The predictive value of the epicardial adipose thickness in the rate of expansion of the aortic root.

Background: Epicardial adipose tissue (ECAT) is metabolically active and is involved in the development of atherosclerosis. The thickness of ECAT has been positively correlated with the dimensions of the ascending aorta. We aimed to examine whether ECAT thickness predicted the expansion of the aortic dimensions.

Methods: The imaging results of patients who had undergone transthoracic echocardiographic (TTE) examinations more than twice during the period 2005-2015 were surveyed. We included adult patients who had undergone TTE examinations at least 1 year apart. The ECAT was measured in the parasternal long-axis view from the index TTE study. End-diastolic dimensions in three consecutive beats were averaged for all measurements. The annulus, root, and sinotubular junction (STJ) were also measured. The amount of increase (if any) in aortic dimensions per year was calculated and the correlation of this increase with the initial thickness of the ECAT was analyzed.

Results: In total, 429 examinations were performed with 197 patients (17 females), from which 394 examinations were analyzed. The ECAT thickness was 8.6 ± 3.6 mm. In the initial examinations, the annulus, STJ, and root measured 23 ± 4, 28 ± 4, and 34 ± 4 mm, respectively. In univariate analysis, for every 1 mm of ECAT thickness, the STJ expanded 0.056 (95% CI: 0.001-0.112 mm/year; p = 0.030) and the aortic root expanded 0.088 mm/year (p < 0.001). In multivariate analysis, ECAT thickness remained an independent predictor of the aortic root expansion. For every 1‑mm increase in ECAT thickness, the aortic root expanded by 0.036 mm (95% CI: 0.010-0.062) per year (p = 0.007).

Conclusion: The thickness of the ECAT is a predictor of more rapid increases in the dimensions of the aortic root. Further studies of patients with established aortic aneurysm are warranted.