[Endothelial dysfunction: pathophysiology, diagnosis and prognosis].

The endothelium plays a crucial role in the regulation of vascular tone. Recent studies have indicated that endothelial dysfunction develops in the presence of cardiovascular risk factors such as hypertension, diabetes mellitus, hypercholesterolemia and in chronic smokers, as well as in patients with a family history of cardiovascular disease. It has now been established that endothelial dysfunction represents the first indicator of vascular damage. Endothelial function can be assessed in coronary and peripheral conductance and resistance vessels by means of invasive and noninvasive (ultrasound-guided) methods such as intracoronary infusion of acetylcholine, the endothelium-dependent vasodilator. It is interesting that endothelial dysfunction in the presence of cardiovascular risk factors can be almost completely corrected by the acute administration of antioxidants such as vitamin C, pointing to a crucial role of reactive oxygen species in mediating this phenomenon. Superoxide producing enzymes involved in the increased production of reactive oxygen species include NADPH oxidase, nitric oxide synthase in the uncoupled state, mitochondrial superoxide sources, cyclooxygenase and xanthine oxidase. Recent studies indicate that the endothelial dysfunction found in coronary and peripheral conductance and resistance vessels provide prognostic information about future cardiovascular events. The role of endothelial dysfunction in the setting of primary prevention is not yet clear, but is being investigated in the current Gutenberg Heart Study.