Abstract 9147: Reduced Delta-6-Desaturase Activity May Be Associated With Major Adverse Cardiac Events During 2 Years Follow Up in Elderly Patients With a Recent Myocardial Infarction

Abstract

Background: Low levels of dihomo-gamma linolenic acid (DGLA) have been related to a bad outcome in patients with acute coronary syndromes. Reduced levels of DGLA may result from reduced conversion of its precursor linoleic acid (LA). An increase in the ratio of LA to DGLA (LA:DGLA) has been shown to reflect reduced delta-6-desaturase activity. Aim: To evaluate the association between the LA:DGLA ratio, reflecting delta-desaturase activity, and the risk of major adverse cardiovascular event (MACE, comprising nonfatal myocardial infarction (MI), unscheduled revascularization, stroke, hospitalization for heart failure, or all-cause death), in patients with a recent MI. Methods: Baseline samples from the OMEMI (Omega-3 Fatty acids in Elderly with Myocardial Infarction) trial* in which a total of 1027 patients, age 70 to 82 years, were included 2-8 weeks after an MI and followed up for 2 years, were used. FAs were measured in serum phospholipids, and the LA:DGLA ratio was calculated at baseline and related to incident MACE by univariate and multivariable Cox regression analyses, adjusted for age, sex, body mass index, omega-3 supplementation at baseline and hypertension. Results: A total of 208 patients experienced MACE during follow-up. The univariate hazard ratio (HR) for MACE in the fourth quartile (Q4) of LA:DGLA compared to the lowest quartile (Q1) was 1.49 (95% confidence interval (CI), 1.00-2.23), p=0.005. After adjustment, the HR for Q4 was weakened [1.47 (0.97-2.25), p=0.072]. The HR for Q2-4 combined as compared to Q1 was borderline significant [1.42 (0.99-2.03)], p=0.055. Although the number of total deaths were more than two-fold higher in Q4 as compared to Q1 [HR 2.30 (1.04-5.06), p=0.038], this did not reach significance in the adjusted models [HR 2.26 (0.95-5.37), p=0.065], and remained non-significant when comparing Q2-4 combined to Q1 [HR 1.74 (0.80-3.77), p=0.16]. Conclusion: Higher levels of LA:DGLA ratio were found to be associated with MACE in elderly patients with a recent MI, suggesting a mechanism to why low levels of DGLA may be associated with increased adverse events. * Circulation 2021; 143(6): 528-39.