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