Lipoprotein(A), Apo(A) Phenotypes and Dyslipidemia in Acute Coronary Syndromes

Although several retrospective studies have shown a strong correlation between lipoproteins and atherosclerotic heart disease, the correlation is unclear in cases with coronary vasospasm. This study sought to examine dyslipidemia including lipoprotein(a) [Lp(a)] and Apo(a) phenotypes in coronary artery disease.
One hundred and fifteen patients with mean age of 58.7±13 years suffering from coronary artery disease were selected. They were divided into groups with stable angina pectoris (SA), unstable angina (USA), acute myocardial infarction (AMI). Control group consisted of 40 age and sex matched apparently healthy individuals. The lipids and lipoproteins including Lp(a) were measured using standard methods. Apo(a) phenotypes were evaluated by SDS-PAGE electrophoresis followed by immunoblotting.
In patients with coronary artery disease, high-density lipoprotein cholesterol (HDL-C) levels were significantly lower than those in control (p<0.01), but in SA its level was higher than those of USA and AMI (p<0.05). The levels of triglyceride and very low-density lipoprotein cholesterol (VLDL-C) were higher in SA and no significant differences were noticed in those of total cholesterol, but the concentrations of low-density lipoprotein cholesterol (LDL-C) in USA and AMI were significantly higher than those of SA and control groups. The ApoB concentration was markedly higher in USA group (p<0.002). The mean ± SD levels of total Lp(a) in USA and AMI groups were higher than those of SA and control groups (p<0.001). Comparing the frequencies of low molecular weight (LMW) and high molecular weight (HMW) Apo(a) phenotypes of patients with control group, high frequencies of LMW Apo(a) and high levels of Lp(a) were noticed in USA and AMI groups (p<0.01 in both cases).
Low serum HDL-C and high serum LDL-C and Lp(a) levels were characteristic in patients with USA and AMI. Comparing the frequencies of Apo(a) phenotypes in SA, USA and AMI with those of control it was concluded that Apo(a) phenotyping along with serum levels of Lp(a), HDL-C and LDL-C could be a useful risk predictors for the development of acute coronary syndromes and may be used in discrimination of different types of the coronary artery diseases.