Familial Hypercholesterolemia, Familial Combined Hyperlipidemia, and Elevated Lipoprotein(a) in Patients With Premature Coronary Artery Disease.

BACKGROUND: Familial hypercholesterolemia (FH), familial combined hyperlipidemia (FCHL), and elevated lipoprotein (a) (Lp[a]) increase risk of premature coronary artery disease (CAD). The objective of this study was to assess the prevalence of FH, FCHL, elevated Lp(a) and their impact on management in patients with premature CAD. METHODS: We prospectively recruited men ≤ 50 years and women ≤ 55 with obstructive CAD. FH was defined as Dutch Lipid Clinic Network scores ≥ 6. FCHL was defined as apolipoprotein B > 1.2 g/L, triglyceride and total cholesterol > 90th population percentile, and family history of premature cardiovascular disease. Lp(a) ≥ 50 mg/dL was considered to be elevated. RESULTS: Among 263 participants, 9.1% met criteria for FH, 12.5% for FCHL, and 19.4% had elevated Lp(a). Among patients with FH, 37.5% had FH-causing DNA variants. Patients with FH, but not other dyslipidemias, were more likely than nondyslipidemic patients to have received lipid-lowering therapy before presenting with CAD (33.3% vs 12.3%, P = 0.04) and combined lipid-lowering therapy after the presentation (41.7% vs 7.7%, P < 0.001). One year after presentation, 58.3%, 54.5%, and 58.8% of patients with FH, FCHL, and elevated Lp(a) had low-density lipoprotein cholesterol (LDL-C) < 1.8 mmol/L, respectively, compared with 68.0 % in reference group. Patients with FCHL were more likely to have non-high-density lipoprotein (HDL) and apolipoprotein B above recommended lipid goals (70.0% and 87.9%, respectively). CONCLUSIONS: FH, FCHL, and elevated Lp(a) are common in patients with premature CAD and have differing impact on treatment and achievement of lipid targets. Assessment for these conditions in patients with premature CAD provides valuable information for individualized management.