Background: Endothelial dysfunction (ED) as a sign of preclinical atherosclerosis should be detected early in children with familiar hypercholesterolemia (FH). Varying sensitivity of many biochemical and ultrasonographic markers makes diagnosis of ED difficult.

Aim of the Study: To assess specific biochemical markers of ED and correlate them with flow mediated dilation (FMD) and deceleration index (DI) in children with FH.

Methods: FH group, n=32, age 14,7 (±2.9) years and group of healthy children, n=30, age 15.1 (±1.7) years were enrolled. The high selective CRP (hsCRP), oxidized LDL (oxLDL), malondialdehyde (MDA), asymmetric dimethylarginine (ADMA), FMD and DI were assessed .

Results: ADMA levels in the FH group was higher than in healthy controls − 0.94 umol/l (±0.18) versus 0.77umol/l (± 0.14), p< 0.001. Levels of oxLDL were significantly higher in the FH group − 73,7 mU/l (±24,9) versus 55,7 mU/l (±30,5), p< 0.01. FMD and DI did not show significant differences between the FH and control groups. No correlations between ADMA, oxLDL, hsCRP and ultrasonographic markers were found.

Conclusion: ADMA and oxLDL appear to be more sensitive markers in detection of ED in children with FH than FMD and DI. The absence of correlation between biochemical and ultrasound markers could be explained by high biological variability of FMD and DI. The combination of ADMA, oxLDL and advanced imaging methods could improve the prediction of cardiovascular risk in children with FH.