Obstructive Sleep
Apnea
September 9th 2012
George Chandy MD MSc FRCPC
Assistant Professor University of
Ottawa
Goals
Discuss the causes and risk factors for OSA
To review the Personal and Societal impact
Therapy
Pulmonary
Hypertension
Stroke
?Hyper-
coagulability
Impaired work
Performance
Increased
Insulin
Resistance
Depression
Driving safety
Cardiovascular
Complications
OSA
Epidemiology
OSA is a disorder of disturbing prevalence
Direct relationship with weight gain
Lack of good Canadian –based population
data
US data is instructive
Consider 1/2 of the Canadian population is
overweight/obese vs 2/3 of the US population.
Table. Prevalence of Obstructive Sleep Apnea (OSA) by Sex and Age Group: 2 US Population Studies4-6.
Young, T. et al. JAMA 2004;291:2013-2016
Copyright restrictions may apply.
Pathophysiology
Reduced Upper airway diameter during
sleep
Excess tissue
Reduced Neural Output at sleep onset and
during sleep
Risk Factors
1. Obesity (90%)
2. Craniofacial Structure
1. Small lower jaw
2. Narrowed/high arched palate
3. Nasal
1. Allergic Rhinitis
2. Nasal Polyps
3. Septal Deviation
4. Genetic predisposition/hereditary
RF (continued)
Upper airway soft tissue
Macroglossia (large tongue)
Elongated soft palate
Tonsillar/adenoid Enlargement
Other systemic RF’s
Acromegaly
Hypothyroidism
PCOS
Diabetes
Cushing’s Syndrome
Heart Failure/fluid retention
Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply.
Somers, V. K. et al. J Am Coll Cardiol 2008;52:686-717
Partial and complete airway obstruction resulting in hypopnea and apnea, respectively
4- Micrognathia
Clinical History
Snoring
Witnessed apneas
Daytime sleepiness
Morning headaches
Nocturnal choking
Frequent awakenings
Nocturia
GERD
Sore throat
Difficulty with memory
Cognitive difficulty
Difficulty concentrating
Definition
Apnea (Cessation of Breathing for > 10 seconds)
Obstructive Apnea
• Thoracic effort with the lack of air flow
Central Apnea
• Lack of thoracic effort with no airflow
APNEA
A drop in the flow sensor to <90% of
baseline
Duration of at least 10 seconds
Flow must be this low for at least 90% of
the event
HYPOPNEA
“A” DEFINITION
Nasal pressure drop by >30%
Lasts at least 10 seconds
>= 4% desaturation
90% of the event meets amplitude
reduction criteria
Severity
Apnea-Hypopnea Index
- Normal: 0-5/hr
- Mild: 5-15/hr
- Moderate: 15-30/hr
- Severe: >30/hr
CASE 1
OSA and Cardiovascular Diseases
Hypertension
Coronary Artery Disease
Congestive Heart Failure
Arrythmias
Hypertension
Prevalence
50% of patients with mod/sev OSA are
Hypertensive
30% of hypertensive patients have a degree
of OSA
Patients with OSA tend to be “non-
dippers”
Hypertension
Prevalence :
83% in patients with 3 anti-hypertensives
who have resistant HTN.
Logan AG.J Hypertens. 2001; 19: 2271–2277
Coronary Artery Disease
Prevalence: 50-67%
Based on post-MI/PCI populations
Risk:
2-4 x risk of Heart attack and Strokes with
untreated moderate to severe OSA
Theoretical risk
Increased
HDL, Blood Glucose, Homocysteine, CRP
Cyclical Hypoxemia
Animal models/ human studies • Premature and increased atherogenesis
CHF
Prevalence of OSA: 15-36%
Mechanisms
• Increased sympathetic tone
• Increased Left heart afterload
• Low oxygen causes increased Right heart
afterload
• Depressed mycocardial (heart muscle) contractility
reserve
Abnormal Heart Rhythm
2-4 x risk of in patients with OSA
Greater difficulty in controlling heart rate
and rhythm.
Summary
OSA exposes the Cardiovascular system
to a profound degree of physiological
stress
Associated development of a number of
cardiovascular risk factors and outcomes
Daytime Sleepiness
Frequent Apneas result in difficulty
attaining and maintaining DEEP sleep
Subsequent daytime sleepiness/fatigue
Poor work/school performance
Increased car accidents (2-7x)
Poor quality of life
Therapy
Positional Therapy
Weight Loss
Positive Airway Pressure
Dental Device
Positional Therapy
Sleeping on ones back is the worst
position
Tennis-ball technique
Body Pillows
Weight Loss
90% of cases of OSA are associated with
Weight
The majority of these patients will
experience resolution of OSA with weight
loss
Figure. Mean Change in the Apnea-Hypopnea Index AHI by Weight Change Category.
Peppard, P. E. et al. JAMA 2000;284:3015-3021
Copyright restrictions may apply.
Positive Airway Pressure
CPAP
(Continuous Positive Airway Pressure)
Air Pressure is utilized to tent open the airway
This is the definitive and gold standard
therapy for OSA
CASE 1
Dental Device
Mandibular Advancement Device
Made by your dentist and molded to your
dentition
This Device advances the bottom jaw forward
and therefore moves the tongue out of the
way
Dental Device
Good option for mild to moderate OSA
Not an option for severe OSA
Therapy - Summary
Weight loss is ALWAYS a good idea
Mild OSA:
Any therapy is reasonable
Mod OSA:
Dental device, CPAP
Severe OSA
Must be treated with CPAP
Summary
Profound public health implications
Additive effect of increasing BMI
80-85% undiagnosed
Particularly disturbing in the CV population
Cost of diagnosis and therapy pales in the
face of secondary complications
Recent Harvard Study estimates the cost of
untreated OSA: $65 – 165 Billion.
Summary
Several Therapeutic options are available
Treatment typically results in a dramatic
improvement in quality of life in addition to
reduction of cardiovascular risk
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