Endothelium-dependent vasoactivity of the human internal mammary artery.

Coronary artery disease is recognized as a major health problem worldwide, particularly because of the associated morbidity and mortality. Coronary artery bypass grafting has been an established mainstay in the treatment of this disease for almost half a century and is arguably the most intensively studied surgical procedure ever undertaken. Because of its unique properties, the human internal mammary artery has long been considered the best graft to use in this type of surgery. Previous studies have shown several advantages of this graft compared with others, that is, lower incidence of atherosclerosis. However, few comparative studies on the reactivity of this artery have been published. Moreover, these studies usually focus on isolated cardiovascular risk factors rather than combined risk factors. In fact, patients who require coronary revascularization usually present multiple risk factors, which can interfere with several pathways of regulation of vascular function, namely endothelial function. Several diseases and cardiovascular risk factors have been shown to interfere with endothelial function, promoting the production of vasoconstrictors, inhibiting the production of vasodilators, or both, and thus eventually leading to endothelial dysfunction. Therefore, it is of great interest to study the endothelial function, particularly of the human internal mammary artery, in the presence of combined cardiovascular risk factors and concomitant diseases. Many techniques have been developed to assess the endothelial function, in particular, studies on isolated arteries, as well as spectroscopic, electrochemical, and immunological methods, among others.