Eicosapentaenoic acid to arachidonic acid (EPA/AA) ratio as an associated factor of high risk plaque on coronary computed tomography in patients without coronary artery disease

Background and aims: Coronary computed tomography angiography (CCTA)-verified high risk plaque (HRP) characteristics including positive remodeling and low attenuation plaque have been associated with acute coronary syndromes. Several studies reported that the n-3 polyunsaturated fatty acids have been associated with cardiovascular events. However, the relationship between serum eicosapentaenoic acid to arachidonic acid (EPA/AA) ratio and CCTA-verified HRP in patients without known coronary artery disease (CAD) is unclear. We aimed at investigating the relation between EPA/AA and CCTA-verified HRP in patients without known CAD. Methods: We included 193 patients undergoing CCTA without known CAD (65.5 ± 12.0 years, 55.0% male). No patient has been treated with EPA. The relation of coronary risk factors, lipid profile, high-sensitivity C-reactive protein, coronary artery calcification score (CACS), number of vessel disease, plaque burden, and EPA/AA with the presence of HRP was evaluated by logistic regression analysis. Incremental value of EPA/AA to predict HRP was also analyzed by C-index, NRI, and IDI. A Cox proportional hazards model was used to estimate the time to cardiovascular event. Results: HRP was observed in 37 (19%) patients. Multivariable logistic regression analysis revealed that current smoking (OR 2.58; p = 0.046), number of vessel disease (OR 1.87; p = 0.031), and EPA/AA ratio (OR 0.65; p = 0.0006) were independent associated factors of HRP on CCTA. Although the addition of EPA/AA to the baseline model did not significantly improve C-index, both NRI (0.60, p = 0.0049) and IDI (0.054, p = 0.0072) were significantly improved. Patients with HRP had significantly higher rate of events compared with patients without HRP (14% vs. 3%, Logrank p = 0.0004). On multivariable Cox hazard analysis, baseline EPA/AA ratio was an independent predictor (HR 0.57, p = 0.047). Conclusions: Low EPA/AA was an associated factor of HRP on CCTA in patients without CAD. In addition to conventional coronary risk factors and CACS, EPA/AA and CCTA might be useful for risk stratification of CAD.