Increased Epicardial Fat Volume Quantified by 64-Multidetector Computed Tomography is Associated With Coronary Atherosclerosis and Totally Occlusive Lesions

Comparison of perinephric fat measurements between malignant and benign renal tumours

Objective

To investigate different parameters derived from the quantity and quality of perinephric fat, and to compare their effectiveness in predicting the malignant pathology of renal tumours.

Methods

Data from patients diagnosed with renal tumour between April 2014 and December 2020 were retrospectively reviewed, and patients were categorized into malignant or benign tumour groups. Fat parameters, including perinephric fat volume (PFV), perinephric fat area (PFA), perinephric fat thickness (PFT), and Mayo adhesive probability (MAP) score were measured using abdominal computed tomography scans. Between-group differences were assessed by analysis of variance and χ²-test. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of perinephric fat parameters in diagnosing malignancy.

Results

A total of 109 patients were included. MAP score, PFV, PFA, and PFT were significantly increased in the malignant versus benign tumour group, and after correction for body mass index (BMI), the indexed PFV/BMI, PFA/BMI, and PFT/BMI values remained significantly higher in the malignant tumour group. All parameters showed fair predictivity of malignancy, with comparable area under the curve values in the ROC curve.

Conclusion

An increased amount of perinephric fat is predictive of malignant pathology for renal tumours. The predictive accuracy for each perinephric fat parameter remained fair after correcting for BMI.

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.

Epicardial fat attenuation, not volume, predicts obstructive coronary artery disease and high risk plaque features in patients with atypical chest pain

OBJECTIVE

This study sought to investigate the association between volume and attenuation of epicardial fat and presence of obstructive coronary artery disease (CAD) and high-risk plaque features (HRPF) on CT angiography (CTA) in patients with atypical chest pain and whether the association, if any, is independent of conventional cardiovascular risk factors and coronary artery calcium score (CACS).

METHODS

Patients referred for coronary CTA with atypical chest pain and clinical suspicion of CAD were included in the study. Quantification of CACS, epicardial fat volume (EFV) and epicardial fat attenuation (EFat) was performed on non-contrast images. CTA was evaluated for presence of obstructive CAD and presence of HRPF.

RESULTS

255 patients (median age [interquartile range; IQR]: 51[41-60] years, 51.8% males) were included. On CTA, CAD, obstructive CAD (≥50% stenosis) and CTA-derived HRPFs was present in 133 (52.2%), 37 (14.5%) and 82 (32.2%) patients respectively. A significantly lower EFat was seen in patients with obstructive CAD than in those without (-86HU [IQR:-88 to -82 HU] vs -84 [IQR:-87 HU to -82 HU]; p = 0.0486) and in patients with HRPF compared to those without (-86 HU [IQR:-88 to -83 HU] vs -83 HU [-86 HU to -81.750 HU]; p < 0.0001). EFat showed significant association with obstructive CAD (unadjusted Odd's ratio (OR) [95% CI]: 0.90 [0.81-0.99];p = 0.0248) and HRPF (unadjusted OR [95% CI]: 0.83 [0.76-0.90];p < 0.0001) in univariate analysis, which remained significant in multivariate analysis. However, EFV did not show any significant association with neither obstructive CAD nor HRPF in multivariate analysis. Adding EFat to conventional coronary risk factors and CACS in the pre-test probability models increased the area-under curve (AUC) for prediction of both obstructive CAD (AUC[95% CI]: 0.76 [0.70-0.81] vs 0.71 [0.65-0.77)) and HRPF (AUC [95% CI]: 0.92 [0.88-0.95] vs 0.89 [0.85-0.93]), although not reaching statistical significance.

CONCLUSION

EFat, but not EFV, is an independent predictor of obstructive CAD and HRPF. Addition of EFat to traditional cardiovascular risk factors and CACS improves estimation for pretest probability of obstructive CAD and HRPF.

ADVANCES IN KNOWLEDGE

EFat is an important attribute of epicardial fat as it reflects the "quality" of fat, taking into account the effects of brown-white fat transformation and fibrosis, as opposed to mere evaluation of "quantity" of fat by EFV. Our study shows that EFat is a better predictor of obstructive CAD and HRPF than EFV and can thus explain the inconsistent association of increased EFV alone with CAD.

Epicardial adipose tissue in patients with chronic kidney disease: a meta-analysis study and trial sequential analysis

BACKGROUND

Cardiovascular disease is the most common cause of death in patients with chronic kidney disease (CKD). Epicardial adipose tissue (EAT) is an independent predictor of cardiovascular disease in the general population, and usually increases in the patients with cardiovascular disease risk. The change of EAT in patients with CKD was still controversial. For further understanding, we conducted a meta-analysis of the relevant literature.

METHODS

Eligible studies were searched in PubMed, EMBASE, Web of Science, and Scopus on March 13, 2020. The summarized standard mean difference (SMD) with 95% confidence intervals (CIs) were used to assess the association between EAT (thickness and volume) and CKD. Trial sequential analysis was conducted to estimate whether the evidence of the results is sufficient.

RESULTS

In total, 17 studies with 1961 participants (1205 patients in the CKD group and 756 participants in the control group) were involved. The EAT thickness was significantly increased in the CKD group compared to the control group (SMD = 1.31, 95% CI 0.89-1.73, P < 0.001) in eleven studies. The EAT volume was significantly increased in the CKD group compared to the control group (SMD = 0.77, 95% CI 0.63-0.91, P < 0.001) in six studies. Trial sequential analysis indicated that the available samples were sufficient and confirmed that firm evidence was reached.

CONCLUSIONS

Patients with CKD have higher EAT thickness and volume compared to control subjects without CKD.

Epicardial Adipose Tissue, Adiponectin and Leptin: A Potential Source of Cardiovascular Risk in Chronic Kidney Disease

The importance of cardiometabolic factors in the inception and progression of atherosclerotic cardiovascular disease is increasingly being recognized. Beyond diabetes mellitus and metabolic syndrome, other factors may be responsible in patients with chronic kidney disease (CKD) for the high prevalence of cardiovascular disease, which is estimated to be 5- to 20-fold higher than in the general population. Although undefined uremic toxins are often blamed for part of the increased risk, visceral adipose tissue, and in particular epicardial adipose tissue (EAT), have been the focus of intense research in the past two decades. In fact, several lines of evidence suggest their involvement in atherosclerosis development and its complications. EAT may promote atherosclerosis through paracrine and endocrine pathways exerted via the secretion of adipocytokines such as adiponectin and leptin. In this article we review the current knowledge of the impact of EAT on cardiovascular outcomes in the general population and in patients with CKD. Special reference will be made to adiponectin and leptin as possible mediators of the increased cardiovascular risk linked with EAT.

Epicardial adipose tissue: A cardiovascular risk marker to evaluate in chronic kidney disease

Chronic kidney disease represents a true inflammatory state, and is related to multiple cardiovascular risk factors. Coronary artery disease is the major complication, and has usually been associated with non-classical or uraemic related factors that include the disturbance of calcium and phosphorus metabolism, among others. Recent clinical evidence shows that specific body fat deposition like epicardial adipose tissue is an additional factor to consider when evaluating cardiovascular risk in the general population and kidney patients. Direct interaction of this tissue and coronary vessels with consequent mediation of pro-atherogenic substances have a local process ending in endothelial damage. Although the population of renal patients has been poorly evaluated, future studies should determine precisely whether an increase in epicardial fat is truly associated with cardiovascular morbidity and mortality in this risk group.

Correlation of epicardial fat quantification with severity of coronary artery disease: A study in Indian population

Objective

We studied the correlation of quantified epicardial fat with severity of coronary artery disease in patients [suspected cases of coronary artery disease (CAD)] referred for computed tomography (CT) coronary angiography and established cutoffs for epicardial fat volume (EFV) for the presence of CAD and obstructive CAD.

Methods

A prospective cum retrospective cross-sectional observational study was carried out on 950 Indian subjects (suspected cases of CAD) who were referred for coronary CT in the year 2013–2016. EFV was quantified using semiautomatic technique on multidetector coronary CT angiography. The presence of atherosclerotic plaques and degree of stenosis was assessed on coronary CT angiography scans. The correlation between quantified EFV and degree of stenosis was assessed. Multivariate analysis was also performed.

Results

A higher quantity of epicardial fat is found in patients with increasing severity of coronary artery stenosis. The EFV cutoff for the presence of CAD and obstructive CAD are 49.75 and 67.69 mL with area under the curve, sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 0.68, 81%, 45.9%,58.24%, 72.2%, and 62.84% and 0.709, 64.9%, 66.4%, 35.84%, 86.55%, and 66%, respectively. EFV correlates with age, weight, and body mass index (BMI). Multivariate analysis revealed EFV to be an independent risk factor for the presence of CAD.

Conclusions

Higher quantities of EFV are found in patients with greater degree of coronary artery stenosis. EFV correlates with age, weight, and BMI. EFV is an independent risk factor for CAD.

Comparison of epicardial adipose tissue radiodensity threshold between contrast and non-contrast enhanced computed tomography scans: A cohort study of derivation and validation

BACKGROUND AND AIMS

Epicardial adipose tissue (EAT) volume derived from contrast enhanced (CE) computed tomography (CT) scans is not well validated. We aim to establish a reliable threshold to accurately quantify EAT volume from CE datasets.

METHODS

We analyzed EAT volume on paired non-contrast (NC) and CE datasets from 25 patients to derive appropriate Hounsfield (HU) cutpoints to equalize two EAT volume estimates. The gold standard threshold (-190HU, -30HU) was used to assess EAT volume on NC datasets. For CE datasets, EAT volumes were estimated using three previously reported thresholds: (-190HU, -30HU), (-190HU, -15HU), (-175HU, -15HU) and were analyzed by a semi-automated 3D Fat analysis software. Subsequently, we applied a threshold correction to (-190HU, -30HU) based on mean differences in radiodensity between NC and CE images (ΔEATrd = CE radiodensity - NC radiodensity). We then validated our findings on EAT threshold in 21 additional patients with paired CT datasets.

RESULTS

EAT volume from CE datasets using previously published thresholds consistently underestimated EAT volume from NC dataset standard by a magnitude of 8.2%-19.1%. Using our corrected threshold (-190HU, -3HU) in CE datasets yielded statistically identical EAT volume to NC EAT volume in the validation cohort (186.1 ± 80.3 vs. 185.5 ± 80.1 cm³, Δ = 0.6 cm³, 0.3%, p = 0.374).

CONCLUSIONS

Estimating EAT volume from contrast enhanced CT scans using a corrected threshold of -190HU, -3HU provided excellent agreement with EAT volume from non-contrast CT scans using a standard threshold of -190HU, -30HU.

Association between epicardial adipose tissue, high-sensitivity C-reactive protein and myocardial dysfunction in middle-aged men with suspected metabolic syndrome

BACKGROUND

As body fat composition and metabolism differ between men and women, we evaluated sex-related differences in the association among epicardial adipose tissue (EAT), secretome profile, and myocardial function of subjects with suspected metabolic syndrome.

METHODS

We evaluated 277 participants (men, n = 140; 56.1 ± 4.7 years) who underwent conventional echocardiography and two-dimensional speckle tracking from the Seoul Metabolic Syndrome cohort. EAT was measured from the right ventricular free wall perpendicular to the aortic annulus at end systole. Global longitudinal strain (GLS) was obtained from 18 apical segments. Apolipoprotein A1, apolipoprotein B, adiponectin, and high-sensitivity C-reactive protein (hs-CRP) levels were measured using immunoturbidimetry assay.

RESULTS

Mean age, body mass index, and hs-CRP level did not differ by sex. Waist circumference, fasting blood glucose level, and triglyceride/high-density lipoprotein cholesterol ratio were higher, and apolipoprotein AI and adiponectin levels were lower in men. No significant difference in mean EAT thickness was found (7.02 ± 1.81 vs. 7.13 ± 1.70 mm, p = 0.613). Men had a higher left ventricular (LV) mass index and lower GLS. EAT thickness was associated with hs-CRP level in men alone (ß = 0.206, p = 0.015). LV mass index (ß = 2.311, p = 0.037) and function represented by e' (ß = - 0.279, p = 0.001) and GLS (ß = - 0.332, p < 0.001) were independently associated with EAT thickness in men alone.

CONCLUSIONS

In middle-aged subjects with suspected metabolic syndrome, EAT was associated with inflammation represented by hs-CRP level, LV mass, and subclinical myocardial dysfunction only in men, suggesting that the inflammatory activity of EAT induced myocardial remodeling and dysfunction in middle-aged subjects but was attenuated in women. Trial registration NCT02077530 (date of registration: November 1, 2013).

Association of epicardial adipose tissue with serum level of cystatin C in type 2 diabetes

Objective

Accumulation of epicardial adipose tissue (EAT) is considered to be a cardiovascular risk factor independent from visceral adiposity, obesity, hypertension and diabetes. We explored the parameters related to EAT accumulation, aiming to clarify the novel pathophysiological roles of EAT in subjects with type 2 diabetes (T2DM).

Methods

We examined the laboratory values, including cystatinC, and surrogate markers used for evaluating atherosclerosis. EAT was measured as the sum of the adipose tissue area, obtained by plain computed tomography scans in 208 subjects with T2DM but no history of coronary artery disease.

Results

EAT correlated positively with age, body mass index (BMI), visceral fat area, leptin, cystatin C and C-peptide, while correlating negatively with adiponectin, estimated glomerular filteration rate (eGFR) and the liver-to-spleen ratio. Multiple linear regression analysis revealed serum cystatin C (β = 0.175), leptin (β = 0.536), BMI (β = 0.393) and age (β = 0.269) to be the only parameters showing independent statistically significant associations with EAT. When cystatin C was replaced with eGFR, eGFR showed no significant correlation with EAT. In reverse analysis, serum cystatin C was significantly associated with EAT after adjustment in multivariate analysis.

Discussion

EAT accumulation and elevated cystatin C have been independently regarded as risk factors influencing atherosclerosis. The strong association between EAT and cystatin C demonstrated herein indicates that EAT accumulation may play an important role in Cystatin C secretion, possibly contributing to cardiometabolic risk in T2DM patients.

Adaptive Immunity and Metabolic Health: Harmony Becomes Dissonant in Obesity and Aging

Adipose tissue (AT) is the primary energy reservoir organ, and thereby plays a critical role in energy homeostasis and regulation of metabolism. AT expands in response to chronic overnutrition or aging and becomes a major source of inflammation that has marked influence on systemic metabolism. The chronic, sterile inflammation that occurs in the AT during the development of obesity or in aging contributes to onset of devastating diseases such as insulin resistance, diabetes, and cardiovascular pathologies. Numerous studies have shown that inflammation in the visceral AT of humans and animals is a critical trigger for the development of metabolic syndrome. This work underscores the well-supported conclusion that the inflammatory immune response and metabolic pathways in the AT are tightly interwoven by multiple layers of relatively conserved mechanisms. During the development of diet-induced obesity or age-associated adiposity, cells of the innate and the adaptive immune systems infiltrate and proliferate in the AT. Macrophages, which dominate AT-associated immune cells in mouse models of obesity, but are less dominant in obese people, have been studied extensively. However, cells of the adaptive immune system, including T cells and B cells, contribute significantly to AT inflammation, perhaps more in humans than in mice. Lymphocytes regulate recruitment of innate immune cells into AT, and produce cytokines that influence the helpful-to-harmful inflammatory balance that, in turn, regulates organismal metabolism. This review describes inflammation, or more precisely, metabolic inflammation (metaflammation) with an eye toward the AT and the roles lymphocytes play in regulation of systemic metabolism during obesity and aging. © 2017 American Physiological Society. Compr Physiol 7:1307-1337, 2017.

The association of epicardial fat volume with coronary characteristics and clinical outcome

Recent studies have demonstrated the relationship between epicardial fat volume (EFV) and coronary atherosclerosis, but their association is modest at best. Our purpose is to elucidate the association of epicardial fat with coronary characteristics and clinical outcome. We performed coronary computed tomographic angiography in 651 patients and divided them into three groups according to tertiles of EFV; low-tertile (n = 215), 36-123 ml; middle-tertile (n = 218), 124-165 ml; high-tertile (n = 218), 166-489 ml. The prevalence of coronary calcium score (CCS) >0 (71.6, 73.4, and 83.9% in low-, middle-, and high-tertile group, respectively) and CCS >100 (39.1, 39.9, and 59.2% in each group) was significantly higher in patients with high-tertile EFV compared to the other two groups (p = 0.0047 and p < 0.0001, respectively). The prevalence of CCS >400 was 17.2, 25.7, and 33.1% in each group, which increased stepwise as EFV increased. The significant stenosis (36.2 vs. 27.0%, p = 0.0383), total coronary occlusion (5.5 vs. 0.9%, p = 0.0156), and high-risk plaque (11.0 vs. 5.6%, p = 0.0368) were more prevalent in patients with high-tertile EFV compared to those with low-tertile EFV. The combined rate of cardiac death and myocardial infarction was 0.9, 2.3, and 6.4% in each patient group, respectively, which was significantly higher in patients with high-tertile EFV compared to those with low-tertile EFV (p = 0.0004). The prevalence of coronary artery calcium, significant stenosis, and high-risk plaque increased sharply in patients with high EFV, which was associated with higher rate of cardiac death and myocardial infarction. Thus, high EFV was associated with advanced coronary atherosclerosis and poor prognosis.

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.

Targeting P-selectin glycoprotein ligand-1/P-selectin interactions as a novel therapy for metabolic syndrome

Obesity-induced insulin resistance and metabolic syndrome continue to pose an important public health challenge worldwide as they significantly increase the risk of type 2 diabetes and atherosclerotic cardiovascular disease. Advances in the pathophysiologic understanding of this process has identified that chronic inflammation plays a pivotal role. In this regard, given that both animal models and human studies have demonstrated that the interaction of P-selectin glycoprotein ligand-1 (PSGL-1) with P-selectin is not only critical for normal immune response but also is upregulated in the setting of metabolic syndrome, PSGL-1/P-selectin interactions provide a novel target for preventing and treating resultant disease. Current approaches of interfering with PSGL-1/P-selectin interactions include targeted antibodies, recombinant immunoglobulins that competitively bind P-selectin, and synthetic molecular therapies. Experimental models as well as clinical trials assessing the role of these modalities in a variety of diseases have continued to contribute to the understanding of PSGL-1/P-selectin interactions and have demonstrated the difficulty in creating clinically relevant therapeutics. Most recently, however, computational simulations have further enhanced our understanding of the structural features of PSGL-1 and related glycomimetics, which are responsible for high-affinity selectin interactions. Leveraging these insights for the design of next generation agents has thus led to development of a promising synthetic method for generating PSGL-1 glycosulfopeptide mimetics for the treatment of metabolic syndrome.

Cystatin-C and epicardial adipose tissue as noninvasive predictors of cardiovascular risk in acromegaly

BACKGROUND

Acromegaly (ACRO) is associated with elevated cardiovascular risk, although the prevalence of coronary artery disease (CAD) is unclear. Increased epicardial adipose tissue (EAT) and elevated cystatin-C (Cys-C) levels are cardiovascular risk factors, also related to the progression of CAD in several populations.

AIMS

To measure the severity and extent of CAD in patients with ACRO and to determine whether either EAT or Cys-C reflect higher cardiovascular risk in patients with ACRO than in healthy controls.

SUBJECTS AND METHODS

Case-control study, of 35 patients with ACRO (19 males, 17 with active disease) and 35 age-, gender- and body mass index (BMI)-matched healthy controls; mean age was 48·1 ± 8·1 years and mean BMI was 27·6 ± 4·8 kg/m² . Cys-C was measured by an immunoturbidimetric assay. The 10-year risk of developing a coronary event was calculated using the Framingham Risk Score (FRS). EAT index (volume indexed to body surface area), and severity and extent of CAD were measured using a 256-slice multidetector computed tomography scanner (iCT-256 Philips Healthcare, Amsterdam).

RESULTS

Coronary artery disease lesions, EAT index and severity/extent of CAD were similar between patients with ACRO and controls. Forty-four per cent of patients with ACRO had mild coronary lesions associated with greater EAT index (ß = 0·022, P = 0·036). Cys-C levels correlated with both EAT index (ρ = 0·386, P = 0·031) and FRS (ρ = 0·477, P = 0·004) in patients with ACRO only, despite similar prevalence of traditional cardiovascular risk factors. In a multiple linear regression model, both Cys-C levels (ß = 0·369, P = 0·007) and EAT index (ß = 0·29, P = 0·025) predicted FRS (R² = 0·613).

CONCLUSIONS

In patients with ACRO, both Cys-C and EAT index might be used as noninvasive predictors of cardiovascular risk.

Epicardial Adipose Tissue Contributes to the Development of Non-Calcified Coronary Plaque: A 5-Year Computed Tomography Follow-up Study

Aim: Epicardial adipose tissue (EAT) has been suggested as a contributing factor for coronary atherosclerosis based on the previous cross-sectional studies and pathophysiologic background. However, a causal relationship between EAT and the development of non-calcified coronary plaque (NCP) has not been investigated.

Methods: A total of 122 asymptomatic individuals (age, 56.0 ± 7.6 years; male, 80.3%) without prior history of coronary artery disease (CAD) or metabolic syndrome and without NCP or obstructive CAD at baseline cardiac computed tomography (CT) were enrolled. Repeat cardiac CT was performed with an interval of more than 5 years. Epicardial fat volume index (EFVi; cm³/m²) was assessed in relation to the development of NCP on the follow-up CT where the results were classified into “calcified plaque (CP),” “no plaque,” and “NCP” groups.

Results: On the follow-up CT performed with a median interval of 65.4 months, we observed newly developed NCP in 24 (19.7%) participants. Baseline EFVi was significantly higher in the NCP group (79.9 ± 30.3 cm³/m²) than in the CP group (63.7 ± 22.7 cm³/m²; P = 0.019) and in the no plaque group (62.5 ± 24.7 cm³/m²; P = 0.021). Multivariable logistic regression analysis demonstrated that the presence of diabetes (OR, 9.081; 95% CI, 1.682–49.034; P = 0.010) and the 3rd tertile of EFVi (OR, 4.297; 95% CI, 1.040–17.757; P = 0.044 compared to the 1st tertile) were the significant predictors for the development of NCP on follow-up CT.

Conclusions: Greater amount of EAT at baseline CT independently predicts the development of NCP in asymptomatic individuals.

Potential beneficial effect of some adipokines positively correlated with the adipose tissue content on the cardiovascular system

Obesity is a risk factor of cardiovascular diseases. However, in the case of heart failure, obese and overweight patients have a more favourable prognosis compared to patients who have a normal body weight. This phenomenon is referred to as the "obesity paradox," and it is explained by, among others, a positive effect of adipokines produced by adipose tissue, particularly by the tissue located in the direct vicinity of the heart and blood vessels. The favourable effect on the cardiovascular system is mostly associated with adiponectin and omentin, but the levels of these substances are reduced in obese patients. Among the adipokines which levels are positively correlated with the adipose tissue content, favourable activity is demonstrated by apelin, progranulin, chemerin, TNF-α (tumour necrosis factor-)α, CTRP-3 (C1q/tumour necrosis factor (TNF) related protein), leptin, visfatin and vaspin. This activity is associated with the promotion of regeneration processes in the damaged myocardium, formation of new blood vessels, reduction of the afterload, improvement of metabolic processes in cardiomyocytes and myocardial contractile function, inhibition of apoptosis and fibrosis of the myocardium, as well as anti-inflammatory and anti-atheromatous effects. The potential use of these properties in the treatment of heart failure and ischaemic heart disease, as well as in pulmonary hypertension, arterial hypertension and the limitation of the loss of cardiomyocytes during cardioplegia-requiring cardiosurgical procedures, is studied. The most advanced studies focus on analogues of apelin and progranulin.

The ratio of epicardial to body fat improves the prediction of coronary artery disease beyond calcium and Framingham risk scores

The association between epicardial fat and coronary artery disease (CAD) might be affected by general adiposity. We aimed to determine whether the percentage of epicardial adipose tissue (%EAT), defined as the mass ratio of epicardial fat to body fat, could improve prediction of asymptomatic CAD. We consecutively enrolled 846 adults who underwent coronary computed tomography angiography as part of a health check-up and assessed their coronary stenosis severity and epicardial fat mass. Body fat mass was measured by bioelectrical impedance analysis. Subjects with CAD history, hyperthyroidism, pitting edema, or subjects taking diuretics or thiazolidinedione were excluded. Obstructive CAD was defined as at least one coronary artery with 50 % or greater obstruction, and severe CAD was defined as 70 % or greater obstruction. The %EAT had the maximum area under the curve for predicting the presence of CAD and superior discriminative performance to EAT and other EAT-indexed parameters. Multivariable logistic regression analysis revealed that %EAT >0.41 % was a predictor of obstructive CAD [odds ratio 3.59 (95 % confidence interval 2.28-5.64)], and %EAT >0.47 % was a predictor of severe CAD [4.01 (2.01-7.99)] after adjustment for calcium score and Framingham risk score. This prediction was more pronounced in subjects with higher body fat percentage (≥25 % for men and ≥35 % for women), Framingham risk score (≥10 %), or calcium score (≥100). A spillover of body fat at epicardium over a critical threshold is associated with significant coronary stenosis. This association was independent of obesity, coronary calcium burden, and Framingham risk factors.

The characteristics of pre-diabetic patients associated with body composition and cardiovascular disease risk factors in the Iranian population

Background:

Different populations have shown various patterns of association between impaired fasting glucose (IFG) and body composition parameters and risk factors of cardiovascular disease (CVD). The current study aimed at investigating the differences between persons with prediabetes and healthy people in terms of CVD risk factors including body composition parameters, blood pressure, and lipid profile in a sample of the Iranian population.

Materials and Methods:

In a case-control setting, a sample containing 386 (193 prediabetic subjects and 193 normal subjects) of the first-degree relatives of diabetic patients aged 35-55 years were investigated. Samples were assessed using glucose tolerance categories. Prediabetes was defined according to the American Diabetes Association (ADA) criteria. Body composition parameters, blood pressure, glucose parameters, and lipid profile were measured and compared between the two groups.

Results:

Prediabetic patients had higher body mass index (BMI), waist circumference (WC), and body fat (BF) in comparison to the control group (P < 0.05). In addition, prediabetic subject had a higher intake of energy, carbohydrate, protein, fat, and cholesterol and it seems that these patients had an unhealthy dietary intake (P < 0.05). Fasting blood glucose (FBG) (P < 0.001), total cholesterol (P = 0.007), low-density lipoprotein cholesterol (LDL-C), and triglyceride (P = 0.021) were higher in prediabetic patients (P < 0.05) than in the controls.

Conclusion:

Both the risk factors of CVD and body composition parameters were different between the prediabetic and normal groups; total cholesterol (TC), triglyceride (TG), and FBS were predictors of the risk of prediabetes.

Quantification of epicardial adipose tissue in coronary calcium score and CT coronary angiography image data sets: comparison of attenuation values, thickness and volumes

OBJECTIVE

The aim of the study was to compare epicardial adipose tissue (EAT) characteristics assessed with coronary calcium score (CS) and CT coronary angiography (CTCA) image data sets.

METHODS

In 76 patients (mean age 59 ± 13 years) who underwent CS and CTCA owing to suspected coronary artery disease (CAD), EAT was quantified in terms of density (Hounsfield units), thickness and volume. The EAT volume was extracted with a semi-automatic software.

RESULTS

A moderate correlation was found between EAT density in CS and CTCA image data sets (-100 ± 19 HU vs -70 ± 24 HU; p < 0.05, r = 0.55). The distribution of EAT was not symmetrical with a maximal thickness at the right atrioventricular groove (14.2 ± 5.3 mm in CS, 15.7 ± 5 mm in CTCA; p > 0.05, r = 0.76). The EAT volume resulted as 122 ± 50 cm(3) in CS and 86 ± 40 cm(3) in CTCA (Δ = 30%, p < 0.05, r = 0.92). After adjustment for post-contrast EAT attenuation difference (Δ = 30 HU), the volume was 101 ± 47 cm(3) (Δ = 17%, p < 0.05, r = 0.92). Based on EAT volume median values, no differences were found between groups with smaller and larger volumes in terms of Agatston score and CAD severity.

CONCLUSION

CS and CTCA image data sets may be equally employed for EAT assessment; however, an underestimation of volume is found with the latter acquisition even after post-contrast attenuation adjustment.

ADVANCES IN KNOWLEDGE

EAT may be measured by processing either the CS or CTCA image data sets.

Metabolic imaging in obesity: underlying mechanisms and consequences in the whole body

Obesity is a phenotype resulting from a series of causative factors with a variable risk of complications. Etiologic diversity requires personalized prevention and treatment. Imaging procedures offer the potential to investigate the interplay between organs and pathways underlying energy intake and consumption in an integrated manner, and may open the perspective to classify and treat obesity according to causative mechanisms. This review illustrates the contribution provided by imaging studies to the understanding of human obesity, starting with the regulation of food intake and intestinal metabolism, followed by the role of adipose tissue in storing, releasing, and utilizing substrates, including the interconversion of white and brown fat, and concluding with the examination of imaging risk indicators related to complications, including type 2 diabetes, liver pathologies, cardiac and kidney diseases, and sleep disorders. The imaging modalities include (1) positron emission tomography to quantify organ-specific perfusion and substrate metabolism; (2) computed tomography to assess tissue density as an indicator of fat content and browning/ whitening; (3) ultrasounds to examine liver steatosis, stiffness, and inflammation; and (4) magnetic resonance techniques to assess blood oxygenation levels in the brain, liver stiffness, and metabolite contents (triglycerides, fatty acids, glucose, phosphocreatine, ATP, and acetylcarnitine) in a variety of organs.

Incremental diagnostic value of epicardial adipose tissue for the detection of functionally relevant coronary artery disease

BACKGROUND AND AIM

To determine the incremental diagnostic value of epicardial adipose tissue (EAT) volume in addition to the coronary artery calcium (CAC) score for detecting hemodynamic significant coronary artery disease (CAD).

METHODS AND RESULTS

122 patients (mean age 61 ± 10 years, 61% male) without a previous cardiac history underwent a non-contrast CT scan for calcium scoring and EAT volume measurements. Subsequently all patients underwent invasive coronary angiography (ICA) in conjunction with fractional flow reserve (FFR) measurements. A stenosis >90% and/or a FFR ≤0.80 were considered significant. Mean EAT volume and CACscore were 128 ± 51 cm(3) and 418 ± 704, respectively. The correlation between EAT volume and the CACscore was poor (r = 0.11, p = 0.24). Male gender (odds ratio [OR] 2.86, p = 0.01), CACscore ([cut-off value 100] OR 3.31, p = 0.003, and EAT volume ([cut-off value 92 cm(3)] OR 4.28, p = 0.01) were associated with flow-limiting disease. The multivariate model revealed that only male gender (OR 2.50, p = 0.045), CAC score (OR 3.60, p = 0.005), and EAT volume (OR 4.95, p = 0.02) were independent predictors of myocardial ischemia. Using the cut-off values of 100 (CAC score) and 92 cm(3) (EAT volume), sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for detecting functionally relevant CAD as indicated by FFR were 71, 57, 77, 50 and 63% and 91, 29, 85, 44 and 52% for the CACscore and EAT volume, respectively. Adding EAT volume to the CAC score and cardiovascular risk factors did not enhance diagnostic performance for the detection of significant CAD (p = 0.57).

CONCLUSION

EAT volume measurements have no diagnostic value beyond calcium scoring and cardiovascular risk factors in the detection of hemodynamic significant CAD.

The Relationship Between Epicardial Adipose Tissue Thickness and Infarct-Related Artery Patency in Patients With ST-Segment Elevation Myocardial Infarction

We investigated the relationship between epicardial adipose tissue (EAT) and infarct-related artery (IRA) patency before mechanical reperfusion in patients with ST-segment elevation myocardial infarction (STEMI). Patients (n = 640) were divided into 2 groups based on the thrombolysis in myocardial infarction (TIMI) flow grade. Impaired flow was defined as TIMI grades 0, 1, and 2, and normal flow was defined as TIMI 3. On the admission angiography, 65 (10.2%) patients had TIMI 3 flow, and the remaining 575 (89.8%) had TIMI 0, 1, or 2 flow. The impaired flow group patients had a higher incidence of diabetes mellitus (53.7% vs 41.5%, P = .035), higher EAT thickness (5.66 ± 1.84 vs 4.87 ± 2.09 mm, P = .001), and lower ejection fraction (43.1% ± 8.9% vs 47.4% ± 9.1%, P = .025). Multivariate stepwise logistic regression analysis showed that IRA patency was independently associated with EAT thickness (odds ratio [OR] 0.785; 95% confidence interval [CI] 0.712-0.858; P = .001) and neutrophil–lymphocyte ratio (OR 0.815; 95% CI 0.732-0.917; P = .025). Thickness of EAT was an independent predictor of lower TIMI flow in IRA in patients with STEMI.

Quantification of epicardial fat: Which method can predict significant coronary artery disease?

AIM: To compare the predictive value of three methods of epicardial fat (EF) assessment for presence of significant coronary artery disease (CAD) [i.e., epicardial fat volume (EFV), EFV indexed with body surface area (EFV/BSA) and EFV indexed with body mass index (EFV/BMI)].

METHODS: The study was performed on 170 patients (85 women and 85 men) with clinical suspicion of CAD. They aged 26-89 years with a median age of 54 years. The patients were classified into three groups: Group 1: 58 patients with normal coronary arteries; group 2: 48 patients with non-significant CAD and group 3: 64 patients with significant CAD. The three methods for assessment of epicardial fat were retrospectively studied to determine the best method to predict the presence of significant CAD.

RESULTS: The three methods for epicardial fat quantification and measurements, i.e., EFV, EFV/BSA and EFV/BMI with post- hoc analysis showed a significant difference between patients with significant coronary artery disease compared to the normal group. Receiver operating characteristic curve analysis showed no significant difference between the three methods of epicardial fat measurements, the area under curve ranging between 0.6 and 0.62. The optimal cut-off was 80.3 cm³ for EFV, 2.4 cm³/m² for EFV indexed with BMI and 41.7 cm³/(kg/m²) for EFV indexed with BSA. For this cut-off the sensitivity ranged between 0.92 and 0.94, while specificity varied from 0.31 to 0.35.

CONCLUSION: Any one of the three methods for assessment of epicardial fat can be used to predict significant CAD since all have the same equivalent predictive value.

Adipose Tissue in Metabolic Syndrome: Onset and Progression of Atherosclerosis

Metabolic syndrome (MetS) should be considered a clinical entity when its different symptoms share a common etiology: obesity/insulin resistance as a result of a multi-organ dysfunction. The main interest in treating MetS as a clinical entity is that the addition of its components drastically increases the risk of atherosclerosis. In MetS, the adipose tissue plays a central role along with an unbalanced gut microbiome, which has become relevant in recent years. Once visceral adipose tissue (VAT) increases, dyslipidemia and endothelial dysfunction follow as additive risk factors. However, when the nonalcoholic fatty liver is present, risk of a cardiovascular event is highly augmented. Epicardial adipose tissue (EAT) seems to increase simultaneously with the VAT. In this context, the former may play a more important role in the development of the atherosclerotic plaque than the latter. Hence, EAT may act as a paracrine tissue vis-à-vis the coronary arteries favoring the local inflammation and the atheroma calcification.

Evaluation of body composition changes, epicardial adipose tissue, and serum omentin-1 levels in overt hypothyroidism

Our aim was to investigate body composition changes, epicardial adipose tissue thickness (EATT), serum omentin-1 levels, and the relationship among them along with some atherosclerosis markers in overt hypothyroidism. Twenty-eight newly diagnosed overt hypothyroid patients were evaluated before and after 6 months of thyroid hormone replacement therapy (THRT) and compared to the healthy subjects in this prospective longitudinal study. Body compositions were measured with dual-energy X-ray absorptiometry, and EATT was measured by echocardiography. Carotid intima-media thickness (c-IMT), flow-mediated dilatation (FMD), thyroid hormone levels, lipid parameters, high sensitive c-reactive protein, homocysteine, and omentin-1 levels were measured in all subjects. Body weight and lean body mass were higher in patients with hypothyroidism compared to euthyroid state after THRT (p = 0.012, 0.034, respectively). EATT was higher in patients with hypothyroidism than the control group (p < 0.001) and decreased with THRT (p = 0.012) but still remained higher than the control group (p < 0.001). Free T4 levels were found to be an independent factor to predict EATT (p < 0.001). In hypothyroid state, omentin-1 levels were lower than controls (p = 0.037) but increased in 6 months with THRT (p = 0.001). The c-IMT was higher, and FMD was lower in hypothyroidism compared to euthyroid state and control group (p < 0.05). Increasing lean body mass, but not adipose tissue mass, was found to be responsible for weight gain in hypothyroidism. The increased amount of EATT and decreased omentin-1 levels can contribute to the development of atherosclerosis in addition to other factors in hypothyroidism.

Lack of association between epicardial fat volume and extent of coronary artery calcification, severity of coronary artery disease, or presence of myocardial perfusion abnormalities in a diverse, symptomatic patient population: results from the CORE320 multicenter study

BACKGROUND

Epicardial fat may play a role in the pathogenesis of coronary artery disease (CAD). We explored the relationship of epicardial fat volume (EFV) with the presence and severity of CAD or myocardial perfusion abnormalities in a diverse, symptomatic patient population.

METHODS AND RESULTS

Patients (n=380) with known or suspected CAD who underwent 320-detector row computed tomographic angiography, nuclear stress perfusion imaging, and clinically driven invasive coronary angiography for the CORE320 international study were included. EFV was defined as adipose tissue within the pericardial borders as assessed by computed tomography using semiautomatic software. We used linear and logistic regression models to assess the relationship of EFV with coronary calcium score, stenosis severity by quantitative coronary angiography, and myocardial perfusion abnormalities by single photon emission computed tomography (SPECT). Median EFV among patients (median age, 62.6 years) was 102 cm(3) (interquartile range: 53). A coronary calcium score of ≥1 was present in 83% of patients. Fifty-nine percent of patients had ≥1 coronary artery stenosis of ≥50% by quantitative coronary angiography, and 49% had abnormal myocardial perfusion results by SPECT. There were no significant associations between EFV and coronary artery calcium scanning, presence severity of ≥50% stenosis by quantitative coronary angiography, or abnormal myocardial perfusion by SPECT.

CONCLUSIONS

In a diverse population of symptomatic patients referred for invasive coronary angiography, we did not find associations of EFV with the presence and severity of CAD or with myocardial perfusion abnormalities. The clinical significance of quantifying EFV remains uncertain but may relate to the pathophysiology of acute coronary events rather than the presence of atherosclerotic disease.

Evaluation of epicardial fat tissue thickness as a marker of cardiovascular risk in patients with subclinical hypothyroidism

BACKGROUND

Epicardial fat thickness (EFT) has been evaluated as a marker of cardiovascular disease, with good correlation with classical cardiovascular risk factors in the general population. The aim of this study was to evaluate the EFT in subclinical hypothyroidism (SCH), in comparison to a group without thyroid dysfunction.

METHODS

A cross-sectional study was performed with 100 participants, including 52 SCH patients and 48 individuals without any thyroid dysfunction (euthyroid group-EU). Transthoracic echocardiography (TE), thyroid hormone levels, lipid profile, and assessment of body composition by bioelectrical impedance (BIA) and anthropometry were measured in all subjects.

RESULTS

The SCH and EU groups were comparable with respect to age, gender, and Framingham risk scores. Serum thyroid-stimulating hormone (TSH) was 6.7 ± 1.4 mIU/L in the SCH group and 2.0 ± 0.84 mIU/L in the control group. EFT was similar in both groups (SCH 3.5 ± 1.3 mm, EU 3.5 ± 1.1 mm, p = 0.43). EFT showed a slight trend for a positive correlation with serum TSH in the SCH group (r s = 0.263, p = 0.05). EFT correlated with the body fat percentage in the SCH group (r s = 0.350, p = 0.03) and EU group (r s = 0.033, p = 0.04). EFT in this cohort was not independently correlated to changes in TSH and Framingham risk score.

CONCLUSIONS

EFT determination by TE does not seem to be a good marker of cardiovascular risk in SCH patients with serum TSH <10.0 mIU/L and no pre-existing cardiovascular morbidity.

Adipokines, Vascular Wall, and 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.

Epicardial fat thickness in patients with prediabetes and correlation with other cardiovascular risk markers

OBJECTIVE

Prediabetes is a condition between a normal metabolic state and diabetes mellitus, which includes impaired glucose tolerance (IGT), impaired fasting glucose (IFG), or both. Prediabetes is related with undesirable cardiovascular outcomes. Epicardial fat thickness (EFT) has been correlated with cardiovascular risk factors. We herein aimed to assess EFT in prediabetic patients.

METHODS

We evaluated 64 patients with prediabetes and 30 age- and gender-matched healthy subjects. Demographic and anthropometric characteristics [age, sex, height, weight, body mass index (BMI), and waist circumference (WC)] and laboratory findings [fasting plasma glucose (FPG), postprandial plasma glucose (PPG), hemoglobin A1c (HbA1c), low density lipoprotein (LDL), high density lipoprotein (HDL), and triglycerides (TG)] were assessed. Transthoracic echocardiography was used to evaluate EFT.

RESULTS

There were no significant differences between the case and control groups in terms of age, gender, height, HDL, WC, systolic and diastolic blood pressure (SBP/DBP), or TG (p>0.05). Body weight, BMI, FPG, LDL, and, in particular, EFT were found to be significantly higher in the case group than control group (p<0.05). When compared with the control group, the median EFT was significantly higher in all prediabetic subgroups (IGT or IFG, p<0.001). However, no statistically significant difference was found between each case subgroup (p=0.795). When groups were adjusted according to age, sex, WC, and BMI with covariance test, the EFT remained increased in the prediabetes subgroups compared to the controls (p<0.001).

CONCLUSION

We found the EFT levels to be increased in all subgroups of prediabetic patients regardless of FPG and HbA1c. Furthermore, EFT directly correlated with the patients' BMI and WC.

Epicardial fat volume correlates with severity of coronary artery disease in nonobese patients

OBJECTIVE

It has been reported that epicardial adipose tissue could locally modulate the coronary artery functions through secretion of proinflammatory and anti-inflammatory cytokines. Epicardial fat tissue is further implicated in the pathogenesis of coronary artery disease (CAD) because of its proximity to the adventitia of the major epicardial coronary arteries. We investigated the relationship between epicardial fat volume (EFV) and severity of CAD in nonobese patients using 64-slice multidetector computed tomography (MDCT).

METHODS

One hundred and forty nonobese patients (BMI <25 kg/m2) were enrolled. EFV and visceral fat area were measured by MDCT. Patients were classified according to the plaque components (noncalcified, mixed and calcified) and severity of CAD. Inflammatory biomarkers were also measured, and compared with each CT parameter.

RESULTS

EFV was significantly correlated with the extent or severity of CAD. Patients with noncalcified or mixed plaque had a greater EFV than those with calcified plaque. Log-transferred high sensitivity C-reactive protein (CRP) was significantly correlated with EFV (r = 0.24, P = 0.04). Adiponectin level was significantly inversely correlated with visceral fat area (r = 0.38, P = 0.0001).

CONCLUSION

Increased EFV is associated with more severe CAD and noncalcified or mixed coronary plaques in nonobese patients.

Ageing, adipose tissue, fatty acids and inflammation

A common feature of ageing is the alteration in tissue distribution and composition, with a shift in fat away from lower body and subcutaneous depots to visceral and ectopic sites. Redistribution of adipose tissue towards an ectopic site can have dramatic effects on metabolic function. In skeletal muscle, increased ectopic adiposity is linked to insulin resistance through lipid mediators such as ceramide or DAG, inhibiting the insulin receptor signalling pathway. Additionally, the risk of developing cardiovascular disease is increased with elevated visceral adipose distribution. In ageing, adipose tissue becomes dysfunctional, with the pathway of differentiation of preadipocytes to mature adipocytes becoming impaired; this results in dysfunctional adipocytes less able to store fat and subsequent fat redistribution to ectopic sites. Low grade systemic inflammation is commonly observed in ageing, and may drive the adipose tissue dysfunction, as proinflammatory cytokines are capable of inhibiting adipocyte differentiation. Beyond increased ectopic adiposity, the effect of impaired adipose tissue function is an elevation in systemic free fatty acids (FFA), a common feature of many metabolic disorders. Saturated fatty acids can be regarded as the most detrimental of FFA, being capable of inducing insulin resistance and inflammation through lipid mediators such as ceramide, which can increase risk of developing atherosclerosis. Elevated FFA, in particular saturated fatty acids, maybe a driving factor for both the increased insulin resistance, cardiovascular disease risk and inflammation in older adults.

[Epicardial fat: Imaging and implications for diseases of the cardiovascular system]

Since the discovery of the obese (ob) gene product leptin, fat has been considered an endocrine organ. Especially epicardial fat has gained increasing attention in recent years. The epicardial fat plays a major role in fat metabolism; however, harmful properties have also been reported. Echocardiography, computed tomography and cardiac magnetic resonance imaging are the non-invasive tools used to measure epicardial fat volume. This review briefly introduces the basic physiological and pathophysiological considerations concerning epicardial fat. The main issue of this review is the presentation of non-invasive measurement techniques of epicardial fat using various imaging modalities and a literature overview of associations between epicardial fat and common cardiovascular diseases.

Dietary and nutraceutical approach to type 2 diabetes

Nutritional medical treatment is the first step to achieve adequate glycemic control and prevent diabetic complications. Lifestyle changes include moderate weight loss (7%) and regular physical activity (150 min/week). The appropriate diet composition is < 30% total fat, < 10% saturated fats, > 15 g/1000 kcal fiber, half soluble, 45-60% of carbohydrates with amoderate intake of sugar (50 g/day) and protein intake of 15-20% of the total calories a day. Patients need to limit the intake of saturated fats to < 7% of the daily calorie intake. Monounsaturated fatty acids such as olive oil and other vegetable oils are recommended. L-carnitine, α-lipoic acid, berberine and ω-3 fatty acids can be useful supplements.

Epicardial fat: definition, measurements and systematic review of main outcomes

Epicardial fat (EF) is a visceral fat deposit, located between the heart and the pericardium, which shares many of the pathophysiological properties of other visceral fat deposits, It also potentially causes local inflammation and likely has direct effects on coronary atherosclerosis. Echocardiography, computed tomography and magnetic resonance imaging have been used to evaluate EF, but variations between methodologies limit the comparability between these modalities.

We performed a systematic review of the literature finding associations of EF with metabolic syndrome and coronary artery disease. The summarization of these associations is limited by the heterogeneity of the methods used and the populations studied, where most of the subjects were at high cardiovascular disease risk.

EF is also associated with other known factors, such as obesity, diabetes mellitus, age and hypertension, which makes the interpretation of its role as an independent risk marker intricate. Based on these data, we conclude that EF is a visceral fat deposit with potential implications in coronary artery disease. We describe the reference values of EF for the different imaging modalities, even though these have not yet been validated for clinical use. It is still necessary to better define normal reference values and the risk associated with EF to further evaluate its role in cardiovascular and metabolic risk assessment in relation to other criteria currently used.

Relation of coronary collateral circulation with epicardial fat volume in patients with stable coronary artery disease

Objective

To investigated the relationship between epicardial fat volume (EFV) and coronary collateral circulation (CCC) in patients with stable coronary artery disease (CAD).

Methods

The study population consisted of 152 consecutive patients with CAD who underwent coronary angiography and were found to have at least 95% significiant lesion in at least one major coronary artery. EFV was assessed utilizing 64-multislice computed tomography. The patients were classifield into impaired CCC group (Group 1, Rentrop grades 0−1, n = 58), or adequate CCC (Group 2, Rentrop grades 2−3, n = 94).

Results

The EFV values were significantly higher in paitients with adequate CCC than in those with impaired CCC. In multivariate logistic regression analysis, EFV (OR = 1.059; 95% CI: 1.035−1.085; P = 0.001); and presence of angina were independent predictors of adequate CCC. In receiver-operating characteristic curve analysis, the EFV value > 106.5 mL yielded an area under the curve value of 0.84, with the test sensitivity of 49.3%, and with 98.3% specifity.

Conclusions

High EFV, and the presence of angina independently predict adequate CCC in patients with stable coronary artery disease. This association offers new diagnostic opportinities to assess collateral flow by conventional ultrasound techniques.

Relationship between epicardial adipose tissue and subclinical coronary artery disease in patients with extra-cardiac arterial disease

OBJECTIVE

Epicardial adipose tissue (EAT) and mediastinal adipose tissue (MAT) are linked to coronary artery disease (CAD). The association between EAT, MAT, and severity of CAD in known extra-cardiac arterial disease was investigated.

DESIGN AND METHODS

Sixty-five cardiac asymptomatic patients (mean age 65 ± 8 years, 69% male) with peripheral arterial disease, carotid stenosis, or aortic aneurysm underwent coronary computed tomography angiography. Patients were divided into non-significant (<50% stenosis, N = 35), single vessel (N = 15) and multi-vessel CAD (N = 15). EAT and MAT were quantified on computed tomography images using volumetric software.

RESULTS

Subgroups did not significantly differ by age, gender, or cardiovascular risk factors. Median EAT was 99.5, 98.0, and 112.0 cm(3) (P = 0.38) and median MAT was 66.0, 90.0, and 81.0 cm(3) (P = 0.53) for non-significant, single vessel, and multi-vessel CAD, respectively. In age- and gender-adjusted analysis, only EAT was significantly associated with CAD (odds ratio [OR] 1.12 [95% confidence interval, 1.01-1.25] per 10 cm(3) increase in EAT; P = 0.04). This remained in multivariate-adjusted analysis (OR 1.21 [1.04-1.39]; P = 0.01).

CONCLUSIONS

In patients with known extra-cardiac arterial disease, CAD is correlated with EAT, but not with MAT. These results suggest that EAT has a local effect on coronary atherosclerosis, apart from the endocrine effect of visceral fat.

Hybrid myocardial imaging for risk stratification prior to kidney transplantation: added value of coronary calcium and epicardial adipose tissue

BACKGROUND

Patient selection and optimal approach to risk stratification prior to kidney transplantation remain uncertain. We sought new predictors of an abnormal myocardial perfusion (MYP) stress test result.

METHODS

Retrospective study of 411 consecutive chronic kidney disease stages 4-5D patients awaiting kidney transplantation referred for risk stratification. PET-CT or SPECT-CT was used to assess MYP and quantify coronary artery calcium (CAC) and epicardial adipose tissue (EAT). Abnormal MYP was defined as a perfusion defect involving ≥5% of the left ventricular myocardium.

RESULTS

Fixed or reversible MYP defects were present in 41 patients (10%). Male sex, smoking, and history of cardiovascular disease were more prevalent; age was higher and CAC and EAT were greater in patients with MYP defects than in those with normal MYP. On multivariate logistic regression, EAT and CAC were independent predictors of abnormal MYP while diabetes mellitus showed a borderline association (P = .08). EAT added incremental diagnostic value to a model including age, CAC and diabetes mellitus [AUC 0.73 (95% CI 0.64-0.81) to 0.76 (95% CI 0.68-0.84; P = .02)]. Furthermore, the model containing EAT showed improved diagnostic discrimination.

CONCLUSIONS

Abnormal MYP on screening stress testing appears to be rare in patients awaiting kidney transplantation suggesting an excess of testing. EAT and CAC may help predict what patients are at higher risk of developing abnormalities of MYP under stress.

Increased epicardial adipose tissue thickness as a predictor for hypertension: a cross-sectional observational study

The aim of the study was to determine whether epicardial adipose tissue thickness (EAT), a new cardiometabolic risk factor, is associated with essential hypertension. The sample included 127 asymptomatic patients with one or more cardiovascular risk factors consecutively referred for cardiac computed tomography angiography. Data were collected retrospectively and compared between hypertensive (n=39) and normotensive (n=88) patients. The hypertensive patients had a significantly higher mean EAT thickness than the normotensive group (2.81±1.6 mm vs 2.07±1.43 mm; P=.011) and a significantly elevated mean coronary artery calcium score (316.8±512.6 vs 108.73±215; P=.0257). The odds ratio for a patient with tissue thickness ≥2.4 mm having hypertension was 1.396 (95% confidence interval, 1.033-1.922). Factors independently associated with hypertension were body mass index, low-density lipoprotein, and age. A model score was developed using the logistic regression coefficients for calculation of individual risk. Hypertensive patients have significantly higher than normal EAT thickness. Epicardial adipose tissue thickness may serve as a risk indicator for hypertension and cardiovascular morbidity.

Association of epicardial fat thickness with TIMI risk score in NSTEMI/USAP patients

BACKGROUND

The association of epicardial adipose tissue (EAT) with coronary artery disease has been shown in previous studies. Furthermore, the relationship between EAT and acute coronary syndrome was studied recently. Herein, we investigated the relationship between EAT thickness and the thrombolysis in myocardial infarction (TIMI) risk score for non-ST-elevation myocardial infarction (NSTEMI) and unstable angina pectoris (USAP).

PATIENTS AND METHODS

The study included 144 patients with NSTEMI/USAP. The study population was divided into two subgroups according to TIMI risk scores as group I (≤ 4, n = 86) and group II (> 4, n = 58). Stepwise multivariable logistic regression analysis was used to assess the independent association of clinical parameters with TIMI risk score.

RESULTS

EAT thickness was higher in group II than in group I (8.2 ± 2.1 vs. 6.2 ± 2.2, p < 0.001). Moreover, patients in group II had higher rates of multivessel disease and Gensini score (p < 0.001). In univariate linear regression analysis, EAT was positively correlated with TIMI risk score and Gensini score. Multivariate regression analysis showed that EAT thickness (OR: 1.56, 95 % CI: 1.17-2.08, p = 0.003), LVEF (OR: 0.93, 95 % CI: 0.85-0.98, p = 0.03), and Gensini score (OR: 1.36, 95 % CI: 1.24-1.98, p = 0.002) were independently associated with a higher TIMI risk score.

CONCLUSION

In conclusion, EAT thickness is independently associated with TIMI risk score and may be an emerging risk factor for adverse events in NSTEMI/USAP patients.

Relationship of epicardial fat volume to coronary plaque, severe coronary stenosis, and high-risk coronary plaque features assessed by coronary CT angiography

BACKGROUND

Associations of epicardial fat volume (EFV) measured on noncontrast cardiac CT (NCT) include coronary plaque, myocardial ischemia, and adverse cardiac events.

OBJECTIVES

This study aimed to define the relationship of EFV to coronary plaque type, severe coronary stenosis, and the presence of high-risk plaque features (HRPFs).

METHODS

We retrospectively evaluated 402 consecutive patients, with no prior history of coronary artery disease, who underwent same day NCT and coronary CT angiography (CTA). EFV was measured on NCT with the use of validated, semiautomated software. The coronary arteries were evaluated for coronary plaque type (calcified [CP], noncalcified [NCP], or partially calcified [PCP]) and coronary stenosis severity ≥70% with the use of coronary CTA. For patients with NCP and PCP, 2 high-risk plaque features were evaluated: low-attenuation plaque and positive remodeling.

RESULTS

There were 402 patients with a median age of 66 years (range, 23-92 years) of whom 226 (56%) were men. The EFV was greater in patients with CP (112 ± 55 cm(3) vs 89 ± 39 cm(3)), PCP (110 ± 57 cm(3) vs 98 ± 45 cm(3)), and NCP (115 ± 44 cm(3) vs EFV 100 ± 52 cm(3)). In the 192 patients with PCP or NCP, on multivariable analysis, after adjusting for conventional cardiovascular risk factors, EFV was an independent predictor of ≥70% coronary artery stenosis (odds ratio [OR], 3.0; 95% CI, 1.3-6.6; P = 0.008), any high-risk plaque features (OR, 1.7; 95% CI, 0.9-3.4; P = 0.04), and low attention plaque (OR, 2.4; 95% CI, 1.1-5.1; P = 0.02) but not of positive remodeling.

CONCLUSIONS

EFV is greater in patients with CP, PCP, and NCP. In patients with NCP and PCP, EFV is significantly associated with severe coronary stenosis, high-risk plaque features, and low attenuation plaque.

Quantification of epicardial fat by computed tomography: why, when and how?

In the past decade, interest has grown in the relation between epicardial fat and cardiovascular disease. Several imaging modalities such as echocardiography, computed tomography, and magnetic resonance imaging can be used to quantify epicardial adipose tissue. Computed tomography provides high spatial resolution and true volume coverage of the heart; therefore, it constitutes an attractive approach to quantifying epicardial fat. An increasing body of evidence has been accumulated which shows a relation between epicardial fat volume and coronary atherosclerosis, cardiovascular outcomes, and even non-atherosclerotic heart disease such as atrial fibrillation. The association of increased epicardial fat volume with cardiac disease remains significant even after correction for weight, body mass index, and traditional cardiovascular risk factors. The mechanisms have not been reliably identified, but metabolic properties of epicardial fat may play a role. At the present time, epicardial fat quantification is not included in recommended algorithms for risk stratification. However, the available data are intriguing enough to warrant further research.

Epicardial and subcutaneous adipose tissue Fatty acids profiles in diabetic and non-diabetic patients candidate for coronary artery bypass graft

INTRODUCTION

We have recently shown that in high cholesterol-fed rabbits, the sensitivity of epicardial adipose tissue to changes in dietary fat is higher than that of subcutaneous adipose tissue. Although the effects of diabetes on epicardial adipose tissue thickness have been studied, the influence of diabetes on profile of epicardial free fatty acids (FFAs) has not been studied. The aim of this study is to investigate the effect of diabetes on the FFAs composition in serum and in the subcutaneous and epicardial adipose tissues in patients undergoing coronary artery bypass graft (CABG).

METHODS

Forty non-diabetic and twenty eight diabetic patients candidate for CABG with >75% stenosis participated in this study. Fasting blood sugar (FBS) and lipid profiles were assayed by auto analyzer. Phospholipids and non-estrified FFA of serum and the fatty acids profile of epicardial and subcutaneous adipose tissues were determined using gas chromatography method.

RESULTS

In the phospholipid fraction of diabetic patients' serum, the percentage of 16:0, 18:3n-9, 18:2n-6 and monounsaturated fatty acids (MUFAs) was lower than the corresponding values of the non-diabetics; whereas, 18:0 value was higher. A 100% increase in the amount of 18:0 and 35% decrease in the level of 18:1n-11 was observed in the diabetic patients' subcutaneous adipose tissue. In epicardial adipose tissue, the increase of 18:0 and conjugated linolenic acid (CLA) and decrease of 18:1n-11, w3 (20:5n-3) and 22:6n-3 were significant; but, the contents of arachidonic acid and its precursor linoleic acid were not affected by diabetes.

CONCLUSION

The fatty acids' profile of epicardial and subcutaneous adipose tissues is not equally affected by diabetes. The significant decrease of 16:0 and w3 fatty acids and increase of trans and conjugated fatty acids in epicardial adipose tissue in the diabetic patients may worsen the formation of atheroma in the related arteries.