Focal and global endothelial function and their association with arterial stiffness
Dr Faisel Khan
Investigators
Dr Faisel Khan, Prof. Jill JF Belch. Prof. Chim C Lang
Institution
Vascular and Inflammatory Diseases Research Unit, The Institute of Cardiovascular Research, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK
Aims
In keeping with the idea that ME/CFS patients have cardiovascular dysfunction, we have recently shown that arterial stiffness, determined by measuring the augmentation index (AIx), is significantly elevated in ME/CFS patients compared with control subjects. The degree of elevation in AIx was associated with levels of serum C-reactive protein (CRP), pointing to a role of low grade inflammation, and oxidative stress. Increased arterial stiffness is associated with a number of adverse haemodynamic effects, including a rise in central pulse pressure, leading to increased cyclic stress on the arterial wall, increased left ventricular afterload, and decreased myocardial perfusion. Thus the combination of augmented arterial stiffness and increased inflammation and oxidative stress may result in unfavourable haemodynamics and an increased risk of a future cardiovascular event in these patients. Based on the association between AIx and CRP, it should be expected that endothelial function, which is a good marker of vascular health and has also been shown to be negatively correlated with CRP, is also impaired in patients with CFS. However, the precise role of endothelial function in CFS patients remains unclear. Endothelial function is well established marker of future cardiovascular events and therefore, its further examination in patients with CFS is warranted.
Methods
This study will assess endothelial function in 30 CFS patients and matched controls, using stimuli other than acetylcholine. We plan to assess both focal endothelial function in the brachial artery and global endothelial function in smaller pre-resistance arteries. As well as assessing arterial stiffness using the gold standard measure of carotid to femoral pulse wave velocity, and determining the relationship between arterial stiffness and focal and global endothelial function, we propose to assess coronary flow reserve and the association of this with measure of arterial stiffness and endothelial function.
