Increased Pericardial Fat Volume Measured From Noncontrast CT Predicts Myocardial Ischemia by SPECT

Abstract

OBJECTIVES We evaluated the association between pericardial fat and myocardial ischemia for risk stratification. BACK GROUND Pericardial fat volume (PFV) and thoracic fat volume (TFV) measured from noncontrast computed tomography (CT) performed for calculating coronary calcium score (CCS) are associated with increased CCS and risk for major adverse cardiovascular events. METHODS From a cohort of 1,777 consecutive patients without previously known coronary artery disease (CAD) with noncontrast CT performed within 6 months of single photon emission computed tomography (SPECT), we compared 73 patients with ischemia by SPECT (cases) with 146 patients with normal SPECT (controls) matched by age, gender, CCS category, and symptoms and risk factors for CAD. TFV was automatically measured. Pericardial contours were manually defined within which fat voxels were automatically identified to compute PFV. Computer-assisted visual interpretation of SPECT was performed using standard 17-segment and 5-point score model; perfusion defect was quantified as summed stress score (SSS) and summed rest score (SRS). Ischemia was defined by: SSS – SRS ≥4. Independent relationships of PFV and TFV to ischemia were examined. RESULTS Cases had higher mean PFV (99.1 ± 42.9 cm3 vs. 80.1 ± 31.8 cm3, p = 0.0003) and TFV (196.1 ± 82.7 cm3 vs. 160.8 ± 72.1 cm3, p = 0.001) and higher frequencies of PFV >125 cm3 (22% vs. 8%, p = 0.004) and TFV >200 cm3 (40% vs. 19%, p = 0.001) than controls. After adjustment for CCS, PFV and TFV remained the strongest predictors of ischemia (odds ratio [OR]: 2.91, 95% confidence interval [CI]: 1.53 to 5.52, p = 0.001 for each doubling of PFV; OR: 2.64, 95% CI: 1.48 to 4.72, p = 0.001 for TFV. Receiver operating characteristic analysis showed that prediction of ischemia, as indicated by receiver-operator characteristic area under the curve, improved significantly when PFV or TFV was added to CCS (0.75 vs. 0.68, p = 0.04 for both). CONCLUSIONS Pericardial fat was significantly associated with myocardial ischemia in patients without known CAD and may help improve risk assessment.

Molecular Biology of Atherosclerosis

“…Furthermore, perivascular fat was much more proinflammatory than fat from other sources and showed greatly increased release of TNF-␣, MCP-1 (CCL2), and MIP-1␣ (CCL3) upon high-fat feeding (1135). These findings provide new impetus for controlling weight gain and other factors that may increase deposition of coronary perivascular fat, recently shown to be strongly associated with atherosclerotic plaques in humans (1114,1161,1750).…”

Original research. The Assessment of Epicardial Adipose Tissue in Acute Coronary Syndrome Patients. A Systematic Review

“…15,17,18 Patients without chest pain who present with major adverse cardiovascular events have a bigger epicardial fat volume compared to event-free patients. 19 The coronary artery calcium score, a marker of CAD severity, has a positive correlation with EAT in patients with both obstructive and non-obstructive…”

Abdominal and Pericardial Fat in Patients with and without Coronary Artery Disease: Computed Tomography Study

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