The prognostic utility of dihomo-gamma-linolenic acid (DGLA) in patients with acute coronary heart disease.

BACKGROUND: We previously investigated the prognostic utility of red blood cell (RBC) n-3 fatty acids (FAs) in survivors of an acute myocardial syndrome (ACS) but found no relationship with all-cause mortality and cardiac death or MI after two years. Here we extend our follow-up to 7years, focusing on the potential predictive power of RBC n-6 FAs. METHODS: We included 398 ACS patients presenting with increased troponin-T (TnT) levels for whom baseline RBC FA data were available. Cox regression analysis was used to relate the risk of future events to RBC n-6 FA levels, both continuously and by quartile. RESULTS: At 7-year follow-up, 183 (46.0%) had died, 128 (32.2%) had experienced another MI and 24 (6.0%) had had a stroke. Death or MI occurred in 227 patients (57.0%); and death, MI or stroke in 235 patients (59.0%). In a multivariable Cox regression model for total death, the hazard ratio (HR) in the highest as compared to the lowest quartile of dihomo-γ-linolenic acid (DGLA) was 0.55 [95% confidence interval (CI), 0.35-0.88, p=0.012, for death or MI [HR 0.62 (95% CI, 0.41-0.94), p=0.025], and for the fully combined endpoint [HR 0.57 (95% CI, 0.38-0.86), p=0.006]. Similar results were found in the per 1-SD analysis. No other RBC n-6 FAs significantly predicted these outcomes in multivariable models. CONCLUSION: RBC DGLA levels had significant independent prognostic value in post-ACS patients. These findings need confirmation, and the possible biochemical pathways by which higher DGLA membrane levels may be cardioprotective should be explored.

Prognostic utility of vitamin D in acute coronary syndrome patients in coastal Norway.

BACKGROUND: An inverse relationship between cardiovascular risk and levels of vitamin D and omega-3 index may exist. OBJECTIVES: To evaluate the prognostic utility of serum 25-hydroxyvitamin D [25(OH)D] in 871 patients with suspected acute coronary syndrome (ACS) and to assess the seasonal correlation between 25(OH)D and the omega-3 index in 456 ACS patients from southwestern Norway. RESULTS: In the univariate analysis the hazard ratio (HR) at 2-year follow-up for all-cause mortality in the highest as compared to the lowest quartile of 25(OH)D in the total population was 0.61 (95% confidence interval (CI), 0.37-1.00), P = 0.050. At 7-year follow-up, the corresponding HR for all-cause mortality was 0.66 (95% CI, 0.49-0.90), P = 0.008, and for females alone 0.51 (95% CI, 0.32-0.83), P = 0.006. Quartile survival did not differ in the multivariable analysis, whereas 25(OH)D < 40 nM (<16 ng/mL) was found to be independently related to mortality. Seasonal differences in 25(OH)D, but not for the omega-3 index, were noted, and the two biomarkers were positively correlated, especially during winter-spring; Pearson's correlation coefficient was 0.358, P < 0.001. CONCLUSION: Vitamin D levels are related to survival, especially in females, and correlate with the omega-3 index.

The role of long-chained marine N-3 polyunsaturated Fatty acids in cardiovascular disease.

This paper reviews the current evidence regarding long-chained marine omega-3 polyunsaturated fatty acids (PUFAs) and cardiovascular disease (CVD), their possible mechanisms of action, and results of clinical trials. Also, primary and secondary prevention trials as studies on antiarrhythmic effects and meta-analyses are summarized. However, the individual bioavailability of n-3 PUFAs along with the highly different study designs and estimations of FAs intake or supplementation dosages in patient populations with different background intake of n-3 PUFAs might be some of the reasons for the inconsistent findings of the studies evaluating the impact of n-3 PUFAs on CVD. The question of an optimum dose of n-3 PUFAs or whether there exists a dose-response relation for n-3 PUFA supplementation is widely discussed. Moreover, the difficulties in interpreting meta-analyses are clearly demonstrated by two recently published meta-analyses (Rizos et al. and Delgado Lista et al.), evaluating the efficacy of n-3 PUFAs on CVD, including 12 common studies, but drawing opposite conclusions. We definitely need more large-scale, randomized clinical trials of long duration, also reporting harmful effects of n-3 PUFAs.

Low levels of the omega-3 index are associated with sudden cardiac arrest and remain stable in survivors in the subacute phase.

In previous studies, low blood levels of n-3 fatty acids (FA) have been associated with increased risk of cardiac death, and the omega-3 index (red blood cell (RBC) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) expressed as weight percentage of total FA) has recently been proposed as a new risk factor for death from coronary artery disease, especially following sudden cardiac arrest (SCA). As blood samples often haven been harvested after the event, the aim of our study was to evaluate the stability of RBC fatty acids following SCA. The total FA profile, including the omega-3 index, was measured three times during the first 48 h in 25 survivors of out-of-hospital cardiac arrest (OHCA), in 15 patients with a myocardial infarction (MI) without SCA and in 5 healthy subjects. We could not demonstrate significant changes in the FA measurements in any of the groups, this also applied to the omega-6/omega-3 ratio and the arachidonic acid (AA)/EPA ratio. Furthermore, we compared the omega-3 index in 14 OHCA-patients suffering their first MI with that of 185 first-time MI-patients without SCA; mean values being 4.59% and 6.48%, respectively (p = 0.002). In a multivariate logistic regression analysis, a 1% increase of the omega-3 index was associated with a 58% (95% CI: 0.25-0.76%) reduction in risk of ventricular fibrillation (VF). In conclusion, the omega-3 index remained stable after an event of SCA and predicted the risk of VF.

(n-3) Fatty acid content of red blood cells does not predict risk of future cardiovascular events following an acute coronary syndrome.

A reduced risk of fatal coronary artery disease has been associated with a high intake of (n-3) fatty acids (FA) and a direct cardioprotective effect by their incorporation into myocardial cells has been suggested. Based on these observations, the omega-3 index (eicosapentaenoic acid + docosahexaenoic acid in cell membranes of RBC expressed as percent of total FA) has been suggested as a new risk marker for cardiac death. In this study, our aim was to evaluate the omega-3 index as a prognostic risk marker following hospitalization with an acute coronary syndrome (ACS). The omega-3 index was measured at admission in 460 patients with an ACS as defined by Troponin-T (TnT) > or = 0.02 microg/L. During a 2-y follow-up, recurrent myocardial infarctions (MI) (defined as TnT > 0.05 microg/L with a typical MI presentation) and cardiac and all-cause mortality were registered. Cox regression analyses were used to relate the risk of new events to the quartiles of the omega-3 index at inclusion. After correction for age, sex, previous heart disease, hypertension, diabetes, smoking, high-sensitivity C-reactive protein, brain natriuretic peptide, creatinine, total cholesterol, HDL-cholesterol, triacylglycerol, homocysteine, BMI, and medication, there was no significant reduction in risk for all-cause mortality, cardiac death, or MI with increasing values of the index. In conclusion, we could not confirm the omega-3 index as a useful prognostic risk marker following an ACS.