Noninvasive evaluation of endothelial vascular reactivity: Should the quest continue?

摘要

Endothelial dysfunction is an early event in the continuum of the pathogenesis of atherosclerosis that persists throughout the disease process. Endothelial dysfunction may be a valuable marker or barometer of the composite effect of the various predisposing factors, even some yet unknown, on the subsequent risk of cardiovascular events. Accumulating data suggest that clinical evaluation of endothelial function may provide incremental value to current risk stratification and to the tailoring of pharmacological and nonpharmacological therapy. This has prompted many investigators to probe the integrity of endothelium-dependent vascular reactivity in an effort to uncover clinically useful methods of evaluating endothelial function. For practical purposes, reactive hyperemia of the forearm has become the most popular stimulus for testing vascular reactivity, and several methods have been developed to quantify this response and study its determinants. High-resolution brachial ultrasound and venous impedance plethysmography are used extensively in mechanistic studies; however, for practical purposes, it is unlikely that these methods could be used in routine clinical practice. Therefore, some alternatives are being actively developed. The greatest remaining challenge is to find firm evidence that endothelial function can be used as a clinical surrogate of cardiovascular events. Validation of these methods and their evaluation in large-scale trials is needed to determine whether abnormal vascular reactivity is indeed a good barometer of cardiovascular risk.