How do apolipoproteins apoB and apoA-I perform in patients with acute coronary syndromes

Abstract

Acute coronary syndromes are the leading cause of hospitalization and death. Results from recent studies suggest that apolipoprotein measurement and apoB:apoA-I are superior to traditional lipids in the estimation of coronary risk. We compared apolipoprotein concentrations and apoB:apoA-I with traditional lipid measures and atherogenic indices in patients diagnosed with acute coronary syndromes (ACS) within 6 hrs from the onset of chest pain. A study group consisted of 227 patients diagnosed with ACS (STEMI=60, NSTEMI=66 and UA=105). Clinically healthy volunteers (n=85) served as controls. Measurements of cardiac TnI, lipid profile, hsCRP, apolipoprotein A-I and apoB100 were performed and apoB:apoA-I, TC-HDL-C, LDL-C:HDL-C ratios were calculated. Patients had increased LDL-C (>3.0 mmol/L) and non-HDL-C (>3.4 mmol/L). Triglycerides were below the cut-off value, but patients had significantly higher TG concentrations and lower HDL-C compared to controls (p<0.001). Apo B and apoA-I concentration in patients remained within the accepted range. Atherogenic indices TC:HDL-C, LDL-C:HDL-C and apoB:apoA-I were significantly increased in patients. ApoB:apoA-I ratio in ACS males was within low risk whereas in females corresponded to medium risk. ApoB:apoA-I and LDL-C:HDL-C ratios were of good diagnostic utility for discrimination between patients and controls (AUC 0.71 and 0.79; respectively). ApoB:apoA-I and LDL-C:HDL-C were of very good diagnostic utility for discrimination between STEMI patients and controls (AUC 0.80 and 0.84). We could not show the superiority of apoB:apoA-I over LDL-C:HDL-C as the discrimination power of both was almost identical. Determination of apolipoproteins should not be recommended for routine clinical use, however, incorporating apoB and apoB:apoA-I into risk assessment could provide additional important information on cardiovascular risk.