[Sleep apnea syndrome and cardiovascular diseases]

The sleep apnea syndrome is a common disease, recognised as a public health problem. Cardiovascular disease is the most frequent cause of morbidity and mortality in these patients, however the underlying mechanisms of this association have not been clearly established. In sleep apnea syndrome different phenomena can be produced which may explain the appearance of cardiovascular problems, such a progressive hypoxia in relationship with the apnea, the increases of intrathoracic pressure cause by the efforts of ventilation system against close upper airway and the modifications of the autonomic nervous system associated with the arousals. In addition, the hypoxia episodes and reoxygenation, which appear in the sleep apnea syndrome, may play a important role in the alteration of the balance between vasoconstriction and vasodilatation substances affecting the vascular homeostasis and conditioning endothelial dysfunction. On the other hand, the increasing of platelets aggregation and the decreased of fibrinolisis in this group of patients may cause vascular diseases.