Association of pericardial fat accumulation rather than abdominal obesity with coronary atherosclerotic plaque formation in patients with suspected coronary artery disease
Introduction
Waist circumference (WC), which reflects abdominal visceral obesity, is an important component of the metabolic syndrome and coronary artery disease (CAD) [1]. There is ample evidence of fat tissue secretion of many adipokines with local and systemic effects on cardiovascular diseases [2]. Ectopic fat deposits in muscle, liver, and pancreas are described as lipotoxic and their levels correlate with insulin resistance and type 2 diabetes mellitus [3]. Pericardial fat is an ectopic visceral fat present around epicardial coronary arteries and considered an important source of vaso-bioactive mediators in coronary atherogenesis [4], [5], [6]. Pericardial fat has been reported to correlate with metabolic risk factors [7], [8], coronary artery stenosis [8], and coronary artery calcification [9]. However, there is no information on whether pericardial fat is associated with coronary plaques in patients with suspected CAD, particularly from the early-stage CAD before stenosis or calcification.
Multislice computed tomography (CT) is currently used to evaluate CAD noninvasively, and it can also detect both stenotic and nonstenotic coronary plaques [10]. Coronary atherosclerotic plaque disruption often evolves from mild to moderate, but not severe stenotic plaques [11], [12], which include noncalcified plaques and those that do not induce myocardial ischemia in stress tests, emphasizing the importance of detection of coronary plaques. Conventional coronary angiography (CAG) is the gold standard procedure used to assess luminal narrowing in CAD, however, multislice coronary CT might be superior in identifying nonstenotic plaques relative to CAG. While intravascular ultrasound can also detect nonstenotic coronary plaques, it is technically complex, invasive, and time-consuming procedure and cannot be practically applied to the three major coronary arteries. In addition, a recent study showed that the mortality rate was higher in patients with nonstenotic plaques detected by CT angiography than those without plaques [13]. Thus, the use of multislice CT to detect any coronary plaques in the whole coronary artery tree could be sound clinical diagnostic strategy for assessment of high-risk patients with suspected CAD.
The aim of the present study was to determine the association between pericardial fat volume (PFV) and the presence of early-stage coronary plaques using 64-slice CT.
Section snippets
Study samples
From April 2006 to December 2008, 210 stable patients with suspected CAD with no history of thoracic surgery, percutaneous coronary intervention, or arrhythmias were registered in the present study. Patients with previous pacemaker implantation (n = 16), poor image quality (n = 20), or incomplete breath-hold (n = 3) were excluded because of artifacts. Thus, 171 consecutive patients were included in the present study. The study was approved by the ethics review committee of our institution, a signed
Study sample characteristics
Table 1 shows the characteristics of the participating patients. Patients with coronary atherosclerotic plaques were older, had larger BMI and WC, higher triglycerides, HOMA-IR, hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein and FRS, and more likely to have hypertension, diabetes, metabolic syndrome, use statin, angiotensin converting enzyme inhibitors or angiotensin II receptor blocker, and aspirin, and lower diastolic BP, high-density lipoprotein (HDL) cholesterol and eGFR, than
Discussion
The present study showed that PFV, as assessed by 64-slice multidetector CT, correlated significantly with the presence of any coronary plaques. Furthermore, PFV, but not WC as an indicator of abdominal fat, was independently and significantly associated with the presence of coronary plaques, especially nonstenotic and noncalcified plaques. These findings suggest that pericardial fat is more highly associated with early development of CAD than simple anthropometric measures of abdominal obesity.
Conclusions
The amount of pericardial fat correlated significantly with the presence of nonstenotic and noncalcified coronary plaques assessed by multislice CT. Accumulation of pericardial fat, rather than abdominal obesity, could be implicated in the early development of CAD.
Conflict of interest
The authors declare no conflicts of interest.
Acknowledgments
The help of Hatemura Masahiro and Shimizu Kie in data analysis is greatly acknowledged.
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