Reactive hyperemia and cardiovascular risk.

Since the description of the classical cardiovascular risk factors by the Framingham group some 50 years ago,1 more recent efforts have explored the utility of biomarkers to further refine risk stratification. Although vascular imaging and biochemical markers have shown considerable promise,2 assessment of vascular function has particular appeal. Endothelial dysfunction is an attendant feature of established atherosclerosis3 and a precursor when only risk factors for atherosclerosis are present.4 It is thought in large part to reflect decreased nitric oxide bioavailability in the vasculature. As such it has been suggested that endothelial dysfunction plays a central pathophysiological role in the development and clinical expression of cardiovascular disease, making it well suited as a surrogate marker of risk.