Lipoprotein(a) levels in familial hypercholesterolemia: an important predictor of cardiovascular disease independent of the type of LDL receptor mutation.

OBJECTIVES

The aim of this study was to determine the relationship between lipoprotein(a) [Lp(a)] and cardiovascular disease (CVD) in a large cohort of patients with heterozygous familial hypercholesterolemia (FH).

BACKGROUND

Lp(a) is considered a cardiovascular risk factor. Nevertheless, the role of Lp(a) as a predictor of CVD in patients with FH has been a controversial issue.

METHODS

A cross-sectional analysis of 1,960 patients with FH and 957 non-FH relatives recruited for SAFEHEART (Spanish Familial Hypercholesterolemia Cohort Study), a long-term observational cohort study of a molecularly well-defined FH study group, was performed. Lp(a) concentrations were measured in plasma using an immunoturbidimetric method.

RESULTS

Patients with FH, especially those with CVD, had higher Lp(a) plasma levels compared with their unaffected relatives (p < 0.001). A significant difference in Lp(a) levels was observed when the most frequent null and defective mutations in LDLR mutations were analyzed (p < 0.0016). On multivariate analysis, Lp(a) was an independent predictor of cardiovascular disease. Patients carrying null mutations and Lp(a) levels >50 mg/dl showed the highest cardiovascular risk compared with patients carrying the same mutations and Lp(a) levels <50 mg/dl.

CONCLUSIONS

Lp(a) is an independent predictor of CVD in men and women with FH. The risk of CVD is higher in those patients with an Lp(a) level >50 mg/dl and carrying a receptor-negative mutation in the LDLR gene compared with other less severe mutations.