Omega-3 fatty acid supplements and risk of atrial fibrillation and 'micro-atrial fibrillation': A secondary analysis from the OMEMI trial.

BACKGROUND & AIMS: Recent randomized clinical trials have raised concerns regarding potential off target adverse effects from supplementation of n-3 polyunsaturated fatty acids (PUFA) on atrial fibrillation (AF) risk. We aimed to assess risk and potential mediators of AF and 'micro-AF' from n-3 PUFA in post-myocardial infarction (MI) patients. METHODS: In the OMEMI trial, 70-82 y. o. patients with a recent MI were randomized to 1.8 g/day of eicosapentaenoic-/docosahexaenoic acid (EPA/DHA) or placebo (corn oil) for two years. New-onset AF and 'micro-AF' was recorded by clinical detection and by screening with Zenicor thumb-ECG (adjudicated by blinded investigators). Serum EPA and DHA were measured at baseline and study end. RESULTS: At baseline, 759 of 1014 (75%) patients had no AF history. These patients were aged 75 ± 4 years and 71% were male. During follow-up, 43 patients developed new-onset AF (39 clinically-detected and 4 by thumb-ECG screening). In addition, 27 patients had episodes of micro-AF, yielding a total of 70 patients with new-onset AF or 'micro-AF'. In the n-3 PUFA group 46 (11.9%) had AF/'micro-AF' (28 AF, 18 'micro-AF') and in the placebo group 24 (6.5%) had AF/micro-AF (15 AF, 9 micro-AF); HR 1.90 (95%CI 1.16-3.11), P = 0.011. Changes in serum EPA (but not DHA) mediated the effect from n-3 PUFA on AF risk, explaining 65% of the association. CONCLUSION: Supplementation of n-3 PUFA post MI increases the risk of 'micro-AF' and AF, and increases in EPA seems to be an important mediator of the treatment effect from n-3 PUFA on the risk of AF. STUDY REGISTRATION: OMEMI Study; ClinicalTrails.gov identifier: NCT0184194.

Total Bilirubin Yields Prognostic Information Following a Myocardial Infarction in the Elderly.

Total bilirubin consists of an unconjugated form, solubilized by its binding to albumin, and a conjugated form representing a minor part of the circulating bilirubin. As total bilirubin in physiological concentrations is a powerful antioxidant, its concentration gradient may reflect the health status of an individual, and serve as a prognostic indicator of outcome in primary and secondary cardiovascular disease prevention. The aim of this study was to assess the association between total bilirubin and incident cardiovascular events following a myocardial infarction. Total bilirubin in serum was measured at baseline 2-8 weeks after hospitalization for an MI in 881 patients, aged 70 to 82 years, included in the OMEMI (Omega-3 Fatty acids in Elderly with Myocardial Infarction) study, where patients were followed-up for up to 2 years. The first major adverse clinical event (MACE) was the primary endpoint and consisted of nonfatal MI, unscheduled coronary revascularization, stroke, hospitalization for heart failure or all-cause death. As total bilirubin was non-normally distributed, log-transformed values and quartiles of bilirubin were analyzed using Cox regression models. The median (Q1, and Q3) baseline concentration of bilirubin was 11 (9, and 14) µmol/L, and higher log-transformed concentrations were associated with male sex, lower New York Heart Association (NYHA) class and non-smoking. MACE occurred in 177 (20.1%) patients during the follow-up. Higher concentrations of bilirubin were associated with a lower risk of MACE: HR 0.67 (95%CI 0.47-0.97) per log-unit increase, p = 0.032. Patients in the lowest quartile of bilirubin (<9 µmol/L) had the highest risk with HR 1.61 (95%CI 1.19-2.18), p = 0.002, compared to quartiles 2-4. This association remained significant even after adjusting for age, sex, body mass index (BMI), smoking status, NYHA class and treatment allocation: HR 1.52 (1.21-2.09), p = 0.009. Low concentrations of bilirubin (<9 µmol/L) are associated with increased nonfatal cardiovascular events or death in elderly patients with a recent myocardial infarction.

Screen-detected atrial fibrillation and 'micro-atrial fibrillation' and risk of cardiovascular events after myocardial infarction in elderly patients.

BACKGROUND: Incident atrial fibrillation (AF) occurs in 5-10% of patients after acute myocardial infarction (AMI) and is associated with adverse outcomes. Guidelines now recommend screening for AF in all elderly patients. However, the relevance of screen-detected AF and short episodes of irregular supraventricular ectopic beats ('micro-AF') after AMI is unknown. OBJECTIVES: To investigate the value of two-week intermittent ECG screening to detect incident AF and 'micro-AF' in elderly patients 12 months after an AMI, and its association with risk of cardiovascular events. METHODS: This was an investigator-initiated, multicenter substudy of the OMega-3 fatty acids in Elderly patients with Myocardial Infarction (OMEMI) trial, in Norway. Women and men aged 70-82 years, with a recent AMI, were recruited during 2012-2018. All participants had a 12-lead ECG performed at 3, 12 and 24 months. Patients without AF one year after the index AMI underwent 2 weeks of intermittent 30-second 'thumb ECG' screening. Incident AF and 'micro-AF' (episodes of ≥3 consecutive irregular supraventricular ectopic beats) were registered, and the association with risk of major cardiovascular events (MACE; non-fatal AMI, stroke, coronary revascularization, hospitalization for heart failure, or all-cause death) was analyzed with logistic regression. RESULTS: Among 1014 patients (198 (28.7%) women), 255 (25.1%) had known AF or AF identified at baseline. New-onset AF was detected clinically or at study visits in 39 (3.8%) patients. By screening participants without AF (n=567), unknown AF was identified in 4 (0.7%) and 'micro-AF' in 27 (4.8%) patients. Among 43 patients with incident AF, 21 (48.8%) experienced a MACE, which was significantly higher than those without AF (n=114, 15.9%; p<0.001), driven by a higher risk of AMI or revascularization. Nine (33.3%) patients with 'micro-AF' and 75 (13.9%) without 'micro-AF' experienced a MACE (p=0.002), explained mostly by a higher risk of heart failure hospitalization (p<0.001). Using patients without AF and 'micro-AF' as reference, 'micro-AF' was associated with an intermediate risk of MACE (OR 2.8; 95% CI 1.2-6.4) and new-onset AF with a high risk of MACE (OR 5.3; 95% CI 2.8-10.0). CONCLUSIONS: Two-week intermittent ECG screening identified few cases of new-onset AF, but a substantial number of patients with 'micro-AF'. 'Micro-AF' was associated with an increased risk of major cardiovascular events, albeit with an intermediate risk compared to those with new-onset AF.

Changes in eicosapentaenoic acid and docosahexaenoic acid and risk of cardiovascular events and atrial fibrillation: A secondary analysis of the OMEMI trial.

BACKGROUND: The cardiovascular benefit from n-3 polyunsaturated fatty acids (PUFAs) after acute myocardial infarction (AMI) is controversial, and the importance of serum eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations for clinical events is unclear. OBJECTIVES: To assess changes in EPA and DHA serum concentrations during n-3 PUFA supplementation and their association with incident cardiovascular events. METHODS: In the OMEMI trial, elderly patients with a recent AMI were randomized to 1.8 g/day of EPA/DHA or control (corn oil) for 2 years. The primary outcome was a composite of AMI, coronary revascularization, stroke, heart failure hospitalization, or all-cause death (major adverse cardiovascular event [MACE]) and the secondary outcome was new-onset atrial fibrillation (AF). RESULTS: EPA and DHA measurements were available in 881 (92% of survivors) participants at randomization and study completion. EPA and DHA increased in the active treatment arm (n = 438) by a median of 87% and 16%, respectively. Greater on-treatment increases in EPA and DHA were associated with decreasing triglycerides, increasing high-density lipoprotein cholesterol, and lower baseline EPA and DHA concentrations. Greater on-treatment increases in EPA were associated with lower risk of MACE (adjusted hazard ratio 0.86 [95% confidence interval, CI, 0.75-0.99], p = 0.034), and higher risk of AF (adjusted hazard ratio (HR) 1.36 [95% CI 1.07-1.72], p = 0.011). Although there were similar tendencies for DHA changes and outcomes, these associations were not statistically significant (HR 0.84 [0.66-1.06] for MACE and 1.39 [0.90-2.13] for AF). CONCLUSION: Greater on-treatment increases in EPA were associated with lower risk of MACE and higher risk of new-onset AF. These data suggest that the cardiovascular effects of increasing n-3 PUFA levels through supplements are complex, involving both potential benefits and harm.

One year of omega 3 polyunsaturated fatty acid supplementation does not reduce circulating prothrombotic microvesicles in elderly subjects after suffering a myocardial infarction.

BACKGROUND & AIMS: Circulating microvesicles (cMV) are both effectors and biomarkers of cardiovascular disease (CVD), and the effects of omega 3 polyunsaturated fatty acids (n3 PUFA) in MV shedding are not yet well known. Therefore, we aimed to investigate the effects of long-term n3 PUFA supplementation on cMV release from cells of the vascular compartment in elderly subjects at very high risk of CVD. METHODS: We included 156 elderly patients 2-8 weeks after suffering an acute myocardial infarction from the OMEMI cohort. Subjects were randomly allocated to receive 930 mg EPA + 660 mg DHA (n3 PUFA intervention) or corn oil (56% linoleic acid, 32% oleic acid, 10% palmitic acid) used as placebo daily for two years. At inclusion and after one-year follow-up, prothrombotic [annexin V (AV)+] cMV derived from blood and vascular cells were phenotyped by flow cytometry. RESULTS: No differences were observed in the levels of cMV between the randomized groups at inclusion in the study. After one-year follow-up, total AV+, platelet-derived CD61+/AV+, and endothelial-derived CD31+/AV+ and CD31+/CD42b-/AV+ cMV increased significantly in both groups. In the n3 PUFA supplemented group, platelet-derived CD62P+/AV+, CD42b+/AV+ and CD31+/CD42b+/AV+; leukocyte-derived CD62L+/AV+, CD45+/AV+, and CD11b+/AV+, as well as endothelial derived CD146+/AV+, CD62E+/AV+, and CD309+/AV+ cMV also increased significantly. No significant differences were however, observed in the changes of cMV levels between groups. CONCLUSION: In elderly Norwegians who have suffered a recent acute myocardial infarction and treated as per guidelines, long-term supplementation with 1.8 g/day n3 PUFA does not modulate prothrombotic MV release from blood and vascular cells. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01841944.

Biomarkers of ageing and cardiac remodeling are associated with atrial fibrillation.

Objectives. Ageing is one of the strongest risk factors for atrial fibrillation (AF), and additional risk factors are also closely related to ageing. Remodeling is part of the pathophysiology of AF, and a possible common denominator of ageing and other AF risk factors. The aim of this study was to investigate any association between the presence of AF and the ageing biomarkers, leukocyte telomere length (LTL) and sirtuin-1 (SIRT-1), and the cardiac remodeling biomarkers Galectin-3 and sST2 in elderly myocardial infarction (MI) patients. Design. Patients were included after admission for MI. Diagnosis of AF was retrieved from medical records and classified as either history of AF before MI or new onset from admission to study inclusion. SIRT-1, sST2 and Galectin-3 were analyzed by ELISAs and LTL by qPCR. Results. In total, 299 patients were included, median age 75 years, 70.2% male. A history of AF was recorded in 38 patients and 30 patients experienced new onset AF. Higher levels of SIRT-1 were associated with lower risk of having a history of AF (OR = 0.46 (95% CI 0.26, 0.81), p = 0.007), whereas higher sST2 levels were associated with higher risk of AF (OR = 4.13 (95% CI 1.69, 10.13), p = 0.002). Results remained significant after adjustment for other AF risk factors. No significant associations with AF were found for Galectin-3 or LTL. None of the biomarkers associated with new onset AF. Conclusion. In elderly patients with MI, higher ST2 and lower SIRT-2 levels were associated with higher prevalence of AF, possibly reflecting both ageing and the remodeling phenomena in AF. Clinical trials registration: ClinicalTrials.gov (NCT01841944).

Effects of n-3 Fatty Acid Supplements in Elderly Patients After Myocardial Infarction: A Randomized, Controlled Trial.

BACKGROUND: High intake of marine n-3 polyunsaturated fatty acids (PUFA) has been associated with reduced risk of cardiovascular events; however, this has not been confirmed in patients with a recent acute myocardial infarction (AMI). Elderly patients are at particularly increased cardiovascular risk after myocardial infarction, but few trials address this group specifically. Omega-3 fatty acids hold the potential to reduce cardiovascular events with limited adverse effects in this vulnerable group. The hypothesis was that daily addition of 1.8g n-3 PUFA to standard of care secondary prophylaxis in elderly patients who have survived an AMI would reduce the risk of subsequent cardiovascular events during 2 years follow-up. METHODS: The OMEMI trial (Omega-3 Fatty acids in Elderly with Myocardial Infarction) is an investigator-initiated, multicenter, randomized clinical trial adding 1.8 g n-3 PUFA (930 mg eicosapentaenoic acid and 660 mg docosohexaenoic acid) versus placebo (corn oil) daily to standard of care in patients aged 70 to 82 years with recent (2-8 weeks) AMI. The primary endpoint was a composite of nonfatal AMI, unscheduled revascularization, stroke, all-cause death, heart failure hospitalization after 2 years. The secondary outcome was new atrial fibrillation. The safety outcome was major bleeding. Serum fatty acids were measured as biomarkers of adherence. RESULTS: In total, 1027 patients were randomized. Follow-up data were available for 1014 patients who were included in the intention-to-treat analysis. Mean±SD age was 75±3.6 years, 294 (29%) were female, and mean triglycerides were 111.4±61.9 mg/dL. The primary endpoint occurred in 108 (21.4%) patients on n-3 PUFA versus 102 (20.0%) on placebo (hazard ratio, 1.08 [95% CI, 0.82-1.41]; P=0.60). The secondary endpoint occurred in 28 (7.2%) patients on n-3 PUFA versus 15 (4.0%) on placebo (1.84 [0.98-3.45]; P=0.06). Median changes in eicosapentaenoic acid and docosahexaenoic acid were +87% and +16% for n-3 PUFA versus -13% and -8% for placebo. Major bleeding occurred in 54 (10.7%) and 56 (11.0%) in the n-3 PUFA and placebo groups, respectively (P=0.87). Similar results were found in per-protocol analysis (n=893). CONCLUSIONS: We could not detect reduction in clinical events in our elderly patients with recent AMI who were treated with 1.8 g n-3 PUFAs daily for 2 years. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01841944.

Leukocyte telomere length and serum polyunsaturated fatty acids, dietary habits, cardiovascular risk factors and features of myocardial infarction in elderly patients.

BACKGROUND: Telomeres are non-coding sequences at the end of eukaryote chromosomes, which in complex with associated proteins serve to protect subtelomeric DNA. Telomeres shorten with each cell division, are regarded as a biomarker for aging and have also been suggested to play a role in atherosclerosis and cardiovascular disease (CVD). The aim of the present study was to explore the associations between leukocyte telomere length and serum polyunsaturated fatty acids, diet, cardiovascular risk factors and features of myocardial infarction (MI) in elderly patients. METHODS: The material is based upon the first 299 included patients in the OMEMI trial, where patients aged 70-82 years of age are randomized to receive omega-3 supplements or corn oil (placebo) after MI. Patients were included 2-8 weeks after the index MI. DNA was extracted from whole blood, and leukocyte telomere length (LTL) was analyzed by qPCR and reported as a number relative to a reference gene. Serum long chain polyunsaturated fatty acid (LCPUFA) content was analyzed by gas chromatography. Diet was evaluated with the validated SmartDiet food frequency questionnaire. Medical records, patient interviews and clinical examination provided previous medical history and anthropometric data. Non-parametric statistical tests were used. RESULTS: Median (25, 75 percentile) LTL was 0.55 (0.42, 0.72). Patients had a median age of 75 years, 70.2% were male and 45.2% used omega-3 supplements. There was a weak, but significant correlation between LTL and linoleic acid (r = 0.139, p = 0.017), but not with other LCPUFAs. There was a trend towards longer telomeres with a healthier diet, but this did not reach statistical significance (p = 0.073). No associations were found between LTL and CVD risk factors or features of MI. CONCLUSIONS: In our population of elderly with a recent myocardial infarction LTL was associated with linoleic acid concentrations, but not with other LCPUFAs. Patients with a healthy diet tended to have longer telomeres. The limited associations may be due to age and the narrow age-span in our population. Further studies, designed to detect longitudinal changes should be performed to explore the role of telomeres in cardiovascular aging. TRIAL REGISTRATION: Clinical trials no. NCT01841944, registration date April 29, 2013.

High Adherence to the Nordic Diet Is Associated with Lower Levels of Total and Platelet-Derived Circulating Microvesicles in a Norwegian Population.

Circulating microvesicles (cMV) are small phospholipid-rich blebs shed from the membrane of activated vascular cells that contribute to vascular disease progression. We aimed to investigate whether the quality of the Nordic diet is associated with the degree of blood and vascular cell activation measured by MV shedding in elderly patients after an acute myocardial infarction (AMI). One-hundred and seventy-four patients aged 70-82 years were included in this cross-sectional study. Fasting blood samples were taken within 2 to 8 weeks after an AMI. Annexin V (AV)+ cMV derived from blood and vascular cells were measured through flow cytometry. A patient's usual diet was recorded with the SmartDiet® questionnaire. Patients with higher adherence to the Nordic diet (highest diet score) had lower levels of total AV+ and platelet-derived (CD61+/AV+ and CD31+/AV+) cMV. Dietary habits influence cellular activation. A high adherence to the Nordic diet (assessed by the SmartDiet® score) in elderly post-AMI patients was associated with lower levels of platelet activation, which was reflected by a lesser release of MV carrying platelet-derived epitopes, potentially contributing to an explanation of the cardioprotective effects of the Nordic diet.

Platelet-, monocyte-derived and tissue factor-carrying circulating microparticles are related to acute myocardial infarction severity.

OBJECTIVE: Circulating microparticles (cMPs) are phospholipid-rich vesicles released from cells when activated or injured, and contribute to the formation of intracoronary thrombi. Tissue factor (TF, CD142) is the main trigger of fibrin formation and TF-carrying cMPs are considered one of the most procoagulant cMPs. Similar types of atherosclerotic lesions may lead to different types of AMI, although the mechanisms behind are unresolved. Therefore, we aimed to investigate the phenotype of cMPs found in plasma of ACS patients and its relation to AMI severity and thrombotic burden. METHODS: In a cross-sectional study, two hundred patients aged 75±4 years were included in the study 2-8 weeks after suffering an AMI. Annexin V positive (AV+)-cMPs derived from blood and vascular cells were measured by flow cytometry. Plasma procoagulant activity (TF-PCA) was measured through a chromogenic assay. RESULTS: STEMI patients (n = 75) showed higher levels of platelet-derived cMPs [CD61+/AV+, CD31+/AV+, CD42b+/AV+ and CD31+/CD42b+/AV+, P = 0.048, 0.038, 0.009 and 0.006, respectively], compared to NSTEMI patients (n = 125). Patients who suffered a heart failure during AMI (n = 17) had increased levels of platelet (CD61+)-and monocyte (CD14+)-derived cMPs carrying TF (CD142+) (P<0.0001 and 0.004, respectively). Additionally, NYHA class III (n = 23) patients showed higher levels of CD142+/AV+, CD14+/AV+ and CD14+/CD142+/AV+ cMPs than those in class I/II (P = 0.001, 0.015 and 0.014, respectively). The levels of these cMPs positively correlated with TF-PCA (r≥0.166, P≤0.027, all). CONCLUSIONS: Platelets and monocytes remain activated in AMI patients treated as per guidelines and release cMPs that discriminate AMI severity. Therefore, TF-MPs, and platelet- and monocyte-MPs may reflect thrombotic burden in AMI patients.

Serum Fatty Acids, Traditional Risk Factors, and Comorbidity as Related to Myocardial Injury in an Elderly Population with Acute Myocardial Infarction.

Background. Epidemiological and randomized clinical trials indicate that marine polyunsaturated n-3 fatty acids (n-3 PUFAs) may have cardioprotective effects. Aim. Evaluate the associations between serum fatty acid profile, traditional risk factors, the presence of cardiovascular diseases (CVD), and peak Troponin T (TnT) levels in elderly patients with an acute myocardial infarction (AMI). Materials and Methods. Patients (n = 299) consecutively included in the ongoing Omega-3 fatty acids in elderly patients with myocardial infarction (OMEMI) trial were investigated. Peak TnT was registered during the hospital stay. Serum fatty acid analysis was performed 2-8 weeks later. Results. No significant correlations between peak TnT levels and any of the n-3 PUFAs were observed. However, patients with a history of atrial fibrillation had significantly lower docosahexaenoic acid levels than patients without. Significantly lower peak TnT levels were observed in patients with a history of hyperlipidemia, angina, MI, atrial fibrillation, intermittent claudication, and previous revascularization (all p < 0.02). Conclusions. In an elderly population with AMI, no association between individual serum fatty acids and estimated myocardial infarct size could be demonstrated. However, a history of hyperlipidemia and the presence of CVD were associated with lower peak TnT levels, possibly because of treatment with cardioprotective medications.

Effects on serum fractalkine by diet and omega-3 fatty acid intervention: relation to clinical outcome.

Introduction. Fractalkine is a chemokine associated with atherosclerosis. Increased serum levels have been reported in unstable coronary artery disease (CAD) and to predict mortality in heart failure. Mediterranean-like diet and omega-3 fatty acids (n3-PUFA) have documented cardioprotective and anti-inflammatory effects. We have investigated the effect of Mediterranean-like dietary counseling and n-3 PUFA on serum fractalkine in an elderly population and its ability to predict cardiovascular disease (CVD). Materials and Methods. 563 men (age 64-75 yrs) at high risk of CAD were randomized into a 2 × 2 factorial designed trial for 3-year dietary counseling and/or n-3 PUFA supplementation (2.4 g/d). Circulating levels of fractalkine were measured at baseline and at end of study. Clinical events were recorded after 3 years. Results. Fractalkine levels were significantly reduced in all groups from baseline to 3 years (P < 0.001, all), but without between-group differences in changes. Fractalkine levels at baseline were not predictive for CVD events (n = 68) or total mortality. Lower fractalkine levels were observed in smokers (P = 0.019). Conclusions. Reduced levels of fractalkine from baseline to 3 years were observed, however, without any influence of Mediterranean-like diet or n-3 PUFA supplementation. Fractalkine levels at baseline were not predictive for later CVD events.

Effects of ω3 supplementation in elderly patients with acute myocardial infarction: design of a prospective randomized placebo controlled study.

BACKGROUND: Both epidemiological and randomized clinical studies suggest that supplementation with very-long-chain marine polyunsaturated n-3 fatty acids (n-3 PUFA) have cardioprotective effects, however these results are not without controversy. Study population, sample-size, type of supplementation and type of endpoint have all varied widely accross different studies.Therefore, the aims of the present study are to evaluate the effect of 2 years supplementation with capsules of very-long chain marine n-3 PUFA on top of standard therapy in elderly patients after acute myocardial infarction (AMI).In addition, special characteristics of this population with regard to prediction of clinical outcome will be investigated. The hypothesis is that this supplementation on top of modern therapy will reduce the occurence of major cardiovascular events (MACE). We present the design of the OMEMI (OMega-3 fatty acids in Elderly patients with Myocardial Infarction) study. METHODS/DESIGN: The OMEMI study is designed as a randomized, placebo-controlled double-blind multicenter trial.Included are patients ≥70-82 years of age who have sustained AMI. Patients of either gender are eligible. Sample size calculation based on existing literature has resulted in the need for 1400 patients followed for 2 years, based on the assumption that the n-3 PUFA supplementation will reduce MACE with 30%. The study medication is Pikasol® Axellus AS, Norway, 3 capsules (1.8 g eicosapentaenoic acid (EPA) + docohexaenoic acid (DHA)) per day, and matching placebo is corn oil. The Primary end-point is the composite of total mortality, first non-fatal recurring AMI, stroke and revascularization. Secondary end-point is the occurrence of new onset atrial fibrillation. Extensive biobanking will be performed, including adipose tissue biopsies. Compliance will be assessed by measurements of the fatty acid profile in serum, sampled at inclusion, after 12 months and at the end of study. DISCUSSION: The OMEMI study is scheduled to terminate when the last included patient has been followed for 2 years. To the best of our knowledge, the OMEMI study is the first to evaluate the effect of n-3 PUFAs on CVDs and mortality in a high risk elderly population having suffered an acute myocardial infarction. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01841944.