Plasma lipoproteins and coronary artery disease (PLACARD STUDY)

Abstract

Atherosclerotic coronary artery disease is well recognised as an inflammatory disorder that is also influenced by oxidative stress. Beta-2-Glycoprotein-I (B2GPI) is a circulating plasma protein that undergoes post-translational modification and exists in free thiol as well as oxidized forms. This study aimed to assess the association between the post-translational redox forms of B2GPI, Apolipoprotein A-I (ApoA-I) and Apolipoprotein B (ApoB) and atherosclerotic coronary artery disease. Stable patients presenting for elective coronary angiography or CT coronary angiography were prospectively recruited. A separate group of patients after reperfused ST-elevation myocardial infarction formed an acute coronary syndrome subgroup. All patients had a collection of fasting serum and plasma for quantification of total and free thiol B2GPI. Coronary artery disease extent was quantified by the Syntax and Gensini scores. A total of 552 patients with stable disease and 44 with acute coronary syndrome were recruited. Whilst total B2GPI was not associated with stable coronary artery disease, a higher free thiol B2GPI was associated with its presence and extent. This finding remained significant after correcting for confounding variables and free thiol B2GPI was a better predictor of stable coronary artery disease than high-sensitivity C-reactive protein. Paradoxically, there were lower levels of free thiol B2GPI after ST-elevation myocardial infarction. In the next chapters total and free thiol, ApoA-I and ApoB were studied to determine a relationship with coronary artery disease. Increasing total ApoA-I levels predict coronary artery disease while the free thiol HDL did not reveal an association with coronary disease. Both total and free thiol ApoB did not predict the presence or the extent of coronary artery disease. Lower free thiol B2GPI levels were seen in patients with ST-elevation myocardial infarction (STEMI) and post percutaneous coronary intervention, and in iatrogenic myocardial necrosis, this did not reach statistical significance.

Conclusions: Free thiol B2GPI is a predictor of coronary artery disease presence and extent in stable patients and free thiol B2GPI was a better predictor than high-sensitivity C-reactive protein. Lower levels of free thiol B2GPI are seen after STEMI. Total ApoA-I predicted coronary artery disease while free thiol ApoA-I did not. Both total and free thiol ApoB did not predict coronary artery disease.