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Obstructive Sleep Apnea and Hypertension

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Normal blood pressure: systolic 120 mmHg and diastolic 80 ... Labile blood pressure. EEG arousals. Fragmented sleep. Increased sympathetic activity ... – PowerPoint PPT presentation

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Title: Obstructive Sleep Apnea and Hypertension


1
Obstructive Sleep Apnea and Hypertension
  • Christine Won, M.D.
  • Stanford Sleep Disorders Center

2
Objectives
  • Hypertension
  • Definition
  • Risk Factors
  • Significance
  • Causes
  • Treatment
  • Obstructive Sleep Apnea
  • Association with Hypertension
  • Physiology
  • Causes
  • Treatment
  • Other Cardiovascular Diseases

3
Definition of Hypertension
  • Normal blood pressure systolic lt120 mmHg and
    diastolic lt80
  • Pre-hypertension systolic 120-139 or diastolic
    80-89
  • Hypertension 
  • Stage 1 systolic 140-159 or diastolic 90-99
  • Stage 2 systolic 160 or diastolic 100

4
Prevalence of Hypertension
Hajjar, I, Kotchen, TA. JAMA 2003 290199.
5
White-Coat Hypertension
Mancia, G, Parati, G, Pomidossi, G, et al,
Hypertension 1987 9209
6
Risk Factors for Hypertension
  • More common and more severe in blacks
  • It is likely that increased salt intake is a
    necessary but not sufficient cause for
    hypertension
  • Excess alcohol intake increases risk
  • High cholesterol may also associated with the
    development of hypertension
  • Hypertension may be more common among those with
    certain personality traits, such as hostile
    attitudes and time urgency/impatience

7
Obesity and Hypertension
  • Obesity is associated with an increased risk of
    hypertension, and weight gain appears to be a
    main determinant of the rise in blood pressure
    that is commonly seen with aging
  • Weight loss improves blood pressure

Stevens, VJ, Corrigan, SA, Obarzanek, E, et al,
Arch Intern Med 1993 153849
8
Why is Hypertension Important?
  • Hypertension is associated with a number of
    serious adverse effects
  • The likelihood of developing these complications
    varies with the blood pressure
  • The increase in risk begins as the blood pressure
    rises above 110/75 mmHg and, at any blood
    pressure, is importantly affected by the presence
    or absence of other risk factors

9
Why is Hypertension Important?
  • Premature cardiovascular disease
  • Coronary heart disease
  • Heart failure
  • Stroke
  • Intracerebral hemorrhage
  • Chronic renal insufficiency and end-stage renal
    disease
  • Acute, life-threatening emergency

10
What Causes Hypertension?
  • Increased sympathetic neural activity
  • Increased angiotensin II activity and
    mineralocorticoid excess
  • Reduced adult nephron mass
  • may be related to genetic factors, intrauterine
    disturbance (eg, hypoxia, drugs, nutritional
    deficiency), and post-natal environment (eg,
    malnutrition, infections)
  • Hypertension is twice as common in those who have
    hypertensive parents genetic factors account for
    approximately 30 of the variation in blood
    pressure

11
Benefit of Treating Hypertension
  • Antihypertensive therapy has been associated with
    40 percent reduction in stroke 25 percent in
    myocardial infarction and more than 50 percent
    in heart failure
  • It is estimated that control of hypertension to
    below 140/90 mmHg could, in men and women,
    prevent 19 and 31 percent of coronary heart
    disease events

12
Lifestyle modifications in the management of
hypertension
The Seventh Report of the Joint National
Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure, JAMA 2003
2892560
13
Obstructive Sleep Apnea and Hypertension
  • Wisconsin Sleep Cohort Study
  • Dose-dependent relationship between severity of
    sleep apnea and risk of developing hypertension
  • Odds for developing hypertension during a 4-8
    year follow-up period compared to subjects with
    no apneas or hypopneas was 2.0 if AHI was 5-15,
    and 3.0 if AHIgt15
  • The Sleep Heart Health Study
  • A cross-sectional analysis of a large
    community-based multi-center population showed an
    increase in odds of 1.4 for hypertension when AHI
    gt 30 compared to those with AHI lt 1.5
  • The Nurses Health Study
  • Increase in risk of 1.6 for the development of
    hypertension over an 8-year follow-up period in
    regular snorers compared to non-snorers

14
The Relationship between Obstructive Sleep Apnea
and Hypertension
  • The odds of having hypertension is 37 greater in
    persons with obstructive sleep apnea
  • The odds of having hypertension is 46 greater in
    those who spend greater percentage of sleep time
    below 90 oxygen saturation

Nieto, F. J. et al. JAMA 20002831829-1836
15
The Relationship between Obstructive Sleep Apnea
and Hypertension
  • Compared to those with AHI0, the odds of having
    hypertension was 42 greater if AHI was 0.1-5, 2x
    greater if AHI was 5-15, and almost 3x greater if
    AHI was more than 15 per hour

Peppard et al. NEJM. 2000 3421378-1384
16
Obstructive Sleep Apnea Physiology
17
Obstructive Sleep Apnea Physiology
www.qeok.com/lung-cancer/asbestosis-picture.jpg
18
Obstructive Sleep Apnea and Cardiovascular Effects
  • EEG arousals
  • Fragmented sleep
  • Increased sympathetic activity
  • Obstructive Apnea
  • Negative Intrathoracic Pressure (Mueller
    Maneuver)
  • Hypoxia
  • Hypercapnia
  • Resumption of breathing
  • Labile blood pressure

19
Overnight Polysomnogram in a Patient with
Obstructive Sleep Apnea
Tilkian AG, Guilleminault C. Ann Intern Med. 1976
Dec85(6)714-9
20
The Sympathetic System
  • Many early studies demonstrated abnormal
    autonomic activity in both animal models and in
    humans with obstructive sleep apnea
  • Increased norepinephrine levels
  • Increased muscle sympathetic nerve activity

21
Sympathetic System Muscle Nerve Activity
  • Compared muscle sympathetic nervous activity
    (MSNA) of blood vessels in untreated and treated
    OSA at baseline and after 1, 6, 12 months of CPAP
  • MSNA was similar during repeated measurements in
    the untreated group
  • In contrast, MSNA decreased significantly over
    time in patients treated with CPAP

Narkiewicz et al. Circulation 19991002332-2335
22
Sympathetic System Norepinephrine
  • 24-hr urinary NE increased 45 in apneic (RDIgt20)
    compared to non-apneic patients.
  • CPAP treatment lowered daytime plasma NE levels
    by 23 Placebo had no effect on NE levels

Dimsdale et al, Sleep 199518377-81
23
Treating Obstructive Sleep Apnea
  • Several trials have demonstrated improved
    systolic and diastolic blood pressures with both
    short-term and long-term CPAP use
  • Regular CPAP use has also shown to improve blood
    pressure in patients with refractory hypertension
    who were requiring three or more antihypertensive
    medications

24
  • The seventh Joint National Committee on
    Prevention, Detection, Evaluation, and Treatment
    of High Blood Pressure recommends evaluating for
    and treating obstructive sleep apnea in adults
    with hypertension

25
Obstructive Sleep Apnea and other Cardiovascular
Diseases
www.rjmatthewsmd.com/Definitions/img/osa-fig3.gif
26
Summary
  • Hypertension is a serious disease that affects
    many people
  • Scientific evidence for a link between
    obstructive sleep apnea and hypertension is
    compelling
  • Sleep apnea is thought to contribute to
    hypertension by increasing sympathetic nervous
    system activity and causing vascular dysfunction
  • Animal studies have demonstrated that sleep apnea
    can cause hypertension
  • Human epidemiological studies confirm that
    untreated sleep apnea increases the risk of
    having hypertension

27
Summary
  • CPAP stabilizes the upper airway, preventing
    collapse and the acute cardiovascular and
    hemodynamic consequences of obstructive sleep
    apnea
  • CPAP applied over several weeks reduces both
    systolic and diastolic blood pressure by 10 mm
    Hg. These reductions are predicted to reduce
    stroke risk by 56 and coronary heart disease
    event risk by 37
  • The United States National Heart, Lung, and Blood
    Institute now recognizes sleep apnea as a
    significant and reversible cause of hypertension

28
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