Obstructive sleep apnea syndrome: coagulation anomalies and treatment with continuous positive airway pressure

Obstructive sleep apnea syndrome (OSAS) is a highly prevalent sleep disorder associated with severe cardiovascular events, morbidity and mortality. Recent evidence has highlighted OSAS as an independent risk factor for an excessive platelet activation and arterial thrombosis, but the underlying mechanisms have not yet been determined. Studies in cell culture and animal models have significantly increased our understanding of the mechanisms of inflammation in OSAS. Hypoxia is a critical pathophysiological element that leads to an intense sympathetic activity, in association with systemic inflammation, oxidative stress and procoagulant activity. While platelet dysfunction and/or hypercoagulability play an important role in the pathogenesis of vascular disease, there are limited studies on the potential role of blood viscosity in the development of vascular disease in OSAS.

Further studies are required to determine the precise role of hypercoagulability in the cardiovascular pathogenesis of OSAS, particularly its interaction with oxidative stress, thrombotic tendency and endothelial dysfunction. Nasal continuous positive airway pressure (nCPAP), the gold standard treatment for OSAS, not only significantly reduced apnea-hypopnoea indices but also markers of hypercoagulability, thus representing a potential mechanisms by which CPAP reduces the rate of cardiovascular morbidity and mortality in OSAS patients.