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<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<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

Circulating secretoneurin concentrations are increased in patients with acute coronary syndrome and provide prognostic information

Background

Secretoneurin (SN) is associated with both myocardial ischemia and cardiomyocyte Ca2+ handling, and circulating SN levels provide incremental prognostic information to established risk indices in patients with acute heart failure, acute respiratory failure, and after cardiac arrest.

Purpose

To determine whether SN concentrations are increased in patients with acute coronary syndrome (ACS), and assess the prognostic value of SN among patients with suspected ACS.

Methods

We included 402 patients hospitalized with chest pain at a teaching hospital and adjudicated all hospitalizations as ACS or non-ACS by two physicians working independently. Blood samples were drawn within 24 h from hospital admission and SN was measured by a novel ELISA assay. Patients were followed for mean 6.2 years and mortality was obtained from the Norwegian Cause of Death Registry.

Results

SN concentrations were higher in patients with ACS (n=161 [40%]) compared to patients with chest pain without ACS (n=241 [60%]): median 32.8 (IQR 27.5–42.8) vs. 28 (24.5–34.0) pmol/L, p<0.001. The C-statistics of SN was 0.66 (95% CI: 0.61–0.71) to separate chest pain patients with ACS from chest pain patients without ACS compared to 0.82 (0.78–0.86) for high-sensitivity cardiac troponin T (hs-cTnT). Patients with ECG changes reflective of acute myocardial ischemia had higher SN concentrations (p=0.005). Sixty-five (16%) patients died during follow-up. Stratifying patients according to SN concentrations separated patients with a poor and favorable prognosis, and patients with SN in the top quartile had 4-fold higher risk of mortality compared to the patients with low SN concentrations (Figure). Higher SN concentrations were also associated with increased risk of mortality in Cox regression models, including in models that adjusted for age, sex, blood pressure, previous myocardial infarction, atrial fibrillation, and heart failure: hazard ratio 1.71 (1.03–2.84), p=0.038. The C-statistics of SN to separate patients with poor prognosis from favorable prognosis was 0.72 (0.65–0.79) and adding SN on top of hs-cTnT improved prognostication as assessed by the integrated discrimination index: 0.05±0.014, p<0.001.

Conclusions

SN concentrations are increased in patients with ACS and provide prognostic information in patients with chest pain.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Akershus Unviersity Hospital, CardiNor AS