Predictive Value of Epicardial Adipose Tissue Thickness for Plaque Vulnerability in Left Coronary Arteries: Histological Evidence from 245 Sudden Cardiac Death Cases

Background/Objectives: Cardiovascular disease remains the leading global cause of death, with atherosclerotic plaque vulnerability, rather than stenosis severity, playing a central role in acute coronary events. Epicardial adipose tissue (EAT) has emerged as a key contributor to coronary atherosclerosis and myocardial ischemia. This study aimed to investigate the relationship between EAT thickness and the development and severity of atherosclerotic plaques in these coronary arteries, and to evaluate the influence of demographic factors on EAT thickness and plaque vulnerability. Methods: A retrospective analysis was conducted on autopsy data from 245 sudden cardiac death (SCD) cases (2021–2023). EAT thickness was measured at the left anterior descending artery (LAD) and left circumflex coronary artery (LCx) levels. From each artery, one segment that showed evidence of an atherosclerotic plaque was collected and sent for histological examination. Additionally, we documented demographic data, including age, sex, and body mass index (BMI) for each case. Results: In the present study, we enrolled 245 subjects with SCD, among whom 175 (71.42%) were male, and 70 (28.58%) were female. The mean age was 62.31 ± 12.69 years, and the mean BMI was 26.12 ± 4.16. We observed a mean EAT thickness value of 0.74 ± 0.26 cm at the LAD artery level and 0.71 ± 0.27 cm at the LCx artery level. We observed a positive correlation between BMI and EAT thickness at the LAD level (r = 0.260, p < 0.001) and similarly at the LCx level (r = 0.260, p < 0.001). Additionally, advancing age is associated with an increase in EAT thickness at both the LAD level (r = 0.188, p = 0.003) and the LCx level (r = 0.242, p < 0.001). Furthermore, we observed a higher EAT thickness at the LAD level (p = 0.0019) and the LCx level (p = 0.0225) among subjects with unstable atherosclerotic plaques. In the logistic regression analysis, the elevated value of EAT thickness was associated with unstable atherosclerotic plaque at LAD (OR: 1.88, p = 0.002) and LCx (OR: 1.51, p = 0.010) for the entire study cohort. Conclusions: Our data revealed that higher baseline values of EAT LCx and EAT LAD are associated with unstable plaque at the level of the left coronary arteries. Furthermore, our findings indicate that male individuals are more susceptible to developing unstable plaques in the coronary arteries.