Coronary artery disease
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 U.S.
The most important factors that increase the risk for CAD are:
Angina is the primary symptom of CAD. Angina feels like gripping pain or pressure in the chest area.
Some patients with CAD have few or no symptoms. Sometimes a heart attack may be 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, cholesterol-lowering drugs (statins), and high blood pressure medications (such as beta blockers, calcium channel blockers and 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:
Coronary artery disease (CAD), also called heart disease or ischemic heart disease, results from a complex process known as atherosclerosis.
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, 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 Lipoproteins. The atherosclerosis process begins with cholesterol and sphere-shaped bodies called lipoproteins that transport cholesterol.
Oxidation. The damaging process called oxidation is an important trigger of atherosclerosis.
Inflammatory Response. 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 Arteries. Eventually the calcified (hardened) arteries become narrower, a condition known as stenosis.
The End Result: Heart Attack. A heart attack can result in several ways from atherosclerosis:
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.
Coronary artery disease (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 U.S. and other industrialized nations.
The risk of coronary artery disease (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.
Men have a greater risk for CAD and are more likely to have heart attacks earlier in life than women. Women's risk for heart disease increases after menopause. Heart disease is the leading cause of death in both women and men.
Genetic Factors and Family History
Certain genetic factors increase the likelihood of developing significant risk factors, such as diabetes and high blood pressure. 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.
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.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.
Alcohol. Moderate alcohol consumption (one or two drinks a day; 5 ounces wine, 12 ounces beer, or 1.5 ounces 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.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.
Physical Inactivity. 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:
There are numerous ways to control your weight and diet.
Unhealthy Cholesterol and Lipid Levels.Low-density lipoprotein (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. High-density lipoprotein (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.High blood pressure (hypertension) is associated with coronary artery disease. 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. 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.
Peripheral Artery Disease.Peripheral artery disease (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 coronary artery disease.
Depression.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 (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. 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.
Lp(a). Lipoprotein-a, also called Lp(a) is a lipoprotein that is associated with coronary artery disease and stroke.
LP PLA2. 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.
Sleep Apnea. 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. 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 coronary artery disease (CAD) include:
Sometimes patients with CAD have few or no symptoms until they have heart attack or heart failure.
Angina 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:
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. 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:
Angina attacks can happen at any time during the day. But more occur between 6 a.m. and noon.
Other symptoms that may indicate angina or accompany the pain or pressure in the chest include:
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:
Unstable angina is usually discussed as part of a set of conditions called 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 developing 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
Prinzmetal's Angina. This type of angina is caused by a spasm of a coronary artery. It almost always occurs when at rest. Irregular heartbeats are common. But the pain is generally relieved promptly with standard treatment (nitrate medications or calcium channel blockers).
Silent Ischemia. Some people with severe coronary artery disease 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:
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 C-reactive protein (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.
The most important wave patterns in diagnosing and determining treatment for heart disease and heart attack are ST deviations and Q waves:
Exercise Stress Test
Exercise stress test for evaluation of coronary artery disease may be performed in the following situations:
Basic Procedure. A stress test (exercise tolerance test) monitors heart rhythms, 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:
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.)
Interpreting Results. To accurately assess heart problems, varieties of factors are measured or monitored using the ECG and other tools during exercise. They include:
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 an 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:
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.
Radionuclide Angiography. 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 acute coronary syndromes. 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 percutaneous coronary intervention (PCI, also called angioplasty and stenting).
In an angiography procedure:
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 coronary artery disease.
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 coronary artery disease. A higher calcium score may indicate an increased risk of current and future coronary artery disease. However, the presence of calcium does not necessarily signify narrowing of the arteries that would need further immediate evaluation or treatment.
CT Angiography. 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 truly has coronary artery disease 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.
Heart disease prevention is important before and after someone is diagnosed with the condition:
Key prevention measures include:
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.
Older guidelines recommended that patients with CAD should aim for LDL cholesterol levels of less than 100 mg/dL (or below 70 mg/dL for certain patients.) If patients cannot reach the LDL target through lifestyle measures, a statin drug is prescribed. Statin drugs are the primary medications used for lowering LDL ("bad") cholesterol levels. The latest guidelines for cholesterol treatment focus on reducing a patient’s overall risk for cardiovascular disease, rather than aiming for a target cholesterol number.
Manage High Blood Pressure
Keep Blood Pressure Low. People in normal health should have a blood pressure reading of 120/80 mm Hg or less. Blood pressure readings of 120/80 are considered normal, readings of 140/90 or higher indicate high blood pressure (hypertension), and readings in between the two are called pre-hypertension. Patients whose blood pressures stay above 140/90 despite lifestyle therapy (diet, exercise, and weight control) should be treated with blood pressure medications.
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 recommend:
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 coronary artery disease 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 coronary artery disease, 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 five 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) 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.
Sexual Activity. 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 never take 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.
Lifestyle changes (such as weight control, exercise, and quitting smoking) are the first approach for all degrees of coronary artery disease. Depending on severity and individual conditions, patients may also need one or more medications, surgery, or both.
Medications. Many types of medications are used to treat angina and CAD. They include:
Interventional Procedures and Surgery. Intervention is usually recommended for people who have:
The two main surgical procedures for patients with coronary artery disease are:
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.
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 surgical procedure cures coronary artery disease, 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 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 may be 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 anti-platelet drugs (one of which is almost always aspirin) are prescribed for patients with unstable angina, acute coronary syndrome (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. 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 coronary artery disease 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.
Clopidogrel. Thienopyridines are antiplatelet drugs. Clopidogrel (Plavix, generic) is the standard thienopyridine for patients with CAD.
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 should not take clopidogrel for at least 5 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:
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.
Side Effects. 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 most patients who have had heart attacks. They are particularly helpful for patients with coronary artery disease who also have diabetes or who have heart failure or left ventricular 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. 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. 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:
Nitroglycerin is very unstable so its potency can be easily lost. Patients should take the following precautions:
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:
Long-acting forms may lose their effectiveness over time, so doctors generally schedule nitrate-free breaks to prevent tolerance.
Side Effects. 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. Withdrawal from nitrates should be gradual. Abrupt termination may cause angina attacks.
Calcium Channel Blockers (CCBs)
Calcium channel blockers 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.
Side Effects. Patients 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 coronary artery disease are:
PCI and CABG are the standard procedures for dealing with narrowed or blocked arteries. PCI and CABG are revascularization procedures, which help restore blood flow (perfusion).
Angioplasty and Stenting (Percutaneous Coronary Intervention)
Angioplasty, also called percutaneous coronary intervention (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 coronary artery disease.
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 coronary artery disease. 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 coronary artery bypass grafting (CABG) may be more effective than angioplasty in preventing heart attacks and death in patients with blockage in several arteries.
Procedure. A typical angioplasty procedure follows these steps:
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 narrowing or reclosure (restenosis) of the artery, which can lead to heart attack if not treated with a repeat procedure. Stenting, anti-clotting drugs, and other advances have significantly helped prevent reclosure and reduce heart attack rates. Nevertheless, a repeat procedure is still needed to restore the opening in 10 to 15% of patients who have stents.
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").
Studies indicate that drug-eluting stents are safe and effective for patients with coronary artery disease 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 acute coronary syndrome, 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
Coronary artery bypass graft surgery (CABG) is an alternative to angioplasty (PCI) for many patients with severe coronary artery disease. 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:
Complications. 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.
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