Epicardial fat amount is associated with the magnitude of left ventricular remodeling in aortic stenosis

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

Immune response following transcatheter aortic valve procedure

Aortic valve stenosis is the most common type of heart valve disease in the United States and Europe and calcific aortic stenosis (AS) affects 2-7% of people aged 65 years and older. Aortic valve replacement (AVR) is the only effective treatment for individuals with this condition. Transcatheter Aortic Valve Replacement (TAVR) has been widely accepted as a minimally invasive therapeutic approach for addressing symptomatic AS in patients who are considered to have a high risk for traditional surgical intervention. TAVR procedure may have a paradoxical effect on the immune system and inflammatory status. A major portion of these immune responses is regulated by activating or inhibiting inflammatory monocytes and the complement system with subsequent changes in inflammatory cytokines. TAVR has the potential to induce various concurrent exposures, including disruption of the native valve, hemodynamic changes, antigenicity of the bioprosthesis, and vascular damage, which finally lead to the development of inflammation. On the other hand, it is important to acknowledge that TAVR may also have anti-inflammatory effects by helping in the resolution of stenosis.The inflammation and immune response following TAVR are complex processes that significantly impact procedural outcomes and patient well-being. Understanding the underlying mechanisms, identifying biomarkers of inflammation, and exploring therapeutic interventions to modulate these responses are crucial for optimizing TAVR outcomes. Further research is warranted to elucidate the precise immunological dynamics and develop tailored strategies to attenuate inflammation and enhance post-TAVR healing while minimizing complications.

Exploring the significance of epicardial adipose tissue in aortic valve stenosis and left ventricular remodeling: Unveiling novel therapeutic and prognostic markers of disease

Aortic stenosis (AS) is a dynamic degenerative process that shares many pathophysiological features with atherogenesis, from initial proinflammatory calcification and focal thickening of the valve leaflets to obstruction of left ventricular outflow due to superimposed of severe calcification and immobilization of the valve leaflets. As the prevalence increases with age, AS is expected to become one of the most common heart diseases worldwide. In both obese and nonobese patients, persistent thickening of epicardial adipose tissue (EAT) is associated with a shift in its normal metabolic functions toward a dysmetabolic and proatherogenic phenotype that may impair the physiology of adjacent coronary arteries and promote the occurrence of coronary atherosclerosis. In tight analogy with atherosclerosis, recent clinical evidence indicates that EAT may also exert a deleterious role in promoting AS and contributing to myocardial dysfunction, leading to increased health risk for elderly patients with AS and an economic burden on the health care system. This review discusses the clinical and pathologic evidence for the association between EAT and AS and concomitant left ventricular hypertrophy, and provides new insights for the future direction of AS diagnosis and treatment.

Epicardial fat volume is associated with preexisting atrioventricular conduction abnormalities and increased pacemaker implantation rate in patients undergoing transcatheter aortic valve implantation

Epicardial fat tissue (EFT) is a highly metabolically active fat depot surrounding the heart and coronary arteries that is related to early atherosclerosis and adverse cardiac events. We aimed to investigate the relationship between the amount of EFT and preexisting cardiac conduction abnormalities (CCAs) and the need for new postinterventional pacemaker in patients with severe aortic stenosis planned for transcatheter aortic valve implantation (TAVI). A total of 560 consecutive patients (54% female) scheduled for TAVI were included in this retrospective study. EFT volume was measured via a fully automated artificial intelligence software (QFAT) using computed tomography (CT) performed before TAVI. Baseline CCAs [first-degree atrioventricular (AV) block, right bundle branch block (RBBB), and left bundle branch block (LBBB)] were diagnosed according to 12-lead ECG before TAVI. Aortic valve calcification was determined by the Agatston score assessed in the pre-TAVI CT. The median EFT volume was 129.5 ml [IQR 94-170]. Baseline first-degree AV block was present in 17%, RBBB in 10.4%, and LBBB in 10.2% of the overall cohort. In adjusted logistic regression analysis, higher EFT volume was associated with first-degree AV block (OR 1.006 [95% CI 1.002-1.010]; p = 0.006) and the need for new pacemaker implantation after TAVI (OR 1.005 [95% CI 1.0-1.01]; p = 0.035) but not with the presence of RBBB or LBBB. EFT volume did not correlate with the Agatston score of the aortic valve. Greater EFT volume is associated independently with preexisting first-degree AV block and new pacemaker implantation in patients undergoing TAVI. It may play a causative role in degenerative processes and the susceptibility of the AV conduction system.

Inflammation and Cardiovascular Diseases in the Elderly: The Role of Epicardial Adipose Tissue

Human aging is a complex phenomenon characterized by a wide spectrum of biological changes which impact on behavioral and social aspects. Age-related changes are accompanied by a decline in biological function and increased vulnerability leading to frailty, thereby advanced age is identified among the major risk factors of the main chronic human diseases. Aging is characterized by a state of chronic low-grade inflammation, also referred as inflammaging. It recognizes a multifactorial pathogenesis with a prominent role of the innate immune system activation, resulting in tissue degeneration and contributing to adverse outcomes. It is widely recognized that inflammation plays a central role in the development and progression of numerous chronic and cardiovascular diseases. In particular, low-grade inflammation, through an increased risk of atherosclerosis and insulin resistance, promote cardiovascular diseases in the elderly. Low-grade inflammation is also promoted by visceral adiposity, whose accumulation is paralleled by an increased inflammatory status. Aging is associated to increase in epicardial adipose tissue (EAT), the visceral fat depot of the heart. Structural and functional changes in EAT have been shown to be associated with several heart diseases, including coronary artery disease, aortic stenosis, atrial fibrillation, and heart failure. EAT increase is associated with a greater production and secretion of pro-inflammatory mediators and neuro-hormones, so that thickened EAT can pathologically influence, in a paracrine and vasocrine manner, the structure and function of the heart and is associated to a worse cardiovascular outcome. In this review, we will discuss the evidence underlying the interplay between inflammaging, EAT accumulation and cardiovascular diseases. We will examine and discuss the importance of EAT quantification, its characteristics and changes with age and its clinical implication.

Association between single-slice and whole heart measurements of epicardial and pericardial fat in cardiac MRI

BACKGROUND

Epicardial (ECF) and pericardial fat (PCF) are important prognostic markers for various cardiac diseases. However, volumetry of the fat compartments is time-consuming.

PURPOSE

To investigate whether total volume of ECF and PCF can be estimated by axial single-slice measurements and in a four-chamber view.

MATERIAL AND METHODS

A total of 113 individuals (79 patients and 34 healthy) were included in this retrospective magnetic resonance imaging (MRI) study. The total volume of ECF and PCF was determined using a 3D-Dixon sequence. Additionally, the area of ECF and PCF was obtained in single axial layers at five anatomical landmarks (left coronary artery, right coronary artery, right pulmonary artery, mitral valve, coronary sinus) of the Dixon sequence and in a four-chamber view of a standard cine sequence. Pearson's correlation coefficient was calculated between the total volume and each single-slice measurement.

RESULTS

Axial single-slice measurements of ECF and PCF correlated strongly with the total fat volumes at all landmarks (ECF: r  =  0.85-0.94, P < 0.001; PCF: r  =  0.89-0.94, P < 0.001). The best correlation was found at the level of the left coronary artery for ECF and PCF (r  =  0.94, P < 0.001). Correlation between single-slice measurement in the four-chamber view and the total ECF and PCF volume was lower (r  =  0.75 and r  =  0.8, respectively, P < 0.001).

CONCLUSION

Single-slice measurements allow an estimation of ECF and PCF volume. This time-efficient analysis allows studies of larger patient cohorts and the opportunistic determination of ECF/PCF from routine examinations.

The role of inflammation and metabolic risk factors in the pathogenesis of calcific aortic valve stenosis

Given the epidemiologic increase of aged population in the world, aortic stenosis (AS) represents now the most common valvular heart disease in industrialized countries. It is a very challenging disease, representing an important cause of morbidity, hospitalization and death in the elderly population. It is widely recognized that AS is the result of a very complex active process, driven by inflammation and involving multifactorial pathological mechanisms promoting valvular calcification and valvular bone deposition. Several evidence suggest that epicardial adipose tissue (EAT), the visceral fat depot of the heart, represents a direct source of cytokines and could mediate the deleterious effects of systemic inflammation on the myocardium. Importantly, obesity and metabolic disorders are associated with chronic systemic inflammation leading to a significant increase of EAT amount and to a pro-inflammatory phenotypic shift of this fat depot. It has been hypothesized that the EAT inflammatory state can influence the structure and function of the heart, thus contributing to the pathogenesis of several cardiac diseases, including calcific AS. The current review will discuss the recently discovered mechanisms involved in the pathogenesis of AS, with particular attention to the role of inflammation, metabolic risk factors and pro-fibrotic and pro-osteogenic signal pathways promoting the onset and progression of the disease. Moreover, it will be explored the potential role of EAT in the AS pathophysiology.

Pericardial fat and its influence on cardiac diastolic function

BACKGROUND

Pericardial fat (PF) has been suggested to directly act on cardiomyocytes, leading to diastolic dysfunction. The aim of this study was to investigate whether a higher PF volume is associated with a lower diastolic function in healthy subjects.

METHODS

254 adults (40-70 years, BMI 18-35 kg/m2, normal left ventricular ejection fraction), with (a)typical chest pain (otherwise healthy) from the cardiology outpatient clinic were retrospectively included in this study. All patients underwent a coronary computed tomographic angiography for the measurement of pericardial fat volume, as well as a transthoracic echocardiography for the assessment of diastolic function parameters. To assess the independent association of PF and diastolic function parameters, multivariable linear regression analysis was performed. To maximize differences in PF volume, the group was divided in low (lowest quartile of both sexes) and high (highest quartile of both sexes) PF volume. Multivariable binary logistic analysis was used to study the associations within the groups between PF and diastolic function, adjusted for age, BMI, and sex.

RESULTS

Significant associations for all four diastolic parameters with the PF volume were found after adjusting for BMI, age, and sex. In addition, subjects with high pericardial fat had a reduced left atrial volume index (p = 0.02), lower E/e (p < 0.01) and E/A (p = 0.01), reduced e' lateral (p < 0.01), reduced e' septal p = 0.03), compared to subjects with low pericardial fat.

CONCLUSION

These findings confirm that pericardial fat volume, even in healthy subjects with normal cardiac function, is associated with diastolic function. Our results suggest that the mechanical effects of PF may limit the distensibility of the heart and thereby directly contribute to diastolic dysfunction. Trial registration NCT01671930.

BMPER is upregulated in obesity and seems to have a role in pericardial adipose stem cells

Pericardial adipose tissue (PAT), a visceral fat depot enveloping the heart, is an active endocrine organ and a source of free fatty acids and inflammatory cytokines. As in other fat adult tissues, PAT contains a population of adipose stem cells; however, whether these cells and/or their environment play a role in physiopathology is unknown. We analyzed several stem cell-related properties of pericardial adipose stem cells (PSCs) isolated from obese and ex-obese mice. We also performed RNA-sequencing to profile the transcriptional landscape of PSCs isolated from the different diet regimens. Finally, we tested whether these alterations impacted on the properties of cardiac mesoangioblasts isolated from the same mice. We found functional differences between PSCs depending on their source: specifically, PSCs from obese PSC (oPSC) and ex-obese PSC (dPSC) mice showed alterations in apoptosis and migratory capacity when compared with lean, control PSCs, with increased apoptosis in oPSCs and blunted migratory capacity in oPSCs and dPSCs. This was accompanied by different gene expression profiles across the cell types, where we identified some genes altered in obese conditions, such as BMP endothelial cell precursor-derived regulator (BMPER), an important regulator of BMP-related signaling pathways for endothelial cell function. The importance of BMPER in PSCs was confirmed by loss- and gain-of-function studies. Finally, we found an altered production of BMPER and some important chemokines in cardiac mesoangioblasts in obese conditions. Our findings point to BMPER as a potential new regulator of PSC function and suggest that its dysregulation could be associated with obesity and may impact on cardiac cells.

Echocardiography in the Era of Obesity

Patients with obesity are at increased risk for coronary artery disease and heart failure and often present with symptoms of dyspnea, fatigue, edema, or chest pain. Echocardiography is frequently used to help distinguish whether these symptoms are due to cardiac disease. Unfortunately, obesity has a significant impact on image quality because of signal attenuation. Ultrasound-enhancing agents may improve the detection of structural remodeling and subclinical left ventricular dysfunction in patients with obesity. Assessment of chamber sizes and cardiac remodeling in severely obese subjects must be interpreted with caution, however, as the current recommendations for indexing cardiac chamber sizes to body size may lead to false conclusions about chamber volumes or mass, particularly in settings in which weight is changing. As a result of increases in stroke volume and cardiac output, obesity may exacerbate hemodynamic compromise in obstructive structural or valvular disease. With regard to assessment of ischemic heart disease, stress echocardiography can effectively risk-stratify patients with obesity and may have advantages over other noninvasive modalities. In general, transesophageal echocardiography is safe in patients with obesity, although some precautions should be observed. Stress echocardiography using the transesophageal approach is an alternative for preoperative or ischemia evaluation in patients with suboptimal transthoracic views.

Effects of epicardial adipose tissue volume and density on cardiac structure and function in patients free of coronary artery disease

PURPOSE

To determine the association of epicardial adipose tissue (EAT) volume and density with cardiac geometry and function.

METHODS

We included 178 consecutive patients who performed coronary computed tomography angiography but were not diagnosed with coronary artery disease (CAD). The EAT volume, density, and following cardiac structure and function parameters were measured: left ventricular ejection fraction, left ventricular mass (LVM), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular stroke volume (LVSV), left ventricular end-diastolic diameter (LVEDD), interventricular septal thickness (IVST) and posterior wall thickness (PWT). All the parameters were standardized using the height^2.7.

RESULTS

A significant correlation was found between larger EAT volume and increased LVM, LVEDV, LVESV, LVSV, LVEDD, IVST and corresponding standardized indexes (P < 0.05 for all). Higher EAT density significantly correlated with increased LVM, LVEDV, LVESV, LVSV, LVEDD, IVST, PWT and corresponding standardized indexes (P < 0.05 for all). The largest cardiac structure and function parameters were observed in the population with above-median EAT volume and density.

CONCLUSION

Both large EAT volume and high EAT density were associated with cardiac structure and function in patients with no CAD. The EAT density may render complementary information to EAT volume regarding cardiac geometry changes.

Correlative Study on Impaired Prostaglandin E2 Regulation in Epicardial Adipose Tissue and its Role in Maladaptive Cardiac Remodeling via EPAC2 and ST2 Signaling in Overweight Cardiovascular Disease Subjects

There is recent evidence that the dysfunctional responses of a peculiar visceral fat deposit known as epicardial adipose tissue (EAT) can directly promote cardiac enlargement in the case of obesity. Here, we observed a newer molecular pattern associated with LV dysfunction mediated by prostaglandin E2 (PGE₂) deregulation in EAT in a cardiovascular disease (CVD) population. A series of 33 overweight CVD males were enrolled and their EAT thickness, LV mass, and volumes were measured by echocardiography. Blood, plasma, EAT, and SAT biopsies were collected for molecular and proteomic assays. Our data show that PGE₂ biosynthetic enzyme (PTGES-2) correlates with echocardiographic parameters of LV enlargement: LV diameters, LV end diastolic volume, and LV masses. Moreover, PTGES-2 is directly associated with EPAC2 gene (r = 0.70, p < 0.0001), known as a molecular inducer of ST2/IL-33 mediators involved in maladaptive heart remodelling. Furthermore, PGE₂ receptor 3 (PTEGER3) results are downregulated and its expression is inversely associated with ST2/IL-33 expression. Contrarily, PGE₂ receptor 4 (PTGER4) is upregulated in EAT and directly correlates with ST2 molecular expression. Our data suggest that excessive body fatness can shift the EAT transcriptome to a pro-tissue remodelling profile, may be driven by PGE₂ deregulation, with consequent promotion of EPAC2 and ST2 signalling.

Correlational study on altered epicardial adipose tissue as a stratification risk factor for valve disease progression through IL-13 signaling

AIMS

Genetic and environmental factors all interact in the risk of progression of valvular dysfunctions. Previous studies reported a relation between valve diseases and epicardial adipose tissue (EAT) thickness. The aim of this study was to verify the possible relationship between the molecular pattern of EAT related to IL-13 fibrogenic cytokine expression and valve dysfunction.

METHODS AND RESULTS

A valvular heart disease (VHD) population was stratified according to their median EAT thickness (7 mm). The molecular expression of IL-13 in EAT is directly related to the molecular expression of genes associated with extracellular matrix (ECM) turnover, macrophage infiltration and promotion of the formation of ectopic calcific nodules involved in aorta coarctation and calcification.

CONCLUSION

IL-13 gene expression in altered EAT is directly related to the expression of genes involved in ECM turnover and the formation of ectopic calcific nodules, suggesting measurements of EAT as a stratification risk factor for valve instability in the VHD patients.