Transcript Ch 36

Chapter 36
Medical Nutrition
Therapy in
Hypertension
Hypertension

Persistently high arterial blood pressure,
defined as systolic blood pressure above
140 mm Hg and/or diastolic blood
pressure above 90 mm Hg
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Circulatory Diseases/Problems
1. Hypertension (HTN)
2. Hyperlipidemias
3. Atherosclerosis
4. Coronary heart disease
5. Congestive heart failure
6. Cerebrovascular disease
7. Peripheral vascular atherosclerotic
occlusive disease
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Circulatory Systems in the Body
1. Coronary—supplies blood to heart muscle
(can form collateral circulation)
2. Cerebral—supplies blood to head
3. Splanchnic—supplies blood to abdomen
(exercise removes blood and food attracts
blood to this area)
4. Pulmonary—supplies blood to lungs
(O2 and CO2 exchange)
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Measures of Heart Function
1. Beats or pulse
2. BP systolic and diastolic
3. ECG
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Determinants of Blood Pressure
1. Blood volume
2. Vascular resistance to pressure
3. Heart stroke volume
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Cardiac Output
■ Amount of blood pumped by heart
(vol/min)
■ Stroke volume times heart rate
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Vascular Resistance
■ Viscosity of blood
■ Width of vessels—(constriction or
dilation)—controlled by muscle tone in
vessel walls
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Regulation of Blood Pressure
1. Sympathetic nervous system (SNS)—responds
immediately; baroreceptors monitor BP
Vasomotor center in brain
SNS innervated tissues contract or dilate vascular
bed
2. Renin-angiotensin system—retains Na and H2O to
increase blood volume; constricts blood vessels;
increases aldosterone
3. Kidneys—respond to renin-angiotensin system;
aldosterone and antidiuretic hormone (ADH) are
sent out as needed
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Homeostatic Control of
Blood Pressure

Short term
—Sympathetic nervous system
—Vasoconstriction
—Vasodilation

Long term
—Fluid volume
—Renin-angiotensin system
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Hypertension
1. 90% HTN is essential HTN (cause
unknown; perhaps prenatal impacts?)
2. 10% HTN is secondary to other diseases
3. HTN is a risk factor for MI, CVA, renal
failure
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Renin-Angiotensin Cascade
Redrawn from Guyton AC: Textbook of medical physiology, ed 8, Philadelphia, 1991, WB Saunders.
© 2004, 2002 Elsevier Inc. All rights reserved.
Classification of Blood Pressure for Adults Ages
18 Years and Older
From the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: Sixth Report
(JNC VI), Arch Intern Med 157:2413, 1997.
*Not taking antihypertensive drugs and not acutely ill. When systolic and diastolic blood pressures fall into different categories, the
higher category should be selected to classify the individual’s blood pressure status. For example, 160/92 mm Hg should be classified
as stage 2 hypertension, and 174/120 mm Hg should be classified as stage 3 hypertension. Isolated systolic hypertension is defined
as systolic blood pressure 140 mm Hg or greater and diastolic blood pressure less than 90 mm Hg and staged appropriately (e.g.,
170/82 mm Hg is defined as stage 2 isolated systolic hypertension). In addition to classifying stages of hypertension on the basis of
average blood pressure levels, clinicians should specify presence or absence of target organ disease and additional risk factors. This
specificity is important for risk classification and treatment.
†Optimal blood pressure with respect to cardiovascular risk is less than 120/80 mm Hg. However, unusually low readings should be
evaluated for clinical significance.
‡Based on the average of two orr more readings taken at each of two or more visits after an initial screening.
© 2004, 2002 Elsevier Inc. All rights reserved.
Treatment of Hypertension—Cause
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
© 2004, 2002 Elsevier Inc. All rights reserved.
Treatment of Hypertension— Pathophysiology
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
© 2004, 2002 Elsevier Inc. All rights reserved.
Treatment of Hypertension—
Medical and Nutritional Therapy
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
© 2004, 2002 Elsevier Inc. All rights reserved.
Risk Factors for Developing Hypertension
(Adapted from National High Blood Pressure Education Program Working Group report on primary prevention of hypertension.
Arch Intern Med 153:186, 1993. Copyright 1993, American Medical Association. Reprinted with permission.)
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Components of Cardiovascular Risk Stratification
in Patients with Hypertension
(From The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. sixth report
(JNC VI). Arch Intern Med 157:2413, 1997.)
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Untreated or Uncontrolled
Hypertension

Leads to increased
Workload on heart
Damage to arteries
Atherosclerosis
Coronary heart disease esp. CHF
Strokes
Transient ischemic attacks (TIAs)
Kidney damage
Microvascular hemorrhages in brain and eye
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Medical Management of
Hypertension Based on Risk

High-normal BP and Stage 1 hypertension in
low- or medium-risk group
—Begin with trial of lifestyle modification for
6 to 12 months

High-normal BP and Stage 1 hypertension in
high-risk group
—Begin with drug therapy in addition to
lifestyle modification

Stages 2 and 3 all risk groups
—Begin with drug therapy in addition to
lifestyle modification
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Steps to Manage High Blood
Pressure

Weight management
—If over 115% of ideal body weight,
exercise and hypocaloric diet estimate 25
kcal/kg minus 500 to 1000kcal/day

Salt restriction
—6 g NaCl or 2400 mg Na/day
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Levels of Na Restriction
g Na
mEq Na
Description
4
174
No added salt
2-3
87-130
Mild to moderate
restriction
1
43
Strict sodium
restriction
0.5
22
Severe sodium
restriction
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Response to Dietary Rx

Salt sensitive respond well to sodium
restriction

Most respond to increased potassium in diet.
– 1.1 to 3.3 g Na is safe
– 1.9 to 5.6 g K is recommended to achieve
ratio Na:K of 1, which is goal

If taking a potassium-wasting diuretic drug,
increased potassium in diet is essential.

Most respond to increased calcium (at least
the RDA)—use the DASH diet protocol
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DASH Diet

Works within 14 days

Lowers BP quite well

Includes more potassium, calcium,
other nutrients
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DASH Diet —cont’d

Pattern
—7-8 whole grains
—4-5 vegetables
—4-5 fruits
—2-3 low-fat or fat-free dairy products
—6 oz or less meat/poultry/fish
—4-5 servings nuts, beans, or legumes/week
—2-3 servings fat (total kcal = 27% fat)
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DASH Diet Website

www.nhlbi.nih.gov/health/public/heart/hb
p/dash/new_dash.pdf
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Food Label Terms

Sodium free, no sodium = <5 mg/serving

Very low sodium = <35 mg/serving and
per 100 g food

Low sodium = <140 mg/serving and per
100 g food

Reduced sodium = 50% less than
comparison food
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Salt Substitutes

Composition: KCl, CaCl, Al-Cl

KCl can provide extra potassium for those
taking diuretics

KCl can be harmful if patient has renal
insufficiency

“Lite” salt contains sodium

Some spices and herbs are low in sodium

Others are high in sodium
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Classification of
Antihypertensive Drugs







Diuretics
—Thiazides
—Loop diuretics
—Potassium-sparing diuretics
Beta blockers
Alpha-beta blockers
Alpha1 receptor blockers
ACE inhibitors
Calcium antagonists
Direct vasodilators
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Antihypertensive Drugs
Volume Depletors
Diuretics
Thiazides
Chlorthalidone
Metolazone
Loop diuretics
Furosemide
K+ sparing
Spironolactone
Triamterene
Amiloride
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Sympathetic Blockers
Peripheral
Reserpine
Guanethidine
Central: methyldopa
Clonidine
ß-receptor: propranolol
Atenolol
Metoprolol
Nadolol
Timolol
α-receptor: phentolamine
Phenoxybenzamine
Prazosin
Lifestyle Modifications for
Prevention of Hypertension

Lose weight if overweight

Limit alcohol

Increase physical activity

Decrease sodium intake

Keep potassium intake at adequate levels

Take in adequate amounts of calcium and
magnesium

Decrease intake of saturated fat and cholesterol

Stop smoking
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Summary

Lifestyle modifications for prevention of
hypertension—quite effective!

Management of hypertension—very
important to reduce risk of heart attack
or stroke!
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