High density lipoproteins (HDL) have many effects that protect against cardiovascular diseases. In an acute heart attack (acute coronary syndrome -ACS), HDL change in composition and structure, reflecting the inflammatory environment that accompanies an ACS. The investigators will examine the function of HDL during an ACS and again when the patient has recovered.

High density lipoproteins (HDL) have pleiotropic effects associated with protection against atherosclerosis. These effects include cellular cholesterol efflux, anti-inflammatory and anti-oxidant effects, increase in nitric acid (NO) production from vascular endothelial cells and differentiation of endothelial progenitor cells for repair at sites of vascular injury. The measurement of the cholesterol mass within HDL (HDL-C) does not provide an adequate measure of HDL function. The investigators therefore propose to test and validate biomarkers of HDL function in patients with acute coronary syndromes (ACS).

Hypothesis: HDL lose their cardiovascular protective functions in ACS. The investigators hypothesize that these changes are transient and partly normalize within 12 weeks. In this proposal, the investigators will examine the function of HDL in acute coronary syndromes (ACS) and 12 weeks later, in the recovery phase. Acute coronary syndromes are characterized by an acute inflammatory reaction, a marked decrease in HDL in plasma and a shift of the HDL proteome to an inflammatory phenotype.

Inclusion Criteria:

• Men and women 18-80 years of age
• Acute Coronary Syndrome within 72 hours of presentation
• Elevated tropinins (T or I)

Exclusion Criteria:

• Refusal to participate
• Inability to return for a 12 week follow-up visit
• Hemodynamic instability requiring vasopressor support, mechanical ventricular assist devices, the need for coronary artery bypass surgery
• Lack of documented atherosclerotic CAD
• Uncontrolled hypertension
• Triglycerides≥5mmol/L
• Severe obesity (BMI≥35)
• Alcohol intake>21 drinks/week
• Presence of thyroid, hepatic, or renal disease
• Autoimmune disease or any chronic or acute infectious or inflammatory illness

Patients presenting to hospital with an acute coronary syndrome, within 72 hours