Influence of the non-lipoprotein(a) apolipoprotein B/lipoprotein(a) ratio and other risk factors on coronary arterial aterosclerotic burden in acute coronary syndrome

Abstract Introduction Traditional cardiovascular risk factors, such as diabetes, are associated with atherosclerotic vascular burden. It is likely to be the same with high lipoprotein (a) Lp(a) levels, although this association is less established. Recent works have reported that the atherogenicity of Lp(a) particles is, at least, five times higher than that of apolipoprotein B (apoB)-containing lipoproteins other than Lp(a) non-Lp(a) apoB. Therefore, a non-Lp(a) apoB/Lp(a) ratio ≤5 would suggest the predominant atherogenic contribution of Lp(a) and could be associated with coronary artery atherosclerotic burden. Purpose Our aim was to assess the association of the non-Lp(a) apoB/Lp(a) ratio, in addition to other cardiovascular risk factors, with three-vessel coronary artery disease (3V-CAD) in patients attended with acute coronary syndrome (ACS). Methods Observational study of patients hospitalised for ACS, with obstructive coronary artery disease. The molar concentration (nmol/L) of apoB and Lp(a) was determined. Non-Lp(a) apoB was calculated by subtracting Lp(a) from apoB. The non-Lp(a) apoB/Lp(a) ratio, depending on whether it was 5 or ≤5, was considered indicative of greater atherogenic liability of non-Lp(a) apoB or Lp(a), respectively. 3V-CAD was considered stenosis ≥70% in the 3 main coronary arteries or 50% of the left main coronary artery and ≥70% in at least two other arteries. Results A total of 494 patients (22.5% female; 66.1±12.2 years) were included. No patient with Lp(a) ≤125 had a non-Lp(a) apoB/Lp(a) ratio ≤5. Non-Lp(a) apoB/Lp(a) ratio ≤5 was found in 58 patients with elevated Lp(a) (125 nmol/L), accounting for 38.9% of this group and 11.7% of the total (figure). 3V-CAD was diagnosed in 166 patients (33.6%). The table shows the main clinical characteristics and lipid-related biochemical parameters according to the presence of 3V-CAD. In the univariate analysis: age, hypertension, diabetes, dyslipidaemia, prior statin therapy and prior coronary artery disease were associated with 3V-CAD. Except for the non-Lp(a) apoB/Lp(a) ratio ≤5, no other biochemical parameter was associated with 3V-CAD, including Lp(a) levels 125 nmol/l. In multivariate analysis: age, hypertension, diabetes, prior coronary artery disease and non-Lp(a) apoB/Lp(a) ratio ≤5 were independently associated with 3V-CAD. Conclusions In our population of ACS patients, a non-Lp(a) apoB/Lp(a) ratio ≤5, suggestive of predominant atherogenic liability of Lp(a), is associated with higher coronary atherosclerotic burden, together with other clinical parameters (age, previous coronary artery disease) and traditional cardiovascular risk factors (hypertension and diabetes). This new atherogenic index could be useful for risk stratification or selection of future treatments in patients with ACS.Figure. Table.Factors associated with 3V-CAD.