72% of patients who have experienced a stroke or transient ischemic attack (TIA) also have sleep-disordered breathing (SDB),1 which is sometimes undiagnosed. SDB is associated with worse functional outcomes following stroke, so investigation of stroke should also include screening for SDB3. Obstructive sleep apnoea is an independent risk factor for stroke and it has been suggested that in patients with moderate to severe OSA and ischaemic stroke that CPAP therapy lowers their risk of mortality.2,4
Patients with SDB experience symptoms that may predispose them to stroke. Primary amongst these are;
experiencing repetitive episodes of hypoxia and reoxigenation during apnoea which has been shown to be associated with oxidative stress3 and systemic inflammation.4
experiencing sleep fragmentation caused from SDB which results in hypersympathetic activity.6
Can SDB predispose people to strokes?
People with SDB may be predisposed to stroke through a number of symptoms they experience.
In particular:
Repetitive drops in nocturnal blood oxygen levels caused by SDB can result in intermittent hypoxia which has been shown to be associated with systemic inflammation.4
Sleep fragmentation from SDB results in hypersympathetic activity, which triggers surges in blood pressure and heart rate.6
What is the impact of SDB on post-stroke rehabilitation?
Patients with both SDB and stroke can negatively affect their rehabilitation and it associated with:
the symptoms of SDB such as excessive daytime sleepiness, fatigue, and impaired cognitive functioning
worsened functional capacity7; a longer period of post-stroke rehabilitation; and
a higher mortality rate
How do I recognise and diagnose SDB in stroke survivors?
Recognising SDB in stroke survivors is often challenging because the symptoms associated with SDB are often attributed to stroke. A complete sleep history from your patient’s family members may help determine whether SDB was present prior to the stroke or developed after the stroke.
Johnson KG, et al. Frequency of sleep apnea in stroke and TIA patients: a meta-analysis. J Clin Sleep Med. 2010, 15; 6(2):131-7.
2
Martínez-García MA, et al. Continuous positive airway pressure treatment reduces mortality in patients with ischemic stroke and obstructive sleep apnea: a 5-year follow-up study. Am J Respir Crit Care Med. 2009, 180(1):36-41.
3
Jelic S, et al. Inflammation, oxidative stress, and the vascular endothelium in obstructive sleep apnea. Trends Cardiovasc Med. 2008, 18(7):253-60.
4
Drager LF, et al. Obstructive sleep apnea: an emerging risk factor for atherosclerosis. Chest. 2011, 140(2):534-42
5
Am J Resp crit care med 2005 Michael Arzt, Terry Young, Laurel Finn, James B. Skatrud, and T. Douglas Bradley http://www.atsjournals.org/doi/full/10.1164/rccm.200505-702OC
6
Michael Arzt, Terry Young, Laurel Finn, James B. Skatrud, and T. Douglas Bradley Association of Sleep-disordered Breathing and the Occurrence of Stroke Am J Resp crit care med 2005
7
Cherkassky T, Oksenberg A, Froom P, Ring H. Sleep-related breathing disorders and rehabilitation outcome of stroke patients: a prospective study. Am J Phys Med Rehabil 2003;82:452–455
