Carotid atherosclerosis in familial combined hyperlipidemia associated with the APOB/APOA-I ratio.

OBJECTIVES: The effects of risk factors on carotid atherosclerosis in familial combined hyperlipidemia (FCHL) remain unclear. We assessed carotid intima-media thickness (IMT) and plaque in relation to classical risk factors and apolipoprotein A-I (apoA-I) and B (apoB) levels in patients with FCHL.

METHODS AND RESULTS: We included 131 unrelated FCHL patients (27 with prior cardiovascular disease (CVD)) diagnosed by standard criteria and 190 age- and sex-matched control subjects. Cardiovascular risk factors were assessed and IMT in the far wall of all carotid segments and plaque burden were determined in FCHL patients and controls. All carotid measurements were increased in FCHL patients compared to controls (P<0.001), irrespective of CVD status. For asymptomatic FCHL, the adjusted difference in mean common carotid IMT was 0.08 mm, corresponding to approximately 16 years of physiological IMT increase. By multivariate analysis in a model with all risk factors, inclusive of the metabolic syndrome, independent associations of IMT were age, the apoB/apoA-I ratio, systolic blood pressure, fasting glucose, family history of CVD and total/HDL cholesterol ratio (r(2)=0.475, P<0.001). The strongest determinant of IMT was the apoB/apoA-I ratio (beta=0.422, P<0.001).

CONCLUSIONS: Patients with FCHL have increased carotid IMT that is strongly related to the apoB/apoA-I ratio, a measure of overall lipid abnormalities. The findings support the atherogenicity of the lipid phenotype in FCHL beyond associated risk factors. They also have implications for diagnosis and management of CVD risk in this condition.