Correlation between pericardial, mediastinal, and intrathoracic fat volumes with the presence and severity of coronary artery disease, metabolic syndrome, and cardiac risk factors

Aims To investigate the association of pericardial, mediastinal, and intrathoracic fat volumes with the presence and severity of coronary artery disease (CAD), metabolic syndrome (MS), and cardiac risk factors (CRFs). Methods and results Two hundred and sixteen consecutive patients who underwent cardiac magnetic resonance (CMR) imaging and had a coronary angiogram within 12 months of the CMR were studied. Fat volume was measured by drawing region of interest curves, from short-axis cine views from base to apex and from a four-chamber cine view. Pericardial fat, mediastinal fat, intrathoracic fat (addition of pericardial and mediastinal fat volumes), and fat ratio (pericardial fat/mediastinal fat) were analysed for their association with the presence and severity of CAD (determined based on the Duke CAD Jeopardy Score), MS, CRFs, and death or myocardial infarction on follow-up. Pericardial fat volume was significantly greater in patients with CAD when compared with those without CAD [38.3 +/- 25.1 vs. 31.9 +/- 21.4 cm(3) (P = 0.04)]. A correlation between the severity of CAD and fat volume was found for pericardial fat (beta = 1, P < 0.01), mediastinal fat (beta = 1, P = 0.03), intrathoracic fat (beta = 2, P = 0.01), and fat ratio (beta = 0.005, P = 0.01). These correlations persisted for all four thoracic fat measurements even after performing a stepwise linear regression analysis for relevant risk factors. Patients with MS had significantly greater mediastinal and intrathoracic fat volumes when compared with those without MS [126 +/- 33.5 vs. 106 +/- 30.1 cm(3) (P < 0.01) and 165 +/- 54.9 vs. 140 +/- 52 cm(3) (P < 0.01), respectively]. However, there was no significant difference in pericardial fat, mediastinal fat, intrathoracic fat, or fat ratio between patients with or without myocardial infarction during the follow-up [33.6 +/- 22.1 vs. 35.7 +/- 23.8 cm(3) (P = 0.67); 115 +/- 26.2 vs. 114 +/- 33.8 cm(3) (P = 0.84); 149 +/- 44.7 vs. 150 +/- 55.7 cm(3) (P = 0.95); and 0.27 +/- 0.15 vs. 0.28 +/- 0.14 (P = 0.70), respectively]. There was no significant difference in pericardial fat, mediastinal fat, intrathoracic fat, or fat ratio between patients who were alive compared with those who died during follow-up [ 36.6 +/- 26.6 vs. 35.3 +/- 23.2 cm(3) (P = 0.76); 114 +/- 40.2 vs. 114 +/- 31.4 cm(3) (P = 0.95); 150 +/- 64.7 vs. 149 +/- 52.5 cm(3) (P = 0.92); and 0.29 +/- 0.15 vs. 0.28 +/- 0.14 (P = 0.85), respectively]. Conclusion Our study confirms an association between pericardial fat volume with the presence and severity of CAD. Furthermore, an association between mediastinal and intrathoracic fat volumes with MS was found.