Recent advances in the management of secondary hypertension-obstructive sleep apnea.

Since obstructive sleep apnea (OSA) is known as a common cause of secondary hypertension, it is necessary to consider OSA a differential diagnosis in treating patients with hypertension. Apnea during sleep causes temporary and repeated hypoxia and subsequent sympathetic nerve activation. Furthermore, dysfunction of endothelial cells due to hypoxia is considered another mechanism leading to enhanced stiffness of the elastic artery and eventually, elevation of blood pressure (BP). As a result, OSA induces a nighttime or morning surge in BP, and long-standing severe OSA also causes daytime hypertension. Therefore, treatment of OSA may be important for BP control, especially in severe OSA cases. For the treatment of OSA, continuous positive airway pressure (CPAP) is a major treatment option, though alternative devices may be useful in CPAP-intolerant cases.