FORMS OF CARDIOVASCULAR DISEASE

The American Heart Association describes the six major forms of CVD as coronary heart disease, hypertension, stroke, congenital heart disease, rheumatic heart disease, and congestive heart failure.  A person may have just one of these diseases or a combination of them at the same time.  Each form exists in varying degrees of severity.  All are capable of causing secondary damage to other body organs systems.

Coronary Heart Disease

This form of CVD, also known as coronary artery disease, involves damage to the vessels that supply blood to the heart muscle.  The bulk of this blood is supplied by the coronary arteries.  Any damage to these important vessels can cause a reduction of blood (and its vital oxygen and nutrients) to specific areas of heart muscle.  The ultimate result of inadequate blood supply is a heart attack.

Atherosclerosis

The principle cause for the development of coronary heart disease is atherosclerosis.  Atherosclerosis produces a narrowing of the coronary arteries.  This narrowing stems from the long-term buildup of fatty deposits, called plaque, on the inner walls of the arteries.  This buildup reduces the blood supply to the specific portions of the heart.  Some arteries of the heart can become so blocked (concluded) that all blood supply is stopped.  Heart muscle tissue begins to die when it is deprived of oxygen and nutrients.  This damage is known as myocardial infarction.  In lay terms, this event is called a heart attack.

Cholesterol and Lipoproteins  For many years, scientists have known that atherosclerosis is a complicated disease that has many causes.  Some of these causes are not well understood, but others are clearly understood.  Cholesterol, a soft, fatlike material, is manufactured in the liver and small intestine and is necessary in the formation of sex hormones, cell membranes, bile salts, and nerve fibers.  Elevated levels of serum cholesterol (200 mg/dl or more for young adults age 20 and older, and 1709 mg/dl or more for young people below age 20) are associated with an increased risk for developing atherosclerosis.

About half of American adults age 20 and older exceed the “borderline high” 200 mg/dl cholesterol level.  It is estimated that nearly 40% of American youth age 19 and below have “borderline high” cholesterol levels of 170n mg/dl and above.  About one out of five American adults has a “high” blood cholesterol level, that is, 240 mg/dl or greater.

Initially, most people can help lower their serum cholesterol level by adopting three dietary changes: lowering their intake of saturated fats, lowering their intake of dietary cholesterol, and lowering their caloric intake to a level that does not exceed body requirements.  The aim is to reduce excess fat, cholesterol, and calories in the diet while promoting sound nutrition.  By carefully following such a diet plan, people with high serum cholesterol levels may be able to reduce their cholesterol levels by 30 to 55 mg/dl.  However, dietary changes do not affect people equally; some will experience greater reductions than others.  Some will not respond at all to dietary changes and may need to take cholesterol-lowering medications and increaser their physical activity.

Cholesterol is attached to structures called lipoproteins.  Lipoproteins are particles that circulate in the blood and transport lipids (including cholesterol).  Two major classes of lipoproteins exist: low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs).  A person’s total cholesterol level is chiefly determined by the amount of the LDLs and HDLs in a measured sample of blood.  For example, a person’s total cholesterol level of 200 mg/dl could be represented by an LDL level of 130 and an HDL level of 40, or an LDL level of 120 and an HDL level of 60.  (Note that other lipoproteins do exist and carry some of the cholesterol in the blood.)

After much scientific study, it has been determined that high levels of LDL are a significant promoter of atherosclerosis.  This makes sense because LDLs carry the greatest percentage of cholesterol in the bloodstream.  LDLs are more likely to deposit excess cholesterol into the artery walls.  This contributes to plaque formation.

For this reason, LDLs are often called the “bad cholesterol.” High LDL Levels are determined partially by inheritance, but they are also clearly associated with smoking, poor dietary patterns, obesity, and lack of exercise.

On the other hand, high levels of HDLs are related to a decrease in the development of atherosclerosis.  HDLs are thought to transport cholesterol out of the bloodstream.  Thus HDLs have been called the “good cholesterol.” Certain lifestyle alterations, such as quitting smoking, reducing obesity, increasing physical activity, and replacing saturated fats with monosaturated fats, help many people increase their level of HDLs.

Reducing total serum cholesterol levels is a significant step in reducing the risk of death from coronary heart disease.  For people with elevated cholesterol levels, a 1% reduction in serum cholesterol level yields about a 2% reduction in the risk of death from heart disease.  Thus a 10% to 15% cholesterol reduction can reduce risk by 20% to 30%.

Angina Pectoris  When coronary arteries become narrowed chest pain, or angina pectoris, is often felt.  This pain results from a reduced supply of oxygen to heart muscle tissue.  Usually, angina is felt when the coronary artery disease patient becomes stressed or exercises too strenuously.  Angina reportedly can range from a feeling of mild indigestion to a severe viselike pressure in the chest.  The pain may extend from the center of the chest to the arms and even up to the jaw.  Generally, the more severe the blockage, the more pain is felt.

Some cardiac patients relieve angina with the drug nitroglycerin, a powerful blood vessel dilator.  This prescription drug, available in slow-release transdermal (through the skin) patches or small pills that are placed under the patient’s tongue, causes a major reduction in the workload of the heart muscle.  Other cardiac patients may be prescribed drugs such as calcium channel blockers or beta blockers.

Emergency Response to Heart Crises

Heart attacks need to be fatal.  The consequences of any heart attack depend on the location of the damage to the heart, the extent to which heart muscle is damage, and the speed with which adequate circulation is restored.  Injury to the ventricles may very well prove fatal unless medical countermeasures are immediately undertaken.  The recognition of a heart attack is critically important.

Cardiopulmonary resuscitation (CPR) is one of the most important immediate countermeasures that trained people can use when confronted with a victim of heart attack.  Programs sponsored by the American Red Cross and the American Heart Association  teach people how to recognize, evaluate, and manage heart attack emergencies.  CPR trainees are taught how to restore breathing and circulation in persons requiring emergency care.  Frequently, colleges offer CPR training through courses in various departments.  With revised CPR procedures in place in 2001, we encourage students to take a new course and become certified.  Additionally, members of the public are encouraged to obtain training in the use of automated external defibrillators (AED).  These devises are now found in most public buildings and can markedly improve the chances of resuscitating a victim.

Diagnosis and Coronary Repair

Once a person’s vital signs have stabilized, further diagnostic examinations can reveal the type and extent of damage to heart muscle.  Initially an ECG might be taken, which may be able to identify if areas of ischemia (insufficient blood flow) or damage has occurred to the heart muscle.  Another test which may be used is echocardiography.  This procedure can also detect ischemia.  The diagnostic ability of both of these tests is improved if used in conjunction with exercise (i.e., stress ECG or stress echocardiography).  This test analyses the electrical activity of the heart.  Heart catheterization, also called coronary arteriography, is a minor surgical procedure that starts with placement of a thin plastic tube into an arm or leg artery.  This tube, called a catheter, is guided through the artery until it reaches the coronary circulation, where a radiopaque dye is then released.  X-ray films called angiograms record the process of the dye through the coronary arteries so that areas of blockage can be easily identified.

Once the extent of the damage is identified, a physician or team of physicians can decide on a medical course of action.  Currently popular is an extensive form of surgery called coronary artery bypass surgery.  An estimated 516,000 patients had bypass surgeries in 2001.  The purpose of such surgery is to detour (bypass) areas of coronary artery obstruction by usually using a section of an artery from the patient’s chest (the internal mammary artery) and grafting it from the aorta to a location just beyond the area of obstruction.  Multiple areas of obstruction result in double, triple, or quadruple bypasses.

Angioplasty Angioplast, an alternative to bypass surgery, involves the surgical insertion of a doughnut-shaped “balloon” directly into the narrowed coronary artery.  When the balloon is inflated, plaque and fatty deposits are compressed against the artery walls, widening the space through which blood flows.  The balloon usually remains in the artery for less than 1 minute.  Renarrowing of the artery will occur in about one quarter of angioplasty patients.  Balloon angioplasty can be used for block-ages in the heart, kidneys, arms, and legs.  The decision whether to have angioplasty or bypass surgery can be a difficult one to make.  Nearly 1,050,000 angioplasty procedures were performed in 2001.

The FDA approved a device for clearing heart and leg arteries.  This devise is called a motorized scraper.  Inserted through a leg artery and held in place by a tiny inflated balloon, this motor-driven cutter shaves off plaque deposits from inside the artery.  A nose cone in the scraper unit stores the plaque until the device is removed.

The use of laser beams to dissolve plaque that blocks arteries has been slowly evolving.  The FDA has approved three laser devices for use in clogged leg arteries.  In 1992 the FDA approved the use of an excimer laser for use in coronary arteries.

Aspirin Studies released a decade age highlighted the role of aspirin in reducing the risk of heart attack in men with no history of previous attacks.  Specifically, the studies concluded that for men with hypertension, elevated cholesterol levels, or both, taking one aspirin per day was a significant factor in reducing their risk of heart attack.  Aspirin works by making the blood less able to clot.  This reduces the likelihood of blood vessel blockages.  Presently,  there is differing opinion regarding the age at which this preventive action should begin.  The safest advice is to check with your physician before starting aspirin therapy is also beneficial for women.

Alcohol For years, scientists have been uncertain about the extent to which alcohol consumption is related to a reduced risk for heart disease.  The current thinking is that moderate drinking (defined as no  more than two drinks per day for men and one drink per day for women) is related to a lower heart disease risk.  However, the benefit is much smaller than proven risk reduction behaviors such as stopping smoking, reducing cholesterol level, lowering blood pressure, and increasing physical activity.  Experts caution that heavy drinking increases cardiovascular risks and that non-drinkers should not start to drink just to reduce heart disease risk.

Heart transplants and Artificial Hearts For approximately 30 years, surgeons have been able to surgically replace a person’s damaged heart with that of another human being.  Although very risky, these transplant operations have added years to the lives of a number of patients who otherwise would have lived only a short time.  In 2001, 2,202 heart transplants have performed in the United States.

Artificial hearts have also been developed and implanted in humans.  These hearts have extended the lives of many patients, but they have kept them unpleasantly tethered with tubes and wires to large power source machines. However, a major medical breakthrough took place in July 2001, when the world’s first self-contained artificial heart was successfully implanted into a 59-year-old patient.

hypertension

just as your car’s water pump recirculates water and maintains water pressure, your heart recirculate blood and maintains blood pressure.  When the heart contracts, blood is forced through your arteries and veins.  Your blood pressure is a measure of the force that your circulating blood exerts against the interior walls of your arteries and veins.

Blood pressure is measured with a sphygmomanometer.  This instrument is attached to an arm-cuff device that can be inflated to stop the flow of blood temporarily in the brachial artery.  This artery is a major supplier of blood to the lower arm.  It is located on the inside of the upper arm, between the biceps and triceps muscles.

A health professional using a stethoscope will listen for blood flow while the pressure in the cuff is released.  Two pressure measurements will be recorded: the systolic pressure is the highest blood pressure against the vessel walls during the heart contraction, and the diastolic pressure is the lowest blood pressure against the vessel walls when the heart relaxes (between heartbeats).  Expressed in units of millimeters of mercury displaced on the sphygmomanometer, blood pressure is recorded as the systolic pressure over the diastolic pressure, for example, 115/82.

Although a blood pressure of less than 120/80 is considered “normal” for an adult, lower values do not necessarily indicate a medical problem.  In fact, many young college women of average weight will indicate blood pressure that seem to be relatively low (100/60, for example), yet these lowered blood pressures are quite “normal” for them.

Hypertension refers to the consistently elevated blood pressure.  Generally, concern about a young adult’s high blood pressure begins when he or she has a systolic reading of 140 or above or a diastolic reading of 90 or above.  Now those with prehypertension are advised to seek lifestyle measures to prevent any further elevation in their blood pressure.  Approximately 58 million American adults and children have hypertension.  The American Heart Association reports that African Americans, Hispanic Americans, and American Indians have higher rates of high blood pressure than white Americans.  In contrast, Asians/Pacific Islanders have significantly lower rates of hypertension.

Although the reasons for 90% to 95% of the cases of hypertension are not known, the health risk produced by uncontrolled hypertension are clearly understood.  Throughout the body, long-term hypertension makes arteries and arterioles become less elastic and thus incapable of dilating under a heavy workload.  Brittle, calcified blood vessels can burst unexpectedly and produce serious strokes (brain accidents), kidney failure (renal accidents), or eye damage (retina hemorrhage).  Furthermore, it appears that blood clots are more easily formed and dislodged in a vascular system affected by hypertension.  Thus hypertension can be a cause of heart attacks.  Clearly, hypertension is a potential killer.

Ironically, despite its deadly nature, hypertension is referred to as “the silent killer” because people with hypertension often are not aware that they have the condition.  The cannot feel the sensation of high blood pressure.  The condition does not produce dizziness, headaches, or memory loss unless one is experiencing a medical crisis.  It is estimated that approximately 30% of the people who have hypertension do not realize they have it.  Many who are aware of their hypertension do little to control it.  Only a small percentage (34%) of people who have hypertension control, regular exercise, relaxation training, and drug therapy.

Hypertension is not thought as a curable disease; rather, it is a controllable disease.  Once therapy is stopped, the condition returns.  As a responsible adult, use every opportunity you can to measure your blood pressure on a regular basis.

Prevention and Treatment

Weight reduction, physical activity, moderation in alcohol use, and sodium restriction are often used to reduce hypertension.  For overweight or obese people, a reduction in body weight may produce a significant drop in blood pressure.  Physical activity helps lower blood pressure by expending calories (which may lead to weight loss in those who are overweight or obese) and through other physiological changes that affect the circulation.  Moderation in alcohol consumption (no more than 1 – 2 drinks daily) helps reduce blood pressure in some people.

The restriction of sodium (salt) in the diet also helps some people reduce hypertension.  Interestingly, this strategy is effective only for those who are salt sensitive estimated to be about 25% of the population.  Reducing salt intake would have little effect on the blood pressure of the rest of the population.  Nevertheless, since our daily intake of salt vastly exceeds our need for salt, the general recommendation to curb salt intake still makes good sense.

In recent years, behavioral scientists have reported the success of meditation, biofeedback, controlled breathing, and muscle relaxation exercises in reducing hypertension.  Look for further findings in these areas in the years to come.

There are literally dozens of drugs available for use by people by people with hypertension.  Unfortunately, many patients refuse to take their medication on a consistent basis, probably because of the mistaken notion that “you must feel sick to be sick,” Nutritional supplements, such as calcium, magnesium, potassium, and fish oil, have not been proven to be effective in lowering blood pressure.

Stroke

Stroke is general term for a wide variety of crises (sometimes called cerebrovascular accidents [CVAs] or brain attacks) that result from blood vessel damage in the brain.  African Americans have a much greater risk of stroke than white Americans do, probably because African Americans have a greater likelihood of having hypertension than white Americans.  Data from 2001 indicate that 163,538 deaths and half a million new cases of stroke occurred.  Just as the heart muscle needs an adequate blood supply, so does the brain.  Any disturbance in the proper supply of oxygen and nutrients to the brain can pose a threat.

Perhaps the common form of stroke results from the blockage of a cerebral (brain) artery.  Similar to coronary occlusions, cerebrovascular occlusions can be started by a clot that forms within an artery, called a thrombus, or by a clot that travels from another part of the body to the brain, called an embolus.  The resultant accidents (cerebral thrombosis or cerebral embolism) cause more than 60% of all strokes.  The portion of the brain deprived of oxygen and nutrients can literally die.

A third type of stroke can result from an artery that bursts to produce a crisis called cerebral hemorrhage.  Damaged, brittle arteries can be especially susceptible to bursting when a person has hypertension.

A fourth form of stroke is a cerebral aneurysm.  An aneurysm is a ballooning or outpouching on a weakened area of an artery.  Aneurysms may occur in various locations of the body and are not always life threatening.  The development of aneurysms is not fully understood, although there seems to be a relationship between aneurysms ad hypertension.  It is quite possible that many aneurysms are congenital defects.  In any case, when a cerebral aneurysm bursts, a stroke results.

A person who reports any warning signs of stroke or any mini stroke, called a transient ischemic attack (TIA), will undergo a battery of diagnostic tests, which could include a physical examination, a serach for possible brain tumors, tests to identify areas of the brain affected, use of the electroencephalogram, cerebral arteriography, and the use of the CT (computer tomography) scan or MRI (magnetic resonance imaging) scan.  Many additional tests are also available.

Treatment of stroke patients depends on the nature and extent of the damage.  Some patients require surgery (to repair vessels and relieve pressure) and acute care in the hospital.  Others undergo drug treatment, especially the use of anticoagulant drugs, including aspirin and TPA (tissue plasminogen activators; the “clot buster” drug).

The advancement made in the rehabilitation of stroke patients are amazing.  Although some severely affected patients have little hope of improvement, our increasing advancement in the application of computer technology to such disciplines as speech and physical therapy offer encouraging signs for stroke patients and their families.

Congenital Heart Disease

A congenital defect is one that is present at birth.  The American Heart Association estimates that each year about 40,000 babies are born with a congenital heart defect.  In 2001, 4,109 children (mostly infants) died of congenital heart disease.

A variety of abnormalities may be produced by congenital heart disease, including valve damage, holes in the walls of the septum, blood vessel transposition, and an underdevelopment of the left side of the heart.  All of these problems ultimately prevent a newborn from adequately oxygenating tissues throughout the body.  A bluish skin color (cyanosis) is seen in some infants with such congenital heart defects.  These infants are sometimes referred to as blue babies

The cause of congenital heart defects is not clearly understood, although one cause, rubella, has been identified.  The fetuses of mothers who contract the rubella virus during the first 3 months of pregnancy are at great risk of developing congenital rubella syndrome (CRS), a catch-all term for a wide variety of congenital defects, including heart defects, deafness, cataracts, and mental retardation.  Other hypotheses about the development of congenital heart disease implicate environmental pollutants; maternal use of drugs, including alcohol, during pregnancy; and unknown genetic factors.

Treatment of congenital defects usually requires surgery, although some conditions may respond well to drug therapy.  Defective blood vessels and certain malformations of the heart can be surgically repaired.  This surgery is so successful that many children respond quite quickly to the increased circulation and oxygenation.  Many are able to lead normal, active lives.

Rheumatic Heart Disease

Rheumatic heart disease is the final stage in a series of complications started by a streptococcal infection of the throat (strep throat).  This bacterial infection, if untreated, can result in an inflammatory disease called rheumatic fever (and a related condition, scarlet fever).  Rheumatic fever, joint pain, skin rashes, and possible brain and heart damage.  A person who has had rheumatic fever is more susceptible to subsequent attacks.  Rheumatic fever tends to run in families.  Over 3,400 Americans died from rheumatic fever and rheumatic heart disease in 2001.

Damage from rheumatic fever centers on the heart’s valves.  For some reason the bacteria tend to proliferate in the heart valves.  Defective heart valve may fail either to open fully (stenosis) or to close fully (insufficiency).  Diagnosis of valve damage might initially come when a physician hears a backwashing or backflow of blood (a murmur).  Further tests – including chest X rays, cardiac catheterization, and echocardiography – can reveal the extent of valve damage.  Once identified, a faulty valve can be replaced surgically with a mental or plastic artificial valve or a valve taken from an animal’s heart.

Congestive Heart Failure

Congestive heart failure is a condition in which the heart lacks the strength to continue to circulate blood normally throughout the body.  In 2001, 52,828 people died from congestive heart failure.  During congestive heart failure, the heart continues to work, but it cannot function well enough to maintain appropriate.  Venous blood flow starts to “back up.”  Swelling occurs, especially in the legs and ankles.  Fluid can collect in the lungs and cause breathing difficulties and shortness of breath, and kidney function may be damaged.

Congestive heart failure can result from heart damage caused by congenital heart defects, lung disease, rheumatic fever, heart attack, atherosclerosis, or high blood pressure.  Generally, congestive heart failure is treatable through a combined program of rest, proper diet, modified daily activities, and the use of appropriate drugs.  Without medical care, congestive heart failure can be fatal.

Additional Condition

The heart and blood vessels are also subject to other pathological conditions.  Tumors of the heart, although rare, occur.  Infectious conditions involving the pericardial sac that surrounds the heart (pericarditis) and the innermost layer of the heart (endocarditis) are more commonly seen.  In addition, inflammation of the veins (phlebitis) is troublesome to some people.

Peripheral Artery Disease also called peripheral vascular disease (PVD), is a blood vessel disease characterized by pathological changes to the arteries and arterioles in the extremities (primarily the legs and feet but sometimes the hands).  These changes result from years of damage to the peripheral blood vessels.  Important causes of PAD are cigarette smoking, a high-fat diet, obesity, and sedentary occupations.  In some cases, PAD is aggravated by blood vessel changes resulting from diabetes.

PAD severely restricts blood flow to the extremities.  The reduction in blood flow is responsible for leg pain or cramping during exercise, numbness, tingling, coldness, and loss of hair in the affected limb.  The most serious consequence of PAD is the increased likelihood of developing ulcerations and tissue death.  These conditions can lead to gangrene and may eventually necessitate amputation.

The treatment of PAD consist of multiple approaches and may include efforts to improve blood lipid levels (through diet, exercise, or drug therapy), reduce hypertension, reduce body weight, and eliminate smoking.  Blood vessels surgery is also a possible treatment approach.