Coronary artery diseaseAngina; Atherosclerosis; Heart disease
An in-depth report on the causes, diagnosis, treatment, and prevention of coronary artery disease (CAD).
Coronary Artery Disease
Coronary artery disease (CAD), also called heart disease, is a condition in which fatty deposits, called plaque, build up in the heart's arteries. These deposits cause arteries to become narrow and blocked, which restricts blood and oxygen flow to the heart muscle. CAD is the leading cause of death for both men and women in the United States.
The most important factors that increase the risk for CAD are:
- Unhealthy cholesterol and lipid levels
- High blood pressure
- Lack of exercise
- Advancing age
Angina is the primary symptom of CAD. Angina feels like gripping pain or pressure in the chest area.
Stable anginais predictable chest pain that lasts a few minutes or less and is usually relieved by rest or medication. It is often triggered by physical exertion or emotional stress.
Unstable anginais unpredictable chest pain and may occur at rest. When patients with stable angina have symptoms that are more severe or occur with less and less activity it is called unstable angina. It is a more serious condition than stable angina and can be a warning sign of a heart attack.
Some patients with CAD have few or no symptoms. Often a heart attack or an episode of unstable angina is the first sign that a person has CAD.
Lifestyle changes (such as a healthy diet and regular physical activity) are essential for preventing and treating CAD.
Medications for preventing and treating CAD include aspirin and related drugs, cholesterol-lowering drugs (statins), and high blood pressure medications (such as beta-blockers, calcium channel blockers and angiotensin converting enzyme [ACE] inhibitors). Some patients take nitrate drugs such as nitroglycerin or other medications (including some blood pressure medications) to treat angina.
Procedures may be needed to open a blocked or narrowed coronary artery and improve blood flow to the heart. These approaches are known as reperfusion therapy. Percutaneous coronary intervention (PCI), also called angioplasty (usually with stenting), uses a small balloon to open the blood vessel. Coronary artery bypass graft (CABG) is a more invasive procedure that is generally recommended for patients with multiple severe blockages. It uses grafts in the form of arteries or veins to reroute blood flow to the heart.
Heart Disease Guidelines
The American College of Cardiology, American Heart Association, and other professional organizations' guidelines recommend:
- For patients with heart disease, controlling blood pressure and lipids is very important, as is the regular use of antiplatelet therapy (usually aspirin).
- Patients deciding between CABG and PCI should meet with an interdisciplinary medical team that includes both a cardiac surgeon and an interventional cardiologist. CABG is a more invasive procedure. But it may work better than PCI for certain patients, depending on the location and number of blockages as well as other factors such as how well the heart is functioning and other medical problems the patient might have, such as diabetes.
- Cardiac rehabilitation is strongly recommended, especially for patients who have undergone bypass surgery. Heart disease patients should also be screened for depression.
- Sexual activity is safe for most patients with stable CAD. But patients with severe heart disease should abstain until their condition stabilizes.
Atherosclerosis is the hardening and narrowing of the arteries caused by the build-up of plaque inside the arteries. (Plaque is the sticky substance made up of fat, cholesterol, calcium, and other substances found in the blood.) Cardiovascular diseases caused by atherosclerosis include CAD, heart attack, peripheral artery disease (PAD), and stroke.
In atherosclerosis, fatty deposits (plaques) of cholesterol and other cellular waste products build up in the inner linings of the heart's arteries. This causes blockage of arteries and prevents oxygen-rich blood from reaching the heart (ischemia). There are many steps in the process leading to atherosclerosis, some not fully understood.
Cholesterol and LipoproteinsThe atherosclerosis process begins with cholesterol and sphere-shaped bodies called
lipoproteinsthat transport cholesterol.
- Cholesterol is a substance found in all animal cells and animal-based foods. It is critical for many functions. But under certain conditions cholesterol can be harmful.
- The lipoproteins that transport cholesterol are referred to by their size. The most commonly known lipoproteins are low-density lipoproteins (LDL) and high density lipoproteins (HDL). LDL is often referred to as "bad" cholesterol. HDL is often called "good" cholesterol.
- Triglycerides are another type of lipid (fat) that lipoproteins help circulate through the blood. High levels of triglycerides, like high levels of LDL, can increase the risk for heart disease.
The damaging process called oxidation is an important trigger of atherosclerosis.
- Oxidation is a chemical process in the body caused by the release of unstable particles known as
free radicals. It is one of the normal processes in the body. But under certain conditions (such as exposure to cigarette smoke or other environment stresses) these free radicals are overproduced.
- In excess amounts, free radicals can be very dangerous, causing damaging inflammation and even affecting genetic material in cells.
- In heart disease, free radicals are released in artery linings where they oxidize LDL. The oxidized LDL is the basis for cholesterol build-up and damage on the artery walls, leading to heart disease.
For the arteries to harden there must be a persistent reaction in the body that causes ongoing harm. This reaction is an immune process known as the inflammatory response.
Blockage in the ArteriesEventually the calcified (hardened) arteries become narrower, a condition known as
- As this narrowing and hardening process continues, blood flow slows, preventing sufficient oxygen-rich blood from reaching the heart muscles. The supply can fall short of the demands of working muscle.
- This oxygen deprivation is called
ischemia. When it is severe enough in the coronary arteries, it causes injury to the tissues of the heart.
- These narrow and stiff arteries not only slow down blood flow. They also become vulnerable to injury and clot formation, which is what usually triggers a heart attack.
The End Result: Heart Attack
A heart attack can result in several ways from atherosclerosis:
- Type 1 heart attack occurs when the plaque develops a fissure or tears. Blood platelets stick to the tears to seal off the plaque, and a blood clot (thrombus) forms. A heart attack can then occur if the blood clot severely or completely blocks blood flow to the heart muscle.
- Type 2 heart attack, which is less common, develops from a problem with oxygen supply and demand. A heart attack can occur if the heart's oxygen demand increases to exceed the (usually narrowed) artery's ability to deliver oxygen-rich blood.
The external structures of the heart include the ventricles, atria, arteries, and veins. Arteries carry blood away from the heart while veins carry blood into the heart. In the following image, the vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.
CAD, also called heart disease or ischemic heart disease, is the leading cause of death in the United States. Over the past few decades, heart disease rates declined in both men and women as they quit smoking and improved dietary habits. However, this improvement has leveled off in recent years, most likely because of the dramatic increase in obesity in the United States and other industrialized nations.
The risk of CAD increases with age. Most people who die from heart disease are over the age of 65. However, many people younger than this are also at risk.
Woman who reach menopause before the age of 35 have a significant increase in risk for heart disease as they age. This increase is primarily due to a rise in levels of LDL (bad) cholesterol and triglycerides, and a decrease in levels of HDL (good) cholesterol
Men have a greater risk for CAD and are more likely to have heart attacks earlier in life than women. After age 60, women's risk of dying from heart disease is very close to that of men. Heart disease is the leading cause of death in both women and men.
Woman with a history of angina, heart attack, or other heart or circulation problems are generally advised not to take hormone therapy when reaching menopause.
Genetic Factors and Family History
Heart disease tends to run in families. People whose parents or siblings developed heart disease at a younger age are more likely to develop it themselves. This is in part due to certain genetic factors which increase the likelihood of developing risk factors, such as diabetes and high blood pressure, but other factors likely play a role as well.
Race and Ethnicity
African-Americans have the highest risk of heart disease, due in part due to higher rates of severe high blood pressure, diabetes, and obesity.
Smoking is the most important lifestyle risk factor for heart disease. Smoking can cause elevated blood pressure, worsen lipids, and make platelets very sticky, raising the risk of clots. Although heavy cigarette smokers are at greatest risk, people who smoke as few as three cigarettes a day are at increased risk for blood vessel abnormalities that endanger the heart. Regular exposure to secondhand smoke also increases the risk of heart disease in nonsmokers.
Moderate alcohol consumption (one or two drinks a day; 5 ounces or 150 mL wine, 12 ounces or 360 mL beer, or 1.5 ounces or 45 mL hard liquor is one drink) can help boost HDL "good" cholesterol levels. Alcohol may also prevent blood clots and inflammation. By contrast, heavy drinking harms the heart. In fact, heart disease is the leading cause of death in alcoholics.
Diet plays an important role in the health of the heart, especially in controlling dietary sources of cholesterol and restricting salt intake that contributes to high blood pressure.
Exercise has a number of effects that benefit the heart and circulation, including improving cholesterol and lipids, lowering blood pressure and blood sugar levels, and improving weight control. People who are sedentary are almost twice as likely to suffer heart attacks as are people who exercise regularly.
Obesity and Metabolic Syndrome
Excess body fat, especially around the waist, is a significant risk factor for heart disease. Obesity also increases the risk for other conditions (such as high blood pressure and diabetes) that are associated with heart disease. Obesity is particularly hazardous when it is part of the metabolic syndrome, a pre-diabetic condition that is significantly associated with heart disease. This syndrome is diagnosed when at least three of the following are present:
- Abdominal obesity (fat around the waist)
- Low HDL (good) cholesterol
- High triglyceride levels
- High blood pressure
- Insulin resistance (diabetes or prediabetes)
There are numerous ways to control your weight and diet.
LDL cholesterol is the "bad" cholesterol responsible for many heart problems. Triglycerides are another type of lipid (fat molecule) that can be bad for the heart. HDL cholesterol is the "good" cholesterol that helps protect against heart disease. Doctors test for a "total cholesterol" profile that includes measurements for LDL, HDL, and triglycerides. The ratio of these lipids can affect heart disease risk.
High blood pressure (hypertension) is associated with CAD. For an adult, a normal blood pressure reading is below 120/80 mm Hg. High blood pressure is generally considered to be a blood pressure reading greater than or equal to 140 mm Hg (systolic) or greater than or equal to 90 mm Hg (diastolic). Blood pressure readings in the prehypertension category (120 to 139 systolic or 80 to 89 diastolic) indicate an increased risk for developing hypertension.
Diabetes, especially for people whose blood sugar levels are not well controlled, significantly increases the risk of developing heart disease. In fact, heart disease and stroke are the leading causes of death in people with diabetes. People with diabetes, both type 1 (so-called "juvenile") and type 2 (so-called "adult onset") are also at risk for high blood pressure and unhealthy cholesterol levels, blood clotting problems, and impaired nerve function, all of which can damage the heart.
PAD occurs when atherosclerosis affects the extremities, particularly the feet and legs. The major risk factors for heart disease and stroke are also the most important risk factors for PAD. (The combination of such conditions with PAD also produces more severe forms of heart or circulatory disease.) Even though signs of heart disease are often not evident in the majority of patients with PAD, most of these patients also have CAD.
Although people with heart disease may become depressed, this does not explain entirely the link between the two problems. Data suggest that depression itself may be a risk factor for heart disease as well as its increased severity. A number of studies indicate that depression has biologic effects on the heart, including blood clotting and heart rate. Guidelines recommend that patients who have undergone coronary artery bypass surgery or angioplasty (percutaneous coronary intervention [PCI]) be screened for depression. Stress may also contribute to risk.
Risk Factors with Unclear Roles
Homocysteine and Vitamin B Deficiencies
Deficiencies in the B vitamins folate (known also as folic acid), B6, and B12 have been associated with a higher risk for heart disease in some studies. Such deficiencies produce higher blood levels of homocysteine, an amino acid that has been associated with a higher risk for heart disease, stroke, and heart failure.
However, while B vitamin supplements do help lower homocysteine levels, they appear to have no effect on heart disease outcomes, including preventing heart attack or stroke. Research indicates that homocysteine may be a marker for heart disease rather than a cause of it.
In general, there is little evidence supporting vitamin supplements for heart disease prevention. According to the United States Preventive Services Task Force, there is insufficient evidence that regular use of multivitamin supplements reduces the risk for heart disease. There is conclusive evidence that vitamin E supplements do not help protect against heart disease.
C-reactive protein (CRP) is a product of the inflammatory process. It is not known if the protein plays any causal role or whether it is simply a marker for other factors in the disease process.
Lipoprotein-a, also called Lp(a) is a lipoprotein that is associated with CAD and stroke.
Lipoprotein-associated phospholipase A2 (LP-PLA2) is a marker of vascular inflammation which is associated with heart disease and stroke.
C pneumoniae and Other Infectious Organisms
Some microorganisms and viruses may possibly contribute to the inflammation and damage in arteries. The most interesting evidence to date suggests a potential role for Chlamydia (C) pneumoniae (an atypical bacterial organism that causes mild pneumonia in young adults). C pneumoniae is sometimes detected in plaques in the arteries of patients with heart disease. However, treatment with appropriate antibiotics has not been found to reduce the risk of future heart problems for patients infected with this organism.Other studies suggest that
cytomegalovirus (CMV), a common virus, may have similar effects. However, many people have been infected with these organisms, and no clear association has been found with any of these infections.
Obstructive sleep apnea (OSA) is a common sleep disorder. It occurs when tissues in the upper airways come too close to each other during sleep, temporarily blocking the inflow of air. There is evidence that severe OSA is an independent risk factor that may cause or worsen a number of heart-related conditions. Patients with severe, untreated OSA are at increased risk for CAD, high blood pressure, stroke, and heart attack.
Periodontal disease and heart disease are both inflammatory conditions that share common risk factors such as smoking and diabetes. According to the American Heart Association, more evidence is needed to establish a cause-and-effect relationship between gum disease and heart disease. Still, periodontists and cardiologists recommend that patients who have periodontal disease and at least one risk factor for heart disease should have a medical evaluation for heart problems. Patients who have CAD should have regular exams to check for signs of periodontal disease.
Common symptoms of CAD include:
- Angina (chest pain)
- Shortness of breath (particularly during physical exertion)
- Rapid heartbeat
Sometimes patients with CAD have few or no symptoms until they have heart attack or heart failure.
AnginaAngina is a symptom, not a disease. It is the primary symptom of CAD and, in severe cases, of a heart attack. It is typically felt as chest pain and occurs as a consequence of a condition called
myocardial ischemia. Ischemia results when the heart muscle does not get as much blood and oxygen as it needs for a given level of work. Angina is usually referred to as one of two states:
Stable Angina, which is predictable.
Unstable Angina, which is new, less predictable, and a sign of a more serious condition.
Angina can be mild, moderate, or severe. The intensity of the pain does not always relate to the severity of the medical problem. Some people might feel a crushing pain from mild ischemia. Others might feel only mild discomfort from severe ischemia.
Stable Angina and Chest Pain
Stable angina is predictable chest pain. Although less serious than unstable angina, it can be extremely painful or uncomfortable. It is usually relieved by rest and responds to medical treatment (typically nitroglycerin). Any event that increases oxygen demand can cause an angina attack. Some typical triggers include:
- Cold weather
- Emotional tension
- Large meals
Angina attacks can happen at any time during the day. But more occur between 6 a.m. and 12 p.m.
- Angina pain or discomfort is typically described by patients as fullness, tingling, squeezing, pressure, heavy, suffocating, or gripping. It is rarely described as stabbing or burning. Changing one's position or breathing in and out does not affect the pain.
- A typical angina attack lasts minutes. If it is more fleeting or lasts for hours, it is probably not angina.
- The pain is usually in the chest, under the breastbone. It often radiates to the neck, jaw, or left shoulder and arm. Less commonly, patients report symptoms that radiate to the right arm or back, or even to the upper abdomen.
- Women, older people, and patients with diabetes are particularly likely to experience atypical symptoms that often involve discomfort in the abdomen, nausea, or unusual fatigue and weakness instead of chest pain.
- Stable angina is usually predictably relieved by rest or by taking nitroglycerin under the tongue.
Other symptoms that may indicate angina or accompany the pain or pressure in the chest include:
- Shortness of breath
- Nausea, vomiting, and cold sweats
- A feeling of indigestion or heartburn
- Unexplained fatigue (more common in women)
- Dizziness or lightheadedness
Unstable Angina and Acute Coronary Syndrome
Unstable angina is a much more serious situation and is often an intermediate stage between stable angina and a heart attack, in which an artery leading to the heart (a coronary artery) becomes sufficiently blocked so that the blood supply to the heart drops and the heart muscle dies. A patient is usually diagnosed with unstable angina under one or more of the following conditions:
- Pain awakens a patient or occurs during rest.
- A patient who has never experienced angina has severe or moderate pain during mild exertion (walking two level blocks or climbing one flight of stairs).
- Stable angina has progressed in severity or occurs with less provocation, and medications are less effective in relieving its pain.
- The patient suffers a fainting episode, usually while or after having some of these other symptoms.
acute coronary syndromes (ACS). ACS also includes a condition called
non ST-segment elevation myocardial infarction (NSTEMI)-- also referred to as
non-Q wave myocardial infarction. With NSTEMI, blood tests indicate a heart attack. The third type of ACS is
ST-segment elevation myocardial infarction (STEMI), during which one of the major heart arteries is completely blocked and full-thickness heart muscle damage may occur.
Other Types of Angina
This type of angina is caused by a spasm of a coronary artery. It generally has no relationship to activity. Irregular heartbeats are common. But the pain is generally relieved promptly with standard treatment (nitrate medicines or calcium-channel blockers).
Some people with severe CAD do not have angina pain. This condition is known as silent ischemia, which may occur when the brain abnormally processes heart pain. Silent ischemia is a dangerous condition because patients have no warning signs of heart disease. Some studies suggest that people with silent ischemia have higher complication and mortality rates than those with angina pain.
Other Causes of Chest Pain or Discomfort
Chest pain is a very common symptom in the emergency room. But heart problems account for less than half of all chest pain episodes. There are many other causes of chest pain or discomfort, including:
- Injured muscles
- Asthma and other lung problems
- Problems with the aorta or other blood vessels
Still, if you are experiencing chest pain, it is best to seek immediate medical attention.
Many tests are used to diagnose heart disease. The choices of which and how many tests to perform depend on the patient's risk factors, history of heart problems, and current symptoms. Usually the tests begin with the simplest and may progress to more complicated ones.
Routine Tests to Determine Risk for Heart Disease
Doctors routinely check for high blood pressure and unhealthy cholesterol levels in all older adults. In some cases, the doctor may test for levels of CRP, which is associated with increased inflammation in the body.
Other tests may also be ordered such as blood tests for Lp(a) and LP-PLA2, or imaging tests (coronary calcium or carotid intima-medial thickness measurement). Specific tests are also important in people who may have risk factors or symptoms of diabetes.
An electrocardiogram (ECG) measures and records the electrical activity of the heart. However, up to half of people who suffer from angina or silent ischemia have normal ECG readings. The waves measured by the ECG correspond to when different parts of the heart contract and relax. Specific waves seen on an ECG are named with letters:
The electrocardiogram (ECG, EKG) is used extensively in the diagnosis of heart disease, from congenital heart disease in infants to myocardial infarction and myocarditis in adults. There are several different portions of an electrocardiogram.
- P. The P wave is associated with the contractions of the
atria(the two chambers that receive blood from outside the heart).
- QRS. The QRS is a series of waves associated with ventricular contractions. (The ventricles are the two major pumping chambers in the heart.)
- T and U. These waves follow the ventricular contractions.
The most important wave patterns in diagnosing and determining treatment for heart disease and heart attack are ST deviations, T-wave abnormalities, and Q waves:
- A depressed ST segment or a T-wave inversion (upside down) suggests some blockage and may indicate the presence of heart disease, even if there is no angina present.
- ST elevations and Q waves are the most important wave patterns in diagnosing and determining treatment for a heart attack. They suggest that an artery to the heart is completely blocked, and that the full thickness of the heart muscle is at risk. However, ST segment elevations alone do not always mean the patient has a heart attack. Other factors are important in making a diagnosis.
Exercise Stress Test
Exercise stress test for evaluation of CAD may be performed in the following situations:
- Patients with possible or probable angina, to help determine the likelihood of CAD being present
- Patients who were previously stable who suddenly began having symptoms
- Follow-up of patients with known heart disease, or following coronary bypass surgery or a percutaneous intervention
- To determine how well the heart can respond when extra demand is needed
- Patients with certain types of heart rhythm disturbances
- After a heart attack, either before leaving the hospital or soon afterward
A stress test (exercise tolerance test) monitors heart rhythms and other parts of the ECG, especially the ST segment, blood pressure, and clinical status. It can tell how well the heart handles work and if parts of the heart have decreased blood supply. A typical stress test involves:
- The patient walks on a treadmill or rides a stationary bicycle. Exercise continues until the heart is beating at least 85% of its maximum rate, until symptoms of heart trouble occur (changes in blood pressure, heart rhythm abnormalities, angina, and fatigue), or the patient simply wants to stop.
- For patients who cannot exercise, the doctor may administer dobutamine, which is a drug that simulates the stress of exercise. In this case, some form of imaging is required.
An ECG is used to monitor heart rhythms during a stress test. (An echocardiogram or more advanced imaging technique may also be used to visualize the actions of the heart and blood flow.)
To accurately assess heart problems, varieties of factors are measured or monitored using the ECG and other tools during exercise. They include:
- Exercise capacity. This is a measure of a person's capacity to reach certain metabolic rates.
- ST waves on the ECG. Doctors specifically look for abnormalities in part of the wave tracing called an ST segment. A certain type of ST segment depression may suggest the presence of heart disease. However, gender, drugs, and other medical conditions can affect the ST segment.
- Heart rate. This is how fast the heart rate goes during exercise and how quickly it returns to normal recovery. Based on age and other factors, everyone's heart rate should go up to a certain level during exercise. If it does not go up to the expected level or stays high too long after stopping exercise, the patient is considered at risk for heart problems.
- Changes in systolic blood pressure. Generally, the blood pressure will go up during exercise. If blood pressure drops or raises quickly this can be a sign of other problems.
- Oxygen levels may also be measured.
Using these and other measures, doctors can determine risk fairly accurately, particularly for men with chronic stable angina. However, the test has limitations, and some are significant. In patients with suspected unstable angina, normal or low risk results may not be as accurate in predicting future risk of cardiac events.
Depending on the type of test and the population studied (young people or those with few risk factors and atypical symptoms) a significant proportion of patients will have false positive test results. In such cases, test results indicate abnormalities when there are no heart problems.
An echocardiogram is a noninvasive test that uses ultrasound images of the heart. This test is more expensive than an ECG-only stress test. But it can provide very valuable information, particularly in identifying whether there is damage to the heart muscle and the extent of heart muscle damage. An echocardiogram also provides other information about heart structure and function, such as the valves.
A stress echocardiogram may be performed to further evaluate abnormal findings from an exercise treadmill test or a routine echocardiogram. Examples include identifying exactly which part of the heart may be involved and quantifying how much muscle has been infected. It may be the first test done when a standard exercise treadmill test cannot be performed.
Radionuclide procedures use imaging techniques and computer analyses to plot and detect the passage of radioactive tracers through the heart. Such tracing elements are given intravenously. Radionuclide imaging is useful for diagnosing and determining:
- Severity of unstable angina when less expensive diagnostic approaches are unavailable or unreliable.
- Severity of chronic CAD.
- Success of surgeries for CAD.
- Whether a heart attack has occurred.
Myocardial Perfusion (Blood Flow) Imaging Test (also called the Thallium Stress Test)
This radionuclide test is typically used with an exercise or chemical stress test to determine blood flow to the heart muscles. It is a reliable measure of severe heart events. It may be useful in determining the need for angiography.
First, a radioactive tracer (such as thallium, technetium, or sestamibi) is given through an IV while the patient is at rest. Then, a scan of the heart is done. Sometime after this exercise/stress is begun, and about a minute before the patient is ready to stop exercising, the doctor administers a radioactive tracer into the intravenous line. Immediately afterward, the patient lies down for a second heart scan.
The images before and after exercise are compared. Sometimes delayed imaging is performed to see if areas of the heart may benefit from revascularization in an area of a prior heart attack.
This test is a technique for evaluating the main pumping chambers of the heart (the ventricles). It uses an injected radioactive tracer and can be performed during exercise, at rest, or with use of stress-inducing drugs. It can help determine the function of the ventricles (left more commonly than the right) and is an alternative to echocardiograms in certain situations.
Angiography is an invasive test. It is used for patients who show strong evidence for severe obstruction on stress and other tests, for patients with severe typical symptoms, and for patients with ACS. It is required when there is a need to know the exact anatomy and disease present within the coronary arteries and is often followed by PCI, also called angioplasty and stenting.
In an angiography procedure:
- A narrow tube is inserted into an artery, usually in the leg or arm, and then threaded up through the body to the coronary arteries.
- A dye is injected into the tube, and an x-ray records the flow of dye through the arteries.
- This process provides a map of the coronary circulation, revealing any blocked areas.
- Once these blocked areas have been identified, PCI is sometimes performed.
Magnetic Resonance Angiography (MRA)
MRA is a newer noninvasive imaging technique that can provide three-dimensional images of the major arteries to the heart.
Computed tomography (CT) scans may be used to evaluate CAD.
Calcium Scoring CT Scans of the Heart
These scans are used to detect calcium deposits on the arterial walls. The presence of calcium correlates well with the presence of atherosclerosis of the heart. If the calcium score is very low, a patient is unlikely to have CAD. A higher calcium score may indicate an increased risk of current and future CAD. However, the presence of calcium does not necessarily signify narrowing of the arteries that would need further immediate evaluation or treatment. Using this test as a screening tool to identify people in the general population for increased risk of heart disease is generally not recommended.
CT scans may also be used to visualize the coronary arteries. When compared to invasive angiography, CT angiography is not as accurate in identifying who has significant CAD and who does not. However, when a patient's CT angiogram is completely normal, it is very unlikely that they have significant blockages. CT techniques include electron beam computed tomography (EBCT) and multidetector computed tomography (MDCT), which use different technologies to generate images of the heart. The optimal way to use these tests has yet to be determined.
Heart disease prevention is important before and after someone is diagnosed with the condition:
Primary prevention.Refers to measures that everyone should take to reduce their risk of heart disease.
Secondary prevention.Refers to measures that a patient, already diagnosed with heart disease, should take to reduce the risk of having additional heart damage. Many of these measures are similar or the same as those recommended for primary prevention.
Key prevention measures include:
- All patients should stop smoking and avoid exposure to secondhand smoke.
- Maintain cholesterol levels at appropriate levels using a heart healthy diet, exercise, and statin medications.
- Maintain an appropriate low blood pressure level using diet and medications.
- Maintain an active lifestyle.
- Maintain a healthy body weight.
- Use an antiplatelet drug such as aspirin or clopidogrel, if appropriate.
- Manage diabetes and kidney disease when present.
- Receive an annual influenza vaccination.
Your doctor should ask about your smoking habits at every visit. Smoking is a chronic condition and often requires repeat therapy using more than one technique.
All patients should start following a heart-healthy diet and exercise regularly, after talking to their doctors.
Healthy diet, regular exercise, and quitting smoking (if you smoke) may prevent heart disease. Follow your health care provider's recommendations for treatment and prevention of heart disease.
When deciding on whether to use statin medications, newer guidelines for cholesterol treatment focus on a patient's overall risk for cardiovascular disease and treating with appropriately potent medications appropriate for the patients risk-level, rather than aiming for a target cholestrol number. Statin drugs are the recommended treatment for lowering LDL (bad) cholesterol levels in patients when lifestyle changes have failed. Statins are recommended:
- For people with known cardiovascular disease.
- For people with diabetes.
- For people with genetic disorders causing elevated LDL cholesterol levels.
- When a number of risk factors including cholesterol blood level, are considered, using what is called a risk calculator. If you are between the ages of 40 and 75 and a risk calculator indicates your risk for heart disease in the next 10 years is at or above 7.5% to 10%, statins are recommended.
Manage High Blood Pressure
People in normal health should have a blood pressure reading of 120/80 mm Hg or less is considered normal, readings of 140/90 mm Hg or higher indicates high blood pressure (hypertension), and readings in between the two are called prehypertension. Patients whose blood pressures stay above 140/90 mm Hg despite lifestyle therapy (diet, exercise, and weight control) should be treated with blood pressure medications.
If you have heart problems, diabetes, kidney problems, or a history of a stroke, medicines may be started at lower blood pressure reading. The most commonly used blood pressure targets for people with these medical problems are below 130 to 140/80 mm Hg.
All patients with diabetes should have their blood sugar (glucose) levels well managed. For most patients, a goal would be to bring HbA1c levels down to around 7%. In general, people with diabetes (both type 1 and type 2) should aim for blood pressure levels of less than 140/80 mm Hg (systolic/diastolic). For some people, especially younger patients, a systolic blood pressure goal of less than 130 mm Hg may be appropriate. People with diabetes and stable heart disease should not take the diabetes drug rosiglitazone (Avandia) because it may increase the risk for heart attack and heart failure.
Current American Heart Association (AHA) for guidelines for a heart-healthy diet recommends:
- Balance calorie intake and physical activity to achieve or maintain a healthy body weight.
- Consume a diet rich in a variety of vegetables and fruits.
- Choose whole-grain, high-fiber foods. These include fruits, vegetables, and legumes (beans). Good whole grain choices include whole wheat, oats/oatmeal, rye, barley, brown rice, buckwheat, bulgur, millet, and quinoa.
- Consume fish, especially oily fish, at least twice a week (about 8 ounces/week or 225 grams/week). Oily fish such as salmon, mackerel, and sardines are rich in the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Consumption of these fatty acids is linked to reduced risk of sudden death and death from CAD. People with existing heart disease who do not eat fish regularly should consider taking daily fish oil supplements of 850 to 1,000 mg EPA and DHA.
- Limit daily intake of saturated fat (found mostly in animal products) to less than 7% of total calories, trans fat (found in hydrogenated fats, commercially baked products, and many fast foods) to less than 1% of total calories, and cholesterol (found in eggs, dairy products, meat, poultry, fish, and shellfish) to fewer than 300 mg per day. Choose lean meats and vegetable alternatives (such as soy). Select fat-free and low-fat dairy products. Grill, bake, or broil fish, meat, and skinless poultry.
- Use little or no sodium (salt) in your foods. Reducing sodium can lower blood pressure and decrease the risk of heart disease and heart failure.
- Cut down on beverages and foods that contain added sugars (corn syrups, sucrose, glucose, fructose, maltose, dextrose, concentrated fruit juice, and honey).
- If you drink alcohol, do so in moderation. The AHA recommends limiting alcohol to no more than 2 drinks per day for men and 1 drink per day for women.
People should aim for a BMI index of 18.5 to 24.9. Weight reduction is recommended for overweight patients who have high blood pressure, high cholesterol levels, metabolic syndrome, or diabetes.
Some obese patients with CAD may consider having bariatric surgery (stomach bypass) to lose excess weight. The weight lost after surgery can help improve blood pressure, cholesterol, blood sugar and other factors associated with CAD.
Inactivity is a major risk factor for CAD, on par with smoking, unhealthy cholesterol, and high blood pressure. In fact, studies suggest that people who change their diet in order to control cholesterol only achieve a lower risk for heart disease when they also follow a regular aerobic exercise program. Resistance (weight) training offers a complementary benefit to aerobics.
Even moderate exercise reduces the risk of heart attack and stroke. Current guidelines recommend at least 40 minutes of moderate-intensity physical activity on 5 or more days per week for a total of 200 to 300 minutes per week.
Your doctor needs to know if your activity causes any angina symptoms. Sudden strenuous exercise (especially snow shoveling or similarly vigorous activities, especially in cold weather) puts many people at risk for angina and heart attack. Patients with angina should never exercise shortly after eating. People with risk factors for heart disease should seek medical clearance and a detailed exercise prescription. And all people, including healthy individuals, should listen carefully to their bodies for signs of distress as they exercise.
Most patients with stable CAD can safely engage in sexual activity. Patients with severe heart disease should abstain from sex until their condition has stabilized. Exercise and cardiac rehabilitation can help lower the risks associated with sexual exertion. Discuss with your doctor how your heart medications may affect your sexual function, and be sure to report to your doctor any symptoms you experience during sex.PDE5 inhibitor drugs sildenafil (Viagra), vardenafil (Levitra), tadalafil (Cialis), avanafil (Stendra) are safe and helpful for most patients with stable CAD who have issues with erectile dysfunction. However, patients who take nitrate drugs in any form must
nevertake PDE5 inhibitors.
Influenza Vaccination (Flu Shot)
Patients with CAD are considered at high risk for complications from influenza. People with CAD should get an annual flu shot.
Chelation is a chemical process in which a substance called EDTA is used to bind molecules, such as metals or minerals, and hold them tightly so that they can be removed from the body. Chelation therapy, administered along with high-dose vitamins, has been studied for the secondary prevention of heart disease.
This therapy may be suggested for secondary prevention of cardiac events in patients with stable CAD. The use of disodium EDTA for heart disease has not been approved by the US Food and Drug Administration.
Lifestyle changes (such as weight control, exercise, and quitting smoking) are the first approach for all degrees of CAD. Depending on severity and individual conditions, patients may also need one or more medications, surgery, or both.
Many types of medications are used to treat angina and CAD. They include:
- Antiplatelets and anticoagulants
- Beta blockers
- Angiotensin converting enzyme (ACE) inhibitors
- Calcium channel blockers
Interventional Procedures and Surgery
Intervention is usually recommended for people who have:
- ACS, such as unstable angina, non-ST elevation MI and ST elevation MI when the procedure is done immediately.
- Recurrent episodes of angina that last more than 20 minutes and do not respond to intensive medical therapy and therefore limit patient's lifestyle.
- Severe CAD (severe angina, multi-artery involvement, evidence of ischemia, or significant narrowing of left main coronary artery), particularly if abnormalities are evident in the left ventricle of the heart, the main pumping chamber.
The two main procedures for patients with CAD are:
- Coronary artery bypass grafting (commonly called bypass or CABG), which is usually reserved for patients with severe CAD.
- PCI (commonly called angioplasty), usually with coronary artery stent placement. PCI is less invasive than CABG. But blood vessels can close up again (restenosis) so that patients require additional procedures.
The decision to choose angioplasty or coronary artery bypass depends on a patient's individual profile, including the number and types of coronary arteries involved, previous procedures, other health conditions, patient preference, and more. PCI is less invasive than CABG and is more commonly performed. However, CABG may provide better outcomes for certain patients, including those with diabetes or heart failure or with blockages in particular locations. Sometimes so-called "hybrid" procedures may be performed where a patient gets a combination of surgical bypass and stenting.
Patients considering surgery should discuss all options and risks with their doctors. Guidelines recommend that patients with CAD discuss their treatment options with a medical team that includes both a cardiac surgeon (who performs CABG) and an interventional cardiologist (who performs PCI). No procedure cures CAD or the systemic process underlying it (atherosclerosis), and patients must continue to rigorously maintain a healthy lifestyle and any necessary medications. For some patients, lifestyle changes and medications may be able to control the disease without surgery or angioplasty.
Statins are the first-line drugs for lowering high LDL (bad) cholesterol levels, and reducing the risk for heart attack and stroke. Current joint guidelines from the American College of Cardiology (ACC) and the American Heart Association (AHA) recommend statin therapy for patients with existing atherosclerotic heart disease and people at risk for heart disease.
The ACC/AHA has designed a special "risk calculator" to compute cardiovascular disease risk percentage. A doctor enters into the calculator a patient's gender, age, race, total cholesterol, HDL (good) cholesterol, blood pressure, diabetes status, and smoking status. If the formula indicates a 7.5% or higher risk for having a heart attack or stroke within the next 10 years, treatment with a statin drug is recommended.
Statin drugs approved in the United States are lovastatin (Mevacor, generic), pravastatin (Pravachol, generic), simvastatin (Zocor, generic), atorvastatin (Lipitor, generic), fluvastatin (Lescol), pitavastatin (Livalo), and rosuvastatin (Crestor).
Anti-Clotting DrugsAnti-clotting drugs that inhibit or break up blood clots are used at every stage of heart disease. They are generally classified as either
antiplatelets or anticoagulants. Both antiplatelets and anticoagulants prevent blood clots from forming. But they work in different ways. Antiplatelets prevent blood platelets from sticking together. Anticoagulants are "blood thinners" that reduce blood clotting. Both of these therapies carry the risk of bleeding, which can lead to dangerous situations, including stroke.
For most patients with CAD, antiplatelet drugs are preferred over anticoagulants. Anticoagulants are often prescribed for patients with atrial fibrillation or prosthetic heart valves. Some patients need both.
Current guidelines recommend that patients with CAD receive antiplatelet therapy with either aspirin or clopidogrel. Other antiplatelet drugs such as prasugrel (Effient), ticagrelor (Brilinta), or ticlopidine (Ticlid) may be recommended. Sometimes two antiplatelet drugs (one of which is almost always aspirin) are prescribed for patients with unstable angina, ACS (unstable angina or early signs of heart attack), or those who have received a stent during PCI.
A thrombus is a blood clot that forms in a vessel and remains there. An embolism is a clot that travels from the site where it formed to another location in the body. Thrombi or emboli can lodge in a blood vessel and block the flow of blood in that location depriving tissues of normal blood flow and oxygen. This can result in damage, destruction (infarction), or even death of the tissues (necrosis) in that area.
Aspirin is known as a nonsteroidal anti-inflammatory drug (NSAID). It stops blood platelets, which are major clotting factors, from sticking together to form a blood clot. Aspirin therapy is extremely beneficial for patients with CAD or history of stroke.
If you have been diagnosed with CAD, your doctor may recommend that you take a daily dose (from 75 to 162 mg) of aspirin. A daily dose of 81 mg is recommended for patients who have undergone PCI (angioplasty). Aspirin can reduce the risk of heart attack and ischemic stroke. However, prolonged use of aspirin can increase the risks for stomach bleeding.
A daily low-dose aspirin (75 to 81 mg) is usually the first choice for preventing heart disease or stroke in high-risk individuals. Daily aspirin is not recommended for prevention in healthy people who are at low risk for heart disease. A doctor needs to consider a patient's overall medical condition and risk factors for heart attack before recommending aspirin therapy. Discuss with your doctor whether aspirin therapy is appropriate for you.
Thienopyridines are antiplatelet drugs. Clopidogrel (Plavix, generic) is the standard thienopyridine for patients with CAD. Other commonly used antiplatelet drugs used with aspirin are prasugrel (Effient) and Ticagrelor (Brilinta).
For heart disease primary and secondary prevention, daily aspirin is generally the first choice for antiplatelet therapy. Clopidogrel is prescribed instead of aspirin for patients who are aspirin allergic or who cannot tolerate aspirin. For most patients, clopidogrel is not taken in combination with aspirin because the two drugs combined can increase the risk of bleeding. However, the combination is common in patients who have had a heart attack or who have received a stent.
Clopidogrel and aspirin is recommended for patients who are undergoing angioplasty with or without stenting. Patients who receive drug-coated stents require prolonged clopidogrel therapy, while those who receive bare-metal stents can often go back to aspirin alone after a shorter period of time. Patients having coronary bypass surgery may be asked to hold their second, non-aspirin antiplatelet medication for several days prior to surgery because of a significant bleeding risk.
Aspirin and thienopyridine antiplatelet drugs like clopidogrel can increase the risk for upper gastrointestinal bleeding, especially for patients who have pre-existing ulcers or other risk factors. For this reason, some doctors recommend that patients who are at high risk of gastrointestinal bleeding take a proton pump inhibitor (PPI) drug along with antiplatelet therapy.
PPI drugs help suppress gastric acid production, which in turn helps heal ulcers. However, certain PPI drugs may interfere with clopidogrel's antiplatelet effects. Discuss with your doctor the risks and benefits of taking a PPI drug along with clopidogrel and whether this is right for you.
Beta blockers are useful for preventing angina attacks and reducing high blood pressure. They reduce the heart's oxygen demand by slowing the heart rate and lowering blood pressure. They can help reduce risk of death from heart disease and from heart surgeries, including PCI and coronary bypass.
Beta blockers are used or recommended in a number of situations:
- They are started in nearly all patients who have just had a heart attack or ACS and are continued for at least 3 years.
- They are the drugs of choice for older patients with stable angina and may also be beneficial for people with silent ischemia.
- They may be used alone or with other medications for management of rhythm disturbances or high blood pressure.
Beta blockers include propranolol (Inderal), carvedilol (Coreg), bisoprolol (Zebeta), acebutolol (Sectral), atenolol (Tenormin), labetalol (Normodyne, Trandate), metoprolol (Lopressor, Toprol-XL), and esmolol (Brevibloc). All of these drugs are available in generic form. A nasal spray form of propranolol may be helpful in reducing exercise-induced angina attacks.
If beta blocker therapy is not appropriate or not effective, a calcium channel blocker, nitrate, or ranolazine are alternative options.
Beta blocker side effects include fatigue, lethargy, vivid dreams and nightmares, depression, memory loss, and dizziness. They can lower HDL ("good") cholesterol. Beta blockers are categorized as non-selective or selective. Non-selective beta blockers, such as carvedilol and propranolol, can narrow bronchial airways. These beta blockers may need to be avoided by patients with asthma, emphysema, or chronic bronchitis.
Patients should never abruptly stop taking these drugs. The sudden withdrawal of beta blockers can rapidly increase heart rate and blood pressure. The doctor may advise a patient to slowly decrease the dose before stopping completely.
Angiotensin Converting Enzyme (ACE) Inhibitors
Angiotensin converting enzyme (ACE) inhibitors are important heart-protective drugs, particularly for people with diabetes, high blood pressure, and heart failure. They reduce the production of angiotensin, a chemical that causes arteries to narrow, and so are commonly used to lower blood pressure. They may also reduce risk for heart attack, stroke, complications of diabetes, and death in patients at with or at high risk for heart disease.
ACE inhibitors are indicated for many patients who have had heart attacks. They are particularly helpful for patients with CAD who also have diabetes or who have heart failure or left ventricular systolic dysfunction (when the heart's main chamber does not pump as well as it should).
ACE inhibitors include captopril (Capoten, generic), ramipril (Altace, generic), enalapril (Vasotec, generic), quinapril (Accupril, generic), benazepril (Lotensin, generic), perindopril (Aceon, generic), and lisinopril (Prinivil, Zestril, generic).
Side effects of ACE inhibitors may include an irritating dry cough. More serious side effects are uncommon, but may include excessive drops in blood pressure, allergic reactions, and high blood potassium levels. If you cannot tolerate the side effects of ACE inhibitors, your doctor may prescribe an angiotensin receptor blocker (ARB) as an alternative high blood pressure drug with similar benefits.
Nitrates are used to control angina symptoms. Nitrates have been used in the treatment of angina for over 100 years. These drugs are vasodilators; they release nitric oxide, which relaxes the smooth muscles in blood vessels and allows blood to flow more easily. Many nitrate preparations are available. The most common are nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates can be absorbed from the gastrointestinal tract (oral tablet), skin (ointment or patch), or from under the tongue (sublingual tablet or spray).
Rapid-acting nitrates are used to treat acute angina symptoms. Nitroglycerin is the most widely used drug for this purpose. It can be administered under the tongue (sublingually or as a spray) or pocketed between the upper lip and gum (buccally) and can relieve angina within minutes. The procedure for taking nitroglycerin during an attack is as follows:
- At the onset of an angina attack, the patient sits or lies down and then administers one sublingual or buccal tablet or one metered dose of the spray.
- If the pain is not relieved within 5 minutes the patient takes a second dose; a third can be taken after another 5 minutes if symptoms persist.
- If pain continues after a total of three doses in 15 minutes, the patient should go immediately to the nearest emergency room or call 911 (they should not drive themselves).
Nitroglycerin is very unstable so its potency can be easily lost. Patients should take the following precautions:
- Keep no more than 100 tablets on hand, stored in their original container.
- When first opened, the cotton filler should be discarded, and the cap screwed on tightly immediately after each use.
- A supply should always be kept close at hand in case of an attack, with the rest kept in a cool dry place.
Intermediate to Long-Term Nitrates
Sublingual tablets of isosorbide dinitrate have a slower onset of action than nitroglycerin and are useful for preventing exertional (activity-induced) angina. Ointments, skin patches, and oral tablets are used for longer-term prevention of angina attacks:
- Transdermal skin patches are applied in the morning to any hair- or injury-free area on the chest, back, stomach, thigh, or upper arm. Hands should be washed after each patch or ointment application, and sites of application should be rotated to avoid skin irritation.
- Nitroglycerin ointment is applied by measuring out an even amount on an applicator paper and then placing, not rubbing or massaging, it on the chest, stomach, or thigh. Any ointment that remains from the previous application should be removed.
Long-acting forms may lose their effectiveness over time, so doctors generally schedule nitrate-free breaks to prevent tolerance.
Nitrates can have many side effects, some of which can be serious.
Common side effects of nitrates include headaches, dizziness, nausea and vomiting, blurred vision, fast heartbeat, sweating, and flushing on the face and neck. Low blood pressure and dizziness can be relieved by lying down with the legs elevated. These effects are significantly worsened by alcohol, beta blockers, calcium channel blockers, and certain antidepressants.
The doctor may prescribe medicines to lessen these side effects. Patients should contact their doctor if these side effects are persistent or severe. Patients who take nitrates in any form should never take medications for erectile dysfunction, such as sildenafil (Viagra), vardenafil (Levitra), tadalafil (Cialis), and avanafil (Stendra).
Serious side effects requiring immediate medical help include fever, joint or chest pain, sore throat, skin rash (especially on the face), unusual bleeding or bruising, weight gain, and swelling of the ankles.
Withdrawal from nitrates should be gradual. Abrupt termination may cause angina attacks.
Calcium Channel Blockers (CCBs)
Calcium channel blockers (CCBs) reduce heart rate and slightly dilate the blood vessels of the heart, thereby decreasing oxygen demand and increasing oxygen supply. They also reduce blood pressure. However, CCBs vary chemically. Although some are helpful, others may even be dangerous for certain patients with CAD.
- Long-acting nifedipine (Adalat, Procardia, generic) and nisoldipine (Sular, generic) and newer CCBs, such as amlodipine (Norvasc, generic) and nicardipine (Cardene, generic), are used to treat angina symptoms. They may be used alone for patients who cannot tolerate beta blockers, or in combination with a beta blocker.
- Short-acting CCBs, including short-acting forms of verapamil, diltiazem, nifedipine, and nicardipine, are helpful for treating Prinzmetal's angina. However, short-acting forms of certain CCBs, such as nifedipine and nisoldipine, can cause severe and even dangerous side effects, including an increase in heart attacks and sudden death in patients with stable or unstable angina. Short-acting CCBs are, therefore, not used for treating stable or unstable angina.
Side EffectsPatients with heart failure have a higher risk for death with these drugs and should not take them. No one should abruptly stop taking calcium channel blockers because sudden withdrawal can dangerously increase the risk of high blood pressure.
Note:Grapefruit and Seville oranges boost the effects of certain CCBs, sometimes to toxic levels. (Regular oranges do not pose any hazard.)
Ranolazine (Ranexa) is used to treat chronic angina in patients who have not responded sufficiently to other angina drugs. Ranolazine is usually taken in combination with a calcium channel blocker, beta blocker, or nitrate drug.
The two main procedural interventions for CAD are:
- PCI also called angioplasty, which usually involves placing a stent
- CABG which is a much more invasive surgical procedure
revascularizationprocedures, which help restore blood flow (
Angioplasty and Stenting (Percutaneous Coronary Intervention)
Angioplasty, also called PCI, involves procedures such as percutaneous transluminal coronary angioplasty (PTCA) that help open the blocked artery.
Angioplasty can help reduce the frequency of angina attacks for patients who have not been helped by drug therapy. It is commonly recommended for patients who have critically blocked arteries or have already had a recent, acute heart attack or unstable angina. However, symptom reduction is the main benefit of angioplasty in lower-risk patients with stable CAD.
Evidence indicates that angioplasty works no better than intensive standard heart medication (drugs to control blood pressure, lower cholesterol, and prevent blood clots) in preventing heart attack, stroke, and hospitalization in patients with stable CAD. For patients with stable heart disease, drug therapy is usually sufficient enough treatment and allow them to safely defer having procedures.
Doctors now recommend angioplasty only for patients who have difficult-to-control symptoms. However, some research suggests that CABG may be more effective than angioplasty in preventing heart attacks and death in patients with blockage in several arteries.
A typical angioplasty procedure follows these steps:
- After giving the patient some mild sedating medications, the cardiologist threads a narrow catheter (a tube) from the groin or wrist area into the blocked vessel.
- The doctor opens the blocked vessel using
balloon angioplasty, in which the surgeon passes a tiny deflated balloon through the catheter to the vessel.
- The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
- To keep the artery open afterwards, doctors use a device called a
coronary stent, an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage. (In some cases, a stent may be used as the
initialopening device instead of just balloon angioplasty.) The stent may be bare metal or it may be coated with a drug that slowly releases medication.
- Once in place, the stent pushes against the wall of the artery to keep it open.
Complications occur in about 5% to 10% of patients (about 80% of them happening within the first day). Success rates are better in hospital settings with experienced teams and backup.
Recuperation and Complications
Angioplasty is less invasive than bypass surgery, requiring only one night in the hospital. Recuperation takes about a week. Chest pain after the procedure is very common and usually due to problems other than ischemia. Mild chest pain is even more common when a stent is used, possibly because the artery is stretched.
The most important short- and long-term complication of angioplasty is acute closure of the artery by a clot (called "stent thrombosis"), which usually results in a serious heart attack and requires immediate treatment to clear the blockage. Stenting, anti-clotting drugs, and other advances have significantly helped prevent reclosure and reduce heart attack rates. Another important condition is restenosis of the artery which is a different process involving the slower growth of tissue within the stent and causes symptoms over time. The desire to reduce this process which can result in the need for repeat procedures due to symptoms led to the development of drug-coated stents.
Stents coated with sirolimus (Rapamune), paclitaxel (Taxol), or other drugs have been increasingly used in recent years. Drug-eluting stents (as they are also called) can help prevent restenosis. However, because drug-eluting stents reduce arterial tissue growth, they can increase the risks of acute blood clots that can block the stent (called "stent thrombosis"). Taking aspirin and an additional antiplatelet (clopidogrel, prasugrel or ticagrelor) faithfully is critical to reducing the risk of this very serious complication.
Studies indicate that drug-eluting stents are safe and effective for patients with CAD when they are used for FDA-approved indications. Some studies have indicated that problems may arise when these stents are used for "off-label" purposes in patients with more complicated health problems, although other studies have found no increased risks. There is still some concern that all stents (both bare metal and drug eluting) may be used too frequently for patients who may be better served by drugs or bypass surgery.
It is very important that all patients who have drug-eluting stents take aspirin and clopidogrel for at least 1 year after the stent is inserted to reduce the risk of blood clots. For patients undergoing PCI who have ACS, two newer antiplatelet drugs, prasugrel (Effient) or ticagrelor (Brilinta), may be options. These drugs, like aspirin, help prevent blood platelets from clumping together.
It is important that patients who have drug-eluting stents take both aspirin and another antiplatelet drug. If for some reason patients cannot stick to a long-term dual antiplatelet regimen, they should receive a bare-metal stent instead of a drug-eluting stent after which the period of mandatory dual antiplatelet therapy may be as short as a month.
Coronary Artery Bypass Graft Surgery (CAGB)
CABG surgery is an alternative to angioplasty (PCI) for many patients with severe CAD. Studies suggest it is superior to PCI for patients with multi-vessel disease (blockage in several arteries.) CABG is generally recommended instead of PCI for patients with multiple blockages who have diabetes or heart failure.
Traditional CABG is an invasive open-heart surgical procedure. Minimally invasive coronary artery bypass surgery (MIDCAB), also called "keyhole heart surgery," may be an option for some patients.
MIDCAB uses various techniques, including endoscopy or robotic-assisted approaches. Unlike standard CABG, with MIDCAB patients do not have their heart stopped and therefore do not have to be put on a heart-lung machine during the procedure. In MIDCAB, the surgeon uses a smaller incision on the left side of the chest. CABG requires a longer incision down the center of the chest.
In a traditional CABG procedure:
- The chest is opened, and the blood is rerouted through a lung-heart machine.
- The heart is stopped during the procedure.
- Blood vessel grafts are taken from arteries or veins in the chest wall or other areas of the body. The grafts are transplanted in front of and beyond the blocked arteries, so the blood flows through the new vessels around the blockage. Patients may require one, two, or three grafts (or more) depending on the number of coronary arteries that are blocked.
- In general, patients with triple bypass procedures stay in the hospital for 5 or 6 days. Those with one-vessel bypass may be able to go home in 3 days.
Complications are generally rare, but can include bleeding, infections, heart attack, and stroke. Finding a surgeon who performs at least 100 of the procedures a year helps reduce the risk for complications.
Blood clots may form in the new graft, closing it up or narrowing the treated vessel over time. Therapy with aspirin and other anti-clotting drugs help keep the graft open and working properly.
Recuperation and Rehabilitation
After leaving the hospital, patients should have cardiac rehabilitation. Guidelines recommend that doctors refer patients who have had CABG or PCI to a comprehensive outpatient cardiac rehabilitation program. Rehabilitation includes education about healthy diet and lifestyle choices, as well as exercise training to rebuild strength and stamina.
A cardiac rehabilitation program is coordinated by a multidisciplinary team that includes cardiologists, cardiac nurses, nutritional counselors, exercise physiologists, and others. The goal of cardiac rehabilitation is to help the patient regain physical strength, improve heart and overall health, and reduce the future risks for heart attack or stroke.
- National Heart, Lung, and Blood Institute -- www.nhlbi.nih.gov
- American Heart Association -- www.heart.org
- American College of Cardiology -- www.cardiosource.org/
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Review Date: 7/13/2016
Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.