Can the treatment of sleep apnea syndrome prevent the cardiovascular consequences?

He et al. indicated that mortality is reduced in treated patients with OSA but the reasons for this are still speculative. CPAP eliminates the acute elevation of blood pressure (BP) that occurs during a night of obstructive apneas. In longer term studies hypertensive patients showed a fall in mean BP from baseline with CPAP both by day and by night. Noncompliant patients do not achieve this benefit and BP does not change in normotensive patients with OSA on CPAP. On the other hand, left ventricular mass does not seem to change in hypertensive OSA patients despite reduction in blood pressure. Some of the benefit in BP reduction may relate to other interventions such as successful weight loss. Clear answers as to the effects of intervention are difficult because of confounding factors such as antihypertensive medication and length of follow up as well as questions of compliance with treatment. Multicenter trials are being currently undertaken but will need some years to yield answers.