[Prevalence of sleep-disordered breathing in patients with acute ischemic stroke: influence of onset time of stroke].

Objective TO analyze the prevalence of sleep-disordered breathing in patients with acute ischemic stroke and the influence of the characteristics of the stroke and time of onset. Patients and Methods Polysomnography was performed with an Autoset Portable Plus II in 139 patients within 72 hours of the onset of symptoms. Standard polysomnographic data, signs and symptoms related with sleep apnea-hypopnea syndrome (SAHS) prior to ischemic stroke, vascular risk factors, and characteristics and onset time (day/night) of ischemic stroke were recorded. The polysomnographic data were compared with results published for subjects of a similar age in the general population. Results The mean age was 73.6 (SD 11.1) years (59% of the patients were men). Prior to the stroke, 64.7% of the patients snored, 21.6% presented repetitive sleep apneas, and 35.6% had daytime sleepiness. The mean apnea-hypopnea index (AHI) was 29.1 (17.9) episodes/hour, the obstructive component of which was 20.1 (15.7) episodes/hour. Five patients presented Cheyne-Stokes breathing. The AHI (for all cut-points from 5 to 50), chronic snoring, and daytime sleepiness were significantly greater than those published for the general population. The stroke characteristics showed no significant differences between daytime and nighttime onset. Nighttime stroke (60.4%) was associated with a significantly higher AHI (33.3 compared to 24.7 episodes/hour) mainly because of obstructive apneas. Nighttime stroke was also associated with a greater nighttime desaturation and a greater probability of SAHS symptoms prior to stroke (odds ratio, 2.62). In contrast, there were no differences in vascular risk factors between daytime and nighttime stroke onset. Conclusion The prevalences of sleep-disordered breathing with clinical signs and symptoms of SAHS were high in this population of patients with acute ischemic stroke. Patients with nighttime stroke had more obstructive sleep-disordered breathing and a higher clinical probability of obstructive SAHS before stroke. These findings support the hypothesis that obstructive SAHS is a risk factor for ischemic stroke, particularly for strokes presenting at night.