Plasma phospholipid omega-3 fatty acids and incidence of postoperative atrial fibrillation in the OPERA trial

Omega-3 Polyunsaturated Fatty Acids: the Role in Prevention of Atrial Fibrillation in Patients with Coronary Artery Disease after Coronary Artery Bypass Graft Surgery

Aim. To estimate the role of omega-3 polyunsaturated fatty acids (PUFAs) administration in atrial fibrillation (AF) prevention after planned coronary artery bypass graft (CABG) surgery.

Material and Methods. Studied were 306 patients divided into two groups: patients of group I didn’t receive PUFAs (158 patients, 82.7% males) and patients of group II received PUFAs (148 patients, 89.3% males). PUFAs were prescribed in daily dose 2000 mg 5 days before surgery and in daily dose 1000 mg in postoperative period during 21 days.

Results. Postoperative AF (POAF) occurred in 29.7% patients in group I and in 16.9% patients in group II (р=0.009). We found that after CABG in patients of the I group median IL-6 level was 39.3% higher (p=0.001), interleukin-10 – 20.2% higher (p=0.01), superoxide dismutase – 78.9% higher (р<0.001), malondialdehyde – 33.8% higher (p=0.03), docosahexaenoic acid – 31.8% lower (p=0.01) and omega-3 index – 43.4%    lower (p=0.04) than in patients of the II group.

According to multivariate regression analysis we found significant association between the factors of inflammation, oxidative stress and the risk POAF development.

Conclusions. In patients who took PUFAs, we found less activation of inflammation, oxidative stress, the increasing of docosahexaenoic acid and omega-3 index accompanied by the decreasing of POAF development rates up to 12.8%.

Statin Therapy in Post-Operative Atrial Fibrillation: Focus on the Anti-Inflammatory Effects

BACKGROUND

Atrial fibrillation (AF) occurring after cardiac surgery, post-operative AF (POAF), is a serious and common complication of this treatment. POAF may be life-threatening and the available preventive strategies are insufficient or are associated with significantly increased risk of adverse effects, especially in long-term use. Therefore, more appropriate treatment strategies are needed.

METHODS

In this paper, the efficacy, safety, and other aspects of using statins in the prevention of POAF focusing on their anti-inflammatory effects are reviewed.

RESULTS

Recent studies have suggested that inflammation has a significant role in POAF, from the first AF episode to its serious complications including stroke and peripheral embolism. On the other hand, statins, the most widely used medications in cardiovascular patients, have pleiotropic effects, including anti-inflammatory properties. Therefore, they may potentially be effective in POAF prevention. Statins, especially atorvastatin, appear to be an effective option for primary prevention of POAF, especially in patients who had coronary artery bypass grafting (CABG), a cardiac surgery treatment associated with inflammation in the heart muscle. However, several large studies, particularly with rosuvastatin, did not confirm the beneficial effect of statins on POAF. One large clinical trial reported higher risk of acute kidney injury (AKI) following high-dose rosuvastatin in Chinese population. In this study, rosuvastatin reduced the level of C-reactive protein (CRP) but did not reduce the rate of POAF.

CONCLUSION

Further studies are required to find the most effective statin regimen for POAF prevention with the least safety concern and the highest health benefits.

Path to precision: prevention of post-operative atrial fibrillation

Development of post-operative atrial fibrillation (POAF) following open-heart surgery is a significant clinical and economic burden. Despite advancements in medical therapies, the incidence of POAF remains elevated at 25-40%. Early work focused on detecting arrhythmias from electrocardiograms as well as identifying pre-operative risk factors from medical records. However, further progress has been stagnant, and a deeper understanding of pathogenesis and significant influences is warranted. With the advent of more complex machine learning (ML) algorithms and high-throughput sequencing, we have an unprecedented ability to capture and predict POAF in real-time. Integration of multimodal heterogeneous data and application of ML can generate a paradigm shift for diagnosis and treatment. This will require a concerted effort to consolidate and streamline real-time data. Herein, we will review the current literature and emerging opportunities aimed at predictive targets and new insights into the mechanisms underlying long-term sequelae of POAF.

Biomarkers of meat and seafood intake: an extensive literature review

Meat, including fish and shellfish, represents a valuable constituent of most balanced diets. Consumption of different types of meat and fish has been associated with both beneficial and adverse health effects. While white meats and fish are generally associated with positive health outcomes, red and especially processed meats have been associated with colorectal cancer and other diseases. The contribution of these foods to the development or prevention of chronic diseases is still not fully elucidated. One of the main problems is the difficulty in properly evaluating meat intake, as the existing self-reporting tools for dietary assessment may be imprecise and therefore affected by systematic and random errors. Dietary biomarkers measured in biological fluids have been proposed as possible objective measurements of the actual intake of specific foods and as a support for classical assessment methods. Good biomarkers for meat intake should reflect total dietary intake of meat, independent of source or processing and should be able to differentiate meat consumption from that of other protein-rich foods; alternatively, meat intake biomarkers should be specific to each of the different meat sources (e.g., red vs. white; fish, bird, or mammal) and/or cooking methods. In this paper, we present a systematic investigation of the scientific literature while providing a comprehensive overview of the possible biomarker(s) for the intake of different types of meat, including fish and shellfish, and processed and heated meats according to published guidelines for biomarker reviews (BFIrev). The most promising biomarkers are further validated for their usefulness for dietary assessment by published validation criteria.

Fish Oil and Perioperative Bleeding

Background Fish oil is among the most common natural supplements for treatment of hypertriglyceridemia or prevention of cardiovascular disease. However, concerns about theoretical bleeding risk have led to recommendations that patients should stop taking fish oil before surgery or delay in elective procedures for patients taking fish oil by some health care professionals. Methods and Results We tested the effect of fish oil supplementation on perioperative bleeding in a multinational, placebo-controlled trial involving 1516 patients who were randomized to perioperative fish oil (eicosapentaenoic acid+docosahexaenoic acid; 8-10 g for 2-5 days preoperatively, and then 2 g/d postoperatively) or placebo. Primary outcome was major perioperative bleeding as defined by the Bleeding Academic Research Consortium. Secondary outcomes include perioperative bleeding per thrombolysis in myocardial infarction and International Society on Thrombosis and Hemostasis definitions, chest tube output, and total units of blood transfused. Participants' mean (SD) age was 63 (13) years, and planned surgery included coronary artery bypass graft (52%) and valve surgery (50%). The primary outcome occurred in 92 patients (6.1%). Compared with placebo, risk of Bleeding Academic Research Consortium bleeding was not higher in the fish oil group: odds ratio, 0.81; 95% CI, 0.53-1.24; absolute risk difference, 1.1% lower (95% CI, -3.0% to 1.8%). Similar findings were seen for secondary bleeding definitions. The total units of blood transfused were significantly lower in the fish oil group compared with placebo (mean, 1.61 versus 1.92; P<0.001). Evaluating achieved plasma phospholipid omega-3 polyunsaturated fatty acids levels with supplementation (on the morning of surgery), higher levels were associated with lower risk of Bleeding Academic Research Consortium bleeding, with substantially lower risk in the third (odds ratio, 0.30 [95% CI, 0.11-0.78]) and fourth (0.36 [95% CI, 0.15-0.87]) quartiles, compared with the lowest quartile. Conclusions Fish oil supplementation did not increase perioperative bleeding and reduced the number of blood transfusions. Higher achieved n-3-PUFA levels were associated with lower risk of bleeding. These novel findings support the need for reconsideration of current recommendations to stop fish oil or delay procedures before cardiac surgery. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT00970489.

Long-chain ω-6 plasma phospholipid polyunsaturated fatty acids and association with colon adenomas in adult men: a cross-sectional study

Dietary lipid intake can be associated with an increased risk for colorectal cancer depending on its composition. Carcinogenesis alters lipid metabolism to facilitate cell growth and survival. For instance, metabolites of polyunsaturated fatty acids (PUFAs) are associated with increasing colon cell proliferation. Moreover, precancerous colon lesions (i.e. adenomas) increase the risk for colorectal cancer. In this study, we investigated associations between plasma PUFAs and the number of colon polyps and polyp type (i.e. hyperplastic and adenoma). Healthy male participants (n=126) of 48-65 years of age were recruited before a routine colonoscopy screening. Plasma phospholipid (PPL) PUFAs were isolated by means of solid phase extraction and methylated. Fatty acid methyl esters were analyzed using gas chromatography. Factor analysis was used to cluster PUFAs into groups, and then generated factors and individual PUFAs were analyzed using polytomous logistic regression. In our age-adjusted and smoking-adjusted polytomous logistic regression, for each unit increase in PPL docosatetraenoic acid (DTA), individuals were 1.43 (1.00-2.06) and 1.33 (0.99-1.80) times more likely to have hyperplastic polyps and adenomas rather than no polyps, respectively. In our factor analysis, high PPL ω-6 PUFA and trans-fatty acid loading scores were associated with increased odds of adenoma presence rather than no polyps. Increases in long-chain PPL ω-6 PUFAs are associated with an increased risk for adenomas. As relative levels of DTA increase in PPLs, individuals had increased odds of having hyperplastic polyps and adenomas. Elevated conversion of ω-6 PUFAs to longer-chain ω-6s such as DTA may indicate altered PUFA metabolism at the tissue level.

Effects of Omega-3 Long Chain Polyunsaturated Fatty Acid Supplementation on Cardiovascular Mortality: The Importance of the Dose of DHA

Recent evidence on the relationship between omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation and cardiovascular health suggests that n-3 LCPUFA may no longer be efficacious. This review summarises the randomised controlled trials (RCTs) that assess the effect of n-3 LCPUFA supplementation on cardiovascular mortality. It appears that in the RCTs that showed no effect of n-3 LCPUFA on cardiovascular mortality, the dose of n-3 LCPUFA (in particular docosahexaenoic acid (DHA)) and hence the n-3 LCPUFA status, may not have been sufficiently high to demonstrate the efficacy, and/or the baseline n-3 LCPUFA status was already too high. The intention-to-treat analysis (ITT) is the gold standard for analysing RCTs and ITT is used for drug intervention trials where exposure to the drug versus no drug exposure provides two clearly distinct groups to determine the efficacy of the drug being studied. This differs in nutrition trials as often the nutrient of interest being studied is already being consumed by both groups (placebo and active) and therefore a true placebo group with absolutely no intake of the nutrient being studied is highly unlikely. Therefore, in n-3 LCPUFA supplementation trials, as there is no clear distinction between the two groups (placebo and n-3 LCPUFA), a per-protocol analysis (comparison of groups that includes only those participants that fully completed the original intervention allocation) should be conducted in addition to ITT analysis. Furthermore, blood analysis pre- and post-supplementation should be conducted to ensure that: (1) that the baseline n-3 status is not too high, in order to alleviate a potential ceiling effect; and (2) that the dose is high enough and hence the increase in omega-3 status will be high enough in order to assess the efficacy of n-3 LCPUFA supplementation.

A novel self-micro-emulsifying delivery system (SMEDS) formulation significantly improves the fasting absorption of EPA and DHA from a single dose of an omega-3 ethyl ester concentrate

BACKGROUND

Absorption of EPA and DHA from Omega-3-acid ethyl ester (EE) concentrate supplements occurs most efficiently when taken in context of a fatty meal; adequate fat intake is required to release bile salts that emulsify and pancreatic enzymes that digest omega-3-containing lipids in the intestine. Current guidelines recommend reduction in fat intake and therefore there is a need to optimize the absorption of Omega-3 in those consuming low-fat or no-fat meals. To this end, BASF has developed an Absorption Acceleration Technology, a novel self-micro-emulsifying delivery system (SMEDS) formulation of highly concentrated Omega-3-acid EE which enables rapid emulsification and microdroplet formation upon entering the aqueous environment of the gut therefore enhances the absorption.

METHODS

Two separate single dose, crossover studies were conducted to determine the relative bioavailability of omega-3-acid EE concentrate, either as a novel SMEDS formulation (PRF-021) or as control, in healthy fasted male and female adults at two dose levels (Study 1 "low dose": 630 mg EPA + DHA in PRF-021 vs. 840 mg EPA + DHA in control; Study 2 "high dose": 1680 mg EPA + DHA in PRF-021 vs. 3360 mg EPA + DHA in control). Blood samples were collected immediately before supplementation and at defined time intervals for 48 h. Plasma concentration of total EPA and DHA were determined for pharmacokinetic analysis, area under the curve (AUC) and maximum observed concentration (Cmax) was determined.

RESULTS

Total EPA plus DHA absorption from SMEDS formulation PRF-021 were 6.4 and 11.5 times higher compared to control in low- and high-dose studies respectively, determined as the ratio of baseline corrected, dose normalized AUC0-24h of PRF-021 over that of control. EPA and DHA individually showed differing levels of enhancement: the AUC0-24h ratio for EPA was 23.8 and 25.7 in low and high dose studies, respectively, and the AUC0-24h ratio for DHA was 3.6 and 5.6 in low and high dose studies, respectively. Cmax was also increased for both EPA and DHA 2.7- to 9.2-fold.

CONCLUSION

PRF-021 is a novel SMEDS formulation of Omega-3-acid EE demonstrating a marked improvement in absorption of a single dose of EPA and DHA EE under fasted conditions. This allows adequate absorption of Omega-3 from the supplement without the requirement of a high-fat meal.

Antioxidant Therapeutic Strategies for Cardiovascular Conditions Associated with Oxidative Stress

Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidant systems, where ROS overwhelms the antioxidant capacity. Excessive presence of ROS results in irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Oxidative stress plays a crucial role in the pathogenesis of cardiovascular diseases related to hypoxia, cardiotoxicity and ischemia-reperfusion. Here, we describe the participation of OS in the pathophysiology of cardiovascular conditions such as myocardial infarction, anthracycline cardiotoxicity and congenital heart disease. This review focuses on the different clinical events where redox factors and OS are related to cardiovascular pathophysiology, giving to support for novel pharmacological therapies such as omega 3 fatty acids, non-selective betablockers and microRNAs.

Nutrition-dependent eicosapentaenoic acid deficiency in care house residents

OBJECTIVE

We have identified that vital prognosis of adults in a group home (GH) in their mid-80s is associated with lower eicosapentaenoic acid (EPA) levels. We investigated the cause of EPA deficiency in residents in a GH and the effect of EPA treatment on cardiac function and nutritional function in 130 older adults.

METHODS

We compared blood chemistry data among three age- and sex-matched groups-outpatient clinic (OPC) attendees (n = 54, 87 ± 5 y old), GH residents (n = 40, 85 ± 8 y old), and older adults in a geriatric welfare home for the elderly (GWHE) (n = 36, 87 ± 6 y old)-using non-parametric test. Furthermore, we investigated the sequential changes in blood chemistry and cardiac function at 4 to 12 mo after the initiation of EPA administration (1800 mg/d).

RESULTS

Non-parametric test revealed that the EPA/arachidonic acid ratio as well as EPA levels were lower in the GH and GWHE residents than in the OPC attendees (OPC: 0.56 ± 0.3, GH: 0.23 ± 0.12, GWHE: 0.31 ± 0.1). Fish consumption was lower in the GH and GWHE group than in the OPC group. Repeated measured analyses using analysis of variance revealed that EPA administration increased serum EPA levels (54.0 ± 29.0 to 210.5 ± 50.6 μg/mL, P < 0.001); decreased arachidonic acid, docosahexaenoic acid, triacylglycerol, and LDL cholesterol levels at 4.5 ± 3.4 mo after administration; and reduced the severity of supraventricular arrhythmias on ambulatory electrocardiogram at 12.5 ± 4.5 mo (P < 0.05).

CONCLUSION

EPA deficiency in GH residents could be related to the nutritional characteristics of older adults in care facilities. EPA treatment induced changes in various lipids and reduced the severity of supraventricular arrhythmias.

Omega 3 and atrial fibrillation: Where are we?

Anti-arrhythmic properties of n-3 polyunsaturated fatty acids, at least in part mediated by anti-oxidant, anti-inflammatory and anti-fibrotic power, have been widely proved. Effect of fish oil on atrial fibrillation, both in primary and in secondary prevention and after cardiac surgery, are controversial, mostly due to lack of homogeneity between studies but also due to individual variability in response to fatty acids administration. Inclusion of measurement of incorporation of fish oil into cell membranes, appears to be essential in future studies, to assess their antiarrhythmic effect.

Effect of fish oil on monoepoxides derived from fatty acids during cardiac surgery

Our objective was to assess the dynamics of monoepoxides derived from polyunsaturated fatty acids (MEFAs), and their response to n-3 PUFA supplementation, in the setting of acute tissue injury and inflammation (cardiac surgery) in humans. Patients (479) undergoing cardiac surgery in three countries were randomized to perioperative fish oil (EPA + DHA; 8-10 g over 2-5 days preoperatively, then 2 g/day postoperatively) or placebo (olive oil). Plasma MEFAs derived from n-3 and n-6 PUFAs were measured 2 days postoperatively. Based on serial measures in a subset of the placebo group, levels of all MEFAs declined substantially following surgery (at postoperative day 2), with declines ranging from 37% to 63% (P < 0.05 each). Compared with placebo at postoperative day 2, levels of EPA- and DHA-derived MEFAs were 40% and 18% higher, respectively (P ≤ 0.004). The n-3 PUFA supplementation did not significantly alter the decline in n-6 PUFA-derived MEFAs. Both enrollment level and changes in plasma phospholipid EPA and DHA were associated with their respective MEFAs at postoperative day 2 (P < 0.001). Under the acute stress of cardiac surgery, n-3 PUFA supplementation significantly ameliorated the reduction in postoperative n-3 MEFAs, but not n-6 MEFAs, and the degree of increase in n-3 MEFAs related positively to the circulating level of their n-3 PUFA precursors.

Pharmacological strategies for prevention of postoperative atrial fibrillation

Atrial fibrillation (AF) complicating cardiac surgery continues to be a major problem that increases the postoperative risk of stroke, myocardial infarction, heart failure and costs and can affect long-term survival. The incidence of AF after surgery has not significantly changed over the last two decades, despite improvement in medical and surgical techniques. The mechanism and pathophysiology underlying postoperative AF (PoAF) is incompletely understood and results from a combination of acute and chronic factors, superimposed on an underlying abnormal atrial substrate with increased interstitial fibrosis. Several anti-arrhythmic and non-anti-arrhythmic medications have been used for the prevention of PoAF, but the effectiveness of these strategies has been limited due to a poor understanding of the basis for the increased susceptibility of the atria to AF in the postoperative setting. In this review, we summarize the pathophysiology underlying the development of PoAF and evidence behind pharmacological approaches used for its prevention in the postoperative setting.

Oxidative Stress Biomarkers and Incidence of Postoperative Atrial Fibrillation in the Omega-3 Fatty Acids for Prevention of Postoperative Atrial Fibrillation (OPERA) Trial

BACKGROUND

Animal study results point to oxidative stress as a key mechanism triggering postoperative atrial fibrillation (PoAF), yet the extent to which specific biomarkers of oxidative stress might relate to PoAF risk in humans remains speculative.

METHODS AND RESULTS

We assessed the association of validated, fatty acid-derived oxidative stress biomarkers (F2-isoprostanes, isofurans, and F3-isoprostanes) in plasma and urine, with incident PoAF among 551 cardiac surgery patients. Biomarkers were measured at enrollment, the end of surgery, and postoperative day 2. PoAF lasting ≥30 seconds was confirmed with rhythm strip or electrocardiography and centrally adjudicated. Outcomes were assessed until hospital discharge or postoperative day 10, whichever occurred first. Urine level of each oxidative stress biomarker rose at the end of surgery (2- to 3-fold over baseline, P<0.001) and subsequently declined to concentrations comparable to baseline by postoperative day 2. In contrast, plasma concentrations remained relatively stable throughout the perioperative course. Urine F2-isoprostanes and isofurans at the end of surgery were 20% and 50% higher in subjects who developed PoAF (P≤0.009). While baseline biomarker levels did not associate significantly with PoAF, end of surgery and postoperative day 2 isoprostanes and isofurans demonstrated relatively linear associations with PoAF. For example, the end of surgery extreme quartile multivariate adjusted OR (95% CI) for urine isofurans and F3-isoprostanes were 1.95 (1.05 to 3.62; P for trend=0.01) and 2.10 (1.04 to 2.25, P for trend=0.04), respectively. The associations of biomarkers with PoAF varied little by demographics, surgery type, and medication use (P≥0.29 for each).

CONCLUSIONS

These novel results add to accumulating evidence supporting the likely key pathogenic role of elevated oxidative stress in PoAF.

CLINICAL TRIAL REGISTRATION

URL: Clinicaltrials.gov Unique identifier: NCT00970489.

Circulating cardiac biomarkers and postoperative atrial fibrillation in the OPERA trial

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery and predicts increased morbidity and mortality. Identification of patients at high risk of POAF with the help of circulating biomarkers may enable early preventive treatment but data are limited, especially in contemporary surgical patients.

METHODS

Plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured at enrollment, on the morning of cardiac surgery, at end surgery, and 2 days postsurgery in 562 patients undergoing cardiac surgery, randomized to perioperative supplementation with oral fish oil or placebo in the Omega-3 Fatty Acids for Prevention of Post-Operative Atrial Fibrillation trial (OPERA). The primary endpoint was incident POAF lasting ≥ 30 s, centrally adjudicated and confirmed electrocardiographically.

RESULTS

Higher levels of NT-proBNP and hs-cTnT before surgery were associated with older age, renal or cardiac dysfunction and EuroSCORE. NT-proBNP peaked on postoperative day 2 (2172 [1238-3758] ng/L, median [Q1-Q3]), while hs-cTnT peaked at the end of surgery (373 [188-660] ng/L). Fish oil supplementation did not alter the time course of the cardiac biomarkers (P > 0.05). Concentrations of NT-proBNP or hs-cTnT, on the morning of surgery, or changes in their level between morning of surgery and postsurgery, were not significantly associated with POAF after adjustment for clinical and surgical characteristics.

CONCLUSION

Among patients undergoing cardiac surgery, NT-proBNP and hs-cTnT are related to clinical and surgical characteristics, have different perioperative time courses but are not independently associated with risk of POAF.