Pericardial Adipose Tissue Determined by Dual Source CT Is a Risk Factor for Coronary Atherosclerosis

Abstract

Objectives-Pericardial fat as a visceral fat depot may be involved in the pathogenesis of coronary atherosclerosis. To gain evidence for that concept we sought to investigate the relation of pericardial fat volumes to risk factors, serum adiponectin levels, inflammatory biomarkers, and the quantity and morphology of coronary atherosclerosis. PϾ0.001). No association was found between BMI and coronary atherosclerosis. PAT volumes Ͼ300 cm 3 were the strongest independent risk factor for coronary atherosclerosis (odds ratio 4.1; CI 3.63 to 4.33) also significantly stronger compared to the Framingham score. We furthermore demonstrated that elevated PAT volumes are significantly associated with low adiponectin levels, low HDL levels, elevated TNF-␣ levels, and hsCRP. Conclusion-In the present study we demonstrated that elevated PAT volumes are associated with coronary atherosclerosis, hypoadiponectinemia, and inflammation and represent the strongest risk factor for the presence of atherosclerosis and may be important for risk stratification and monitoring. Key Words: cardiac CT Ⅲ pericardial fat Ⅲ obesity Ⅲ adiponectin Ⅲ plaque imaging T here is growing evidence that regional visceral fat distribution may contribute to an unfavorable metabolic and cardiovascular risk profile. 1,2 In patients with obesity, insulin resistance, diabetes, and hyperlipidemia visceral fat hypertrophies and transforms into a multifunctional organ that produces and secretes multiple endocrine and paracrine factors promoting inflammation, neovascularization, and oxidative stress, features that also characterize atherosclerosis. 3 Pericardial fat as a local visceral fat depot with close proximity to coronary arteries may serve as a source of inflammatory cytokines and cells that may locally enhance systemic proatherogenic effects via outside to inside signaling. 4,5 Thus it may be a specific parameter indicating an unfavorable cardio-metabolic state and may be used for risk stratification. To date, however, only little attention has focused on this regional fat depot located around the heart and its relation to cardiovascular risk factors, and the quantity and composition of coronary atherosclerosis is not well studied yet. Methods and Results-UsingMulti-slice CT is a noninvasive tool that allows to reliably assess both obstructive and nonobstructive subclinical coronary artery disease in an earlier stage than invasive angiography. 6 -9 Based on density measurements, plaques can be further characterized in noncalcified, mixed, and calcified plaques. 7 By using the same scan data this tool furthermore allows to quantify the exact pericardial fat volume. 9 We thus sought to assess the relation of pericardial fat volume to cardiovascular risk factors, levels of inflammatory cytokines, adiponectin, and to the extent and the phenotype of coronary atherosclerosis.

Assessment of epicardial fat volume and myocardial triglyceride content in severely obese subjects: relationship to metabolic profile, cardiac function and visceral fat

“…12,14,31,[37][38][39] However, only EF surrounds the adventitia of coronary arteries without any fibrous layer, and its embryological origin is different from that of pericardial fat. 7 Although it is difficult to differentiate these two fat depots in lean subjects, it was considered important to make this distinction in our study.…”

“…8,9 It has been shown that this ectopic fat is associated with the development of atherosclerotic coronary artery disease. [8][9][10][11][12][13][14][15][16] Its anatomic location, without any barrier to the adjacent myocardium, enables local paracrine interaction between EF and the myocardium, suggesting that EF could also have a functional and mechanical role in obesity-related dilated cardiomyopathy. 17,18 Myocardial lipid deposition (that is, lipid accumulation in the myocyte cytoplasm) is also a marker of ectopic fat accumulation.…”

Chemerin is associated with markers of inflammation and components of the metabolic syndrome but does not predict coronary atherosclerosis

“…Dual-source multi-slice CT-coronary angiography CT-coronary angiography and image analyses were performed as previously described (11,12). Briefly, for the analysis of coronary plaque morphology, all reconstructed data sets were evaluated at different ECG-phases for diagnostic image quality and the optimal data set was then chosen.…”

Thermogenic potential and physiological relevance of human epicardial adipose tissue

“…4,10 In fact, in comparison with the Framingham risk score (where smoking and type 2 diabetes mellitus only account for 1.6-and 3-fold risk of having CAD, respectively), pericardial fat volume was identified as the strongest predictor of developing CAD (odds ratio of 4.1). 30,31 In addition, a case-control study identified pericardial fat volume to be a strong predicator of myocardial ischemia in patients without CAD. 32 The question of whether such predictive capabilities can be attributed specifically to epicardial fat has been addressed by recent studies such as the Heinz Nixdorf Recall study, where epicardial fat volume was significantly associated with coronary events over the course of 8 years, even after adjusting for traditional cardiovascular risk factors.…”

“…30 It has been observed in both animal and human studies that segments of coronary arteries that are covered by intramyocardial bridges instead of epicardial fat do not develop atherosclerosis. 30,47 Indeed, epicardial fat has been proposed to influence the myocardium and coronary arteries via paracrine and vasocrine mechanisms. 48 Human epicardial fat is known to be a source of various bioactive molecules including adipokines and cytokines that are altered under CAD conditions.…”