Introduction: Epicardial fat volume (EF) has been shown to represent a reliable marker of increased in-flammation, at the same time being significantly corre-lated with vulnerability features of the coronary plaqu-es. However, the role of pericoronary adipose tissue, representing the fat accumulated in the close vicinity of a coronary plaque, as a major player for increasing lo-cal inflammation and in the development of vulnerable coronary plaques, has yet to be established.
Objective: We sought to evaluate the relationship between increased of pericoronary fat (PF) volumes measured in proximity to unstable coronary plaques, and markers of plaque instability, severity of CAD, with the use of coronary computed tomography angiogra-phy (CCTA).
Methods: T he study enrolled 82 subjects with mini-mum one plaque causing >50% stenosis, in which 128-CCTA was performed. The imaging analysis included assessment of: the overall EFV, the PV at the level of the target lesion, markers for plaque vulnerability (low attenuation plaque – LAP; napkin ring sign – NRS; positive remodeling – PR), calcium scoring (CCS), de-gree of stenosis (S%), lesion length (LL), plaque related volumes (total plaque volume – TPV; fibrotic volume – FV; calcified volume – CV; non-calcified volume – NCV); vascular indexes (eccentricity index – EI; re-modeling index – RI). The study lot was divided in 2 groups according to the median value of the measured PF (0.58 mm³) as follows: lot 1 – 41 patients with low PF ≤0.58 mm³; lot 2 – 41 patients with increased PF of >0.58 mm³.
Results: The mean PF volume was 0.33±0.15 mm3 for gr.1 and 0.95±0.30 mm³ for gr. 2. There were no di-fferences between groups related to age (59.21±10.41 vs. 63.29±11.39 years, p=0.095), gender (29.27% vs. 24.39% males, p=0.618), EFV (177.20±109.12 vs. 202.91±96.43 mm³, p=0.154), CCS (346.17±741.56 vs. 275.41±513.19 HU, p=0.823) and S% (57.35±12.23 vs. 55.41±9.87%, p=0.656). The presence of coronary plaque vulnerability markers did not differ between lots (LAP – p=0.635; NRS – p=0.349; PR – p=0.120). Pati-ents with increased PF volume presented significantly longer lesions (lot 1. 16.71±4.65 vs. lot 2. 19.68±5.23, p=0.009). Plaque related volumes (mm³) between lot 1 and lot 2 were: TPV: 158.90±72.08 vs. 208.94±117.03, p=0.022; FV: 117.84±65.76 vs. 167.45±103.21, p=0.011; CV: 30.68±35.46 vs. 27.61±35.34, p=0.578; NCV: 79.94±21.90 vs. 85.19±20.28, p=0.164. The RI was significantly higher in lot 2 (lot 1. 1.01±0.28 vs. lot 2. 1.14±0.29, p=0.045), EI was not significantly different (p=0.169). There was a significant correlation betwe-en the PF and TPV (r=0.426, p<0.0001), the NCV (r=0.435, p<0.0001) and the FV (r=0.436, p<0.0001).
Conclusions: An increase in the adipose tissue surro-unding the coronary artery plaques appears to be linked to increased plaque volumes and plaque length, as well as to features that indicate increased plaque in-stability, including higher vascular remodeling index and non-calcified plaques. The present study supports the theory that an increased local epicardial adipose tissue, possibly due to enhanced local inflammation, can trigger plaque vulnerabilization.