Abstract
Background
Age is a key risk factor contributing to vascular endothelial dysfunction. Whether the impact of ageing is uniform on various vascular beds is unknown. Endothelial function is classically evaluated by the brachial flow mediated dilatation (FMD) after a brief occlusion which mainly involves nitric oxide (NO) production. However, FMD measurement, requiring highly trained technicians, has been shown to be associated with a high degree of variability. Endothelial function could be also assessed by cutaneous iontophoresis combined with Laser Doppler. By contrast to FMD, this method is easily done by nurses and shows less variability. In parallel, myocardial imaging allows measurement of coronary flow reserve (CFR) coupled with an adenosine challenge leading to both a NO release and a modulation of potassium channels.
Purpose
The aim of this study was to determine the impact of ageing on vasodilation of peripheral (cutaneous) and coronary blood vessels in healthy volunteers.
Methods
This prospective single German center study enrolled 75 healthy non-smoking normotensive volunteers, taking no medication. They were divided into three age-subgroups (n=25/group): 18–30, 50–59, and 60–70 years (women: 54, 27 and 23%, respectively). All subjects underwent clinical and laboratory evaluation.
Peripheral endothelial function, expressed in cutaneous blood flow (delta CBF), was assessed through cutaneous microcirculation dilation by the non-invasive method using Laser Doppler Speckle Contrast Imaging (LSCI, Perimed) coupled with iontophoresis to locally deliver 125 nmoles of acetylcholine (Ach). The CFR was determined by cardiac magnetic resonance (CMR) coupling with an intravenous infusion of adenosine at 140 μg/kg/min for at least 3 minutes.
Results
Age was associated with a 23% reduction of peripheral endothelial function (delta CBF, p=0.005) in the elderly group (60–70y) vs. the younger one (18–30y) (median: 56.4 vs. 73.6). By contrast, calculated CFR was unchanged (median: 4.1 vs. 4.2, p=0.38). No relationship was observed between peripheral endothelial function (delta CBF) and CFR (r=0.01, p>0.97) in healthy volunteers.
Conclusion
In healthy volunteers, ageing is associated with a progressive peripheral but not with a coronary vascular dysfunction. This suggests that the impact of age on endothelial dysfunction depends on different vascular beds. Peripheral endothelial function assessment does not predict coronary vascular function in healthy volunteers.
Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Servier
Coronary Flow Reserve Is a Comprehensive Indicator of Cardiovascular Risk Factors in Subjects With Chest Pain and Normal Coronary Angiogram
