Abstract 6060: Impaired Arterial Function and Structure in Patients with Familial Combined Hyperlipidemia
Familial combined hyperlipidemia (FCH) is a polygenic disorder of lipid metabolism which is associated with increased cardiovascular risk. Endothelial function, arterial stiffness and arterial wall thickness are important determinants of cardiovascular performance and predictors of the corresponding risk. In the present study we evaluated the effect of FCH on these arterial characteristics. We studied 63 first-diagnosed, never-treated patients with FCH (mean age 42.4 y, 46 men) and 66 normolipidemic subjects matched for age and gender (age 42.2 y, 48 men) with a thorough vascular approach. No hypertensives or diabetics were included. Flow-mediated dilatation of the brachial artery (FMD, an index of endothelial function), carotid-femoral pulse wave velocity (PWV, a measure of aortic stiffness), central augmentation index (AIx, a composite index of arterial stiffness and wave reflections), and intima media thickness (IMT) of the common carotid artery (an index of subclinical atherosclerosis) were measured with non-invasive methods. Compared to controls, the FCH patients had higher BMI (28.5±4.1 vs 24.1±3.3 kg/m2), higher mean arterial pressure (95±11 vs 89±11 mmHg), higher levels of LDL-cholesterol (200±40 vs 112±25 mg/dL) and triglycerides (259±112 vs 75±29 mg/dL) and lower level of HDL-cholesterol (43±10 vs 57±16 mg/dL), (all P<0.001). The FCH group had lower FMD (3.8±3.6 vs. 5.9±3.7 %, P=0.002) and higher PWV (8.1±1.2 vs. 6.1±1.3 m/sec, P<0.001), higher AIx (21.3±12.3 vs. 14.4±14.9%, P=0.006) and higher carotid IMT (0.84±0.17 vs. 0.67±0.15 mm, P<0.001) than controls. Multivariable analysis adjusting for BMI and mean pressure showed that FCH is independently associated with FMD (P<0.001), PWV (P<0.001) and IMT (P<0.001), but not with AIx (P=NS). In the FCH group, LDL-C was correlated with IMT (r=0.51, P<0.01) and AIx (r=0.29, P<0.05). We did not observe any relationships between lipid levels and FMD or PWV in the FCH patients. FCH is associated with an impairment of arterial structure and function compared to matched normolipidemic subjects. The increased lipid levels do not sufficiently explain the degree of the arterial impairment in subjects with FCH.