Control of hypertension in nonsleepy patients with obstructive sleep apnea

The long-term effects of continuous positive air pressure (CPAP) ventilation on hypertension control in patients with obstructive sleep apnea (OSA) is still matter of debate. The demonstration of a close link between OSA and hypertension has been provided by longitudinal investigations supporting the hypothesis of a causal link between OSA and the appearance or worsening of a high blood pressure condition. Based on such data, the presence and severity of repeated airway obstruction during sleep may represent an independent risk factor for a persistent increase in blood pressure values often associated with a loss of the typical ‘‘dipping’’ pattern during ambulatory blood pressure monitoring. The mechanisms responsible for hypertension in OSA are only partly understood. Alterations in autonomic responses, with increased sympathetic activity secondary to chemoreflex stimulation by repeated hypoxemia, have been reported to play an important role, together with disruption of ventilator mechanics, activation of inflammatory processes, endothelial dysfunction, and alterations in arousal mechanisms. Aim of this paper is to summarize available evidence on this issue.