The endothelium was shown to reduce vascular stiffness of muscular arteries by producing vascular smooth muscle relaxing, vasodilatative factors. Stiffening of arteries with advancing age and risk factor exposure predominantly involves the elastic segments of the arterial tree. It is not known to what extent the stiffness of large elastic arteries is under endothelial control. This study was designed to investigate the relationship between endothelial function and stiffness of the carotid artery, a representative of central elastic arteries.

Conduit artery endothelial function was assessed in 58 subjects by measuring brachial artery flow mediated dilatation (FMD). Carotid artery elastic parameters were calculated from carotid pulse pressure measured by local tonometry and from pulsatile distension determined by echo wall-tracking. Systemic arterial stiffness was assessed by aorto-femoral pulse wave velocity (PWV). Relations between variables were determined by univariate correlation analysis.

All measured values fell within age related normal ranges. FMD was inversely related to age and DBP (r = −0.49 and −0.48, respectively; p<0.01 for both). FMD was also significantly and inversely related to PWV (r = −0.46; p<0.05), but was not related to any parameter of carotid artery elasticity.

We suggest that age-related impairment in large elastic vessel function may not be significantly influenced by the loss of vasodilatative capacity of the endothelium.