Physician Vincent E. Friedewald, Jr., a specialist in cardiovascular medicine and the author of the “Ask the Doctor” series of medical books for laypersons, answers a wide variety of questions about illnesses and their treatments. Friedewald focuses in particular on hypertension, its causes, its symptoms, ways to prevent it, and the medications commonly used to combat it. He also discusses the new classes of drugs developed in recent years, explaining how ACE inhibitors, beta blockers, and calcium channel blockers work.

Questions and Answers About Medicine

Q: What is an angiotensin-converting enzyme (ACE) inhibitor?

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A: ACE inhibitors are a remarkable class of drugs for treating hypertension. These drugs target the kidneys, which trigger a complex series of chemical reactions to release hormones that raise blood pressure. ACE inhibitors interfere with, or inhibit, these reactions in order to lower blood pressure.

Since the release of the first ACE inhibitor in the 1980s, known generically as captopril, there are now several different ACE inhibitors available on the market. Many of them are also available in combination with other types of hypertension medications, such as diuretics.

ACE inhibitors have achieved astounding popularity because they are markedly effective and cause few side effects. Some people do experience a chronic cough that is bad enough in some cases to cause them to quit taking ACE inhibitors. Others may develop angioedema, which can cause severe swelling of the face, tongue, vocal cords, and extremities. ACE inhibitors also elevate potassium levels in the body, and they are not approved for use during pregnancy.

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Besides lowering blood pressure, ACE inhibitors have become one of the best treatments for heart failure. Other uses for this drug, such as therapy for heart attacks and diabetes mellitus, are under study.

Q: Does alcohol intake affect hypertension?

A: Despite how relaxed you may feel after downing a brew or two, alcohol actually raises blood pressure.

In moderation alcohol does not pose a problem for blood pressure. However, excess alcohol intake is a definite risk factor for hypertension—men who have three or more drinks a day and women (and smaller men) who have two or more drinks a day roughly double their chance for developing high blood pressure.

In addition to its direct effect on blood pressure, excess alcohol intake is a bad habit for those with hypertension (as well as everyone else) because it also does the following:

• Increases the risk for strokes
• Increases the risk for heart failure
• Interferes with the effectiveness of blood pressure medications
• Increases the level of triglycerides, one of the blood fats

One positive note about alcohol, even though most health experts and law enforcement officers would agree we’d all be better off without it: Alcohol, in small amounts, does appear to effect some protection against coronary heart disease. In other words, a glass of wine at dinner is okay.

Q: What is a beta blocker?

A: Beta blockers are a class of medications officially ranked as first-line therapy for hypertension. Because they are commonly used to treat a variety of other conditions as well, beta blockers are one of the most important types of drugs available today.

Exactly how beta blockers lower blood pressure is uncertain, but they appear to act in several ways, including the following:

• Reducing the amount of blood pumped into the circulation
• Blocking the effect of nerves and hormones that raise blood pressure
• Lowering the volume of blood
• Relaxing smaller arteries
• Resetting the body’s internal “thermostat” for blood pressure

Beta blockers reduce both systolic and diastolic pressure, and they are effective in treating isolated systolic hypertension. Unlike some blood pressure drugs, they can be used (with caution) during pregnancy.

In addition to lowering blood pressure, beta blockers are useful in treating coronary heart disease, certain abnormalities of the heart beat and heart muscle (such as cardiomyopathy), essential tremor, and migraine headaches.

Persons with asthma, chronic obstructive lung disease, low blood sugar (hypoglycemia), and certain forms of heart failure should avoid using beta blockers or use them only with caution. These drugs may cause side effects, especially fatigue. When side effects occur, reducing the dose, sometimes with the addition of a diuretic prescribed to treat hypertension, may be all that is needed.

Q: What do the two numbers used in blood pressure readings indicate?

A: Blood pressure numbers represent the pressures inside the major arteries at two critical times: during each actual heartbeat and between beats, when the heart is relaxed. Each number corresponds to the height of the column of mercury, expressed in millimeters, on a sphygmomanometer, a device used to measure blood pressure.

Assume your blood pressure is measured at 120/80, a normal blood pressure measurement. The first number, in this case 120, is called the systolic pressure. This is the pressure inside the large arteries of the body during systole, when the heart is ejecting blood. The second number represents the diastolic pressure. This is the pressure inside the large arteries of the body during diastole, between heartbeats.

Both systolic and diastolic pressures are important. A person with elevation of either the systolic or diastolic pressure (or both) may have hypertension. A healthy person at rest who is measured using proper procedures should have a systolic pressure below 140 and the diastolic pressure under 90. Under some circumstances, such as when a person has diabetes mellitus or coronary heart disease, even lower blood pressures may be desirable.

The importance of these numbers lies in the proof, beyond any doubt, that even slight elevation of the arterial pressure poses major danger to the arteries themselves, as well as the organs they serve, especially the heart, brain, and kidneys.

Q: What factors increase the risk for hypertension?

A: Several risk factors contribute to high blood pressure. Some of these factors you can change with dietary and lifestyle adjustments, and other risk factors you can’t change.

The most important factors that you can change:

• Weight: Those who are overweight are more likely to have higher blood pressure.
• Salt: A diet high in salt causes some (not all) people to develop higher blood pressure.
• Alcohol: One to two drinks a day is okay, but regular, heavy alcohol use drives up blood pressure.
• Sedentary lifestyle: Aside from its potential to raise blood pressure, inactivity also leads to weight gain, which contributes to high blood pressure.
• Medications: Many prescription and over-the-counter drugs increase blood pressure, including oral contraceptives, steroids, nonsteroidal anti-inflammatory drugs, nasal and oral drugs for colds, diet pills, certain antibiotics, and some forms of antidepressants.

Although these factors are considered uncontrollable, you can avoid compounding your risk by taking care of the controllable factors. For example, if you are African American, avoiding salt in your diet becomes even more critical to lessen the risk of high blood pressure. Aging persons with hypertension have an added reason to maintain active lifestyles.

Q: What is a calcium channel blocker?

A: Calcium channel blockers (also called calcium antagonists) are a group of highly effective drugs used to treat hypertension. They also treat angina pectoris, in which a lack of blood flow to the heart causes chest pain. Calcium channel blockers are particularly useful for the treatment of hypertension due to kidney disease, and hypertension in people with diabetes mellitus.

Although there are great differences in the mode of action among these drugs, they act mainly by dilating smaller arteries that play a key role in maintaining blood pressure levels.

Calcium channel blockers have gained wide popularity because they are effective and relatively easy to take—most require only a once-per-day dosage. Calcium channel blockers also tend to have few side effects, although these vary from drug to drug.

The most common side effects, depending on the specific type of calcium channel blocker used, include constipation, flushing, palpitations, ankle swelling (edema), and slow heart rate. Some of the older drugs (especially short-acting forms) have been associated with more serious heart problems, and anyone taking these older drugs should check with their doctor about them. Calcium channel blockers should not be taken during pregnancy.

These drugs can be taken alone or in combination with other blood pressure medications, especially beta-blockers and ACE inhibitors.

Q: What is the DASH diet?

A: The Dietary Approaches to Stop Hypertension (DASH) diet is an eating plan designed to prevent and treat hypertension. Funded by the United States government, this diet was developed and tested at several major medical centers. The effectiveness of the diet in reducing hypertension was reported in the April 17, 1997, issue of the New England Journal of Medicine.

The study reported that the DASH diet lowered blood pressure in those patients with normal blood pressure and those with hypertension.

The DASH diet is rich in fruits, vegetables, and dairy products that are low in total and saturated fat. DASH also includes portions of meat, poultry, and fish, providing ample protein. In addition DASH provides large amounts of fiber, potassium, calcium, and magnesium.

Based on their experience prescribing the diet, the scientists who developed the DASH diet offer these tips:

• Start small. Make gradual changes in your eating habits.
• Center your meal around carbohydrates, such as pasta, rice, beans, or vegetables.
• Treat meat as one part of your whole meal, instead of as the main course.
• Use fruits or low-fat, low-calorie foods such as sugar-free gelatin for desserts and snacks.

The DASH experts add: “Remember! If you use the DASH diet to help prevent or control high blood pressure, make it part of a lifestyle that includes choosing foods lower in salt and sodium, keeping a healthy weight, being physically active, and, if you drink alcohol, doing so in moderation.”

Q: What is a diuretic?

A: A diuretic is a chemical that increases urination. In medicine, diuretics are used to rid the body of salt in the form of sodium chloride. This, in turn, shrinks the volume of circulating blood and lowers blood-flow resistance in the arteries. The end result is to lower blood pressure. Diuretics are often the first drugs used when treating hypertension. They are commonly used in combination with other classes of blood pressure medications.

Most of us, including practically everyone in Seattle, begin the day by taking the most famous of all diuretics—caffeine. Unfortunately the type of urination stimulated by coffee isn’t effective for lowering blood pressure because little salt is lost in the process. It’s the amount of sodium chloride in our bodies that is one of the keys to controlling hypertension.

There are many forms of diuretics used to treat hypertension. All of them cause diuresis, or increased urination, by acting on some part of the kidneys. The most common types, in order of potency, are loop-of-Henle diuretics, thiazide diuretics, and potassium-sparing diuretics. The main problem with the more potent diuretics is that they cause potassium loss. For this reason, combinations of thiazide and loop-of-Henle diuretics are often prescribed with potassium-sparing diuretics. Diuretics taken in high doses may cause dehydration and raise total cholesterol and blood sugar levels in the blood, as well as uric acid (which may precipitate gout).

Q: How does aspirin prevent heart disease?

A: In addition to relieving ordinary aches and pains, aspirin has powerful effects on the body’s blood clotting system. And blood clots, called thromboses, play a major role in heart attacks and other forms of coronary heart disease.

When a heart attack strikes, the immediate cause is usually a blood clot forming next to a fatty deposit in the wall of a coronary artery. Numerous research studies have proven that aspirin (and also some similar drugs), because of its ability to prevent blood clots, can not only keep heart attacks small, but also prevent them entirely in some instances, when it is given early enough.

While we don’t fully understand how aspirin accomplishes this, we do know at least a couple of ways it works. First, aspirin lessens the “stickiness” (called platelet inhibition) of blood platelets, which are a key component of clots. This occurs by means of its effect on a substance called thromboxane A2. Second, aspirin reduces inflammation, which is another important component of clot formation in diseased coronary arteries.

Aspirin is so effective that a routine part of treating heart attack victims is to give a chewable, rapidly absorbed form as soon as possible after symptoms begin. Among persons with coronary heart disease, aspirin may reduce the number of heart attacks by as much as one-third.

A note of caution: Some people should not take aspirin, including people with bleeding disorders or gastrointestinal ulcers. Therefore, when possible, aspirin should not be taken without first consulting a medical professional.

Q: Is the heart located on the left—where people place their hand during the Pledge of Allegiance?

A: You may have noticed that doctors place their hand over the center of the chest during the Pledge of Allegiance. That’s because most of the heart is located in the middle, behind the breastbone, or sternum, in an area called the middle mediastinum. This position, with the backbone behind, gives the heart a lot of bony protection. However, in our era of fast cars, even this location isn’t entirely safe. A strong blow to the front of the chest can shove the sternum backward, causing serious—even fatal—damage to the heart. That’s why airbags mounted on the steering wheel are a good idea.

If you place your hand over the left side of your chest during the Pledge of Allegiance, you aren’t really wrong, either. Much of the heart actually does extend to the left, including the left ventricle, the main pumping chamber of the heart. As a result, the heartbeat can be felt a little below the left nipple in most people. That’s why an important part of the physical examination involves the doctor placing one hand over this area—a technique called cardiac palpation. By merely feeling the heartbeat, a physician can simply and safely learn important information, such as whether the heart is enlarged.

Q: What is a heart murmur?

A: A heart murmur is a sound created by blood flowing through the heart; generally heart murmurs are heard with a stethoscope. Most murmurs are not due to abnormalities in the heart. Such “innocent” murmurs are especially common in children and athletes. They also occur with a variety of conditions originating outside the heart itself (such as fever, hyperthyroidism, and anemia), especially when blood is being pumped rapidly.

Common murmurs are classified as systolic, occurring during the heartbeat, and diastolic, heard between heartbeats. A third, uncommon type, called a continuous murmur, occurs throughout systole and diastole and is usually caused by a congenital abnormality of the heart.

Any change in the structure of the heart can cause a murmur. The most common murmurs due to heart disease are created by abnormalities involving the heart valves. These include scarring of the valves, congenital abnormalities, and infection. Other common causes of murmurs are holes in the tissue separating the chambers (septal defects) and abnormal thickening of the heart muscle (cardiomyopathy). A very common murmur is generated by mitral insufficiency due to coronary heart disease, in which the muscle supporting the mitral valve loses its strength, allowing blood to flow backward, from the left ventricle to the left atrium.

A doctor can usually decide whether you should be concerned about a murmur based solely on your history and a physical examination. However, certain tests, such as echocardiography, can be performed to determine the significance of a murmur.

Q: My relative has just been told for the second time that she has high potassium. What causes this and what are the symptoms? She is cold all the time, but otherwise has no real symptoms.

A: High potassium is commonly caused during blood donation if there is too much time between the application of the tourniquet around the arm and the drawing of the blood. It may also be caused by poor handling of the blood after it is drawn. Blood cells break down after removal from the body, releasing potassium into the serum, because these cells are so rich in potassium. The longer the time before re-infusion, the more breakdown there is.

However, among the actual physiological conditions that cause elevations in the blood potassium level (hyperkalemia), the following are most important:

• * Advanced forms of kidney failure, because the body’s main route for eliminating potassium is through the kidneys
• * Conditions associated with excessive destruction of red blood cells (known as hemolysis) or other types of cells, such as may occur during large muscle trauma, because potassium is present in high concentration inside cells
• * Certain abnormalities of the adrenal glands, such as Addison’s disease, because adrenal hormones play an important role in regulating potassium
• * Elevated blood sugar, such as in poorly controlled diabetes mellitus
• * Some medications (including digoxin, succinlycholine, beta-blockers, arginine, lysine, potassium-sparing diuretics, NSAIDs, heparin, and ACE inhibitors), especially at very high blood levels, because they can elevate the potassium

Symptoms of high potassium are inconsistent and are mainly muscle weakness and tingling around the lips (perioral peristhesia).

The main problem with hyperkalemia is that dangerous, life-threatening irregularities of the heartbeat may occur. Therefore, very high blood potassium should be treated aggressively. Fortunately, proper treatment can return high potassium to a normal level quickly.

Q: How dangerous is hypertension?

A: Very. It’s called the silent killer for good reason. In the United States alone hypertension

• contributes to more than 200,000 deaths each year, including almost one-third of all African American deaths.
• afflicts more than 50 million Americans (one in every four adults overall, and one in every three African Americans).
• is on the rise, increasing 35 percent in just ten years from the late 1980s to the late 1990s.
• costs more than $37 billion per year in health care.

These figures are even more dismal when you consider that, although hypertension is an easily detectable and treatable disease,

• almost one-third of persons with hypertension don’t know they have it.
• about half of those who know they have hypertension are receiving inadequate therapy or no treatment at all.
• only about one-quarter of those with hypertension receive adequate treatment.

The bottom line? If you don’t know your blood pressure, take a few minutes and get it checked—it doesn’t hurt!

If you have hypertension, talk to your doctor about the best way to bring your blood pressure down to normal—and keep it there.

Q: How can hypertension damage the heart and arteries?

A: Hypertension causes several different abnormalities of the heart and arteries. First, because hypertension causes the heart to pump with greater force, the heart muscle thickens—a process called hypertrophy. Eventually, usually over many years, the thickened muscle may simply be unable to keep up with the increased blood pressure. When this occurs, congestive heart failure, one of the main complications of hypertension, occurs.

Second, hypertension damages arterial walls directly, causing them to become stiff. Normally, the arteries are quite elastic, stretching with each heartbeat and contracting when the heart relaxes between beats. Damage to the small arteries of the kidneys occurs as well, sometimes leading to kidney failure.

Third, arterial walls may be weakened by hypertension. This weakening can lead to ballooning of the arteries, called aneurysm. Aneurysms typically involve the aorta, the largest artery in the body, and the cerebral arteries in the brain. Such aneurysms may burst, resulting in life-threatening emergencies. An aneurysm in the aorta causes massive internal bleeding. When an aneurysm in a cerebral artery ruptures, it produces a stroke. Aneurysms may even occur in the wall of the heart itself, mostly after heart attacks in persons with hypertension, leading to heart failure or heart muscle rupture in rare instances.

Finally, hypertension speeds up the process of atherosclerosis in all major arteries. Atherosclerosis blocks the arteries. This causes a heart attack, known as myocardial infarction, when a coronary artery is involved. When atherosclerosis blocks a carotid artery or vertebral artery, an ischemic stroke occurs.

Q: What are the symptoms of hypertension?

A: Hypertension is not called “the silent killer” because it wears sneakers—one-third of the 50 million Americans with hypertension don’t even know they have the disease. Hypertension often goes undiagnosed, and it can be deadly.

For most people, hypertension does not cause any symptoms unless it has reached an extremely severe stage or is accompanied by other ailments. In cases where blood pressure is very high, with diastolic pressures ranging from 110 to 130 mmHG or greater, headaches, nosebleeds, vertigo (dizziness), and tinnitus (ringing in the ears) may develop.

Hypertension that is accompanied by other medical problems may also produce symptoms. In some cases, in what is known as secondary hypertension, another disease causes blood pressure to rise. One example is a rare tumor called pheochromocytoma, which originates in special cells of the adrenal glands. The tumor causes the overproduction of powerful hormones that induce high blood pressure, among other symptoms. Persons with this tumor typically have sudden bouts of sweating, palpitations, and headaches.

Another setting in which hypertension occurs with symptoms is when a complication arises, such as the severe headache of stroke due to rupture of an artery to the brain, known as subarachnoid hemorrhage or cerebral hemorrhage. Chest pain from a rupture of a thoracic aortic aneurysm or back pain from an abdominal aortic aneurysm are other symptoms of complications.

Q: What is mitral valve prolapse?

A: Mitral valve prolapse (MVP) is a condition in which one or both leaflets of the heart’s mitral valve “bulge” back into the chamber of the left atrium when the heart contracts. It has many other names, including the floppy valve syndrome, Barlow’s syndrome, and the click-murmur syndrome.

MVP is very common, usually occurring in persons never aware they have it unless a doctor hears a murmur or it is detected on an echocardiogram. Most people have no symptoms, and only a small percentage of people with MVP ever require any type of treatment.

There are several causes of mitral valve prolapse, but the most important one is thickened valve tissue, termed myxomatous degeneration. Exactly why this occurs is uncertain, but in some people there is a genetic component.

When symptoms occur, they vary from person to person and they are not specific for this condition. Symptoms include palpitation, fatigue, and chest pain not necessarily related to physical exertion.

When listening to the heart, the doctor may detect MVP as a murmur, “clicking” sounds, or both.

Some people with mitral valve prolapse develop leakage of blood through the valve, termed mitral insufficiency. Although seldom severe enough to warrant medical or surgical therapy, the presence of significant mitral insufficiency means that a person may be susceptible to an infection on the thickened valves, called infective endocarditis. Such infection occurs when bacteria enter the bloodstream, most commonly during dental work. For this reason, people with mitral insufficiency, regardless of the cause, are usually advised to take a short course of antibiotics before dental work and similar procedures.

Q: What is multiple gate acquisition (MUGA) and what is it used for?

A: MUGA, also known as nuclear ventriculography, is a test designed mainly to observe and evaluate the pumping motion of the heart. (If you are a confused wine aficionado, yes, there is also a Spanish wine by the same name.)

The test is done in several steps. First, pyrophosphate, a chemical that attaches to the red blood cells, is injected into the bloodstream. This is followed by an injection into the bloodstream of technetium, a very low-dose, safe radioactive substance; the technetium attaches to the pyrophosphate on the red blood cells. Then scanners designed to detect radioactivity record the blood as it flows through the heart. The MUGA scan may be conducted while the patient is at rest, or it may be conducted while the patient exercises on either a treadmill or a stationary bicycle.

Information from a MUGA test is useful in detecting coronary heart disease before a heart attack occurs and in determining whether a heart attack has already taken place. It also helps evaluate other causes of abnormal heart wall motion, as well as the pumping ability of the heart.

The primary advantage of the MUGA scan is that it is much safer than cardiac catheterization, in which dye is injected directly into the heart. However, cardiac catheterization enables doctors to see the coronary arteries themselves, and this is not possible with a MUGA scan. Therefore, when a MUGA test is abnormal, cardiac catheterization and coronary angiography may be necessary.

Q: What is phlebitis?

A: All words ending with -itis mean one thing: inflammation. So what is a phleb? The answer, as any Greek major will tell you, is that phlebo pertains to a vein. Therefore, phlebitis is inflammation of veins.

Unfortunately, phlebitis is a little more complex than its name implies. It is really a common and too often deadly disease. Other terms for phlebitis, which better illustrate its severity, are deep venous thrombosis and thrombophlebitis.

Whenever veins are subject to stagnation of the blood flowing within, or whenever the walls of the veins are damaged for any reason, the blood at that point is prone to forming a clot. This is called thrombosis, which is a congregation of platelets and numerous other substances in the bloodstream. When a thrombus develops, the walls of the vein surrounding the clot become acutely inflamed, adding to the clotting tendency at that site.

Phlebitis can occur in any vein in the body, but it is most often found in the large, hidden (“deep”) veins in the lower extremities. In most folks that’s where blood flows slowest, especially when they’ve done a lot of sitting. Another problem area is in the big veins in the pelvis.

Some—but not all—people with thrombophlebitis have leg (especially calf) pain. But the main problem is the clot itself. Blood clots in veins have the nasty habit of breaking off, like an iceberg crumbling from a glacier. And like an iceberg loose in the North Atlantic, a large blood clot loose in the bloodstream means major problems as it heads for its next stop: an artery to the lungs. This is called pulmonary embolism.

Q: Does potassium help lower blood pressure?

A: Yes, potassium has a favorable effect on blood pressure, although scientists are not certain exactly why. In addition, there is good evidence that a diet high in potassium actually may prevent hypertension from occurring in the first place. Just as important, it has been clearly proven that folks who ingest more potassium have a lower risk for stroke.

Potassium is richly present in the DASH diet, which is recommended for persons with hypertension. This diet is high in fruits and vegetables and, as a result, provides other valuable nutrients, such as calcium, magnesium, vitamins, and fiber. All of these nutrients are also beneficial for people with elevated blood pressure.

Experts generally do not advocate taking potassium in a tablet form unless expressly prescribed under specific circumstances. Pure potassium supplementation does not afford the added benefits of other healthful components of the DASH diet or similar diets high in fruits and vegetables. Potassium taken in pill form can also be dangerous in certain cases. It can cause high potassium levels in persons with kidney disorders or diabetes mellitus and in persons taking blood pressure medications such as ACE inhibitors and angiotensin-2 receptor blockers.

In some cases, certain disorders and specific diuretics cause dangerous potassium loss from the body. For these persons, potassium supplements may be prescribed, but the blood potassium level should be carefully monitored.

Q: What is preeclampsia?

A: Preeclampsia is a condition that occurs only during pregnancy, usually after the 20th week. It is characterized by high blood pressure, protein in the urine (known as proteinuria), and edema (fluid buildup in tissues). Preeclampsia causes additional abnormalities that involve the liver, kidney, and blood clotting. The exact cause of preeclampsia is unknown, although it may involve an abnormality of the arteries in the placenta.

Preeclampsia endangers both the mother and her unborn baby. In the later stages of pregnancy, preeclampsia may be accompanied by eclampsia, in which the mother suffers from convulsions and sometimes coma. Preeclampsia also slows fetal growth, resulting in a baby that is born with a low birth weight. In severe cases, preeclampsia may cause the death of the baby.

Symptoms of preeclampsia should be reported to a physician as soon as they develop. They include severe headache, fast heartbeat, changes in hearing or vision, drowsiness, nausea and vomiting, abdominal pain, blood in the urine, and reduced or absent urine output.

If preeclampsia is diagnosed, a doctor may recommend that the mother stay in bed or enter the hospital, where she can be closely observed. Using medications to treat high blood pressure caused by preeclampsia is controversial—preeclampsia itself cannot be cured by medications, and lowering blood pressure alone will not benefit the baby. If blood pressure rises to levels high enough to threaten the mother, however, a variety of antihypertensive medications may be used, but these are used cautiously to prevent harm to the baby.

The only cure for preeclampsia is to induce delivery as soon as the baby can survive outside the uterus. If eclampsia occurs, administration of magnesium sulfate is the standard treatment.

Q: What are the risk factors for preeclampsia?

A.: The risk factors for preeclampsia are

• First pregnancy
• Preeclampsia in a prior pregnancy
• Family history of preeclampsia
• Multiple prior pregnancies
• Diabetes mellitus
• Obesity
• Preexisting hypertension
• Kidney disease
• Younger or older age for pregnancy

Q. What is the role of blood pressure in the body?

A. Blood pressure is the force that keeps blood moving through the body to deliver life-sustaining oxygen and essential nutrients to cells and to remove carbon dioxide and waste products. The force that keeps blood moving is determined by many factors, including the strength of the heartbeat, the makeup of blood itself, the amount of blood in circulation, and the stiffness of the blood vessel walls. These factors regulate blood flow to each organ, tissue, and cell in the body by widening or constricting small muscular blood vessels called arterioles.

Most cells require nonstop blood circulation to function properly. As a result, the body has developed an elaborate control system to maintain blood pressure under all circumstances. For example, the simple act of rising from bed in the morning elevates your head well above the level of your heart. Within seconds a rapid series of changes in the heart, nervous system, and blood vessels assure that blood pressure is maintained in the vessels to the brain cells. Without these adjustments, blood would not reach your brain cells and you would faint.

The critical role of blood pressure also explains why it constantly changes. Sudden fright, such as a nearby explosion, triggers physiological changes that alert your body to prepare to run. Because running demands increased oxygen for your leg muscles, blood pressure immediately rises to enable more blood to pump to muscle cells to help you flee from danger.

Q: Can the damage caused by hypertension be reversed?

A: Sometimes the cardiovascular abnormalities caused by hypertension can be reversed. This area is the focus of intense research. Echocardiography studies of hypertension patients with heart muscle thickening, known as left ventricular hypertrophy, have shown that reducing blood pressure can help return hypertrophied heart muscle to normal thickness, thereby lessening the risk of heart failure. In addition, some hypertension patients with impaired kidney function who receive effective therapy can reduce the excess protein expelled in their urine. The increased blood vessel stiffness caused by hypertension appears to be lessened in animal studies, although this has not been proven in humans. Virtually all medications that lower blood pressure appear to reverse damage, but some types of drugs, especially ACE inhibitors, seem to be more effective than others.

Unfortunately, what cannot be reversed is the damage to the heart muscle caused by heart attack and to the brain tissue lost during a stroke. Heart attacks and strokes are two life-threatening illnesses common in people with uncontrolled hypertension. In recent years studies have found that even in heart attacks and strokes, not all tissue is permanently destroyed at the outset. Early, aggressive steps to lower blood pressure elevations in heart attack and stroke patients may lessen the extent of the final damage.

Q: What is secondary hypertension?

A: In most cases of hypertension, the cause is unknown. This form of hypertension is known as primary hypertension. But in about 5 to 10 percent of cases, the cause of hypertension is known to be an underlying disorder. This rarer form of high blood pressure is known as secondary hypertension.

After hypertension is diagnosed, doctors typically perform an evaluation to determine whether another condition is the cause. A medical history, a physical examination, or routine laboratory tests and X rays may suggest that secondary hypertension is present. Sometimes specialized tests are required to determine whether one of the secondary causes of hypertension is present or absent.

Some of the major causes of secondary hypertension:

• Coarctation of the aorta: A narrowing of the largest artery in the body that is present from birth. This is a common cause of hypertension in children.
• Hormone abnormalities: Diseases of the thyroid, parathyroid, pituitary, and adrenal glands, and two uncommon conditions, pheochromocytoma (a tumor of the adrenal gland) and carcinoid syndrome (in which symptoms are caused by a tumor that secretes excessive serotonin hormone).
• Nervous system disorders: Brain tumors, head trauma, certain infections, and other disorders involving the brain or nerves.
• Low blood sugar
• Drugs or toxic substances, including

Secondary hypertension is often cured when the disorder causing the problem is treated. In other cases secondary hypertension can be treated with medications, although usually these medications are different from those used to treat primary hypertension.

Q: Does smoking raise blood pressure?

A: Yes, raising blood pressure is just one of the numerous harmful effects of smoking—in any form, not just cigarettes. Smoking stimulates the sympathetic nervous system, which originates in the brain. This system acts directly on the heart, glands, hormones, blood vessels, and kidneys to elevate blood pressure.

The effect of just one cigarette (but who smokes just one?) is to raise the blood pressure for several minutes. This is why blood pressure should not be measured within 30 minutes of smoking a cigarette. Smoke an entire pack … and you get the picture.

More importantly, smoking is a major risk factor for many of the same diseases associated with hypertension, especially heart attack and other conditions caused by athrosclerosis. Smoking also makes hypertension much more difficult to treat with medications. Therefore, the advice for smokers who have hypertension is clear: Stop smoking forever.

Q: What is a sphygmomanometer?

A: A sphygmomanometer is a device used to measure blood pressure. It is connected to a cuff wrapped around the upper arm, and except with electronic versions, it is used in conjunction with a stethoscope. A sphygmomanometer is more often simply called a blood pressure monitor.

Sphygmomanometers come in three basic types: the mercury manometer, the mechanical aneroid manometer, and the electronic aneroid manometer.

Mercury manometers are used almost exclusively in hospitals and doctors’ offices. They use a column of mercury, like a giant thermometer. Mercury manometers provide the most accurate form of blood pressure measurement, but they are heavy and cumbersome to haul around.

The mechanical aneroid manometer is lightweight, compact, and designed more for home use. Although not as accurate as the mercury manometer, calibrating this device after regular comparisons to mercury manometer readings during visits to the doctor’s office makes the mechanical aneroid manometer highly useful at home.

The electronic aneroid manometer automatically senses sounds over the artery, supposedly eliminating the need for a stethoscope. Although use of this type is easy for people other than medical professionals, especially those with hearing impairments, it is less accurate. Comparison of readings in the doctor’s office is particularly important.

Devices that measure blood pressure on the fingers are inaccurate.

Q: What causes varicose veins?

A: Varicose veins are superficial veins (just under the surface of the skin), usually in the legs, that have become elongated, tortuous, and enlarged. They tend to run in families.

Normally, blood in the veins of the legs is able to flow upward, against gravity, as a result of numerous small valves inside the veins. In addition, the motion of leg muscles “kneads” the blood flowing through the veins on its return toward the heart.

When the valves become defective and no longer totally prevent blood from flowing downward, the veins become engorged with blood and dilate; they have then become varicose. As this worsens, the blood pooling causes the legs to swell (called edema), especially when the legs are left in a “dependent” position for a period of time. The swelling becomes even more severe during inactivity, when the relaxed muscles fail to provide the massaging action that helps propel the blood upward.

Obviously, sitting in one position (with the lower extremities bent for prolonged periods), such as on long airline or automobile rides, is a bad situation for persons with varicose veins.

Q: What is an echocardiogram?

A: An echocardiogram, or echo, is a procedure in which ultra-high-frequency sound waves are used to examine the heart. Echocardiography is especially valuable because so much can be learned about the heart with this safe, quick, and painless test.

The echo’s sound waves are far above the range of human hearing. The waves are transmitted from an ultrasound machine into the heart, where they reflect off structures within the heart. The reflected waves return to the ultrasound machine, where they are usually recorded on paper or videotape. They can then be analyzed by a cardiologist.

The echo provides detailed information about the structure and motion of most parts of the heart, including the heart muscle itself, the heart valves, and the heart chambers. It also provides data about blood circulating within the heart.

Echocardiography has many forms. Most commonly, the test is conducted by placing a small probe (containing a piezoelectric crystal) directly on the chest. Occasionally, certain structures are best viewed from a device inserted into the esophagus (this is called transesophageal echocardiography, or TEE). Some echoes require injecting a substance (a contrast agent) into the bloodstream during the test to obtain the proper images.

The standard echocardiogram has one major limitation: It is not possible to get a good exam reading for everyone. Ultrasound waves may be blocked by air within the lungs, or by ribs, hiding critical parts of the heart in some people. For example, folks with chronic lung disease, in which the lungs may be greatly expanded over the front of the heart, are sometimes difficult to examine.

Q: What is white-coat hypertension?

A: Your doctor wears a white coat (or most used to), and when he or she takes your blood pressure, a higher-than-normal reading may result due to the frightening circumstances of being in a doctor’s office. This increase is known as white-coat hypertension. An isolated instance of a high blood pressure that occurs only in scary settings such as emergency rooms or doctors’ offices does not necessarily mean that you have hypertension. Studies estimate that about 20 percent of people with blood-pressure elevations in doctors’ offices have white-coat hypertension, not true hypertension.

How does a person know if a blood pressure elevation is white-coat hypertension or the real thing? The best answer is to measure blood pressure at a place where there are no doctors around, such as at home. A blood pressure device can be purchased and used at home. As long as it is properly calibrated and used with the proper technique, home blood-pressure monitors can be as reliable as those found in doctors’ offices.

Another way to determine actual blood pressure is to wear a special device that provides continuous monitoring of blood pressure for 24 hours. Any doctor can arrange for this special device. If properly measured blood-pressure readings are consistently normal outside the doctor’s office, then real hypertension is unlikely.

One warning: Some folks who have white-coat hypertension tend to develop genuine hypertension later on, so they should continue to have their blood pressures checked on a regular basis.

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Medicine; Drug; Hypertension