Central sleep apnea is associated with increased risk of ischemic stroke in the elderly.

ABSTRACT

OBJECTIVES: Sleep apnea/hypopnea syndrome is a well-recognized independent risk factor for stroke in middle-aged population, but controversy remains in older subjects. We examined the possible association between different respiratory parameters and risk of stroke in a prospective population-based cohort of 394 stroke-free elderly subjects. MATERIAL AND METHODS: Fully overnight polysomnography was performed at baseline. Over the 6 year follow-up period, 20 ischemic strokes occurred. Differences in stroke-free survival between subjects according to central apnea index (CAI) were assessed. RESULTS: We just observed association with incident ischemic stroke on central sleep apnea (CSA) episodes. Obstructive sleep apnea, time passed under 90% oxygen saturation, or arousal index were not associated. The event-free survival was lowest in the highest CAI group. This association was independent of any other vascular risk factors. CONCLUSIONS: CSA is the specific respiratory event associated with stroke in the elderly. Additionally, CSA could be a marker of silent brain ischemia, as a sign of disturbed regulation of central respiratory mechanisms, tentatively of ischemic origin.