Pericardial fat burden on ECG-gated noncontrast CT in asymptomatic patients who subsequently experience adverse cardiovascular events

Objectives: We aimed to evaluate whether pericardial fat has value in predicting the risk of future adverse cardiovascular outcomes.

Background: Pericardial fat volume (PFV) and thoracic fat volume (TFV) can be routinely measured from noncontrast computed tomography (NCT) performed for calculating coronary calcium score (CCS) and may predict major adverse cardiac event (MACE) risk.

Methods: From a registry of 2,751 asymptomatic patients without known cardiac artery disease and 4-year follow-up for MACE (cardiac death, myocardial infarction, stroke, late revascularization) after NCT, we compared 58 patients with MACE with 174 same-sex, event-free control subjects matched by a propensity score to account for age, risk factors, and CCS. The TFV was automatically calculated, and PFV was calculated with manual assistance in defining the pericardial contour, within which fat voxels were automatically identified. Independent relationships of PFV and TFV to MACE were evaluated using conditional multivariable logistic regression.

Results: Patients experiencing MACE had higher mean PFV (101.8 +/- 49.2 cm(3) vs. 84.9 +/- 37.7 cm(3), p = 0.007) and TFV (204.7 +/- 90.3 cm(3) vs. 177 +/- 80.3 cm(3), p = 0.029) and higher frequencies of PFV >125 cm(3) (33% vs. 14%, p = 0.002) and TFV >250 cm(3) (31% vs. 17%, p = 0.025). After adjustment for Framingham risk score (FRS), CCS, and body mass index, PFV and TFV were significantly associated with MACE (odds ratio [OR]: 1.74, 95% confidence interval [CI]: 1.03 to 2.95 for each doubling of PFV; OR: 1.78, 95% CI: 1.01 to 3.14 for TFV). The area under the curve from receiver-operator characteristic analyses showed a trend of improved MACE prediction when PFV was added to FRS and CCS (0.73 vs. 0.68, p = 0.058). Addition of PFV, but not TFV, to FRS and CCS improved estimated specificity (0.72 vs. 0.66, p = 0.008) and overall accuracy (0.70 vs. 0.65, p = 0.009) in predicting MACE.

Conclusions: Asymptomatic patients who experience MACE exhibit greater PFV on pre-MACE NCT when they are compared with event-free control subjects with similar cardiovascular risk profiles. Our preliminary findings suggest that PFV may help improve prediction of MACE.