Endothelial function is associated with pulse pressure, pulse wave velocity, and augmentation index in healthy humans

Arterial stiffness is an independent predictor of mortality and is regulated by a number of factors, including vascular smooth muscle tone. However, the relationship between endothelial function and definitive measures of arterial stiffness and wave reflections has not been described in healthy individuals. Therefore, we tested the hypothesis that endothelial function is inversely correlated with aortic pulse wave velocity (PWV), central pulse pressure, and augmentation index in healthy individuals. Peripheral and central pulse pressure and augmentation index were determined at rest, and global endothelial function was measured using pulse wave analysis and administration of sublingual nitroglycerin and inhaled albuterol. Aortic PWV was also determined at baseline in a subset of 89 subjects. In a separate group of subjects (n=89), aortic PWV was measured and brachial artery flow-mediated dilatation assessed as a measure of conduit artery endothelial function. Global endothelial function was significantly and inversely correlated with aortic PWV (r=-0.69; P < 0.001), augmentation index (r=-0.59; P < 0.001), and central (r=-0.34; P < 0.001) and peripheral pulse pressure (r=-0.15; P=0.03). Moreover, there was a stronger correlation between central rather than peripheral pulse pressure. After adjusting for potential confounders, global endothelial function remained independently and inversely associated with aortic PWV and augmentation index. There was also a significant, inverse relationship between conduit artery endothelial function and aortic PWV (r=0.39, P < 0.001), which remained independent after adjusting for confounding factors. In healthy individuals, a decline in endothelial function is associated with increased large artery stiffness, wave reflections, and central pulse pressure.