Disorders of Blood Pressure Regulation

Arterial Blood Pressure (Definitions)

• Systolic pressure: pressure at the height of the pressure pulse

• Diastolic pressure: the lowest pressure• Pulse pressure: the difference between systolic and

diastolic pressure• Mean arterial pressure: the average pressure in the

arterial system during ventricular contraction and relaxation

Arterial Blood Pressure

• Represents the pressure of the blood as it moves through the arterial system

• Cardiac output = HR x SV• Peripheral resistance (PR)• Mean arterial pressure = CO x PR

Mechanisms of Blood Pressure Regulation

• Short-term regulation: corrects temporary imbalances in blood pressure – Neural mechanisms– Humoral mechanisms

• Long-term regulation: controls the daily, weekly, and monthly regulation of blood pressure– Renal mechanism

Factors Determining Systolic and Diastolic Blood Pressure

• Systolic pressure– The characteristics of the stroke volume

being ejected from the heart – The ability of the aorta to stretch and

accommodate the stroke volume• Diastolic pressure– The energy stored in the aorta as its elastic

fibers are stretched during systole– The resistance to the runoff of blood from

the peripheral blood vessels

Factors Influencing Mean Arterial Blood Pressure

• Physical – Blood volume and the

elastic properties of the blood vessels

• Physiologic factors – Cardiac output– Peripheral vascular

resistance

Question• Which of the following does not directly affect

arterial blood pressure?a. Heart rateb. Peripheral resistancec. Venous constrictiond. Blood volume

Answer

a. Heart rate

b. Peripheral resistance

c. Venous constriction: Venous constriction will not affect arterial pressure, but the other factors will have immediate effects.

d. Blood volume

What is Blood Pressure?

• The force of blood against the wall of the arteries.

• Systolic- as the heart beats• Diastolic - as the heart relaxes• Written as systolic over diastolic.• Normal Blood pressure is less than 130 mm Hg

systolic and less than 85 mm Hg diastolic.

• A consistent blood pressure of 140/90 mm Hg or higher is considered high blood pressure.

• It increases chance for heart disease, kidney disease, and for having a stroke.

• 1 out of 4 Americans have High Bp.• Has no warning signs or symptoms.

Why is High Blood Pressure Important?

• Makes the Heart work too hard.• Makes the walls of arteries hard.• Increases risk for heart disease and stroke.• Can cause heart failure, kidney disease, and

blindness.

How Does It Effect the Body?The Brain

• High blood pressure is the most important risk factor for stroke.

• Can cause a break in a weakened blood vessel which then bleeds in the brain.

The Heart

• High Blood Pressure is a major risk factor for heart attack.

• Is the number one risk factor for Congestive Heart Failure.

The Kidneys

• Kidneys act as filters to rid the body of wastes.• High blood pressure can narrow and thicken

the blood vessels.• Waste builds up in the blood, can result in

kidney damage.

The Eyes

• Can eventually cause blood vessels to break and bleed in the eye.

• Can result in blurred vision or even blindness.

The Arteries

• Causes arteries to harden.

• This in turn causes the kidneys and heart to work harder.

• Contributes to a number of problems.

What causes High Blood Pressure?

• Causes vary• Narrowing of the arteries• Greater than normal volume of blood• Heart beating faster or more forcefully than it

should• Another medical problem• The exact cause is not known.

Who can develop High Blood Pressure?

• Anyone, but it is more common in:

• African Americans- get it earlier and more often then Caucasians.

• As we get older. 60% of Americans over 60 have hypertension.

• Overweight, family history • High normal bp:135-

139/85-89 mm Hg.

Detection

• Dr.’s will diagnose a person with 2 or more readings of 140/90mm Hg or higher taken on more than one occasion.

• White-Coat Hypertension• Measured using a spygmomameter.

Categories of High Blood Pressure

• Ages 18 Years and Older)

• Blood Pressure Level (mm Hg)

• Category Systolic Diastolic

• Optimal** < 120 < 80 • Normal < 130 < 85 • High Normal 130–139

85–89

Categories of High Blood Pressure

High Blood Pressure

• Stage 1 140–159 /90–99 • Stage 2 160–179 /100–109 • Stage 3 180 /110

Categories of Hypertension

• Primary hypertension (essential hypertension)– Chronic elevation in blood pressure that occurs

without evidence of other disease– Also known as Idiopathic or Essential

hypertension• Secondary hypertension– Elevation of blood pressure that results from

some other disorder, such as kidney disease

Primary Hypertension

Primary Hypertension

• Results from a complicated interaction between genetics and the environment– Increases peripheral resistance– Increased blood volume

• Sympathetic Nervous System• RAAS

Increased Sympathetic Nervous System Activity Leading to Hypertension

• Increase Heart Rate and Peripheral Resistance• Vascular Remodeling– Causes narrowing of vessels and vasospasms

RAAS out of control

• Maintains adequate blood pressure• If not functioning can lead to – Persistent increases in peripheral resistance and– Renal salt retention

• Contributes to insulin resistance– Causes endothelial dysfunction and narrowing of

blood vessels

Angiotensin II

• Structural changes to blood vessels– Remodeling• Permanent increases in PR

• Hypertrophy of the myocardium

Naturiuretic peptide

• Atrial natriuretic hormone (ANH)– Powerful vasodilator secreted by the atria of the

heart– Decreases sodium reabsorption– Reduces Aldosterone secretion

Atrial Natriuretic Peptides

• Atrial natriuretic peptide

• Brain natriuretic peptide

• C-type natriuretic peptide

• urodilantin

• Regulates sodium excretion

• Affected by– Stretch of the

myocardium – Excessive sodium intake – Inadequate intake of

potassium, magnesium, calcium

– Obesity

Leads to

• Salt retention

Results in

• Water retention and• Increased blood pressure

Promotes

Sodium Reabsorptio

n

• Renal vasoconstriction and Tissue Ischemia

Decreased renal salt excretion

Genetics

SNS

Increased dietary sodium intake

Obesity

Insulin Resistance

RAAS

Decreased dietary

potassium, magnesium,

calcium

Endothelial Dysfunction

Inflammation and Hypertension

• Endothelial injury causes release of– Vasoactive inflammatory cytokines• Histamine• Prostaglandins

• In the Kidneys– Vasoconstriction and decreased perfusion leads to

ischemia and tissue necrosis• Increased Salt Retention!!!!!

Obesity and Hypertension

• Adipocytes secrete Leptin and Adiponectin• Leptin - interacts with the hypothalamus to

control body weight and fat deposition• Inhibits the appetite

– Chronically high levels of Leptin lead to SNS• Adiponectin - reduced during Obesity leading

to– Activation of the RAAS – Activation of the SNS

Insulin Resistance and Hypertension

• Associated with Endothelial Dysfunction– Insulin protects endothelial cell lining and

production of NO• Diabetes and insulin resistance causes changes

in– SNS– RAAS

• Leads to hypertension

Question

• Renal failure results in Na+ and water retention. This results in hypertension. How would you classify this type of hypertension?

a. Primary hypertensionb. Secondary hypertensionc. Malignant hypertensiond. Systolic hypertension

Answer

a. Primary hypertension

b. Secondary hypertension: Secondary hypertension accompanies an underlying disease.

c. Malignant hypertension

d. Systolic hypertension

a. Primary hypertensionb. Secondary hypertensionc. Malignant hypertensiond. Systolic hypertension

Secondary Hypertension

Most Common Causes of Secondary Hypertension

• Kidney disease (renovascular hypertension)• Adrenal cortical disorders• Pheochromocytoma• Sleep apnea

Adrenal Disorders and Secondary Hypertension

• Cushing Syndrome– Facilitates sodium and water

retension

• Primary Aldosteronism– Excess Aldosterone

• Promotes sodium retention

• Pheochromocytoma– Excess catecholamines

• Increases vascular tone and increases peripheral resistance

• Eating too much Licorice raises blood pressure too!

Sleep Apnea

• Intermittent inability to breath while sleeping– Causes ischemia

• Endothelial injury• Myocardial damage• Kidney damage

Chronic Hypertension

• Damages vessel walls– Vascular remodeling

• Secretion of – Angiotension II,

Catecholamines, Inflammatory cytokines

• Myocardial damage due to increase work load

• Ischemia to the brain and retina of the eye

• RAAS secretion stimulated due to reduced blood flow

Types of Hypertension in Pregnancy

• Gestational hypertension• Chronic hypertension• Preeclampsia/eclampsia• Preeclampsia superimposed on chronic

hypertension

Pre-Eclampsia/Eclampsia

• Unknown Etiology• Possible causes may

include:– Insufficient blood flow to

the uterus– Damage to the blood

vessels– A problem with the

immune system– Poor diet

Diagnosis and Treatment of Hypertension in Pregnancy

• Early prenatal care • Refraining from alcohol and tobacco use• Salt restriction• Bed rest • Carefully chosen antihypertensive medications

High Blood Pressure in Children and Adolescents

• Blood pressure norms for children are based on age, height, and gender-specific percentiles.

• Secondary hypertension is the most common form of high blood pressure in infants and children. – Kidney abnormalities – Pheochromocytoma and adrenal cortical

disorders • In infants, hypertension is associated most

commonly with high umbilical catheterization and renal artery obstruction caused by thrombosis.

Factors Affecting Treatment Strategies for Hypertension

• Lifestyle • Demographics • Motivation for adhering

to the drug regimen • Other disease

conditions and therapies

• Potential for side effects

Preventing Hypertension

Adopt a healthy lifestyle by:

• Following a healthy eating pattern.• Maintaining a healthy weight.• Being Physically Active.• Limiting Alcohol.• Quitting Smoking.• http://www.youtube.com/watch?v

=wqJA2FfTPwk&feature=related

DASH diet

• Dietary Approaches to Stop Hypertension.• Was an 11 week trial.• Differences from the food pyramid:• an increase of 1 daily serving of veggies.• and increase of 1-2 servings of fruit.• inclusion of 4-5 servings of nuts,seeds, and

beans.

Tips for Reducing Sodium

• Buy fresh, plain frozen or canned “no added salt” veggies.

• Use fresh poultry, lean meat, and fish. • Use herbs, spices, and salt-free seasonings at

the table and while cooking.• Choose convenience foods low in salt.• Rinse canned foods to reduce sodium.

Maintain Healthy Weight

• Blood pressure rises as weight rises.

• Obesity is also a risk factor for heart disease.

• Even a 10# weight loss can reduce blood pressure.

Be Physically Active

• Helps lower blood pressure and lose/ maintain weight.

• 30 minutes of moderate level activity on most days of week. Can even break it up into 10 minute sessions.

• Use stairs instead of elevator, get off bus 2 stops early, Park your car at the far end of the lot and walk!

Limit Alcohol Intake

Alcohol raises blood pressure and can harm liver, brain, and heart

What counts as a drink?• 12 oz beer• 5 oz of wine• 1.5 oz of 80 proof

whiskey

Quit Smoking

• Injures blood vessel walls• Speeds up process of hardening of the arteries.

Other Treatment

• If Lifestyle Modification is not working, blood pressure medication may be needed, there are several types:

• Diuretics-work on the kidney to remove access water and fluid from body to lower bp.

• Beta blockers-reduce impulses to the heart and blood vessels.

Other Treatment

• ACE inhibitors- cause blood vessels to relax and blood to flow freely.

• Angiotensin antagonists- work the same as ACE inhibitors.

• Calcium Channel Blockers- causes the blood vessel to relax and widen.

• Alpha Blocker- blocks an impulse to the heart causing blood to flow more freely.

Other Treatment

• Alpha-beta blockers- work the same as beta blockers, also slow the heart down.

• Nervous system inhibitors- slow nerve impulses to the heart.

• Vasodilators- cause blood vessel to widen, allowing blood to flow more freely.

Orthostatic Hypotension

• Definition– An abnormal decrease in

blood pressure on assumption of the upright position

• Causes– Decrease in venous return to

the heart due to pooling of blood in lower part of body

– Inadequate circulatory response to decreased cardiac output and a decrease in blood pressure

Causes of Orthostatic Hypotension

• Conditions that decrease vascular volume– Dehydration

• Conditions that impair muscle pump function – Bed rest– Spinal cord injury

• Secondary to Diseases– Diabetes mellitus– Adrenal insufficiency– Hypothyroidism

Causes of Orthostatic Hypotension (cont.)

• Conditions that interfere with cardiovascular reflexes– Medications– Disorders of autonomic nervous system– Effects of aging on baroreflex function• Sympathetic Nervous System

Common Causes of Orthostatic Hypotension Related to Hypovolemia

• Excessive use of diuretics• Excessive diaphoresis• Loss of gastrointestinal fluids through vomiting

and diarrhea• Loss of fluid volume associated with

prolonged bed rest

Complaints Associated With Orthostatic Intolerance

• Dizziness• Visual changes• Head and neck discomfort• Poor concentration while standing• Palpitations• Tremor, anxiety• Presyncope, and in some cases syncope• http://www.youtube.com/watch?v

=OvENfW6scZk&feature=related

Question

• Increased vascular compliance may contribute to which condition?

a. Systolic hypertensionb. Orthostatic hypotensionc. Orthostatic hypertensiond. Diastolic hypertension

Answer

a. Systolic hypertension

b. Orthostatic hypotension: Orthostatic hypertension is the result of lower pressures, and increased compliance would decrease the vascular resistance and result in lower pressures.

c. Orthostatic hypertension

d. Diastolic hypertension

Joint National Committee on Detection, Evaluation, and Treatment of Hypertension

• Systolic pressure less than 120 mm Hg and a diastolic pressure of less than 80 mm Hg are normal.

• Systolic pressures between 120 and 139 mm Hg and diastolic pressures between 80 and 89 mm Hg are considered prehypertensive.

• A diagnosis of hypertension is made if the systolic blood pressure is 140 mm Hg or higher and the diastolic blood pressure is 90 mm Hg or higher.

• For adults with diabetes mellitus, the goal is BP less than 130/80 mm Hg

Classifications of Essential Hypertension

• Systolic/diastolic hypertension – Both the systolic and diastolic pressures are

elevated.• Diastolic hypertension – The diastolic pressure is selectively elevated.

• Systolic hypertension – The systolic pressure is selectively elevated.

Tips for Having your blood pressure taken.

• Don’t drink coffee or smoke cigarettes for 30 minutes before.

• Before test sit for five minutes with back supported and feet flat on the ground. Test your arm on a table even with your heart.

• Wear short sleeves so your arm is exposed.

Tips for having blood pressure taken.

• Go to the bathroom before test. A full bladder can affect bp reading.

• Get 2 readings and average the two of them.• Ask the Dr. or nurse to tell you the result in

numbers.

Classification that is suggested for adults aged > 18 years

BP classification Systolic BP (mmHg)

Diastolic BP (mmHg)

Normal <120 And <80

Pre-hypertension

120–139 Or 80–89

Stage 1 hypertension

140–159 Or 90–99

Stage 2 hypertension

≥160 Or ≥100

Category Systolic BP (mmHg) Diastolic BP (mmHg)

Optimal < 120 < 80

Normal < 130 < 85

High-normal 130–139 85–89

Grade 1 hypertension (mild)

140–159 90–99

Subgroup: borderline 140–149 90–94

Grade 2 hypertension (moderate)

160–179 100–109

Grade 3 hypertension (severe

≥ 180 ≥ 110

Isolated systolic hypertension

≥ 140 < 90

Subgroup: borderline 140–149 < 90

Kortokoff Sounds

• Phase I: marked by the first tapping sound, which gradually increase in intensity

• Phase II: period in which a murmur or swishing sound is heard

• Phase III: period during which sounds are crisper and greater in intensity

• Phase IV: period marked by distinct abrupt muffling or by a soft blowing sound

• Phase V: point at which sounds disappear

Conclusion

• Hypertension is a very controllable disease, with drastic consequences if left uncontrolled.

• Great Resource: www.nhlbi.nih.gov

• Malignant hypertension– An accelerated form of hypertension

• Systolic hypertension – Systolic pressure of 140 mm Hg or greater and

a diastolic pressure of less than 90 mm Hg