Nutritional preconditioning by marine omega-3 fatty acids in patients with ST-segment elevation myocardial infarction: A METOCARD-CNIC trial substudy.

BACKGROUND: Marine omega-3 eicosapentaenoic acid (EPA) is readily incorporated into cardiomyocyte membranes, partially displacing the omega-6 arachidonic acid (AA). Whereas AA is a substrate for pro-inflammatory eicosanoids, the release of EPA from cell membranes generates anti-inflammatory lipid mediators, contributing to the infarct-limiting effect observed experimental models. Clinical data are lacking. METHODS: In this observational study conducted in 100 patients with a reperfused anterior ST-elevation myocardial infarction (STEMI), at hospital admission we quantified by gas-chromatography the red blood cell proportions of AA, EPA, and the AA:EPA ratio, a valid surrogate for cardiomyocyte membrane content. Patients underwent cardiac magnetic resonance imaging in the acute phase (one week post-STEMI), and at long-term (6 months) follow-up. Infarct size (delayed gadolinium enhancement) and cardiac function (left ventricular ejection fraction [LVEF]) were correlated with exposures of interest by multivariate regression analysis. RESULTS: AA:EPA ratio directly related to acute infarct size (coefficient [95% CI]: 6.19 [1.68 to 10.69], P = 0.008) and inversely to long-term LVEF (coefficient [95% CI]: − 4.02 [− 7.15 to − 0.89], P = 0.012). EPA inversely related to acute infarct size (coefficient [95% CI]: − 6.58; [− 11.46 to − 1.70]; P = 0.009), while a direct association with LVEF at follow-up (coefficient [95% CI]: 3.67 [0.25 to 7.08]; P = 0.036) was observed. CONCLUSIONS: A low AA:EPA ratio in red blood cells at the time of STEMI is associated with smaller acute infarct size and preserved long-term ventricular function. Our results are consistent with prior work in experimental models and add to the notion of omega-3 fatty acids as a healthy fat. TRIAL REGISTRATION: http://www.clinicaltrials.gov/NCT01311700