Clinical Impact of Lipoprotein (a) and Cumulative Low-Density Lipoprotein Cholesterol Exposure on Coronary Artery Disease in Patients with Heterozygous Familial Hypercholesterolemia.

Aims: Elevated lipoprotein (a) (Lp[a]), predominantly determined by genetic variability, causes atherosclerotic cardiovascular disease (ASCVD), particularly in patients with familial hypercholesterolemia (FH). We aimed to elucidate the clinical impact of Lp(a) and cumulative exposure to low-density lipoprotein cholesterol (LDL-C) on CAD in patients with FH.

Methods: One hundred forty-seven patients clinically diagnosed with heterozygous familial hypercholesterolemia (HeFH) were retrospectively investigated. Patients were divided into 2 groups according to the presence of CAD. Their clinical characteristics and lipid profiles were evaluated.

Results: There were no significant differences in untreated LDL-C levels between the 2 groups (p=0.4), whereas the cumulative exposure to LDL-C and Lp(a) concentration were significantly higher in patients with CAD (11956 vs. 8824 mg-year/dL, p＜0.01; 40 vs. 14 mg/dL, p＜0.001, respectively). A receiver operating characteristic (ROC) curve analysis demonstrated that the cutoff values of Lp(a) and cumulative LDL-C exposure to predict CAD in patients with FH were 28 mg/dL (AUC 0.71) and 10600 mg-year/dL (AUC 0.77), respectively. A multivariate analysis revealed that cumulative LDL-C exposure ≥ 10600 mg-year/dL (p＜0.0001) and Lp(a) level ≥ 28 mg/dL (p＜0.001) were independent predictors of CAD. Notably, the risk of CAD remarkably increased to 85.7% with smoking, Lp(a) ≥ 28 mg/dL, and cumulative LDL-C exposure ≥ 10600 mg-year/dL (odds ratio: 46.5, 95%CI: 5.3-411.4, p＜0.001).

Conclusions: This study demonstrated an additive effect of Lp(a) and cumulative LDL-C exposure on CAD in patients with HeFH. Interaction with traditional risk factors, particularly smoking and cumulative LDL-C exposure, enormously enhances the cardiovascular risk in this population.