Sleep Apnea and Cardiovascular Disease Mohammed Fakhry
AbdulMohsen, MD, FACC Associate Professor and Consultant
Internist/Cardiologist University of Dammam and King Fahd Hospital
of the University.
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Sleep Apnea and Cardiovascular Disease Sleep-related breathing
disorders are highly prevalent in patients with established
cardiovascular disease. Obstructive Sleep Apnea (OSA) affects
15.000.000 adult Americans and is present in large number of
patients with HTN and other CVD such as CAD, Stroke and AF. Central
Sleep Apnea (CSA) occurs mainly in patients with Heart Failure
(HF)
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Sleep Apnea and Cardiovascular Disease Objectives: To describe
the types and prevalence of SA and its relevance to individuals who
are at risk for or already have established CVD. To help develop
the platform from which with the collaboration with specialist in
sleep medicine and related disciplines, such consensus may
develop.
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Sleep Apnea and Cardiovascular Disease
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1. Airway narrowing/obstruction 2. Decreased air flow 3.
Increased effort 4. Oxygen saturation swings and hypoxia 5.
Increased BP and HR 6. Disrupted sleep
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Sleep Apnea and Cardiovascular Disease
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Table 1. Definitions of Terms (5) Apnea: Cessation of airflow
for 10 s Hypopnea: A reduction in but not complete cessation of
airflow to 50% of normal, usually in association with a reduction
in oxyhemoglobin saturation AHI: The frequency of apneas and
hypopneas per hour of sleep; a measure of the severity of sleep
apnea OSA and hypopnea: Apnea or hypopnea resulting from complete
or partial collapse, respectively, of the pharynx during sleep
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Sleep Apnea and Cardiovascular Disease Table 1. Definitions of
Terms (5) CSA and hypopnea: Apnea or hypopnea resulting from
complete or partial withdrawal of central respiratory drive to the
muscles of respiration during sleep Oxygen desaturation: Reduction
in oxyhemoglobin saturation, usually as a result of an apnea or
hypopnea Sleep apnea syndrome: At least 10 to 15 apneas and
hypopneas per hour of sleep associated with symptoms of sleep
apnea, including loud snoring, restless sleep, nocturnal dyspnea,
headaches in the morning, and excessive daytime sleepiness
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Sleep Apnea and Cardiovascular Disease Table 1. (Contd)
Polysomnography: Multichannel electrophysiological recording of
electroencephalographic, electrooculographic, electromyographic,
ECG, and respiratory activity to detect disturbance of breathing
during sleep NREM sleep: Nonrapid eye movement or quiet sleep REM
sleep: Rapid eye movement or active sleep; associated with skeletal
muscle atonia, rapid movements of the eyes, and dreaming Arousal:
Transient awakening from sleep lasting 10 s
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Sleep Apnea and Cardiovascular Disease Table 2: Obstructive
Sleep Apnea Signs, symptoms, and risk factors: - Disruptive snoring
- Witnessed apnea or gasping - Obesity and/or enlarged neck size -
Hypersomnolence - Other signs and symptoms include male gender,
crowded-appearing pharyngeal airway, HTN, morning headache, sexual
dysfunction, behavioral changes (especially in children)
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Sleep Apnea and Cardiovascular Disease Screening and diagnostic
tests - Questionnaires - Holter monitoring - Overnight oximetry -
Home-based/ambulatory unattended polysomnography - In-hospital
attended overnight polysomnography. Treatment options: - Positional
therapy - Weight loss - Avoidance of alcohol and sedatives -
Positive airway pressure - Oral appliances
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Sleep Apnea and Cardiovascular Disease Table 3: Central Sleep
Apnea (CSA) Signs, symptoms, and risk factors: -Congestive heart
failure -Paroxysmal nocturnal dyspnea -Witnessed apnea
Fatigue/hypersomnolence -Other signs and symptoms include male
gender, older age, mitral regurgitation, atrial fibrillation,
Cheyne Stokes Respiration (CSR) while awake, hyperventilation with
hypocapnia
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Central Sleep Apnea In HF Figure 2. Schematic outlining
possible mechanisms underlying development of CSA and the possible
feedback from CSA resulting in exacerbation of heart failure.
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Sleep Apnea and Cardiovascular Disease Table 3: Central Sleep
Apnea (CSA): Screening and diagnostic tests: -Overnight oximetry
-Ambulatory (unattended) polysomnography -In-hospital (attended)
polysomnography Treatment options: -Optimize treatment of heart
failure -Positive airway pressure -Supplemental oxygen
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Sleep Apnea and Cardiovascular Disease OSA and Cardiovascular
disease: There is a clear association between OSA and
cardiovascular disease Higher incidence of adverse cardiovascular
events in untreated patients with OSA Postgrad Med J 2008; 84:15-22
SLEEP 2007;30(3):291-304 CHEST 2008; 133:793-804 Proc Am Thorac Soc
2008; 5:200-206
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Sleep Apnea and Cardiovascular Disease Postgrad Med J 2008;
84:15-22
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OSA is an independent risk for hypertension
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OSA and Hypertension:
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OSA and Hypertension, Why does it happen? OSA can lead to
hypoxia (low oxygen levels), repetitive changes in oxygen
saturations, and large swings in intrathoracic pressures These
changes are detected by receptors in the brain and in the periphery
(carotid bodies) Stimulate a sympathetic response (fight or flight
response, stress response) increased heart rate and blood pressure
Postgrad Med J 2008; 84:15-22
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OSA and Hypertension Why does it happen? Repeated stimulation
increased sympathetic tone during the day High blood pressure
Studies have showed: Increased tonic chemoreflex drive
Abnormalities in HR and BP variabilities during normal awake hours
in patients with OSA Postgrad Med J 2008; 84:15-22
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OSA and Hypertension Some Numbers Wisconsin prospective sleep
cohort (2000) 709 patients with OSA Risk of developing HTN over 4
years: Minimal OSA: 1.42 x normal Mild-moderate: 2.03 x normal
Moderate-severe: 2.89 x normal After adjusting for other risk
factors
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OSA and Hypertension Some Numbers ~40% of people with OSA have
HTN while awake 40-80% of people with non-controlled HTN have
OSA
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OSA and Hypertension How to treat it? Effective CPAP therapy
can reduce BP One study showed a fall in systolic BP by 10 mmHg
after 4 weeks of CPAP Improvement in blood pressure correlated with
improvement in sleepiness
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OSA and Coronary Artery Disease
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OSA and Heart Attacks People with sleep disordered breathing
(SDB) have a high prevalence of coronary heart disease (CHD) People
with CHD have a high prevalence of SDB
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OSA and Heart Attacks: Why does it Happen? Multiple nightly
stresses on the heart: Repetitive fluctuations in oxygen levels
Increased blood pressure surges High sympathetic nervous system
tone
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OSA and Heart Attacks Marin et al. 2005 10 year follow-up study
looking at CV events and OSA (including heart attacks and strokes)
Included 264 healthy men, 377 snorers, 403 untreated mild-mod OSA,
235 untreated severe OSA and 372 treated with CPAP
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OSA and Heart Attacks Gami et al. looked at 112 patients who
underwent a sleep study Followed them for 5 years Sudden death from
cardiac causes (between midnight and 6 am) occurred in 46% of pts
with OSA vs 16% of general population
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OSA and Heart Failure
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CSA is the SDB most commonly associated with HF. Javaheri 2006
49% with CHF have SDB (37% CSA, 12% OSA) Heart Failure is 2.38 x
more common in mild- moderate OSA than in no OSA Postgrad Med J
2008; 84:15-22
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OSA and Heart Failure: Why does it happen? Hypertension Left
ventricular diastolic dysfunction Atrial fibrillation CHEST 2008;
133:793804
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OSA and Heart Failure: Effect of treatment 2 randomized studies
of CPAP for OSA in CHF, showed some improvement in EF over 1-3
months Effect of CPAP treatment on mortality/morbidity from heart
failure is unknown CHEST 2008; 133:793804
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Sleep Apnea and Cardiovascular Disease
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OSA and Cardiac Arrhythmias
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Abnormal heart rhythms have been associated with OSA 1983
Guilleminault et al.: 400 pts with OSA 48% had cardiac arrhythmias
at night 2% sustained VT, 11% sinus arrest, 8% AV block, 19% PVC
Postgrad Med J 2008; 84:15-22
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OSA and Cardiac Arrhythmias; Atrial Fibrillation: Four times
increased risk of AF in pts with OSA (AHI>30) (Sleep Heart
Health Study 2006) Onset of >75% of persistent A fib episodes in
pts with OSA occur at night (8pm-8am) A fib recurrence after
cardioversion twice as high in untreated OSA Observational review
over 17 yrs suggests that nocturnal hypoxemia influences the onset
of A fib Postgrad Med J 2008; 84:15-22 Proc Am Thorac Soc 2008;
5:200-206
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OSA and Cardiac Arrhythmias; Ventricular Arrhythmias: Reported
in pts with OSA Causative role not proven NEJM 2005, a study
observed higher incidence of sudden death during night hours
(12am-6am) in pts with OSA, suggesting but not proving a causative
effect Proc Am Thorac Soc 2008; 5:200-206
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Sleep Apnea and Cardiovascular Disease
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OSA and Strokes
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OSA is a risk factor for stroke 2 prospective cohort studies
following 1022 and 1651 pts found a higher incidence of stroke in
OSA SLEEP, Vol. 30, No. 3, 2007
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OSA and Strokes: Why does it happen? Increased CRP
(inflammation) and atherogenesis Increased thrombotic risks
(clotting of blood) Increased blood pressure Hypoxia Theoretically
PFO? SLEEP, Vol. 30, No. 3, 2007
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OSA and Strokes; Treatment effect: No randomized controlled
trials Observational studies are controversial on whether treatment
of OSA would prevent strokes or not SLEEP, Vol. 30, No. 3,
2007