Examination of endothelial dysfunction and arterial stiffness (Experience of a large epidemiological study)

Whereas advanced atherosclerosis manifests through vascular stenoses and occlusions with sequelae such as myocardial infarction and stroke, early stages of the atherosclerotic disease process are characterized by reversible vascular dysfunction and increased arterial stiffness without relevant reduction of vascular diameter. Central regulator of vascular homeostasis is the endothelium. Endothelial dysfunction is one of the first steps in the development of atherosclerosis. Individuals with manifest atherosclerosis show impaired endothelial function. Endothelial function is influenced by various factors such as age, sex, blood pressure among others. To early identify vascular dysfunction during screening e.g. in occupational health practice, novel noninvasive vascular function measurements to determine vascular function and arterial stiffness seem to be attractive. However, methods to determine endothelial function (flow-mediated dilation, peripheral pulse amplitude) and arterial stiffness applied in clinical trials are relatively personnel intensive, observer dependent and provide valid results only under standardized conditions. Parameters of study participants that acutely influence vascular function and need to be tightly controlled are physical activity, smoking, nutrition among others. Disadvantage of current methods is the relative lack of large-scale prospective data which can support the advantage of these measurements for risk assessment for cardiovascular diseases. Only few studies have examined novel methods compared to classical risk algorithms such as the Framingham risk score. Risk stratification improvement was minor. Even in prospective data in older adults in the general population the measurement of FMD in addition to the Framingham risk score did not significantly improve the C statistic (discrimination), but seemed to help reclassify individuals in low, intermediate and high risk categories. Whether the testing is cost-efficient needs to be determined. At present the application of the introduced methods can only be recommended in the context of studies.