Impact of Eicosapentaenoic Acid Treatment on the Fibrous Cap Thickness in Patients with Coronary Atherosclerotic Plaque: An Optical Coherence Tomography Study

AIM: Previous clinical trials have demonstrated the effectiveness of eicosapentaenoic acid (EPA) in preventing cardiovascular events. The aim of the present study was to investigate the effects of EPA treatment on the accumulation of coronary atherosclerotic plaque using optical coherence tomography (OCT). METHODS: A total of 46 acute coronary syndrome (ACS) patients without dyslipidemia were divided into two groups: those who received 1,800 mg/day of EPA (n = 15) or the control group (n = 31). Serial OCT examinations were performed at baseline and after eight months of follow-up. The target for the OCT analysis was non-culprit plaque with a percent diameter of stenosis of 30% to 70% in non-culprit vessels of ACS. RESULTS: Between the baseline and follow-up visits, the serum EPA levels increased (50 ± 26 mg/dL to 200 ± 41 mg/dL, p ＜ 0.001) in the EPA group, although they did not change in the control group. According to the OCT analysis, the lipid arc did not change in the EPA group (131 ± 52 degrees to 126 ± 54 degrees, p = 0.106) or the control group (137 ± 50 degrees to 138 ± 50 degrees, p=0.603). In contrast, the fibrous cap thickness significantly increased in both the EPA group (169 ± 70 μm to 201 ± 49 μm, p ＜ 0.001) and the control group (164 ± 63 μm to 174 ± 72 μm, p=0.018); however, the relative change in the fibrous cap thickness was significantly greater in the EPA group than in the control group (131 ± 35% vs. 106 ± 15%, p = 0.001). CONCLUSIONS: In the present study, the administration of EPA for eight months significantly increased the fibrous cap thickness in patients with coronary atherosclerotic plaque.