Eicosapantaenoic acid treatment based on the EPA/AA ratio in patients with coronary artery disease: follow-up data from the Tochigi Ryomo EPA/AA Trial in Coronary Artery Disease (TREAT-CAD) study

Eicosapentaenoic acid (EPA) administration has been reported to decrease the incidence of cardiovascular events, and the serum EPA/arachidonic acid (AA) ratio has been identified as a potential new risk marker for coronary artery disease (CAD). The present study aimed to investigate the value of EPA treatment based on the EPA/AA ratio at baseline. We retrospectively analyzed clinical outcome data from 149 CAD patients with a baseline EPA/AA ratio 0.4 who had received purified EPA (EPA group) or not (no EPA group) and CAD patients with an EPA/AA ratio > 0.4 who had not received EPA (control group). The baseline EPA/AA ratios were similar in the EPA and no EPA groups and were significantly lower than those in the control group (P < 0.0001). The EPA/AA ratio significantly increased in the EPA group (P < 0.0001) and the no EPA group (P < 0.001) but not in the control group. The cumulative incidence of cardiovascular death tended to be lower in the EPA group (log-rank test: P = 0.07). Receiver operating characteristic curve analysis demonstrated that the cut-off value of the target EPA/AA ratio after EPA treatment for all-cause death was 1.23 (AUC = 0.85, P = 0.016). These results suggest that EPA treatment may improve the long-term prognosis in CAD patients with an EPA/AA ratio 0.4 and that an EPA/AA ratio > 1.2 may be an appropriate EPA treatment target value to reduce mortality.