Introduction: Lipoprotein(a) (Lp(a)) is associated with the severity of coronary lesions evaluated using Syntax score in patients with stable coronary artery disease (CAD). However, the effect of low-density lipoprotein cholesterol (LDL-C) levels on the association of Lp(a) levels with Syntax score remains unclear.
Methods: A total of 646 patients with stable CAD were enrolled in the present study. Lp(a) levels were measured with an AU5800 Chemistry Analyzer. Syntax scores were calculated by two advanced interventional cardiologists. SPSS 22.0 was used for statistical analyses.
Results: The concentration of Lp(a) ranged from 1 to 192 mg/dL. Pearson’s correlation analysis showed a positive correlation between Syntax score and the level of Lp(a) (r = 0.108, p = 0.006). The LDL-C ≥ 100 mg/dL group presented with a higher Lp(a) level, 16 (9– 29) vs 13 (7– 24). Pearson’s correlation analysis identified a correlation between Lp(a) level and Syntax score (r = 0.249, p < 0.001) only in the LDL-C ≥ 100 mg/dL group. Multivariate logistic regression analysis revealed the positive predictive value of an Lp(a) level > 30 mg/dL for a Syntax score ≥ 23 only in the LDL-C ≥ 100 mg/dL group, adjusted odds ratio 2.895, p = 0.010. A receiver operating characteristic curve analysis confirmed the predictive value of Lp(a) levels for a Syntax score ≥ 23 in the LDL-C ≥ 100 mg/dL group with a cutoff value for Lp(a) > 30 mg/dL.
Discussion: The association between Lp(a) level and Syntax score was only maintained in the LDL-C ≥ 100 mg/dL group. An Lp(a) level > 30 mg/dL was an independent predictor of a Syntax score ≥ 23 only in the LDL-C ≥ 100 mg/dL group. The effect of LDL-C levels on the association of Lp(a) levels with Syntax score requires further investigations.
Keywords: lipoprotein(a), low-density lipoprotein cholesterol, stable coronary artery disease, syntax score