Its well known that
patients with obstructive sleep apnea (OSA) are at risk for cerebrovascular and
cardiovascular events. But patients who suffer strokes are also particularly at
high risk for OSA, and this has implications for both morbidity and mortality
in these patients.
Sharma and Culebras (Sharma
2016) note that about 50-70% of patients with
stroke have sleep-disordered breathing (SDB) as defined by AHI≥10/hour,
with OSA being the most common pathology though some studies show that during
the first 5 days poststroke central sleep apnea predominates. Males had a
higher percentage of SDB (AHI>10) than females (65% vs 48%) and patients
with recurrent strokes had higher percentage of SDB than patients with first
stroke (74% vs 57%). Worsening of OSA may also be found after acute stroke due
to impairment of respiratory muscle coordination and the presence of dysphagia
may predict the development of OSA in patients with acute stroke. Traditional
risk factors for OSA, such as a high BMI and large neck circumference, also
predict OSA in acute stroke patients.
A recent meta-analysis (Seiler
2018)
identified 54 studies performed in the acute phase after stroke (<1 month
after stroke), 23 studies in the subacute phase (after 13 months) and 12 studies
in the chronic phase (> 3 months). An AHI> 5/h and >30/h was found in
71% and 30% of patients, respectively. The severity of SDB was similar in all
phases after stroke; however, only three studies assessed the same patients
over time. The authors conclude that almost 1/3 of stroke patients present
severe SDB, which appears to persist over time. Another recent study (Chakraborty
2017)
found that the risk of OSA, as assessed by the STOP-BANG OSA risk tool, remains
high at one month following discharge from hospitalization for acute stroke.
Of course, many of
the risk factors for OSA are also risk factors for stroke. So, it should not be
surprising that the occurrence of OSA is high in stroke patients. But it is
also likely that mechanisms related to stroke may cause or accentuate OSA. For
example, those strokes that lead to dysphagia or dysphonia have likely impacted
pharyngeal musculature that is important in keeping the airway open. Patients
with bilateral strokes are also more likely to have pharyngeal dysfunction (pseudobulbar),
which may explain why some studies have shown OSA is more frequent in patients
with recurrent strokes.
Annual Meeting of the Associated Professional Sleep Societies)
illustrates how Hennepin County Medical Center used a quality improvement
project to substantially increase recognition of OSA in their acute stroke or
transient ischemic attack (TIA) patients (Metzler
2018). They implemented two sets of interventions (in July 2015 and March
2016), including an education session for resident physicians, an electronic
stroke discharge note template, and email reminders. They then did retrospective
chart review on ischemic stroke and TIA patients discharged over two
consecutive months to collect OSA screening and referral data before and after
each intervention, as well as a year later, to assess retention. The rate of
OSA screening in ischemic stroke and TIA patients at discharge increased from
baseline 2.4% in 2014 to 24.1% in 2015 following the first intervention. It
further increased to 66.0% in 2016 after continued efforts for implementation.
After reiteration, in 2017, the OSA screening rate improved to 69.4%. Moreover,
all patients (100%) who screened positive had a sleep referral ordered at
discharge. Physician survey before and after interventions found increase in
self-reported screening rate (69% to 100%) and increase in satisfaction with
the discharge template.
The Davis paper
mentioned above (Davis 2013) summarized
many of the studies assessing the impact of CPAP in acute stroke patients with
OSA. Another recent systematic review
and meta-analysis was done on randomized controlled trials (RCTs) examining the
effectiveness of continuous positive airway pressure (CPAP) in stroke patients
with sleep disordered breathing (SDB) (Brill 2018). The
combined analysis of the neurofunctional scales (NIH Stroke Scale and Canadian
Neurological Scale) showed an overall neurofunctional improvement with CPAP,
but with a considerable heterogeneity across the studies. However, tolerability
of CPAP was an issue. Mean CPAP use across the trials was only 4.53 hours per
night and the odds ratio of dropping out with CPAP was 1.83. The authors
conclude that CPAP use after stroke is acceptable once the treatment is
tolerated and that CPAP might be beneficial for neurologic recovery, which
justifies larger RCTs.
Many of you are already aware of a recent JAMA publication that
questioned the ability of CPAP to reduce cardiovascular and cerebrovascular
outcomes in patients with OSA (Yu
2017).
They found no significant association of PAP with major adverse cardiovascular
events (RR 0.77), cardiovascular death (RR 1.15), or all-cause death (RR 1.13).
The same was true for ACS (acute coronary syndrome), stroke, and heart failure.
They concluded that use of PAP, compared with no treatment or sham, was not
associated with reduced risks of cardiovascular outcomes or death for patients
with sleep apnea. They acknowledge that there are other benefits of treatment
with PAP for sleep apnea, but these findings do not support treatment with PAP
with a goal of prevention of these outcomes. There have been numerous questions
about the conclusions of that study, including whether compliance with PAP was
adequate in the included studies and whether the power of the studies was
adequate to make any firm conclusions. The study also did not specifically look
at a subgroup of patients with acute stroke.
But both the Brill
study and the Yu study leave us with the understanding that larger RCTs,
focusing on subsets such as the patient with acute stroke, are needed.
Our prior columns on
obstructive sleep apnea:
June 10, 2008 Monitoring
the Postoperative COPD Patient
August 18, 2009 Obstructive
Sleep Apnea in the Perioperative Period
August 17, 2010 Preoperative
Consultation Time to Change
July 2010 Obstructive
Sleep Apnea in the General Inpatient Population
July 13, 2010 Postoperative
Opioid-Induced Respiratory Depression
November 2010 More
on Preoperative Screening for Obstructive Sleep Apnea
February 22, 2011 Rethinking
Alarms
November 22, 2011 Perioperative
Management of Sleep Apnea Disappointing
March 2012
Postoperative
Complications with Obstructive Sleep Apnea
May 22, 2012 Update
on Preoperative Screening for Sleep Apnea
February 12, 2013 CDPH:
Lessons Learned from PCA Incident
February 19, 2013 Practical
Postoperative Pain Management
March 26, 2013 Failure
to Recognize Sleep Apnea Before Surgery
June 2013 Anesthesia
Choice for TJR in Sleep Apnea Patients
September 24, 2013 Perioperative
Use of CPAP in OSA
May 13, 2014 Perioperative
Sleep Apnea: Human and Financial Impact
March 3, 2015 Factors
Related to Postoperative Respiratory Depression
August 18, 2015 Missing
Obstructive Sleep Apnea
June 7, 2016 CPAP
for Hospitalized Patients at High Risk for OSA
October 11, 2016 New
Guideline on Preop Screening and Assessment for OSA
November 21, 2017 OSA,
Oxygen, and Alarm Fatigue
References:
Sharma S, Culebras A. Sleep apnoea and stroke. Stroke and Vascular Neurology 2016;
https://svn.bmj.com/content/1/4/185
Seiler A, Camilo M, Korostovtseva L, et al. Prevalence of Sleep-Disordered
Breathing After Stroke and Transitory Ischemic Attack: A Meta-Analysis. Exhibit
0464. SLEEP 2018;
Sleep 2018: 41(suppl_1):
A175A176
https://academic.oup.com/sleep/article-abstract/41/suppl_1/A175/4988501?redirectedFrom=fulltext
Chakraborty A, Tanielian M, Tzeng D, Doghramji
K. 1149 Sleep Apnea is a Significant Co-Morbidity One Month Following
Stroke. Sleep 2017: 40(suppl_1):
A429
https://academic.oup.com/sleep/article/40/suppl_1/A429/3781212?searchresult=1
Davis AP, Billings ME, Longstreth
WT, Khot SP. Early diagnosis and treatment of
obstructive sleep apnea after stroke. Are we neglecting a modifiable stroke
risk factor? Neurol Clin Pract. 2013; 3(3): 192-201
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3721244/
Metzler A, Lindsay
D, Irfan M. 0569 Screening for Obstructive Sleep Apnea in Patients with
Ischemic Stroke and Transient Ischemic Attack. Sleep 2018: 41(suppl_1): A212
https://academic.oup.com/sleep/article-abstract/41/suppl_1/A212/4988606?redirectedFrom=fulltext
Brill AK, Horvath T,
Seiler A, et al. CPAP as treatment of sleep apnea after stroke: a meta-analysis
of randomized trials. Neurology 2018; 90(14): e1222-e1230
http://n.neurology.org/content/90/14/e1222.long
Yu J, Zhou Z, McEvoy
D, et al. Association of Positive Airway Pressure With
Cardiovascular Events and Death in Adults With Sleep ApneaA
Systematic Review and Meta-analysis. JAMA 2017; 318(2): 156-166
https://jamanetwork.com/journals/jama/fullarticle/2643307?resultClick=1
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