Effects of omega-3 fatty acid supplementation on the risk of atrial fibrillation (AF) and micro-AF in the OMEMI trial

Background

Findings from recent clinical outcome trials have raised concerns regarding potential off target adverse effects from supplementation with n-3 polyunsaturated fatty acids (PUFA) on atrial fibrillation (AF) risk.

Purpose

We aimed to assess AF and “micro-AF” in elderly patients with myocardial infarction (MI), randomized to n-3 PUFA or placebo.

Methods

In the OMEMI trial, 70–82 years old patients with a recent MI were randomized to 1.8g/day of eicosapentaenoic/docosahexaenoic acid (EPA/DHA) or placebo (corn oil) for two years. New-onset AF was recorded by clinical detection and by screening, also for “micro-AF” (episodes of ≥3 consecutive irregular supraventricular ectopic beats), by two weeks Zenicor thumb ECG (adjudicated by investigators blinded to treatment allocation). Serum phospholipid content of EPA and DHA was determined by gas chromatography at baseline and study end.

Results

Of 1014 patients in the OMEMI trial, 759 (75%) had no history of AF at baseline. These patients were aged 75±4 years and 542 (71%) were male. During the two year 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 and 18 micro-AF) while in the placebo group 24 (6.5%) had AF/micro-AF (15 AF and 9 micro-AF); HR 1.90 (95% CI 1.16–3.11, P=0.011; Figure 1, panel A). In both treatment arms combined, EPA increased with a mean of 60% in no-AF, 80% in micro-AF and 110% in AF (P=0.003 for linear trend; Figure 1, panel B). In patients randomized to n-3 PUFA, EPA increased with a mean of 120% in no-AF, 130% in micro-AF and 180% in clinical-AF (P=0.04 for linear trend). There were no significant associations between changes in DHA and new-onset AF.

Conclusion

Supplementation with 1.8 g of n-3 PUFA to post MI patients increased the risk of micro-AF and AF, and there seemed to be a graded association between increases in serum EPA and the risk of micro-AF and AF. Changes in serum DHA was not related to the risk of AF/micro-AF.

Funding Acknowledgement

Type of funding sources: None.

Changes in novel cardiac extracellular matrix biomarkers in STEMI: associations with adverse outcomes

Background

Ischemia-reperfusion (IR)-injury contributes to adverse outcomes following myocardial infarction undergoing reperfusion. Exaggerated remodelling of the extracellular matrix (ECM) is likely to be involved in IR-injury, potentially releasing ECM components to the systemic circulation. To improve prognostication and future therapeutic options in patients with myocardial infarction, more knowledge is warranted about ECM components associated with IR-injury.

Purpose

To investigate whether ECM components quantified in serum samples associate with myocardial injury and function, and clinical outcomes in patients with ST-elevation myocardial infarction (STEMI).

Methods

We selected biomarkers previously suggested to be involved in ECM changes in the heart, i.e. growth differentiation factor 15 (GDF-15), periostin, osteopontin, syndecan-1, syndecan-4, and bone morphogenetic protein 7. The concentrations of the biomarkers were measured in serum samples from patients with STEMI (n=239) enrolled in the POSTEMI trial, at day 1 and month 4 after hospital admission. Infarct size, microvascular obstruction (MVO), left ventricular remodelling, and left ventricular ejection fraction (LVEF) were determined by cardiac magnetic resonance imaging. Major adverse cardiovascular events (MACE) and all-cause mortality were recorded after 12 months and with a median of 70 months, respectively.

Results

Serum levels of GDF-15, osteopontin, syndecan-1 and syndecan-4 declined, whereas periostin increased, from day 1 to month 4. Higher levels of syndecan-1 were associated with the presence of MVO (n=116) (day 1 OR 1.39 (1.06–1.82); month 4 OR 1.53 (1.08–2.17)), while higher GDF-15 and syndecan-1 were associated with the development of large infarct size (>75th percentile, n=57) and reduced cardiac function defined as LVEF <50% (n=64) at month 4. Higher levels of GDF-15 at month 4 and periostin at both time points were associated with increased risk of both MACE (n=16) (GDF-15: HR 1.42 (1.04–1.94); periostin day 1: HR 1.88 (1.09–3.25); periostin month 4: HR 1.64 (1.03–2.62)) and all-cause mortality (n=20) (GDF-15: HR 1.59 (1.28–1.97); periostin day 1: HR 1.85 (1.16–2.95); periostin month 4: HR 2.02 (1.35–3.02)) (Figure 1). On the contrary, elevated levels of syndecan-4 at month 4 were associated with lower risk of adverse outcomes, including all-cause mortality (HR 0.48 (0.28–0.84)) (Figure 1) and less IR-injury as assessed by a higher myocardial salvage index.

Conclusion

Elevated serum levels of GDF-15, periostin, and syndecan-1 were associated with a higher risk of adverse outcomes or detrimental remodelling in patients with STEMI. Increased levels of syndecan-4 measured 4 months after STEMI were associated with a reduced risk of all-cause mortality. Our results suggest the potential use of these biomarkers as prognostic tools and may suggest a role for these ECM components in IR injury.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): South-Eastern Norway Regional Health AuthorityNorwegian Health Association

Screen-detected atrial fibrillation (AF) and “micro-AF” after myocardial infarction in patients 70–82 years and risk of cardiovascular events in the OMEMI trial

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 yield of extended AF screening after AMI has not been investigated. Short episodes of consecutive irregular supraventricular ectopic beats, entitled “micro-AF”, are associated with the development of AF, but the prognostic importance of such findings after an AMI is unknown.

Purpose

To investigate the added value of two-week intermittent ECG screening to detect incident AF and “micro-AF” in elderly patients 12 months after an AMI, and its relation to risk of cardiovascular endpoints.

Methods

The OMega-3 fatty acids in Elderly patients with Myocardial Infarction (OMEMI) study investigated the effect of Omega-3 fatty acid supplementation on 2-year risk of major cardiovascular events (MACE; non-fatal AMI, stroke, revascularization, or hospitalization for heart failure) in 70–82 years old patients with a recent AMI. All patients had a 12-lead ECG performed at 3, 12 and 24 months. In addition, patients without known AF one year after the index AMI underwent a 2-week period of intermittent 30-second “thumb ECG” screening. Incident AF and “micro-AF” (episodes of ≥3 consecutive irregular supraventricular ectopic beats) were registered and adjudicated by at least two investigators who were blinded to outcome, and the association with risk of MACE was analyzed with logistic regression.

Results

Among 1014 patients in the OMEMI trial, 255 (25.1%) had known AF or AF identified at baseline. New-onset AF was detected clinically or at study visits in 39 patients. Screening by 2-week “thumb ECG” was performed in 567 participants without known AF, and identified unknown AF in 4 (0.7%) patients. Another 27 (4.8%) patients had “micro-AF” in at least one ECG recording. In 43 patients with incident AF, 21 (48.8%) experienced a MACE, compared to 114 out of 716 without any AF (15.9%; p<0.001), driven by a higher risk of new AMI or revascularization. Nine (33.3%) patients with “micro-AF” and 63 (12.2%) without “micro-AF” experienced a MACE (p=0.002), explained mostly by a higher risk of hospitalization for heart failure (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).

Conclusion

Two-week intermittent ECG screening identified few new 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 a higher risk of major cardiovascular events associated with new-onset AF.

Funding Acknowledgement

Type of funding sources: None.

Effect of Revascularization on Exercise-Induced Changes in Cardiac and Prothrombotic Biomarkers in Patients with Coronary Artery Disease

We examined whether resting levels and exercise-induced changes during exercise ECG stress test (EST) of cardiac Troponin T (cTnT), NT-proBNP and prothrombotic markers were affected by revascularization in patients with coronary artery disease (CAD).

EST1 was performed before coronary angiography and revascularization, and patients (n  =  20) with confirmed CAD, performed another EST (EST2) 9 weeks later. Blood samples were drawn at rest and within five min after termination of ESTs.

cTnT and NT-proBNP increased during exercise at both ESTs (p < 0.001, all). Resting cTnT levels at EST2 versus EST1 were significantly higher (p  =  0.02) whereas NT-proBNP did not differ. At both visits, increased D-dimer (p  =  0.008 and <0.001), pro-thrombin fragment 1  +  2 (p  =  0.009 and 0.001) and tissue factor pathway inhibitor (TFPI) (p < 0.001 and 0.001) during exercise were demonstrated. Resting levels of endogenous thrombin potential (ETP) and TFPI were reduced at EST2 versus EST1 (p < 0.01).

Revascularization did not affect exercise-induced release of cardiac and prothrombotic biomarkers and did not reduce resting levels of cTnT or NT-proBNP, suggesting revascularization per se not to prevent secretion of biomarkers. The lower resting levels of ETP and TFPI after revascularization may however, be indicative of reduced thrombin generation and endothelial activation.

Clinicaltrials.gov, CADENCE, NCT01495091 https://clinicaltrials.gov/ct2/show/NCT01495091?term = 01495091&draw = 2&rank = 1.

Complement activation is associated with neutrophil extracellular traps and all-cause mortality in ST-elevation myocardial infarction

Background

The complement system and neutrophil extracellular traps (NETs) are both parts of the innate immune system, and have been implicated in the ischemia-reperfusion injury in patients with ST-elevation myocardial infarction (STEMI). There is experimental evidence of reciprocal activation between the complement system and NETs. Any such link in patients with STEMI has not been investigated.

Purpose

To investigate a potential association between complement activation and clinical outcomes after STEMI, and assess any interplay between complement activation and NETs in this situation.

Methods

Patients with ST-elevation myocardial infarction were included at a median of 18 hours after percutaneous coronary intervention (n=864). The terminal complement complex (TCC) was measured by ELISA as a marker of complement activation. As markers of NETs were myeloperoxidase-deoxynucleic acid (MPO-DNA) and citrullinated histone 3 (CitH3) measured by ELISAs, while double stranded DNA (dsDNA) was measured by a nucleic acid stain. Patients were followed for a median of 4.6 years. The primary endpoint was a composite of new myocardial infarction, unscheduled revascularization, stroke, hospitalization for heart failure and death, whichever occurred first. All-cause mortality was also recorded.

Results

The composite endpoint occurred in 184 (21.3%) patients, while 70 (8.1%) died during follow-up. When dichotomizing at median TCC, the group with above-median TCC levels did not have an increased risk of reaching the composite endpoint (hazard ratio (HR): 1.069, 95% CI: [0.801, 1.428], p=0.651). However, this group exhibited an increased risk of all-cause mortality (HR: 1.650, 95% CI: [1.020, 2.671], p=0.041). This risk persisted when adjusting for age, sex, hypertension and LDL-cholesterol (HR: 1.673, 95% CI: [1.014, 2.761], p=0.044), but the significance was lost when adjusting for NT-proBNP (HR: 1.492, 95% CI: [0.885, 2.515], p=0.133). TCC was correlated to dsDNA (r=0.127, p&lt;0.001) and CitH3 (r=0.102, p=0.003), but not MPO-DNA. The group with both TCC and dsDNA in the highest quartile exhibited a significantly higher incidence of all-cause mortality than the remaining population (17.6% vs, 7.2%, p=0.002). When examining the predictive value of TCC and dsDNA on all-cause mortality in ROC curve analysis, the area under the curve (AUC) for TCC was 0.549 (95% CI: [0.472, 0.625]), while the AUC for dsDNA was 0.653 (95% CI: [0.584, 0.722]). When combining TCC and dsDNA the predictive value was marginally higher than for TCC alone (AUC: 0.649, 95% CI: [0.579, 0.720])

Conclusion

In this STEMI population, complement activation measured by TCC was not associated with the primary composite endpoint, but was associated with increased risk of death. TCC was weakly correlated with markers of NETs. Despite a high mortality rate in patients with high levels of TCC and dsDNA, combining these variables did not increase the prognostic value compared to TCC alone.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stein Erik Hagen's Foundation for Clinical Heart Research Survival according to cox regression

Changes in EPA and DHA during supplementation with omega-3 fatty acids and incident cardiovascular events: secondary analysis from the OMEMI trial

Background

In the OMEMI trial, elderly post-MI patients did not achieve reduction in cardiovascular events from supplementation of 1.8g n-3 polyunsaturated fatty acids (PUFA). In two recent trials of hypertriglyceridaemic patients the REDUCE-IT trial demonstrated an association between high levels of serum eicosapentaenoic acid (EPA) and reduced risk of CV events with 4 g/day icosapent ethyl supplements while in the STRENGTH trial no such association was present in patients treated with 4 g/day of EPA+ docosahexaenoic acid (DHA).

Purpose

To assess associations between changes in concentrations of EPA and DHA during two years supplementation with n-3 PUFA and incident cardiovascular events in the OMEMI trial.

Methods

In the randomized controlled OMEMI trial, 1014 elderly patients with a recent acute myocardial infarction (AMI) were treated with 1.8g/day of EPA and docosahexaenoic acid (DHA) or placebo for two years, and followed for the primary outcome of MACE (AMI, coronary revascularization, stroke or heart failure hospitalization) and secondary outcome of new-onset atrial fibrillation (AF). Serum concentrations of EPA and DHA were measured at inclusion and at study completion by gas chromatography, and reported as % weight of total FA (%wt) in serum phospholipids.

Results

Serial EPA and DHA measurements at study inclusion and completion were available in 881 patients (92% of survivors). At baseline EPA and DHA concentrations were (mean±SD) 2.84±1.41 and 5.71±1.35%wt, respectively. Higher baseline EPA and DHA concentrations were associated with previous n-3 PUFA supplementation, lower prevalence of current smoking and diabetes, lower levels of triglycerides and higher levels of HDL-cholesterol (all p&lt;0.05). In patients randomized to n-3 PUFA, EPA and DHA increased with 2.32±1.92 and 0.91±1.19%wt, respectively, whereas in the placebo group EPA and DHA decreased with −0.39±1.37 and −0.43±1.13%wt, respectively. Greater increases in EPA and DHA during follow-up were associated with a lowering of triglyceride concentrations, increasing HDL concentrations, and lower baseline concentrations of EPA and DHA (all p&lt;0.001). Among patients treated with n-3 PUFA (n=438), a greater increase in EPA was associated with a lower risk of incident MACE (HR 0.89 [95% CI 0.78–1.00] per %wt, p=0.059) and higher risk of new-onset AF in patients free of AF at inclusion (n=339): HR 1.31 [1.06–1.62] per %wt, p=0.012 (Figure). There were no such associations for changes in DHA: HR 0.86 (95% CI 0.70–1.05), p=0.13 for MACE and HR 1.29 (0.91–1.83), p=0.16 for new-onset AF.

Conclusion

Patients treated with 1.8 g/day n-3 PUFA for two years experienced a doubling of serum EPA concentrations. Greater increases in EPA were associated with a lower risk of MACE, but also a higher risk of new-onset AF. Changes in DHA concentrations were not associated with outcomes, suggesting that EPA may be the more important n-3 PUFA with respect to risk of cardiovascular events.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Oslo University Hospital, Ullevål Figure 1

Plaque and remodeling markers in coronary thrombi

Background

Matrix Metalloproteinases (MMPs) and their inhibitors are considered to be of importance in development of atherosclerotic coronary artery disease. MMP-9 has been associated with unstable atherosclerotic plaques and rupture, as well as left ventricular remodeling after myocardial infarction (MI), whereas MMP-2 seems to be more related to progression of stable plaques. MMP activity is modulated by Tissue Inhibitors of Metalloproteinases (TIMPs). TIMP-1 has been associated with cardiac remodeling post MI, and TIMP-2 has been discussed to inhibit plaque development and destabilization. The extracellular MMP Inducer, EMMPRIN, stimulates both MMPs and TIMPs, and has been found upregulated on the surface of monocytes in patients with acute MI, and associated with MMP-9 activity.

Purpose

To study whether genes encoding MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN are expressed in coronary thrombi and in circulating leukocytes from STEMI patients, and whether these are related to the degree of myocardial injury measured by troponin T, and time from symptoms to PCI.

Methods

Intracoronary thrombi were aspirated from 33 patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI. The thrombi were snap-frozen in RNA-later solution for gene expression analyses. Peripheral blood samples with Pax-gene tubes were drawn at end of the PCI procedure. RNA was isolated from the thrombi and leukocytes, and the actual genes relatively quantified by RT PCR. Peak troponin T was collected from clinical records.

Results

Genes coding for the five different markers were present in 84–100% of the thrombi. Median peak troponin T was 3434 m/L. The expression of TIMP-1 in the thrombi correlated significantly to peak troponin T (r=0.393, p=0.026), and dividing peak troponin T values into quartiles, the median value of TIMP-1 mRNA in Q4 was 2.5-fold higher compared to Q1–3 (p=0.107). Peak troponin T also correlated to the expression of TIMP-1 in circulating leukocytes (r=0.469, p=0.006), and in Q4 of troponin T, the median value was 1.6-fold higher compared to Q1–3 (p=0.056). There were no significant correlations between the other measured genes and troponin T, and also no associations of any genes expressed in the thrombi or in circulating leukocytes to time from symptom to PCI (median 152 min).

Conclusion

Genes coding for MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN were highly expressed in human coronary thrombi. The positive correlation between peak troponin T and the expression of TIMP-1 both in thrombi and in circulating leukocytes at time of PCI in patients with STEMI, may indicate that the role of TIMP-1 is important in cardiac remodeling immediately post-MI.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Stein Erik Hagens Foundation for Clinical Heart Research

Effect of revascularization on exercise-induced changes in cardiac and pro-thrombotic biomarkers in patients with coronary artery disease

Introduction

Exercise-induced increase in cardiac and pro-thrombotic biomarkers have previously been shown in patients with coronary artery disease (CAD) before revascularization, which may be due to myocardial ischemia.

Purpose

We aimed to examine whether resting levels and exercise-induced changes of high sensitive cardiac Troponin T (cTnT), NT-proBNP, pro-thrombin fragment (F) 1+2, D-dimer, tissue factor pathway inhibitor (TFPI) and endogenous thrombin potential (ETP) were affected by revascularization in patients with CAD. We hypothesized that resting and exercise-induced levels of the biomarkers would be reduced after revascularization.

Methods

Patients presenting with symptoms of CAD were included. A maximal exercise ECG stress test (EST) (EST1) was performed, and venous blood samples were drawn at rest and within five min after termination. All patients underwent coronary angiography. Patients (n=20) with confirmed CAD, fully revascularized with percutaneous coronary intervention (PCI) and without symptoms of angina, were invited to perform a second EST (EST2), at the same workload (median 145W), at a median of 66 days after revascularization. Mean exercise duration at both time points were 11:30 min:sec. Of the total population 15 patients were treated with PCI on stenosis located on LAD and 5 patients with stenosis on RCA.

Results

Significant increase in cTnT and NT-proBNP from resting to post exercise levels at EST1 was found as expected (p&lt;0.001, both). Also at EST2, increased levels were observed (p&lt;0.01, both), however, not significantly different from the changes at EST1. Resting levels of cTnT at EST2 compared to EST1 were significantly higher (median 8.1 vs 7.1 ng/L, p=0.02). At both visits significant increase in D-dimer (p=0.008 and &lt;0.001), F1+2 (p=0.009 and 0.001) and TFPI (p&lt;0.001 and 0.001) during exercise were demonstrated, with no difference in these changes. There were no significant changes in ETP during exercise at any visit, but resting levels were reduced at EST2 vs EST1 (p&lt;0.01). Also resting levels of TFPI were reduced at EST2 (p&lt;0.01).

Conclusion

After revascularization there was still significant increase in exercise-induced release of cardiac and pro-thrombotic biomarkers, thus revascularization does not affect the ability to release these biomarkers. Also, the higher resting levels of cTnT after revascularization indicate that revascularization per se does not affect secretion of cardiac biomarkers, probably due to the disease state. The lower resting levels of ETP and TFPI after revascularization may, however, be indicative of reduced thrombin generation potential and endothelial activation.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stein Erik Hagens Foundation for Clinical Heart Research, Oslo, Norway

Gut leakage markers in response to strenuous exercise in patients with suspected coronary artery disease

Introduction

Although regular physical activity is associated with reduced risk of cardiovascular disease (CVD), acute vigorous exercise seems to transiently increase the risk of acute coronary events in patients with underlying CVD. Some studies have reported regular physical activity to associate with microbial diversity, whereas elevated levels of gut leakage markers have been shown after strenuous exercise in healthy individuals. Any predictive value of a temporary increase in gut leakage markers on the risk of coronary events in susceptible individuals is unknown.

Purpose

We aimed to explore gut leakage markers in response to a bout of strenuous exercise in patients with symptoms of chronic coronary syndrome (CCS). We hypothesized that gut leakage markers would increase after acute strenuous exercise, and that the increase would be higher in patients with angiographically verified CAD.

Methods

Patients referred to exercise stress testing or coronary angiography due to symptoms suggestive of CCS were included (n=327). A maximal exercise ECG stress test was performed using a bicycle ergometer. Venous blood samples were drawn at rest prior to the test and within 5 min after the test ended, for analysis of soluble cluster of differentiation 14 (sCD14), lipopolysaccharide-binding protein (LBP) and intestinal fatty-acid binding protein (I-FABP) by ELISAs. Quantification of lipopolysaccharide (LPS) and relative quantification of gene expression of the toll-like receptor 4 (TLR4) in circulating leukocytes was performed in a subset of patients (n=101). Patients then underwent coronary angiography, and were grouped according to the degree of CAD.

Results

Of the 287 patients who completed the exercise stress test and coronary angiography, 69 (24%) had no CAD, 88 (31%) had non-significant CAD and 130 (45%) had significant CAD. Mean exercise duration was 10:05±4:46 min and the duration did not differ between the groups. There were no significant differences in resting levels of gut leakage markers between the groups. In the total population, sCD14, LBP and LPS increased significantly after exercise (p&lt;0.0001, all), whereas I-FABP did not. The gene expression of TLR4 decreased significantly after exercise (p&lt;0.0001). There were no differences in exercise-induced changes in any of the measured markers between groups with no CAD, non-significant CAD and significant CAD.

Conclusion

In patients with symptoms suggestive of CCS, LPS, LBP and sCD14 increased significantly after strenuous exercise, suggesting that even short bouts of vigorous exercise are associated with gut leakage. The decrease in gene expression of TLR4 may be discussed to be compensatory to the increase in LPS or possibly reflecting an increase in TLR4 translation in response to LPS. The presence of CAD or not did not seem to impact exercise-induced increase in gut leakage markers.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stein Erik Hagen Foundation for Clinical Heart Research, Olso, Norway

Low levels of dihomo-gamma-linolenic acid are associated with all-cause death in elderly patients with a recent myocardial infarction

Background

In a previous study*, low levels of the omega-6 fatty acid (FA) dihomo-gamma (γ)-linolenic acid (DGLA; C20:3w6), were independently associated with poor 7-year outcome in elderly patients after acute coronary syndrome.

Aim

In order to further evaluate DGLA as a predictor of outcome, we measured n-6 FAs including DGLA in serum samples from elderly subjects with a recent acute myocardial infarction (AMI).

Methods

Baseline samples from the OMEMI (Omega-3 Fatty acids in Elderly with Myocardial Infarction) trial* in which a total of 1027 patients, aged 70 to 82 years, were included 2–8 weeks after an MI, were used. The pre-specified primary outcome during 2 years follow-up was major adverse cardiac events (MACE), which consisted of nonfatal MI, unscheduled coronary revascularization, stroke, all-cause death, or hospitalization for heart failure. Cox regression analysis was used to relate serum n-6 FA levels, measured by gas chromatography and reported as % weight of total FA (%wt) to the risk of incident cardiovascular events. Three models were employed in the multivariable analysis, adjusting for: 1) age, sex and body mass index; 2) + baseline omega-3 FA supplementation; 3) + prevalent hypertension.

Results

Median DGLA levels at baseline (n=1.002) were 2.89 (Q1–Q3 2.43–3.38) %wt. After 2 years follow-up, 152 patients experienced incident MACE, including n=55 all-cause death.

The univariate hazard ratio (HR) for MACE, employing continuous DGLA values was 0.89 (95% CI 0.72–1.08) per %wt increase in DGLA, p=0.24, and for all-cause death 0.72 (95% CI 0.48–1.07), p=0.11. In the multivariable Cox regression models for MACE, concentrations of DGLA did not reach statistical significance; p=0.12, 0.09 and p=0.07 in Models 1, 2 and 3, respectively.

In univariate analysis, HR for total death in the three higher quartiles of DGLA as compared to the lowest quartile was 0.51 (95% CI 0.30–0.80), p=0.016. Results remained statistically significant in all the multivariable models. Model 1: HR 0.54 (0.31–0.95), p=0.03; Model 2: HR 0.50 (0.28–0.91) p=0.02; Model 3: HR 0.49 (0.27–0.88), p=0.017.

Conclusion

Low serum levels of DGLA were associated with increased risk of all-cause death after AMI in elderly patients, thus, suggesting DGLA to be protective.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stein Erik Hagen Foundation for Clinical Heart Research, Oslo, Norway.

The role of IL-6 receptor trans-signalling in ischemia-reperfusion injury, infarct healing and future adverse events in patients with ST-Elevation Myocardial Infarction

Background

Inflammation has emerged as a new treatment target in patients with coronary artery disease, and inflammation seems to play an important role in the ischemia/reperfusion injury in ST-elevation myocardial infarction (STEMI). The pro-inflammatory cytokine interleukin-6 (IL-6) has been shown to be associated with myocardial injury and poor prognosis in patients with STEMI.

Purpose

The aim of the study was to further elucidate possible associations between the IL-6 trans-signalling system and final infarct size, myocardial function, adverse remodelling, and future cardiovascular events in patients with STEMI.

Methods

A total of 272 patients with first-time STEMI included in the POSTEMI study on ischaemic postconditioning, with symptom duration &lt;6 hours and treated with percutaneous coronary intervention (PCI), were included. Blood samples for analysis of IL-6 and IL-6 receptor (IL-6R) were collected before PCI, immediately after PCI, at day 1 (median 18.3 hours after PCI), and at 4 months follow-up. Cardiac magnetic resonance imaging (CMR) was performed in the acute phase, median 2 days after admission, and repeated after 4 months. Clinical events and all-cause mortality were registered during 12 months' and 70 months' follow-up, respectively.

Results

There was a significant increase in IL-6 levels from admission to day 1 with a subsequent decline from day 1 to 4 months (Figure 1A). No significant change in IL-6R levels were found from admission to day 1 (Figure 1B). There was no difference between patients treated by postconditioning compared to routine PCI. High levels of IL-6 (&gt; median) at all sampling points were significantly associated with increased infarct size and reduced left ventricular ejection fraction (LVEF) measured by CMR. Additionally, high levels of IL-6 (&gt; median) at day 1 were associated with lower myocardial salvage, more presence of microvascular obstruction and larger increase in indexed LV end diastolic volume (LVEDVi). IL-6R measured during hospitalisation was significantly associated with change in LVEDVi, but did not associate with infarct size, LVEF or myocardial salvage. High levels of IL-6 (&gt;75th percentile) at all sampling points were associated with an increased risk of having an adverse clinical event during the first year and with long-term all-cause mortality (Figure 2), whereas there was no association between IL-6R and adverse clinical events.

Conclusion

Patients with high IL-6 levels during the acute phase of STEMI had larger infarct size, reduced myocardial salvage, reduced LV function and worse clinical outcome than patients with lower levels of IL-6. High levels of IL-6 measured after 4 months were associated with larger infarct size, reduced LVEF and increased all-cause mortality. IL-6R was significantly associated with increase in LVEDVi. The results add important information to the role of IL-6 in myocardial injury in acute STEMI and the IL-6 pathway as a potential treatment target.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Stein Erik Hagen Foundation for Clinical Heart Research, Oslo, Norway. Figure 1Figure 2

The inflammasome signaling axis in thrombi from STEMI patients is related to degree of myocardial injury

Background

The NLRP3-inflammasome and the IL-6-pathways, i.e. the inflammasome signaling axis, seems to be central mechanisms in the inflammatory response related to myocardial reperfusion injury after revascularization. The beneficial results shown by treating MI-patients with canakunimab, an antibody blocking IL1-β, in the CANTOS trial*, and by treatment of NSTEMI patients with the IL6-receptor antagonist tocilizumab**, are looked upon as proof of concept for inflammasome inhibition.

Purpose

To study whether genes encoding inflammasome-related proteins are present in coronary thrombi and in circulating cells from STEMI patients, and whether these are related to the degree of myocardial injury as measured by troponin T, and time from symptoms to PCI.

Methods

Intracoronary thrombi were aspirated from 33 patients with STEMI treated with primary PCI. The thrombi were snap-frozen in RNA-later solution for gene expression analyses. Peripheral blood samples with Pax-gene tubes were drawn at end of the PCI-procedure. mRNA of NLRP3, caspase1, IL1-β, IL18, IL6, IL6-receptor (IL6-R) and gp130 were isolated from the thrombi and leukocytes in peripheral blood, and relatively quantified by RT PCR. Peak troponin was collected from clinical records.

Results

Genes coding for the 7 different markers were present in 76–100% of the thrombi. The expression of NLRP3 in thrombi significantly correlated to peak troponin T (r=0.468, p=0.024). Dividing peak troponin T values into quartiles, the median value of NLRP3 mRNA in Q4 was 2.0-fold higher compared to Q1–3 (p=0.012). Peak troponin T also correlated with the expression in circulating leukocytes of NLRP3 (r=0.420, p=0.0149) and IL1-β (r=0.394, p=0.023), and borderline to caspase1 (r=0.321, p=0.069) and IL18 (r=0.310, p=0.079).

IL6-R expression in thrombi correlated significantly to peak troponin T (r=0.434, p=0.019), with a 2.5-fold higher median level in Q4 vs Q1–3 of troponin T (p=0.017). gp130 expression in thrombi correlated inversely with peak troponin T (r=−0.398, p=0.050), as did IL6-R expression in circulating leukocytes (r=−0.421, p=0.015). There were no significant correlations between genes expressed in the thrombi and time from symptom to PCI (median 152 minutes), whereas genes for IL6 in circulating leukocytes correlated inversely (r=−0.385, p=0.027).

Conclusion

The inflammasome signaling pathway was actively regulated in coronary thrombi and in circulating leukocytes from patients with STEMI. Genes encoding NLRP3 and IL6-R were increasingly expressed in thrombi from patients with increased myocardial damage, measured by troponin T, supporting the beneficial effects of medically targeting this pathway.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Stein Erik Hagens Foundation for Clinical Heart Research

Biomarkers in patients with cryptogenic stroke/TIA and subclinical atrial fibrillation

Background

A large proportion of patients with cryptogenic stroke or transitory ischemic attack (TIA) have underlying subclinical atrial fibrillation (SCAF) detected on follow up. It is not clear whether SCAF is the underlying primary entity in the pathogenesis of stroke in these patients, or merely a marker of atrial myopathy associated with left atrial remodeling, fibrosis and inflammation.

Purpose

As a hypothesis generating study, we investigated a panel of selected biomarkers involved in fibrosis, inflammation, and thrombosis: growth differentiation factor 15 (GDF-15), transforming growth factor b (TGFb), galectin-3, soluble suppressor of tumorgenicity2 (sST2), von Willebrand factor (vWF), Tissue metalloprotease1 (TIMP1), Matrix metalloprotease9 (MMP9), Emmprin, Interleukin6 (IL6), C-reactive protein (CRP), Tissue factor (TF), Plasminogen activator inhibitor (PAI1), and their relation to the occurrence of SCAF during follow-up in patients after cryptogenic stroke or TIA. We hypothized that biomarker levels were increased in patients with subclinical AF.

Methods

236 patients, median age 71 years (range 21–94) of which 38% were women, with their first cryptogenic stroke or TIA were included 2–4 days after the index event and followed with an Implantable Cardiac Rhythm Monitor for &gt;1 year. Echocardiography and blood sampling were performed at inclusion. ELISA methods were used.

Results

SCAF occurred in 84 patients (36%). Only GDF-15 was significantly increased in AF- vs no-AF patients: 1010 pg/mL (inter quartile range: 814–1416) vs 860 pg/mL (inter quartile range: 622–1197) (p=0.018), and correlated with the number of premature atrial contractions (PAC)/24h (by Holter ECG during index hospitalization) (rs=0.314, p&lt;0.001) and AF-burden during follow-up (rs=0.149, p=0.022). Furthermore, there was a significant trend across quartiles of GDF-15 for having AF, and patients in the three highest quartiles (Q2–4) compared with Q1 had an odd ratio of having AF of 2.16 (95% CI 1.10–4.25), adjusted for sex and body mass index. The significance, however, was lost when adjusting for age, which correlated significantly to GDF-15 (rs=0.283; p&lt;0.001). ROC curve analyses showed an AUC of 0.593 (0.52–0.68) for GDF-15 compared to 0.617 (0.54–0.69) for age. GDF-15 was also associated with co-morbidities such as hypertension (p&lt;0.001), diabetes (p&lt;0.001), and vascular disease (p&lt;0.001).

Conclusion

In patients with a cryptogenic stroke or TIA experiencing SCAF during follow up, only levels of GDF-15 were elevated and correlated with PAC/24h and AF-burden. However, GDF-15 was highly related to age and co-morbidities and did not add significantly to the prediction of AF in a multivariate analysis.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Stiftelsen Dam, Norwegian Atrial Fibrillation Research Network

2232Circulating levels of ST2 are associated with myocardial injury, left ventricular function and future adverse clinical events in patients with ST-elevation myocardial infarction

Background

Soluble ST2, a member of the IL-1 receptor family, seems to be associated with adverse outcome in acute myocardial infarction and heart failure (HF), and is suggested to be involved in left ventricular (LV) remodelling.

Purpose

To elucidate a possible role of ST2 in LV injury, remodelling and prognosis in ST-elevation myocardial infarction (STEMI) patients. The main objectives of the study were to investigate whether circulating ST2 levels were associated with infarct size, LV function, adverse remodeling and clinical outcome in a cohort of patients with STEMI.

Methods

270 patients with clinically stable first-time STEMI treated with primary percutaneous coronary intervention (PCI) were included. Blood samples were drawn before and immediately after the PCI procedure, at day 1 (median 18.3 hours after PCI) and after 4 months. Cardiac magnetic resonance (CMR) was performed in the acute phase and after 4 months. Clinical events and all-cause mortality were registered during 12 months' and 70 months' follow-up, respectively. A composite endpoint was defined as death, MI, unscheduled revascularisation >3 months after the index infarction, rehospitalisation for HF or stroke. Associations between ST2 and CMR parameters and clinical events were evaluated with linear regression and logistic regression, respectively.

Results

There was a significant increase in ST2 levels from the PCI procedure to day 1 with a subsequent decline from day 1 to 4 months in the POSTEMI cohort. Patients with high ST2 levels (>median) at all sampling points during hospitalisation had significantly larger infarct size, lower myocardial salvage, lower LVEF, larger increase in EDV and higher frequency of MVO. After adjustment for relevant clinical variables, peak CRP and peak troponin T, ST2 measured at day 1 remained associated with infarct size (β 2.0 per SD of ST2, p<0.001) and LVEF (β −1.8 per SD of ST2, p=0.02) at 4 months. High levels of ST2 measured at day 1 (>75th percentile) were associated with increased risk of having an adverse clinical event during the first year and with long-term all-cause mortality (Figure). High levels of ST2 measured in a stable phase 4 months after STEMI were also associated with an increased risk of all-cause mortality (Figure).

Figure 1

Conclusions

High levels of ST2 in STEMI patients were associated with large infarct size, impaired recovery of LV function, and adverse clinical outcome in patients with STEMI. ST2 measured 4 months after STEMI remained associated with all-cause mortality.

Effects of Gemfibrozil on Lipids and Haemostasis after Myocardial Infarction

The effects of gemfibrozil on haemostatic variables were studied in 43 survivors of myocardial infarction with serum triglycerides (TG) ≥2 mmol/1 2 weeks prior to randomization. The study was double-blind, placebo-controlled and stratified for chronic betablockade. Twenty-two individuals were given gemfibrozil 600 mg twice daily and 21 individuals received matching placebo. After 8 weeks the TG level was unchanged in the placebo group, whereas a 44% reduction was noted in the gemfibrozil group (p <0.0001). Fibrinogen increased in both groups, while bleeding time and platelet count were unchanged. Clotting factor VH-phospholipid complex decreased in both groups, but the change was more marked and attained statistical significance only in the gemfibrozil group (60% reduction, p <0.01). By DDAVP-stimulated D-Dimer agglutination test 8 in 21 patients in the placebo group (38%) still had reduced fibrinolytic capacity versus none in the gemfibrozil group (p = 0.001). Thus, in this study, gemfibrozil improved reduced fibrinolytic capacity and may have reduced hypercoagulability by lowering the clotting factor VH-phospholipid complex.

Galectin-3, a marker of cardiac remodeling, is inversely related to serum levels of marine omega-3 fatty acids. A cross-sectional study

OBJECTIVE

Marine polyunsaturated n-3 fatty acids (n-3 PUFA) may have cardioprotective effects and beneficial influence on the fibrotic process. We evaluated the associations between serum marine n-3 PUFA and selected biomarkers of fibrosis and cardiac remodeling in elderly patients with acute myocardial infarction.

SETTING

From the ongoing OMega-3 fatty acids in Elderly patients with Myocardial Infarction (OMEMI) trial, 299 patients were investigated. Soluble ST2 (sST2), Galectin-3 (Gal-3) and the serum content of major marine n-3 and n-6 PUFA were analyzed 2-8 weeks after the index acute myocardial infarction.

RESULTS

Gal-3 was inversely correlated to eicosapentaenoic acid (r = -.120, p = .039) and docosahexaenoic acid (r = -.125, p = .031) and positively correlated to the n-6/n-3 ratio (r = .131, p = .023). Gal-3 levels were significantly higher in diabetics vs non-diabetics (12.00 vs 9.61 ng/mL, p = .007) and in patients with NYHA class ≥III for dyspnea at inclusion (11.33 vs 9.75 ng/mL, p = .006).

CONCLUSIONS

The associations between the marine n-3 PUFA and levels of Gal-3 indicate beneficial effects of n-3 PUFA on cardiac remodeling in an elderly population with acute myocardial infarction.

Cigarette smoking represses expression of cytokine IL-12 and its regulator miR-21-An observational study in patients with coronary artery disease

RATIONALE

The heterodimer IL-12 is an inducer of Th1 responses and stimulates INFƴ production. Micro-RNA-21 (miR-21) is described as a key regulator of the pro-inflammatory response and has IL-12p35 mRNA as one of its main targets. The IL-12p40 1188A/C genetic variant located in 3'untranslated region (UTR), thus environmentally exposed, has further been reported to modify IL-12 levels. We have previously reported on the lowering effect of cigarette smoke on circulating IL-12 in patients with coronary artery disease (CAD).

OBJECTIVES

To explore if cigarette smoking affects IL-12p35, IL-12p40, INFƴ and miR-21 gene-expression and further modulates any effect of the IL-12p40 polymorphism on circulating IL-12 levels.

METHODS AND RESULTS

The IL-12p40 1188A/C polymorphism was analyzed in 1001 stable CAD patients, of which 330 subjects were included for IL-12p35, IL-12p40 and INFƴ gene-expression analyses in circulating leukocytes and 200 were further selected for plasma miR-21 analysis. Smoking associated with lower expression of miR-21 and its target IL-12p35 mRNA (adjusted p<0.05, both) whereas the influence on INFƴ expression tended to be high-dose reliant (p = 0.057). The IL-12p40 CC genotype associated with elevated circulating IL-12 levels, however, when stratified according to smoking, only in the non-smoking group (adjusted p < 0.05). Although the markers were mainly downregulated in current smokers, their inter-correlations were potentiated.

CONCLUSION

Smoking associated with reduced miR-21 gene-repression and the results can therefore not explain the previously observed reduction in circulating IL-12. Smoking attenuated the IL-12 pro-inflammatory axis in which the investigated IL-12p40 genetic variant may have different clinical impact in smokers vs non-smokers.

Markers of thrombin generation are associated with myocardial necrosis and left ventricular impairment in patients with ST-elevation myocardial infarction

Introduction

Platelet activation, thrombin generation and fibrin formation play important roles in intracoronary thrombus formation, which may lead to acute myocardial infarction.

We investigated whether the prothrombotic markers D-dimer, pro-thrombin fragment 1 + 2 (F1 + 2) and endogenous thrombin potential (ETP) are associated with myocardial necrosis assessed by Troponin T (TnT), and left ventricular impairment assessed by left ventricular ejection fraction (LVEF) and N-terminal pro b-type natriuretic peptide (NT-proBNP).

Materials/Methods

Patients (n = 987) with ST-elevation mycardial infarction (STEMI) were included. Blood samples were drawn at a median time of 24 h after onset of symptoms.

Results

Statistically significant correlations were found between both peak TnT and D-dimer (p < 0.001) and F1 + 2 (p < 0.001), and between NT-proBNP and D-dimer (p = 0.001) and F1 + 2 (p < 0.001). When dividing TnT and NT-proBNP levels into quartiles there were significant trends for increased levels of both markers across quartiles (all p < 0.001) D-dimer remained significantly associated with NT-proBNP after adjustments for covariates (p = 0.001) whereas the association between NTproBNP and F1 + 2 was no longer statistically significant (p = 0.324).

A significant inverse correlation was found between LVEF and D-dimer (p < 0.001) and F1 + 2 (p = 0.013). When dichotomizing LVEF levels at 40 %, we observed significantly higher levels of both D-dimer (p < 0.001) and F1 + 2 (p = 0.016) in the group with low EF (n = 147).

Summary/conclusion

In our cohort of STEMI patients we demonstrated that levels of D-dimer and F1 + 2 were significantly associated with myocardial necrosis as assessed by peak TnT. High levels of these coagulation markers in patients with low LVEF and high NTproBNP may indicate a hypercoagulable state in patients with impaired myocardial function.

A brief review on high on-aspirin residual platelet reactivity

Although aspirin is effective in secondary prevention in coronary heart disease, new thromboembolic events in patients on aspirin are frequently seen. In trials on aspirin-treated patients, platelet function tests have revealed large variability in platelet aggregation. This phenomenon has been named aspirin resistance, aspirin non-responsiveness or high-on-aspirin residual platelet reactivity. The mechanism of aspirin antiplatelet effect is due to the inhibition of cyclooxygenase-1 enzyme in platelets. In some trials, almost all patients on aspirin have a very low level of serum thromboxane B2, indicating that the measured platelet reactivity in aspirin-treated patients might be due to platelet activation via other pathways, such as ADP or thrombin. The prevalence of real aspirin resistance seems to be very low, and probably the term "high-on-aspirin residual platelet reactivity" should be preferred to describe this phenomenon.