Epicardial adipose tissue is related to coronary collateral vessel formation in patients with acute coronary syndrome

The Role of Epicardial Adipose Tissue in Acute Coronary Syndromes, Post-Infarct Remodeling and Cardiac Regeneration

Epicardial adipose tissue (EAT) is a fat deposit surrounding the heart and located under the visceral layer of the pericardium. Due to its unique features, the contribution of EAT to the pathogenesis of cardiovascular and metabolic disorders is extensively studied. Especially, EAT can be associated with the onset and development of coronary artery disease, myocardial infarction and post-infarct heart failure which all are significant problems for public health. In this article, we focus on the mechanisms of how EAT impacts acute coronary syndromes. Particular emphasis was placed on the role of inflammation and adipokines secreted by EAT. Moreover, we present how EAT affects the remodeling of the heart following myocardial infarction. We further review the role of EAT as a source of stem cells for cardiac regeneration. In addition, we describe the imaging assessment of EAT, its prognostic value, and its correlation with the clinical characteristics of patients.

Is echocardiographic epicardial fat thickness increased in patients with coronary artery disease? A systematic review and meta-analysis

Background

The relation of epicardial fat thickness (EFT) to coronary artery disease (CAD) has recently been reported in multiple studies. Echocardiography is a safe and relatively inexpensive and accessible approach to assess regional EFT, which can be performed easily in many centers.

Objective

To determine the association between echocardiographic EFT and the presence or the absence of CAD.

Methods

This was a systematic review and meta-analysis conducted on literature available in electronic databases up to March 2018. The articles measuring EFT by echocardiography in the right ventricular (RV) free wall were included in the study. The quality of the enrolled items was assessed using the Methodological Index for Non-Randomized Studies (MINORS) checklist. The analyses were performed using the Comprehensive Meta-Analysis version 2 software. Cochran’s Q test and I² index were used to evaluate heterogeneity.

Results

This meta-analysis was performed on 13 studies involving 2,436 patients (1,622 with CAD, and 814 without CAD). The maximum EFT reported by echocardiography was 12.9±2.7 mm in the CAD group and 8.4±2.5 mm in the non-CAD group. The minimum EFT reported by echocardiography was 2.2±1.8 mm in the CAD group and 1.8±1.4 mm in the non-CAD group. The heterogeneity was found among the researched studies (I²=91.8%, p=0.000, Q-value=146.43, df [Q] =12) using the random effect model. The patients with CAD had a significantly higher echocardiographic EFT than those without CAD (SMD=1.03, 95% CI= 0.70–1.37, p=0.000).

Conclusion

According to the findings of this meta-analysis, the echocardiographic EFT in the subjects with CAD was significantly higher than that of those without CAD. The measurement of echocardiographic EFT seems to be an acceptable strategy for risk stratification of heart diseases considering ease of use, cost-effectiveness and non-exposure characteristics, compared to other imaging interventions.

Relation of Quantity of Subepicardial Adipose Tissue to Infarct Size in Patients With ST-Elevation Myocardial Infarction

According to the so-called obesity paradox, obesity might present a protective role in patients with myocardial infarction. We aimed to assess the influence of the epicardial adipose tissue (EAT) volume on cardiac healing and remodeling in patients with acute ST-elevation myocardial infarction. We prospectively included 193 consecutive patients presenting a first STEMI without known coronary artery disease. Cardiac magnetic resonance imaging was performed at baseline and after a 3-month follow-up. EAT volume was computed, and the population was divided into quartiles: the highest quartile of EAT defining the high EAT group (h-EAT). h-EAT was associated with increased body mass index, higher rate of history of hypertension, and smaller infarct size at initial CMR assessment (18.3 ± 11.9% vs 23 ± 13.7% of total left ventricular [LV] mass, p = 0.041). Moreover, microvascular obstruction was less frequent in the h-EAT group (36.2% vs 59.3%, p = 0.006). There were no differences in LV ejection fraction (LVEF), LV volumes, systolic wall stress, coronary artery burden, and clinical events during the index hospitalization between the EAT groups at baseline and at follow-up. Linear regression analysis showed h-EAT to be associated with smaller infarct size at baseline (β coefficient = -3.25 [95% CI -5.89 to -0.61], p = 0.016). h-EAT also modified positively the effect of infarct size on LV remodeling, as assessed by the change in LVEF (p = 0.046). In conclusion, h-EAT was paradoxically related to smaller infarct size and acted as an effect modifier in the relation between the extent of infarct size and LVEF changes. Patients with higher extent of EAT presented better cardiac healing.