Evaluation of Endothelial Function by Flow-Mediated Dilation: a Comprehensive Review in Rheumatic Disease

Flow-mediated dilation (FMD) represents a non-invasive marker of endothelial function to evaluate vascular homeostasis, which reflects the effects of several mechanisms, including vessel tone regulation, cell proliferation, and inflammatory responses. Beyond classical atherosclerotic risk factors such as arterial hypertension, diabetes mellitus, smoking, obesity, and dyslipidemia, chronic inflammation contributes to the endothelial dysfunction causing plaque formation and there is growing evidence of a significantly higher cardiovascular morbidity associated with autoimmune diseases. The endothelium reacts to several endogenous and exogenous stimuli, through surface receptors and intracellular signalling, and releases numerous vasoactive substances, including endothelins, prostacyclins, and nitric oxide (NO). Chronic inflammatory rheumatic diseases are commonly associated with decreased endothelial NO production, vascular damage, and premature atherosclerosis. Despite partially eclipsed by pulse wave velocity measure in the modern scientific literature, we provide a comprehensive overview and critically discuss the available data supporting FMD as a surrogate marker of endothelial function and, therefore, its potential role in predicting early atherosclerosis in patients with rheumatic diseases.