High blood pressure controlling the silent killer

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More than 61 million people in the United States have high blood pressure, or hypertension, and nearly half don't even know they have it, according to the American Heart Association.

Because high blood pressure usually doesn't give early warning signs, it is known as the "silent killer." Nearly 33,000 Americans died of diseases related to high blood pressure in 1990 (the latest year for which figures are available), reports the National Center for Health Statistics, and that doesn't include deaths from heart attacks and strokes caused by hypertension.

High blood pressure increases the risk of stroke seven times, says Fletcher McDowell, M.D., of the National Stroke Association, but, "it is clearly the most major risk factor that can be controlled."

In fact, people diagnosed as hypertensive today have less chance of complications such as stroke than they did a decade ago, for physicians now know more about controlling high blood pressure with antihypertensive drugs and certain lifestyle changes.

Blood Pressure Basics
Arterial blood pressure is the pressure of blood within arteries as it's pumped through the body by the heart. Whether your blood pressure is high, low or normal depends mainly on several factors: the output from your heart, the resistance to blood flow by your blood vessels, the volume of your blood, and blood distribution to the various organs, says Victor Raczkowski, M.D., of the Food and Drug Administration's Center for Drug Evaluation and Research. "Your nervous system and some of your hormones can affect these factors," he says, "and thus play roles in regulating your blood pressure."

Everyone experiences hourly and even moment-by-moment blood pressure changes. For example, your blood pressure will temporarily rise with strong emotions such as anger and frustration, with water retention caused by too much salty food that day, and with heavy exertion, which makes your heart beat harder and faster, increasing its output by pushing more blood into your arteries. These transient elevations in blood pressure usually don't indicate disease or abnormality.

Blood pressure is spoken of as a fraction, such as 120/80 millimeters of mercury (mmHg). The numerator (120) is called the systolic pressure--the pressure of blood within arteries when the heart is pumping. The denominator (80) is called the diastolic pressure--the pressure in the arteries when the heart is resting between beats. A typical blood pressure for a young adult might be l 20/80 mmHg. What is "normal," though, varies from person to person.

Defining Hypertension
While there's no clear dividing line between high blood pressure and normal blood pressure, most authorities define hypertension in adults as persistent elevation of the diastolic blood pressure above 90 mmHg. "When the diastolic pressure is less than this," Raczkowski says, "a person is considered to have borderline hypertension if the systolic pressure is between 140 and 159 mmHg and definite hypertension if the systolic pressure is 160 mmHg or greater." To be diagnosed as hypertensive, a person should have at least two to three readings performed on each of three separate visits, he says.

When persistently elevated blood pressure is due to a medical problem, such as hormonal abnormality or an inherited narrowing of the aorta (the largest artery leading from the heart), it's called "secondary hypertension." That is, the high blood pressure arises secondary to another condition. A person also may have secondary hypertension because:

the blood vessels are chronically constricted or have lost elasticity from a buildup of fatty plaque on the inside walls of the vessel, a condition known as atherosclerosis. Narrowed or inelastic blood vessels exert a greater-than-normal resistance against the flow of blood, causing the blood pressure to rise.

the heart pumps the blood at a greater rate. This increased rate of blood flow through the arteries will raise blood pressure.

the kidneys function poorly, causing retention of excess sodium and fluid. The resulting increase in blood volume within the vessels causes high blood pressure. Kidneys may also elevate blood pressure by secreting substances that constrict the vessels.

The causes of most cases of hypertension are unknown, however. These cases are known as "essential hypertension." Because the cause remains a mystery, essential hypertension cannot be cured. But it can be controlled.

Who's at Risk?
Some risk factors for hypertension can't be changed--a family history of the disease, for instance. In addition, as reported in the Public Health Service's Healthy People 2000: National Health Promotion and Disease Prevention Objectives, hypertension affects more than half of people over age 65 and about a third more Afro-Americans than whites. Blacks at ages 24 to 44 are 18 times more prone than whites to kidney failure due to hypertension.

Men tend to develop hypertension more often than pre-menopausal women, though the risk for women increases when they take contraceptives or are pregnant. It's especially important that pregnant women have their blood pressure monitored frequently by their physicians, as untreated hypertension can suddenly progress to severe problems later in the pregnancy.

People with hypertension who also have uncontrolled blood sugar from diabetes have an increased risk of a complication of high blood pressure such as heart attack or stroke.

Daily living habits can contribute to hypertension. Chronic stress, such as that produced by a job involving daily frustration, can cause blood pressure to become elevated. Overweight people have an increased risk of hypertension. Some people whose diet is high in salt may be at increased risk. Alcoholics appear to have an increased incidence of hypertension. Also, blood pressure can rise as a result of certain drugs, including cocaine, oral contraceptives, corticosteroids, sodium-containing antacids, some over-the-counter appetite suppressants and decongestants, and some nonsteroidal antiinflammatory drugs.

Assessing Your Blood Pressure
Though giving you no sign of its presence, hypertension can be steadily damaging your heart and arteries. For this reason, it's important to have your blood pressure checked at least once a year. A doctor or nurse simply places a pressure cuff around your upper arm, pumps up the cuff, and listens with a stethoscope to measure the blood pressure.

Despite the simplicity of this procedure, some people react emotionally to it so that their blood pressure shoots up when they enter a doctor's office. This reaction is known as "white coat hypertension," says Gordon Johnson, M.D., director of health affairs at FDA's Center for Devices and Radiological Health, which regulates blood pressure monitors and other medical devices.

"When you have this problem," Johnson says, "make it a point to arrive at least 15 minutes early for your appointment. This will give you time to relax. AS YOU sit there, breathe deeply and think soothing thoughts. Also, don't talk while the measurement is being taken. Talking seems to raise blood pressure."

You can team up with your physician in monitoring your blood pressure by using a home monitoring device. (See accompanying article.) "Daily readings help the doctor make a more accurate assessment of your blood pressure," Johnson says.

Living a Healthy Lifestyle
Adult patients with mild hypertension, such as 140/90, rare]y need drugs and are often able to bring their blood pressure reading down with changes in diet and activity. Controlling even mild hypertension is vitally important, though, to stem its progression. At the University of Minnesota, patients are advised to lower their daily sodium intake to no more than the equivalent of I teaspoon (about 2,000 milligrams) of salt a day, lower and control their weight by obtaining no more than 30 percent of their calories from fat, and engage daily in a moderate form of exercise such as walking.

Some 80 million Americans have increased sensitivity to dietary sodium, according to Healthy People 2000. Whereas "salt-sensitive'7 people who eat a high-sodium diet develop hypertension, those who don't have this sensitivity can eat a great deal of sodium without a rise in blood pressure. Blacks in particular are prone to salt-sensitive hypertension.

There's no harm in moderate restriction (avoiding salty foods and not adding salt when preparing food), even for hypertensive patients who are not sensitive to salt, says Walter Glinsmann, M.D., associate director for clinical nutrition at FDA's Center for Food Safety and Applied Nutrition. "However," he says, "people with hypertension should not severely restrict their salt intake, as with a special diet, unless this is done under a physician's care." Glinsmann says that when some people follow such a diet their kidneys don't adequately retain sodium, whose main role in the body is to maintain fluid balance.

Hypertensive patients often indirectly benefit from reducing dietary fat, "particularly when they're overweight or at increased risk for coronary heart disease and stroke because of an elevated blood cholesterol level," Glinsmann says. Cholesterol contributes to atherosclerosis, which in some people is aggravated by hypertension, he says.

The National Cholesterol Education Program of the National Heart, Lung and Blood Institute recommends a diet with no more than 30 percent fat, made up of equal amounts of saturated, polyunsaturated and monounsaturated fats. "Diets that contain polyunsaturated and monounsaturated fats may actually lower blood cholesterol levels when compared with diets with saturated fats," Glinsmann says. Polyunsaturated fats are found in sunflower, corn, soybean, cottonseed, and safflower oils; monounsaturated fats are in olive, canola, and peanut oils. Eating less red meat and more fish can help, too.

Stopping smoking is important. The nicotine in tobacco triggers the body to release adrenalin, which causes the blood vessels to constrict, which in turn raises blood pressure.

Learning to relax is good for your blood pressure. When you relax, your heart rate slows and tissues throughout your body demand less oxygen. As a result, your blood pressure decreases. Simple stretching and deep breathing exercises just a few minutes once or twice a day may provide this benefit.

Regular physical activity (at least three days a week for 20 minutes or more) can not only help prevent or manage hypertension, it also may give your mental health a boost by countering stress and improving your mood and self-esteem.

Finally, it's wise to limit alcohol consumption and all drugs that can increase blood pressure. Some physicians believe that a daily drink, such as a 4-ounce glass of wine with dinner, benefits your heart. But not all experts agree. If you drink, it's a good idea to discuss this with your doctor, especially if you have high blood pressure.

Drug Therapy
While it's best to control hypertension without drugs, this is not always possible.

Anti-hypertensive drugs can reduce the risk of stroke, heart failure, and death. As reported in The Lancet in 1990, data on nearly 37,000 patients in 14 studies demonstrated that reducing blood pressure by just 5 or 6 points (for example, from 140/110 to 140/105) reduced the risk of stroke 42 percent and coronary disease 14 percent.

Some patients taking antihypertensive drugs experience side effects. These effects vary greatly among medications and from person to person. As hypertension tends to produce few, if any, symptoms, such people may feel worse during therapy and make the mistake of stopping the drugs without medical advice. If you are taking a medicine that has unwelcome side effects, tell your doctor. For there are now a large number and a wide variety of drugs available (see chart on page 32), and it's likely that one or a combination of several can be found that will control your blood pressure without making you uncomfortable.

Monitoring your progress is essential to success in treating hypertension, especially when your therapy includes medication. To control your hypertension and reduce the risk of complications:

Incorporate the lifestyle changes recommended by your doctor.

Take your medication regularly and faithfully, as prescribed.

Note any side effects from the drug therapy and report them to your doctor. Never stop taking the drug without first discussing it with your doctor.

Weigh yourself weekly.

Ask your doctor how often you should have your cholesterol checked.

Consider measuring your blood pressure at home with one of the many self-monitoring systems.

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by Dixie Farley

Dixie Farley is a stay/writer for FDA Consumer. Joan Luckmann, a medical-surgical nurse in San Antonio, Texas, also contributed to this article.

DRUGS THAT TREAT HIGH BLOOD PRESSURE
Several classes of medications are used to treat hypertension. Here are some commonly prescribed brands from each class and a description of how they work:

Angiotensin-converting enzyme inhibitors appear to act in the body by inhibiting the production of angiotensin, a chemical that causes blood vessels to constrict, and by preserving the retention of chemicals that cause blood vessels to relax. They also inhibit production of substances that cause the kidneys to retain fluid:

captopril (Capoten)

enalapril (Vasotec)

lisinopril (Prinivil, Zestril)

ramipril (Altace)

Beta blockers block certain nerve signals to help slow the heartbeat and decrease the heart's workload and output:

acebutolol (Sectral)

atenolol (Tenormin)

betaxolol (Kerlone)

carteolol (Cartrol)

Iabetalol (Normodyne, Trandate)

metoprolol (Lopressor)

nadolol (Corgard)

penbutolol (Levatol)

pindolol (Visken)

propranolol (Inderal)

timolol (Blocadren)

Calcium channel blockers act on the heart's muscles and nerve impulses to relax arteries throughout the body and decrease the heart's workload:

diltiazem (Cardizem SR)

nicardipine (Cardene)

nifedipine (Adalat, Procardia Xl.)

verapamil (Calan, Isoptin, Verelan)

Diuretics cause the kidneys to increase excretion of sodium and water, thus decreasing the volume the heart must pump through the vessels. There are several types of diuretics:

Thiazide Diuretics bendroflumethiazide (Naturetin)

benzthiazide (Exna)

chlorthalidone (Hygroton, Thalitone)

chlorothiazide (Diuril)

hydrochlorothiazide (Esidrix, HydroDIURIL, Oretic)

hydroflumethiazide (Diucardin, Saluron)

methyclothiazide (Aquatensen, Enduron)

metolazone (Diulo, Mykrox, Zaroxolyn)

quinethazone (Hydromox)

polythiazide (Renege)

Potassium-Sparing Diuretics
amiloride (Midamor)

spironolactone (Aldactone)

triamterene (Dyrenium)

Combination Diuretics
amiloride/hydrochlorothiazide (Moduretic)

spironolactone/hydrochlorothiazide (Aldactazide,

Spirozide)

triamterene/hydrochlorothiazide (Co-Triamterzide,

Dyazide, Maxzide)

Loop Diuretics
bumetanide (Bumex)

ethacrynic acid (Edecrin)

furosemide (Lasix)

Vasodilators relax the blood vessels:

hydralazine (Apresoline)

minoxidil (Loniten)

Centrally acting agents act on the control centers in the brain to lower blood pressure:

methyldopa (Aldomet)

clonidine (Catapres)

guanfacine (Tenex)

guanabenz (Wytensin)

Peripherally acting agents achieve their effect by acting on nerve substances throughout the body:

guanadrel (Hylorel)

guanethidine (Ismelin)

mecamylamine (Inversine)

prazosin (Minipress)

rauwolfia alkaloids (Harmonyl, Raudixin, Rauzide, Serpasil)

terazosin (Hytrin)

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By Dixie Farley

USING HOME BLOOD PRESSURE MONITORING DEVICES
People with hypertension may benefit from using home blood pressure monitoring devices. Measuring blood pressure at home on a regular schedule may:

help identify people whose blood pressure is only high when taken during a medical visit

enable patients to collaborate with their doctors in controlling their high blood pressure

reduce the frequency with which a patient needs a doctor for blood pressure evaluation.

The mechanical gauge, or sphygmomanometer, is the type of blood pressure equipment most often used in physicians' offices. It consists of an instrument called a manometer to measure the pressure, an inflatable cuff (air bladder), and a pressure bulb with a release valve to pump up the cuff. Some gauges use mercury manometers (the height of a column of mercury indicates blood pressure), while others use aneroid manometers (the pressure is read on a gauge dial).

Mechanical gauges are much less expensive than electronic sets and give more accurate readings when they function properly. When taking your own blood pressure, however, you must pump up the cuff with one hand, read a dial, and listen with a stethoscope. In other words, these devices require dexterity, good eyesight, acute hearing, and some training.

Automated electronic gauges generally measure blood pressure by either the Korotkoff method or the oscillometric technique. Korotkoff devices use a microphone built into the cuff to detect arterial sounds related to blood pressure; they are subject to false readings caused by noises from the patient's surroundings or patient movement. Oscillometric devices measure and analyze the vibrations (oscillations) from the artery to determine blood pressure. Patient movement can cause false readings with these devices as well.

Finger cuff monitors typically are the oscillometric variety. Because they measure blood pressure at the fingers, they tend to have reduced accuracy and increased sensitivity to the effects of temperature and poor blood circulation.

For best results with automated gauges:

Avoid eating, smoking or exercising for at least a half hour before measuring your blood pressure.

Test daily at about the same time; plan ahead to give yourself time to get over feeling angry or anxious.

When using a finger cuff device, be sure your body temperature is normal; a room colder than 60 degrees Fahrenheit can cause an inaccurate or unreliable reading.

Sit quietly and eliminate extraneous noise.

Follow the manufacturer's instructions carefully.

Position your arm at heart level, palm up. Wrap the cuff just above the elbow--sleeve rolled above the cuff--and be sure it's not too tight. With a finger device, slip the finger fully into the cuff, keeping it level with the heart.

Be sure the hoses from the cuff aren't tangled or pinched.

Take care not to move the hoses during the reading.

Wait at least five minutes with the cuff fully deflated before taking another reading.

Bring the device along on medical visits once or more a year to check its accuracy against your doctor's measurements.

Also, the standard-size arm cuff on blood pressure monitors fits arms up to 13 inches in diameter. People with larger arms should order a larger cuff.

Who Has High Blood Pressure?
Men 33%

Women 27%

Blacks 38%

Whites 29%

At ages 18 to 74,
hypertension
affects more men
than women and
a third more
blacks than
whites.
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By Dixie Farley

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