Familial hypercholesterolemia affects microvascular autoregulation in children

Objective. Familial hypercholesterolemia (FH) impairs macrovascular endothelial function in childhood and causes an increase of cardiovascular risk in later life. Whether microvascular function is affected in children with FH is unknown. The aim of this study was to investigate the impact of FH on microvascular autoregulation in children by post occlusive reactive hyperemia (PORH). Methods. PORH of the skin was assessed using laser Doppler fluxmetry. Baseline perfusion, biological zero, defined as no-flow laser Doppler signal during suprasystolic occlusion, peak perfusion after release of suprasystolic occlusion, as well as time to peak perfusion and recovery time, defined as time until baseline perfusion is resumed, were measured in 16 children, who were diagnosed with FH according to current guidelines, and in 91 healthy controls. Results. In children with FH, peak perfusion was higher (PH: 1.60 +/- 0.68 vs. controls: 1.26 +/- 0.50 AU [arbitrary units], p = 0.02), recovery time was longer (110 +/- 42.61 vs. 83.18 +/- 35.08 s, p = 0.01) and biological zero was lower than in controls (0.12 +/- 0.04 vs. 0.18 +/- 0.05 AU, p<0.001). Baseline perfusion and time to peak were not different between children with PH and controls (baseline perfusion: 0.43 +/- 0.21 vs. 0.38 +/- 0.15 AU, p = 0.18; time to peak: 15.44 +/- 12.25 vs. 18.18 +/- 17.79 s, p = 0.56). Conclusion. For the first time the present study reveals an impact of PH on microvascular autoregulation in children: the differences of PORH between children with PH and controls indicate an affected autoregulation of microvascular blood flow in PH, which has its onset in childhood. (C) 2013 Elsevier Inc. All rights reserved.