Higher levels of serum omega-3 fatty acids at the time of ST-segment elevation myocardial infarction (STEMI) are associated with lower incidence of major adverse cardiovascular events (MACE) and all-cause mortality, a new study suggests. Researchers examined data on 944 consecutive STEMI patients who underwent primary percutaneous coronary interventions. After three years of follow-up, a total of 211 patients had MACE, 130 were readmitted for cardiovascular causes, and 108 died. At the time of STEMI, patients' mean proportion of omega-3 eicosapentaenoic acid (EPA) in serum phosphatidylcholine (PC) was 0.58 and the mean proportion of serum-PC alpha-linolenic acid (ALA) was 0.25. Both are measures of recent dietary consumption, the authors note in Journal of the American College of Cardiology. Each 1 standard deviation (SD) increase in serum-PC EPA was associated with a lower risk of MACE (hazard ratio 0.76) and cardiovascular readmission (HR 0.74), the analysis found. In addition, each 1-SD increase in serum-PC ALA was associated with a lower risk of all-cause mortality (HR 0.65). "Whether patients with a STEMI and high omega-3 do have other healthier lifestyle habits is beyond the scope of our study, but it certainly indicates healthy eating - in terms of a diet rich in cold-water oily fish such as salmon, anchovies, herring, mackerel, tuna, sardines; seeds; and nuts in the weeks preceding the infarct has an impact on prognosis," said senior study author Dr. Antoni Bayes-Genis, head of the heart institute at Hospital Germans Trias i Pujol in Barcelona. Participants' median age was 61 years, and many of them had a history of smoking (76.3%), hypertension (53.5%), diabetes mellitus (23.4%), dyslipidemia (57.4%), and coronary artery disease (21.4%). One limitation of the study is that researchers lacked data to determine whether pre-STEMI dietary omega-3 fatty acids impacted long-term prognosis, the study team notes. In addition, serum-PC APA and serum-PC ELA demonstrate recent dietary fatty acid levels, but don't depict long-term levels as accurately as testing adipose tissue or red blood cells. Moreover, not all omega-3 fatty acids function in the same way, and additional research is needed to help clarify the exact roles of omega-3 fatty acids in human biology, said Dr. Deepak Bhatt, executive director of interventional cardiovascular programs at Brigham and Women's Hospital Heart & Vascular Center and a professor at Harvard Medical School in Boston. However, there was a very large body of observational evidence supporting an association between higher levels of omega-3 fatty acids in the diet and blood with lower rates of adverse cardiovascular events prior to the study, said Dr. Bhatt, who coauthored an editorial accompanying the study. "Without randomized trials, it is nearly impossible to prove causality versus just an association," Dr. Bhatt said in an email. "However, it is very difficult to conduct large, long-term randomized trials of nutritional interventions," Dr. Bhatt added. "Therefore, when studies such as this one come out, I tell patients not to focus on just one element of the diet, but rather on achieving an overall balanced, healthy diet that is high in fresh fruits and vegetables and whole grains, as well as nuts and seeds as long as they are not allergic." —Lisa Rapaport Source
