From the International Journal of Cardiology, 10 November 2011.
Large and small artery endothelial dysfunction in chronic fatigue syndrome
David J Newton, Gwen Kennedy, Kenneth KF Chan, Chim C Lang, Jill JF Belch, Faisel Khan
Vascular and Inflammatory Diseases Research Unit and Department of Clinical Pharmacology, Institute of Cardiovascular Research, University of Dundee, Dundee
Background and aim:
There is accumulating evidence that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is associated with increased cardiovascular
risk. Autonomic dysfunction, impaired blood pressure regulation, raised oxidative stress, low‐grade inflammation and increased arterial stiffness have all been reported in ME/CFS patients. However, measurements of endothelial function in the disease have had conflicting results, which are probably due to the methodology used.
The aim of this study was to assess vascular endothelial function directly in the forearm macro and microcirculations of patients with ME/CFS.
Flow‐mediated dilatation was assessed using ultrasound to measure the percentage increase in brachial artery diameter during the hyperaemia following 5 minutes of ischaemia in 30 ME/CFS patients and 27 healthy controls. In addition, post‐occlusive reactive hyperaemia was assessed in 9 ME/CFS patients and 9 healthy controls using laser Doppler flowmetry to measure the increase in forearm skin microcirculation after 5 minutes of ischaemia. Venous blood samples were taken for the laboratory measurement of haematological markers.
Flow‐mediated dilatation was significantly lower in the ME/CFS group than in the control group (median [interquartile range]: 5.99 [3.65] versus 9.24 [3.47]%, p<0.001).
Post‐occlusive reactive hyperaemia in the forearm microcirculation was also significantly lower in ME/CFS patients (area under the response curve: 19.76 [15.46] versus 38.70 [18.14] AU∙min, p=0.012).
Furthermore, ME/CFS patients had significantly higher levels of serum high‐sensitivity C‐reactive protein (p=0.016) and triglycerides (p=0.034), and lower levels of serum high‐density lipoprotein cholesterol (p=0.041), compared with healthy controls.
These findings provide direct evidence of endothelial dysfunction in both the large and small vessels of patients with ME/CFS, which may warrant a large prospective trial of cardiovascular outcomes in the disease.