Non-invasive detection of early endothelial dysfunction in hypercholesterolaemic subjects Original Research Article

Hypercholesterolaemia is associated with accelerated atherogenesis. Before the evidence of morphological lesions or plaques, endothelial dysfunctions, such as impairment in endothelium-dependent vascular tone regulation, may occur. We studied 32 subjects, 16 with primary hypercholesterolaemia and 16 normocholesterolaemic controls. Flow-dependent vasodilation, an endothelium-dependent phenomenon, was evaluated by measuring femoral artery diameter and flow velocity in basal conditions and during distal post-ischaemic hyperaemia, using a high resolution echo-Doppler. Arterial distensibility and compliance were evaluated for the common carotid and femoral arteries, using a pulsed echo-tracking system and measuring the absolute and relative stroke change in arterial diameter. In the hypercholesterolaemic group there was no flow-dependent arterial relaxation, indicated by the area under the curve of percentage diameter variation as a function of time. This parameter was inversely correlated with both total and LDL-cholesterol values in all population subjects. No difference was observed between the two groups in endothelium-independent vasodilation induced by glyceryl trinitrate administration or arterial wall distensibility and compliance, confirming the hypothesis of a functional defect.