A METHODOLOGICAL STUDY OF ARTERIAL-WALL FUNCTION USING ULTRASOUND TECHNIQUE

We aimed to establish reference values for three important properties of the arterial wall using a conventional ultrasound scanner. We measu red: (1) intima-media thickness (IMT) of the carotid arteries with the internal trace function of the ultrasound system; (2) wall stiffness by pulsatile diameter changes in the right common carotid artery asses sed by M-mode; and (3) endothelial function expressed as flow-mediated dilatation (FMD) of the brachial artery. IMT and wall stiffness measu rements and reproducibility were compared with those obtained by exter nal analysing systems, All variables were obtained in healthy subjects (n = 20), 29-53 years old. IMT increased with age (P<0.01). There was no difference in IMT between men and women. The inter-operator variab ility for measuring IMT was 6-9%. The same order of reproducibility wa s obtained with an external PC-based analysing system. Regarding wall stiffness, no correlation was found with age, nor any difference betwe en men and women. A low intra-operator variability (CV<10%) was found for measurements of wall stiffness with both M-mode and an external wa ll tracking system. FMD of the brachial artery diminished with age (P< 0.01). There was a relation between FMD and brachial artery size (P<0. 01) and, therefore, as men have larger arterial diameters (P<0.01), sm aller FMD in men. We conclude that it is possible to characterize arte rial wall function non-invasively in an adequately reproducible manner using a conventional ultrasound system in healthy middle-aged men and women.