Longitudinal study of endothelial function in children with familial hypercholesterolemia.

Endothelial function (EF) is impaired in diseases associate with vascular complications, such as diabetes and familialhypercholesterolemia (FH). The impairment of EF assessed as flow mediated dilation (FMD) of brachial artery can predict futurecardiovascular disease. To assess the alteration of EF, we longitudinally evaluate FMD in prepubertal patients with geneticallyconfirmed FH. Twelve children (7 M, 5 F; 8.19±2.90 yr.) with FH and 20 control subjects entered the study. Subjects withdiabetes, obesity or other metabolic disorders were excluded. In all FH patients lipid values and FMD were determined at thebeginning of the study and after 32.8±9.55 mo. of diet low in saturated fat and cholesterol. FMD function was assessed bymeasurement of endothelium-dependent vasodilation of the brachial artery using an ultrasound system. FMD was expressed aspercentage change of diameter following reactive hyperemia from baseline. The lower FMD values obtained in our control patientwas 7% so we considered it as cut-off. The baseline evaluation showed that FMD in FH children was not significantly different thancontrol peers (20.9±23.3 vs 12.5±7.28%; p=0.143). According to sex, M were significantly older than F and had a longer followup (38.1±7.52 vs 25.5±7.09 mo.; p = 0.015). At the end of the study, despite T-CH, LDL, HDL, and TG levels were unmodified,FMD values significantly decreased (20.9±23.3 vs 2.75±9.07%; p=0.034) resulting significantly lower than in normal subjects(p=0.002). The impairment was shown in 75% vs. 25% of children found at the start. No correlation was demonstrated betweenFMD and lipid levels, age and duration of the follow-up. Our data show that after few years patients with FH have a decrease ofFMD values not apparently related to lipid control or to duration of diet. This difference, more evident in males, suggests that furtherstudies are needed to better understand which factors are involved in functional changes of endothelial dysfunction.