HDL Phospholipids, but Not Cholesterol Distinguish Acute Coronary Syndrome From Stable Coronary Artery Disease

BACKGROUND: Although acute coronary syndromes (ACS) are a major cause of morbidity and mortality, relationships with biologically active lipid species potentially associated with plaque disruption/erosion in the context of their lipoprotein carriers are indeterminate. The aim was to characterize lipid species within lipoprotein particles which differentiate ACS from stable coronary artery disease. METHODS AND RESULTS: Venous blood was obtained from 130 individuals with de novo presentation of an ACS (n=47) or stable coronary artery disease (n=83) before coronary catheterization. Lipidomic measurements (533 lipid species; liquid chromatography electrospray ionization/tandem mass spectrometry) were performed on whole plasma as well as 2 lipoprotein subfractions: apolipoprotein A1 (apolipoprotein A, high‐density lipoprotein) and apolipoprotein B. Compared with stable coronary artery disease, ACS plasma was lower in phospholipids including lyso species and plasmalogens, with the majority of lipid species differing in abundance located within high‐density lipoprotein (high‐density lipoprotein, 113 lipids; plasma, 73 lipids). Models including plasma lipid species alone improved discrimination between the stable and ACS groups by 0.16 (C‐statistic) compared with conventional risk factors. Models utilizing lipid species either in plasma or within lipoprotein fractions had a similar ability to discriminate groups, though the C‐statistic was highest for plasma lipid species (0.80; 95% CI, 0.75–0.86). CONCLUSIONS: Multiple lysophospholipids, but not cholesterol, featured among the lipids which were present at low concentration within high‐density lipoprotein of those presenting with ACS. Lipidomics, when applied to either whole plasma or lipoprotein fractions, was superior to conventional risk factors in discriminating ACS from stable coronary artery disease. These associative mechanistic insights elucidate potential new preventive, prognostic, and therapeutic avenues for ACS which require investigation in prospective analyses.