P19 INFLUENCE OF BRACHIAL ARTERY STIFFNESS ON FLOW-MEDIATED DILATATION IN HEALTHY YOUNG AND OLDER POPULATIONS

Abstract

Background: Increased brachial artery (BA) stiffness has previously been shown to affect the magnitude of FMD response in patients with high cardiovascular risk. However, it is unclear whether increased BA stiffness explains the diminished FMD response typically observed in a healthy older population. We determined whether BA stiffness would be greater in the older than the young population, and whether it would influence FMD responses in the former. Methods: Data from 33 young (YNG: 27.5±4.9yrs) and 33 older (OLD: 64.9±3.6yrs) individuals were analysed. FMD was assessed with reactive hyperaemia using Ultrasound Advanced Open Platform (ULA-OP). All acquired raw data were post-processed using custom-designed software to obtain parameters of WSR and diameter. BA stiffness was calculated from BA systolic and diastolic diameters with simultaneous contra-lateral BA blood pressure measurements, and was expressed as pulse wave velocity (PWV) and β-stiffness index. Results: Both PWV [YNG: 9.5(8.7−10.3) vs OLD: 9.4(8.6–10.2) m/s] and β-stiffness index [YNG: 17.5(14.7–20.2) vs OLD: 16.7(13.9–19.4) au] were similar between populations. In YNG, there was no association between BA stiffness parameters and diameter changes obtained during FMD and nitroglycerin-mediated dilatation assessments. The association was also absent in OLD during either assessment. Conclusions: These results demonstrate that BA stiffness is not increased in the healthy older population compared to the young counterpart. Furthermore, there is no association between BA stiffness parameters and the FMD response in either population, suggesting that BA stiffness may not influence BA vasodilatory response in healthy adults.