Diagnostic value of lipoprotein (a) and its indices as markers of significant coronary artery obstruction in patients with stable ischemic heart disease

The aim of the study was to determine the diagnostic value of lipoprotein (a) (Lp (a)) and its indices as markers of significant coronary artery (CA) obstruction in patients with stable ischemic heart disease (IHD). Materials and methods. We performed a single-center cross-sectional study of 61 patients with stable IHD (40 men and 21 women, median age — 67 years). Serum lipid levels, including Lp (a), were determined, lipid tetrad index (LTI) and modified lipid tetrad index (MLTI) were calculated. The patients were divided into two groups according to the presence of significant (n=42) or insignificant (n=19) CA obstruction. Results. Patients with stable IHD and significant epicardial coronary stenosis had statistically significantly higher levels of Lp (a), LTI and MLTI. All of them correlated with the Gensini score and the number of affected coronary segments. ROC-analysis was used to find out the optimal cut-off values for these diagnostic tests: Lp (a) >43 mg/dL (sensitivity — 45.2%, specificity — 94.7%), LTI >7127 (sensitivity — 60%, specificity — 73.7%) and MLTI >6072 (sensitivity — 60%, specificity — 73.7%). Conclusions. Lp (a) has high specificity but low sensitivity for significant CA obstruction detection in patients with stable IHD. Since the diagnostic accuracy of Lp (a), LTI and MLTI is not high, an integrated multi-marker approach using clinical, laboratory and instrumental data is considered promising.