial infarction, or whether death was due to a coronary or a noncoronary condition. A weak correlation was found between body mass index and heart weight in both men and women and in both floating and nonfloating hearts. The massive quantity of cardiac adipose tissue (floating heart) appears to have increased enormously in recent decades in the United States.

Excessive interatrial adiposity is associated with left atrial remodeling, augmented contractile performance in asymptomatic population

PURPOSE

Pericardial adipose tissue had been shown to exert local effects on adjacent cardiac structures. Data regarding the mechanistic link between such measures and left atrial (LA) structural/functional remodeling, a clinical hallmark of early stage heart failure (HF) and atrial fibrillation (AF) incidence, in asymptomatic population remain largely unexplored.

METHODS

This retrospective analysis includes 356 subjects free from significant valvular disorders, atrial fibrillation, or clinical HF. Regional adipose tissue including pericardial and periaortic fat volumes, interatrial septal (IAS), and left atrioventricular groove (AVG) fat thickness were all measured by multidetector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). We measured LA volumes, booster performance, reservoir capacity as well as conduit function, and analyzed their association with adiposity measures.

RESULTS

All four adiposity measures were positively associated with greater LA volumes (all P < 0.05), while IAS and AVG fat were also related to larger LA kinetic energy and worse reservoir capacity (both P < 0.01). In multivariate models, IAS fat thickness remained independently associated with larger LA volumes, increased LA kinetic energy and ejection force (β-coef: 0.17 & 0.15, both P < 0.05), and impaired LA reservoir and conduit function (β-coef: -0.20 & -0.12, both P < 0.05) after adjusting for clinical variables.

CONCLUSION

Accumulated visceral adiposity, especially interatrial fat depots, was associated with certain LA structural/functional remodeling characterized by impaired LA reservoir and conduit function though augmented kinetic energy and ejection performance. Our data suggested that interatrial fat burden may be associated with certain detrimental LA functions with compensatory LA adaptation in an asymptomatic population.

The association among MDCT-derived three-dimensional visceral adiposities on cardiac diastology and dyssynchrony in asymptomatic population

Background

Visceral adipose tissue, a biologically active fat depot, has been proposed as a reliable marker for visceral adiposity and metabolic abnormalities. Effects of such adiposity on LV diastolic function and dyssynchrony remained largely unknown.

Methods

We assessed pericardial fat (PCF) and thoracic peri-aortic fat (TPAF) by three-dimensional (3D) volume-vender multi-detector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). Echo-derived diastolic parameters and tissue Doppler imaging (TDI) defined mitral annular systolic (S’), early diastolic (E’) velocities as well as LV filling (E/E’) were all obtained. Intra-ventricular systolic (Sys-D) and diastolic (Dias-D) dyssynchrony were assessed by TDI method.

Results

A total of 318 asymptomatic subjects (mean age: 53.5 years, 36.8 % female) were eligible in this study. Greater PCF and TPAF were both associated with unfavorable diastolic indices and higher diastolic dyssynchrony (all p < 0.05). These associations remained relatively unchanged in multi-variate models. PCF and TPAF set at 81.68 & 8.11 ml yielded the largest sensitivity and specificity (78.6 and 60 % for PCF, 75 and 66.6 % for TPAF, respectively) in predicting abnormally high LV diastolic dyssynchrony, which was defined as Dias-D≧55 ms.

Conclusion

Increasing visceral adiposity may be associated with adverse effects on myocardium, primarily featured by worse diastolic function and greater degree of dyssynchrony.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-015-0136-8) contains supplementary material, which is available to authorized users.

Association of systemic inflammation with epicardial fat and coronary artery calcification

BACKGROUND

Increased epicardial fat volume (EFV) has been shown to be associated with coronary atherosclerosis. While it is postulated to be an independent risk factor, a possible mechanism is local or systemic inflammation. We analyzed the relationship between coronary atherosclerosis, quantified by coronary calcium in CT, epicardial fat volume and systemic inflammation.

METHODS

Using non-enhanced dual-source CT, we quantified epicardial fat volume (EFV) and coronary artery calcium (CAC) in 391 patients who underwent coronary computed tomography for suspected coronary artery disease. In addition to traditional risk factors, serum markers of systemic inflammation were measured (IL-1α, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10,IL-12, IL-13, IL-15, IL-17, IFN-γ, TNF-α, hs-CRP, GM-CS, G-CSF, MCP-1, MIP-1, Eotaxin and IP-10). In 94 patients follow-up data were obtained after 1.9 ± 0.5 years.

RESULTS

The 391 patients had a mean age of 60 ± 10 years, and 69 % were males. Mean EFV was 116 ± 50 mL. Median CAC was 12 (IQR 0; 152). CAC and EFV showed a significant correlation (ρ = 0.37; P < 0.001). EFV and CAC were significantly correlated with the traditional risk factors like age, male gender, diabetes, smoking and hypertension. With regard to biomarkers, CAC was significantly associated (negatively) to G-CSF and IL-13. EFV (median binned) was significantly associated (positively) with IP-10 (P = 0.002) and MCP-1 (ρ = 0.037). In follow-up, EFV showed a mean annualized progression of 6 mL (IQR 3; 9) (P < 0.001); CAC progressed by a mean of six Agatston Units (IQR 0; 30). The progression of CAC was significantly correlated with the extent of EFV (P < 0.001) while there was no significant correlation between progression of EFV or CAC with systemic inflammation markers.

CONCLUSION

Epicardial fat volume and the baseline extent as well as progression of coronary atherosclerosis-measured by the calcium score-are significantly correlated. While both baseline EFV and CAC displayed significant correlations with systemic inflammation markers, biomarkers were not predictive of the progression of CAC or EFV.

Evaluation of the relationship between epicardial fat volume and left ventricular diastolic dysfunction

PURPOSE

The aim of the present study was to evaluate the relationship between epicardial fat tissue (EFT) volume and left ventricular diastolic function.

MATERIALS AND METHODS

A total of 63 patients (29 male, 34 female, mean age 57.8 ± 10.9 years) were enrolled in the study. Multidetector computed tomography (MDCT) and 2D transthoracic echocardiography were performed in 29 patients with left ventricular diastolic dysfunction and 34 patients with normal diastolic function. EFT volume and coronary calcium score were measured by MDCT.

RESULTS

Mean EFT volume was 137.2 ± 56.2 cm(3) for the whole study group. Mean EFT was 114.1 ± 46.6 cm(3) in patients with normal left ventricular diastolic function and 164.4 ± 54.9 cm(3) in those with left ventricular diastolic dysfunction (p = 0.0002). Diastolic dysfunction had no significant correlation with diabetes, hypertension, and coronary calcium scoring (p > 0.05). Also in our patient group EFT volume had no significant correlation with coronary calcium score (r = 0.148, p = 0.248).

CONCLUSION

Patients with left ventricular diastolic dysfunction had significantly increased EFT volume.

Association of epicardial fat with left ventricular diastolic function in subjects with metabolic syndrome: assessment using 2-dimensional echocardiography

Background

Metabolic syndrome (MetS) is related with left ventricular diastolic dysfunction (LVDD) and poor cardiovascular outcome. Epicardial adipose tissue (EAT) thickness, measured by echocardiography, is increased in subjects with MetS. However, the association of EAT with LV diastolic function has not been evaluated in subjects with MetS.

Methods

In this retrospective study, EAT thickness was measured in 1,486 consecutive asymptomatic patients with no known heart disease who had transthoracic echocardiography during a self-referred healthcare exam. Subjects with a history of ischemic heart disease, cardiomyopathy or significant valvular heart disease were excluded. LVDD was defined as E/e’ ratio ≥ 15. Subjects were grouped into two groups, those with MetS and those without.

Results

MetS was present in 346 subjects. There was no difference in LV systolic function between the two groups. However compared to patients without MetS, patients with MetS had larger left atrium (LA) size and higher E/e’ ratio (38 ± 5 versus 35 ± 5 mm for LA and 10.0 ± 3.3 versus 8.7 ± 2.7 for E/e’ ratio in subjects with versus without MetS both p < 0.001). LVDD was found in 27 (7.8%) subjects with MetS, compared to 30 (2.6%) subjects without MetS (p < 0.001). In subjects with MetS, EAT was significantly correlated with LVDD, even after adjusting for other cardiometabolic risk factors such as age, systolic blood pressure, BMI, blood glucose and LDL cholesterol (OR 1.845, 95% CI 1.153-2.951, p = 0.011).

Conclusion

Greater EAT is found in subjects with MetS. EAT is significantly associated with LVDD in subjects with MetS, even after adjusting for other risk factors.

Relationship of epicardial adipose tissue thickness with early indicators of atherosclerosis and cardiac functional changes in obese adolescents with metabolic syndrome

OBJECTIVE

Epicardial adipose tissue thickness (EATT) is suggested as a new cardiometabolic risk factor. Carotid intima-media thickness (IMT) is a potential indicator of subclinical atherosclerosis in patients with metabolic syndrome (MS). We investigated the association of EATT with carotid IMT and cardiac functional changes in obese adolescents with MS.

METHODS

One hundred thirty-eight obese adolescents and 63 lean subjects were enrolled in the study. The obese subjects were divided into two subgroups based on the presence or absence of MS (MS group and non-MS group). All subjects underwent transthoracic echocardiographic examination for determination of left ventricular (LV) function, LV mass index (LVMI), and myocardial performance index (MPI). EATT and carotid IMT were also measured during echocardiography.

RESULTS

The average LVMI measurements were higher in both MS and non-MS obese patients in comparison with the lean children. The MS group had significantly higher LVMI measurements than the non-MS and lean groups (88.5±23.0, 67.5±24.8 g/m2, and 62.4±18.2 g/m2, respectively; p<0.01). Carotid IMT was higher in both the MS and non-MS obese patients in comparison with the lean group. The MS group had significantly higher carotid IMT measurements than the non-MS and lean groups (0.91±0.23, 0.78±0.18, and 0.52±0.08 mm, respectively; p<0.01). The EATT was also increased significantly in patients with MS compared to lean adolescents (7.42±1.55 vs. 4.28±0.79mm; p=0.001). EATT was positively correlated with body mass index-SDS, waist circumference, fasting glucose, insulin, homeostasis model assessment-insulin resistance, triglyceride levels, LV thickness, LVMI, and MPI in the MS obese group. EATT was the only independent predictor of carotid IMT in the multivariate analysis (β= 0.69, p<0.001).

CONCLUSION

The findings of the present study demonstrate a close relationship of EATT with carotid IMT and early cardiac dysfunction in obese adolescents with MS. Assessment of EATT and carotid IMT in routine echocardiographic examinations is suggested as a feasible and reliable method for the evaluation of obesity with MS and its related cardiovascular risks in children and adolescents.

Relation of epicardial fat thickness and brachial flow-mediated vasodilation with coronary artery disease

OBJECTIVE

The purpose of this study is to investigate the presence of a statistical association between epicardial fat thickness (EFT) and coronary artery disease (CAD) and between flow-mediated vasodilation (FMD) and CAD.

METHODS

We measured the EFT and FMD in 64 subjects with suspected stable angina pectoris. The patients were separated into two groups according to their coronary angiography results: 34 patients with CAD and 30 patients with normal coronary arteries (NCA).

RESULTS

EFT was significantly higher in the patients with CAD than the NCA group (6.43 ± 0.90 mm vs. 5.35 ± 0.75 mm, p<0.001) while FMD was significantly lower in the patients with CAD than those in the NCA group (6.41 ± 2.51% vs. 8.33 ± 3.45%, p=0.015). No significant correlation was found between EFT and FMD. After adjustment for EFT, FMD, age, sex, ejection fraction, glucose, and low-density lipoprotein cholesterol through multivariate logistic regression analysis, EFT (odds ratio: 6.325, 95% confidence interval 2.289-17.476, p<0.001) and age (odds ratio: 1.093, 95% confidence interval 1.008-1.185, p=0.032) remained significant predictors of CAD. A cut-off value of EFT≥5.8mm predicted the presence of CAD with 77% sensitivity and 70% specificity.

CONCLUSION

An echocardiographic EFT assessment is independently associated with the presence of CAD. Thus, EFT may be helpful in cardiometabolic risk stratification and therapeutic interventions.

Impact of obesity on cardiovascular health

This review examines the impact of obesity on cardiovascular health. We will review first, relationship between obesity and hypertension. Second, we will describe obesity-related subclinical abnormalities in cardiovascular function and structure. Third, we will summarize evidence linking obesity to overt cardiovascular disease including coronary artery disease, congestive heart failure, stroke, arrhythmias and sudden cardiac death. Fourth, we will discuss the potential mechanisms underlying increased cardiovascular risk in obese subjects. Last, we will discuss contribution of sleep apnea to the link between obesity and cardiovascular disease. Despite recent progress in understanding epidemiologic and pathophysiological links between obesity and cardiovascular disease, several issues remain to be addressed in the future studies. There is a clear need to identify better markers of obesity-related subclinical cardiovascular damage. Furthermore, we should improve identification of obese subjects at highest cardiovascular risk.

The role of cardiac fat in insulin resistance

PURPOSE OF REVIEW

To evaluate the relationship between cardiac fat accumulation and insulin resistance. We discuss the current knowledge regarding the different techniques for measuring, in vivo in humans, cardiac fat deposition, the effects of systemic and myocardial insulin resistance and the clinical relevance of the relation between atherosclerosis and cardiac fat in conditions of insulin resistance.

RECENT FINDINGS

In humans, fat accumulates mainly around the heart, as epicardial, perivascular and intrathoracic fat, but also inside the cardiomyocytes. All these cardiac fat depots have been shown to be markers of cardiac lipotoxicity, mitochondrial dysfunction, inflammation and local and systemic insulin resistance as well as of atherosclerosis and cardiac dysfunction.

SUMMARY

Although cardiac fat is associated with impairment in heart metabolism and cardiac dysfunction, the interplay among cardiac fat accumulation, insulin resistance and cardiac dysfunction remains to be fully established.

Cellular cross-talk between epicardial adipose tissue and myocardium in relation to the pathogenesis of cardiovascular disease

Epicardial and perivascular fat depot size is considered an index of cardiac and visceral obesity. The functional and anatomic proximity of epicardial adipose tissue (EAT) to myocardium has drawn increasing attention in recent years among researchers attempting to elucidate its putative role as an endocrine organ. This includes the role of EAT as a lipid storing depot and as an inflammatory tissue secreting cytokines and chemokines under pathogenic conditions such as cardiovascular diseases. In this review, we discuss the current state of knowledge regarding the potential EAT mediators of inflammation and the paracrine cross-talk between EAT and the underlying myocardium. We also highlight the most recent findings on the causes and correlates of myocardial steatosis/cardiac lipotoxicity and its association with cardiac dysfunction.

Effects of statins on the epicardial fat thickness in patients with coronary artery stenosis underwent percutaneous coronary intervention: comparison of atorvastatin with simvastatin/ezetimibe

Background

Epicardial fat is a visceral thoracic fat and known to be related with presence of dyslipidemia and coronary arterial stenosis. We evaluated the effects and differences of statins on epicardial fat thickness (EFT) in patients underwent successful percutaneous coronary intervention (PCI).

Methods

In this retrospective cohort study, we enrolled consecutive patients underwent successful PCI and scheduled six to eight-months follow-up coronary angiography from March 2007 to June 2009. EFT was measured by echocardiography twice at the time of PCI and the follow-up coronary angiography. We included 145 patients (58 females; mean, 63.5 ± 9.5 years).

Results

Of the 145 patients, 82 received 20 mg of atorvastatin (atorvastatin group) and 63 medicated with 10 mg of simvastatin with 10 mg of ezetimibe (simvastatin/ezetimibe group). With statin treatments, total cholesterol concentration (189.1 ± 36.1 to 143.3 ± 36.5 mg/dL, p < 0.001), triglycerides (143.5 ± 65.5 to 124.9 ± 63.1 mg/dL, p = 0.005), low density lipoprotein-cholesterol (117.4 ± 32.5 to 76.8 ± 30.9 mg/dL, p < 0.001) and EFT (4.08 ± 1.37 to 3.76 ± 1.29 mm, p < 0.001) were significantly decreased. Atorvastatin and simvastatin/ezetimibe showed similar improvements in the cholesterol profiles. However, atorvastatin decreased EFT more significantly than simvastatin/ezetimibe (EFT change 0.47 ± 0.65 in the atorvastatin vs. 0.12 ± 0.52 mm in the simvastatin/ezetimibe group; p = 0.001).

Conclusion

In this study, the atorvastatin group showed significant reduction in EFT than in the simvastatin/ezetimibe group. This might be originated from the statin difference. More large, randomized study will be needed to evaluate this statin difference.

Relation of echocardiographic epicardial fat thickness and myocardial fat

Epicardial and myocardial fats increase with degree of visceral adiposity and possibly contribute to obesity-associated cardiac changes. Echocardiographic epicardial fat thickness is a new and independent marker of visceral adiposity. The aim of this study was to test whether echocardiographic epicardial fat is related to myocardial fat. Twenty consecutive Caucasian men (body mass index 30.5 +/- 2 kg/m(2), 42 +/- 7 years of age) underwent transthoracic echocardiography for epicardial fat thickness, morphologic and diastolic parameter measurements, hydrogen-1 magnetic resonance spectroscopy for myocardial fat quantification, and magnetic resonance imaging for epicardial fat volume estimation. Hydrogen-1 magnetic resonance spectroscopic myocardial fat content, magnetic resonance imaging of epicardial fat volume, and echocardiographic epicardial fat thickness range varied from 0.5% to 31%, 4.5 to 43 ml, and 3 to 15 mm, respectively. Myocardial fat content showed a statistically significant correlation with echocardiographic epicardial fat thickness (r = 0.79, p <0.01), waist circumference (r = 0.64, p <0.01), low-density lipoprotein cholesterol (r = 0.54, p <0.01), plasma adiponectin levels (r = -0.49, p <0.01), and isovolumic relaxation time (r = 0.59, p <0.01). However, multivariate linear regression analysis showed epicardial fat thickness as the most significant independent correlate of myocardial fat (p <0.001). Although this study is purely correlative and no causative conclusions can be drawn, it can be postulated that increased echocardiographic epicardial fat accumulation could reflect myocardial fat in subjects with a wide range of adiposity.

Echocardiographic epicardial fat: a review of research and clinical applications

Epicardial fat plays a role in cardiovascular diseases. Because of its anatomic and functional proximity to the myocardium and its intense metabolic activity, some interactions between the heart and its visceral fat depot have been suggested. Epicardial fat can be visualized and measured using standard two-dimensional echocardiography. Standard parasternal long-axis and short-axis views permit the most accurate measurement of epicardial fat thickness overlying the right ventricle. Epicardial fat thickness is generally identified as the echo-free space between the outer wall of the myocardium and the visceral layer of pericardium and is measured perpendicularly on the free wall of the right ventricle at end-systole. Echocardiographic epicardial fat thickness ranges from a minimum of 1 mm to a maximum of almost 23 mm. Echocardiographic epicardial fat thickness clearly reflects visceral adiposity rather than general obesity. It correlates with metabolic syndrome, insulin resistance, coronary artery disease, and subclinical atherosclerosis, and therefore it might serve as a simple tool for cardiometabolic risk prediction. Substantial changes in echocardiographic epicardial fat thickness during weight-loss strategies may also suggest its use as a marker of therapeutic effect. Echocardiographic epicardial fat measurement in both clinical and research scenarios has several advantages, including its low cost, easy accessibility, rapid applicability, and good reproducibility. However, more evidence is necessary to evaluate whether echocardiographic epicardial fat thickness may become a routine way of assessing cardiovascular risk in a clinical setting.

Relation of epicardial fat thickness to right ventricular cavity size in obese subjects

Epicardial fat is the visceral fat depot of the heart and is commonly increased in obese subjects. Obesity is also associated with right ventricular (RV) enlargement. Nevertheless, whether epicardial fat might be independently associated with RV morphology is unknown. I evaluated the correlation between echocardiographic epicardial fat and RV cavity size in subjects with a wide range of adiposity. Echocardiographic epicardial fat thickness and RV end-diastolic diameter (RVEDD) were assessed in 50 obese and 50 normal weight subjects. Patients with clinical conditions that could affect the RVEDD were excluded. Obese subjects had a significantly greater epicardial fat thickness and RVEDD than normal weight subjects (10 +/- 4 vs 5 +/- 2 mm and 22 +/- 10 vs 15 +/- 5, respectively; p <0.01 for both). The univariate relation between the epicardial fat thickness and RVEDD was very significant (r = 0.82, p <0.01) for overall obese and normal weight subjects. Multiple regression analysis showed that epicardial fat thickness was the best independent correlate of RVEDD (r(2) = 0.42, p <0.01) in overall subjects. In conclusion, increased RV epicardial fat accumulation is associated with enlarged RV cavity size.

Pericardial fat, intrathoracic fat, and measures of left ventricular structure and function: the Framingham Heart Study

BACKGROUND

Pericardial fat has been implicated in the pathogenesis of obesity-related cardiovascular disease. Whether the associations of pericardial fat and measures of cardiac structure and function are independent of the systemic effects of obesity and visceral adiposity has not been fully explored.

METHODS AND RESULTS

Participants from the Framingham Heart Study (n=997; 54.4% women) underwent chest and abdominal computed tomography and cardiovascular magnetic resonance imaging between 2002 and 2005. Pericardial fat, intrathoracic fat, and visceral adipose tissue quantified from multidetector computed tomography, along with body mass index and waist circumference, were examined in relation to cardiovascular magnetic resonance measures of left ventricular (LV) mass, LV end-diastolic volume, and left atrial dimension. In women, pericardial fat (r=0.20 to 0.35, P<0.001), intrathoracic fat (r=0.25 to 0.37, P<0.001), visceral adipose tissue (r=0.24 to 0.45, P<0.001), body mass index (r=0.36 to 0.53, P<0.001), and waist circumference (r=0.30 to 0.48, P<0.001) were directly correlated with LV mass, LV end-diastolic volume, and left atrial dimension. In men, pericardial fat (r=0.19 to 0.37, P<0.001), intrathoracic fat (r=0.17 to 0.31, P<0.001), visceral adipose tissue (r=0.19 to 0.36, P<0.001), body mass index (r=0.32 to 0.44, P<0.001), and waist circumference (r=0.34 to 0.44, P<0.001) were directly correlated with LV mass and left atrial dimension, but LV end-diastolic volume was not consistently associated with adiposity measures. Associations persisted after multivariable adjustment but not after additional adjustment for body weight and visceral adipose tissue, except for pericardial fat and left atrial dimension in men.

CONCLUSIONS

Pericardial fat is correlated with cardiovascular magnetic resonance measures, but the association is not independent of or stronger than other ectopic fat stores or proxy measures of visceral adiposity. An important exception is left atrial dimension in men. These results suggest that the systemic effects of obesity on cardiac structure and function may outweigh the local pathogenic effects of pericardial fat.

Substantial changes in epicardial fat thickness after weight loss in severely obese subjects

We sought to evaluate the effect of weight loss on echocardiographic epicardial fat thickness, as index of visceral adiposity, and whether epicardial fat change after the weight loss can be proportionally different from overall body weight changes and related to cardiac parameters changes in severely obese subjects. This was an interventional study in 20 severely obese subjects (12 women, 8 men, BMI 45+/-5 kg/m(2), 35+/-10 years) who underwent 6-month very low calorie diet weight loss program. Baseline and after 6-month weight loss anthropometrics, echocardiographic epicardial fat thickness, left ventricular mass (LVM), and diastolic function parameters were assessed. Subjects lost 20% of original body weight, BMI reduced by 19% of original BMI, waist circumference decreased by 23% of initial waist circumference. Epicardial fat thickness decreased from 12.3+/-1.8 to 8.3+/-1 mm P<0.001 after the 6-month very low calorie diet, as -32% of baseline epicardial fat thickness. LVM and diastolic function changes were better correlated with epicardial fat changes. We showed that significant weight loss can be associated with significant reduction in the epicardial fat thickness, marker of visceral adiposity in severely obese subjects. Epicardial fat decrease, therefore visceral fat decrease, can be proportionally higher than overall adiposity decrease. Epicardial fat changes are significantly associated with obesity-related cardiac morphological and functional changes during weight loss. Measurement of echocardiographic epicardial fat thickness may provide an additional tool in understanding the metabolic risk associated with variation in fat distribution.

Threshold values of high-risk echocardiographic epicardial fat thickness

OBJECTIVE

Echocardiographic epicardial adipose tissue is a new index of cardiac and visceral adiposity with great potential as a diagnostic tool and therapeutic target. In this study, we sought to provide threshold values of echocardiographic epicardial fat thickness associated with metabolic and anthropometric risk factors.

METHODS AND PROCEDURES

Epicardial fat thickness was measured in 246 consecutive white subjects (120 women, 126 men, median age 46 years (30-65), median BMI 32 kg/m(2) (22-52), median waist circumference 100.5 cm (85-140)), who underwent routine transthoracic echocardiogram for standard clinical indications. Metabolic syndrome (MetS), Insulin resistance, BMI, and waist circumference categories were identified and epicardial fat was calculated.

RESULTS

Among 246 subjects, 58% had MetS. These subjects showed median values of epicardial fat thickness of 9.5 and 7.5 mm (in men and women, respectively), significantly higher than those found in subjects without MetS (no MetS) (P < 0.001). Receiver operating characteristics (ROC) analysis showed that epicardial fat thickness of 9.5 and 7.5 mm maximize the sensitivity and specificity to predict MetS, in men and women, respectively. In separate analyses, median epicardial fat thickness values of 9.5 and 7.5 mm were cutoff points associated with high abdominal fat in men and women, respectively. When insulin sensitivity was considered separately, epicardial fat thickness of 9.5 mm was associated with insulin resistance.

DISCUSSION

Median values of 9.5 and 7.5 mm should be considered the threshold values for high-risk echocardiographic epicardial fat thickness in white men and women, respectively. Echocardiographic epicardial fat measurement may be of help for cardiometabolic risk stratification and therapeutic interventions targeting the fat.

Relationship of epicardial fat thickness and fasting glucose

In this study we sought to evaluate whether increase in echocardiographic epicardial fat thickness, index of cardiac and visceral adiposity, is associated with impaired fasting glucose (IFG). Epicardial fat thickness and fasting plasma glucose (FPG) were measured in 115 consecutive non-diabetic Caucasian subjects [65 men, 50 women, median age of 42 years (range 30-64 years), median body mass index (BMI) of 27 kg/m(2) (range 22-33 kg/m(2)), who underwent routine transthoracic echocardiogram. Study subjects were designated as having normal fasting glucose (NFG) with FPG<100 mg/dl; and IFG with FPG (100 and <126 mg/dl). Epicardial fat thickness was significantly higher in IFG than NFG subjects (8+/-3 vs 6+/-2 mm; 7.1+/-4 vs 5.8+/-3 mm, p<0.001 for both and respectively in men and women. Epicardial fat thickness was significantly correlated with FPG (r=0.60, p<0.001). Our data indicate for the first time that higher epicardial fat thickness is associated with IFG in non-diabetic men and women. Echocardiographic epicardial fat measurement may be an additional tool for diabetes-related cardiac risk stratification.

Do cardiac and perivascular adipose tissue play a role in atherosclerosis?

Recent evidence suggests that epicardial and perivascular adipose tissue could mechanically and functionally affect the heart and vasculature, thereby possibly playing a role in adiposity-related atherosclerosis. Experimental and clinical observations suggest both favorable and unfavorable effects of epicardial and perivascular fat. The double role of epicardial and perivascular adipose tissue in the development of cardiovascular pathology and/or in protecting the heart and arteries warrants further studies.

Relation of epicardial fat and alanine aminotransferase in subjects with increased visceral fat

BACKGROUND

Increased visceral adipose tissue (VAT) is a risk factor for an unfavorable cardio-metabolic profile and fatty liver. Individuals with human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART) can be associated with metabolic syndrome (MS) and higher visceral fat. However, the potential link between cardiac adiposity, emerging index of visceral adiposity, and fatty liver is still unexplored.

OBJECTIVE

To evaluate whether echocardiographic epicardial adipose tissue, index of cardiac adiposity, could be related to serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, surrogate markers of fatty liver, in HIV-infected patients with (HIV+MS+) and without HAART-associated MS (HIV+MS-).

METHODS AND PROCEDURES

This was a cross-sectional observational study on 57 HIV+MS+ patients, 52 HIV+MS- and 57 HIV-negative subjects with MS (HIV-MS+), as control group. Epicardial fat thickness and intra-abdominal VAT were obtained by echocardiography and magnetic resonance imaging (MRI), respectively. Serum ALT and AST activity, plasma adiponectin levels, and MS biochemical parameters were measured.

RESULTS

Echocardiographic epicardial fat thickness was correlated with MRI-VAT (r = 0.83, P < 0.01), AST/ALT ratio (r = 0.77, P < 0.01), ALT (r = 0.58, P < 0.01), AST (r = 0.56, P < 0.01), and adiponectin (r = -0.45, P < 0.01) in HIV+MS+. MRI-VAT and AST/ALT ratio were the best correlates of epicardial fat thickness (r (2) = 0.45, P < 0.01).

DISCUSSION

This study shows for the first time a clear relationship of epicardial fat, index of cardiac and visceral adiposity, and serum ALT and AST activity, markers of fatty liver, in subjects with increased visceral adiposity and cardio-metabolic risk. This correlation seems to be independent of overall adiposity and rather function of excess visceral adiposity.

Relation of subepicardial adipose tissue to carotid intima-media thickness in patients with human immunodeficiency virus

Patients infected with human immunodeficiency virus (HIV) are at increased risk for subclinical atherosclerosis. Whether increased cardiac adiposity may be related to HIV subclinical atherosclerosis is still unexplored. The objective of this study was to evaluate whether echocardiographically determined subepicardial adipose tissue, an index of cardiac adiposity, is related to carotid intima-media thickness (IMT), an index of subclinical atherosclerosis, in HIV-infected patients receiving highly active antiretroviral therapy. Echocardiographic epicardial fat thickness and ultrasonographic IMT were measured in 103 consecutive HIV-infected Caucasian subjects receiving highly active antiretroviral therapy. Echocardiographic subepicardial adipose tissue showed an excellent correlation with IMT (r = 0.92, p <0.01). Multiple regression analysis showed that IMT was best predicted by epicardial fat thickness (r(2) = 0.81, p <0.01). In conclusion, this study suggests, for the first time, that epicardial adipose tissue, an index of cardiac adiposity, may be significantly related to subclinical atherosclerosis in HIV-infected patients.