Coronary Artery Disease

Table of Contents

Coronary artery disease (CAD) is the most common type of heart disease. 

CAD occurs when the arteries that supply blood to the heart muscle become hardened and narrowed. This is due to the buildup of cholesterol and other materials, called plaque, on the inner walls. This buildup is called atherosclerosis. Plaque buildup occurs over the years. Over time, plaque can harden or break (break open). The hardened plaque constricts the coronary arteries and reduces the flow of oxygen-rich blood to the heart.

If plaque breaks, blood clots can form on the surface. Large blood clots can largely or completely block blood flow through the coronary arteries. Over time, plaque rupture also hardens and narrows the coronary arteries.

As a result, the heart muscle cannot get the blood or oxygen it needs. This can cause chest pain (angina) or a heart attack. Most heart attacks occur when a blood clot suddenly cuts off the heart’s blood supply, causing permanent heart damage.

Over time, CAD can also weaken the heart muscle and contribute to heart failure and arrhythmias. Heart failure means the heart cannot pump blood properly to the rest of the body. Arrhythmias refers to changes in your heart beat rhythm.

Overview of Coronary Artery Disease

If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, an angina or a heart attack can occur. Angina is pain or discomfort in the chest. You may feel pressure against your chest. Pain can also occur in the shoulder, arm, neck, jaw, or back. Angina pain may even feel like a digestion problem.

A heart attack occurs when the flow of oxygen-rich blood to a part of the heart muscle is cut off. If blood flow doesn’t recover quickly, that part of the heart muscle begins to die. Without prompt treatment, a heart attack can lead to serious health problems or death.

Over time, CAD can weaken the heart muscle and lead to heart failure and arrhythmias. Heart failure is a condition in which your heart can’t pump enough blood to meet your body’s needs. Arrhythmias are problems with the rate or rhythm of the heartbeat.

Lifestyle changes, medications, and medical procedures can help prevent or treat coronary heart disease. This treatment can reduce the risk of related health problems.

Causes of Coronary Artery Disease

Research shows that coronary artery disease (CAD) starts when certain factors damage the inner lining of the coronary arteries. These factors include: 

  • Smoking habits
  • High levels of certain fats and cholesterol in the blood
  • High blood pressure
  • High sugar levels in the blood due to insulin resistance or diabetes
  • Inflammation of blood vessels

Plaque may start to build up in the damaged part of the artery. The buildup of plaque in the coronary arteries may begin since childhood.

Over time, plaque can harden or rupture (break open). The hardened plaque constricts the coronary arteries and reduces the flow of oxygen-rich blood to the heart. This can cause angina (chest pain or discomfort in the chest).

If the plaque breaks, fragments of blood cells called platelets attach to the injured part.  The plaque fragments may collect to form a blood clot.

Blood clots can further narrow the coronary arteries and worsen angina. If they become large enough, the blood clot can largely or completely block the coronary arteries and cause a heart attack.

Risk Factors of Coronary Artery Disease

Certain characteristics, conditions, or habits can increase your risk of developing CAD. The more risk factors you have, the higher chances for you to develop the disease.

You can control many risk factors that can help prevent or delay CAD.

Main Risk Factors

  • Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called “bad” cholesterol) and low HDL cholesterol (sometimes called “good” cholesterol).
  • High blood pressure. High blood pressure is when it stays at or above 140/90 mmHg from time to time. If you have diabetes or chronic kidney disease, high blood pressure is at 130/80 mmHg or higher. (mmHg is a millimeter of mercury – a unit used to measure blood pressure.)
  • Smoking habits. Smoking can damage and constrict blood vessels, increase unhealthy cholesterol levels, and raise blood pressure. Smoking can also limit how much oxygen gets into the body’s tissues.
  • Insulin resistance. This condition occurs when the body cannot use its own insulin properly. Insulin is a hormone that helps move blood sugar to the cells where it is used to produce energy. Insulin resistance can lead to diabetes.
  • Diabetes. Diabetes is when your blood sugar level is too high since your body neither produces enough insulin nor uses its insulin properly.
  • Being overweight or obese. The terms “overweight” and “obese” refer to weight that is higher than what is considered as a healthy weight for a given height. 
  • Metabolic syndrome. Metabolic syndrome refers to  a group of risk factors that increase your risk of developing CAD and other health problems, such as diabetes and stroke.
  • Lack of physical activity. Being physically inactive can worsen other risk factors for CAD – such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and being overweight or obese.
  • Unhealthy diet. An unhealthy diet can increase your risk of developing CAD. Food sources that are high in saturated and trans fats, cholesterol, sodium, and sugar can worsen other risk factors for CAD.
  • Older age. Genetic or lifestyle factors cause plaque to build up in your arteries as you get older. In men, the risk of coronary heart disease might start increasing at age 45. In women, the risk of coronary heart disease may start increasing at age 55.

Family history of coronary artery disease is also a risk factor for developing coronary heart disease – particularly, if your father or brother is diagnosed before the age of 55, or when your mother or sister is diagnosed before age 65.

Although older age and a family history of heart disease are risk factors, it does not mean that you will develop CAD if you have one or both. Controlling other risk factors can help lower genetic influence and help prevent CAD – even in older adults.

Emerging Risk Factors

Researchers are still studying other possible risk factors for CAD.

High levels of a protein called C-reactive protein (CRP) in the blood can increase the risk of CAD and heart attack. High CRP levels are a sign of inflammation in the body. Inflammation is how your body reacts to an injury or infection. Damage to the inner walls of the arteries can trigger inflammation and promote plaque growth.

Researchers are still trying to find out whether reducing inflammation and lowering CRP levels can also reduce the risk of CAD and heart attack.

High levels of triglycerides in the blood can also increase the risk of CAD, especially in women. Triglycerides are a type of fat found in your blood.

Other Risks Associated with Coronary Artery Disease

Other conditions and factors can also contribute to CAD, including:

  • Sleep apnea. Sleep apnea is a common disorder, in which you have one or more pauses in breathing or shallow breaths during sleep. Untreated sleep apnea can increase your risk of high blood pressure, diabetes, and even heart attack or stroke.
  • Stress. Research shows that the most commonly reported “triggers” for heart attacks are upsetting life events — particularly those involving anger. 
  • Alcohol. Consuming excess alcohol can damage the heart muscle and worsen other risk factors for CAD. It is recommended for men to have not more than two alcohol drinks a day. As for women, it is recommended to have not more than one alcohol drink a day.
  • Preeclampsia. This condition can occur during pregnancy. The two main signs of preeclampsia are increased blood pressure and excess protein in the urine. Preeclampsia is associated with an increased lifetime risk of heart disease, including CAD, heart attack, heart failure, and high blood pressure.

Signs and Symptoms of Coronary Artery Disease

A common symptom of coronary heart disease (CAD) is angina. Angina is chest pain or chest discomfort that occurs when an area of ​​your heart muscle does not get oxygen-rich blood. Angina may feel like pressure or squeezing in the chest. You can also feel it in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. The pain tends to get worse when you perform daily activities and may go away when you rest. Emotional stress can also trigger the pain.

Another common symptom of CAD is shortness of breath. These symptoms occur if CAD causes heart failure. When you have heart failure, your heart cannot pump enough blood to meet your body’s needs. Fluid builds up in the lungs, making it difficult for you to breathe.

The severity of these symptoms varies – they may become more severe as plaque buildup continues to narrow the coronary arteries.

Signs and Symptoms of Heart Problems Related to Coronary Artery Disease

Some people who have CAD have no signs or symptoms — a condition called silent CAD. This disease may not be diagnosed until a person experiences signs or symptoms of a heart attack, heart failure, or arrhythmia (irregular heartbeat).

Heart attack

A heart attack occurs when the flow of oxygen-rich blood to a part of the heart muscle is cut off. This can occur if the plaque area in the coronary artery ruptures (breaks open).

Blood cell fragments called platelets attach to the injury site and may collect to form a blood clot. If the clot becomes large enough, it can largely or completely block blood flow through the coronary arteries. If the blocked artery is not reopened quickly, the part of the heart normally nourished by the artery begins to die. The healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe, persistent complications.

The most common symptom of a heart attack is chest pain or discomfort in the chest. Most heart attacks involve discomfort in the center or left side of the chest that often lasts for more than a few minutes or comes and goes away. Your chest may feel uncomfortable pressure, squeezing, or dull pain. Heart attack pain can sometimes feel like indigestion or a burning sensation in the chest (heartburn).

The symptoms of angina may be similar to heart attack. Angina pain usually lasts only a few minutes and disappears as you rest.

Chest pain or discomfort that does not go away or changes from its usual pattern (for example, occurs more frequently or when you are resting) may be a sign of a heart attack. If you are not sure if your chest pain is angina or a heart attack, call the hospital right away.

All chest pain symptoms should be examined by a doctor.

Other common signs and symptoms of a heart attack include:

  • Upper body discomfort in one or both arms, back, neck, jaw, or upper abdomen
  • Shortness of breath, which may occur with or before chest discomfort
  • Nausea, vomiting, dizziness or fainting, or cold sweats
  • Sleep problems, fatigue (tiredness), lack of energy

Heart failure

Heart failure is a condition in which your heart cannot pump enough blood to meet your body’s needs. Heart failure does not mean your heart has stopped or will stop working.

The most common signs and symptoms of heart failure are shortness of breath or difficulty breathing; fatigue; and swelling of the ankles, feet, legs, abdomen, and veins in the neck.

All of these symptoms are a result of fluid buildup in your body. When symptoms start, you may feel tired and experience shortness of breath after doing routine physical activity, such as climbing stairs.


Arrhythmias are problems with the rate or rhythm of the heartbeat. When you have an arrhythmia, you may notice that your heart is beating too fast.

Some people describe arrhythmia as a feeling of palpitations in the chest. 

Some arrhythmias can cause your heart to suddenly stop beating. This condition is called sudden cardiac arrest (SCA). SCA can cause sudden death if not treated within minutes.

Diagnosis of Coronary Artery Disease

Your doctor will diagnose coronary artery disease (CAD) based on your personal and family’s health history, risk factors for CAD, a physical exam, and the results of tests and procedures.

There is no single test that can diagnose CAD. If your doctor thinks you have CAD, he or she may recommend one or more of the following tests.

ECG (Electrocardiogram)

An ECG is a simple, painless test that detects and records the electrical activity of the heart. The test shows how fast the heart is beating and its rhythm (normal or irregular). The ECG also records the strength and timing of electrical signals as they pass through the heart.

An ECG can show signs of heart damage from CAD and signs of a previous or current heart attack.

Stress Test

In a stress test, you will be asked to exercise to make your heart work harder and beat faster while a heart test is being done. If you are unable to exercise, you may be given medication to increase your heart rate.

When it is working harder and beating faster, the heart needs more blood and oxygen. Narrowed arteries due to plaque cannot provide oxygen-rich blood to meet the needs of your heart.

A stress test can show possible signs and symptoms of CAD, such as:

  • Abnormal changes in your heart rate or blood pressure
  • Shortness of breath or chest pain
  • Abnormal changes in your heart rhythm or the electrical activity of your heart

If you can’t exercise for as long as what is considered normal for someone your age, your heart may not be getting enough oxygen-rich blood. However, other factors can also keep you from exercising long enough –for example, lung disease, anemia, or poor general health. 

As part of some stress tests, pictures are taken of your heart while you exercise and while you rest. This imaging stress test can show how well blood is flowing in your heart and how well your heart pumps blood when it beats.


Echocardiography (echo) uses sound waves to create a moving picture of your heart. The images show the size and shape of your heart and how well your heart chambers and valves are working.

Echo can also show areas of poor blood flow to the heart, areas of the heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow.

Chest X-ray

A chest x-ray or x-ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels.

Chest X-rays can reveal signs of heart failure, as well as lung disorders and other causes of symptoms not related to CAD.

Blood Test

Blood tests check the levels of fats, cholesterol, sugar, and certain proteins in your blood. Abnormal levels may be a sign that you are at risk for CAD.

Coronary Angiography and Cardiac Catheterization

Your doctor may recommend coronary angiography if tests or other factors suggest that you may have CAD. This test uses a dye and special X-rays to show the inside of your coronary arteries.

To get dye into the coronary arteries, the doctor will use a procedure called cardiac catheterization. A thin, flexible tube called a catheter is inserted into a blood vessel in your arm, groin (upper thigh), or neck. The tube is inserted into your coronary artery, and the dye is released into your bloodstream.

A special X-ray is taken as the dye travels through your coronary arteries. The dye allows your doctor to study the blood flow through your heart and blood vessels.

Cardiac catheterization is usually done in a hospital. You will stay awake during the procedure. It normally causes little or no pain – although you may feel some pain in the vein when the doctor inserts the catheter.

Treatment for Coronary Artery Disease

Treatment for coronary artery disease includes heart-healthy lifestyle changes, medications, medical and surgical procedures, and cardiac rehabilitation. The objectives of treatment may include:

  • Reduce the risk of blood clots forming (blood clots can cause a heart attack)
  • Prevent complications of coronary heart disease
  • Reduce risk factors in an attempt to slow, stop, or reverse plaque buildup
  • Relieve symptoms
  • Widen or bypass blocked arteries

Lifestyle Changes for Better Heart Health

Your doctor may recommend heart-healthy lifestyle changes if you have coronary heart disease. Heart-healthy lifestyle changes include:

  • Heart-healthy diet
  • Maintain a healthy body weight
  • Manage stress
  • Physical activity
  • Quit smoking


Sometimes lifestyle changes are not enough to control blood cholesterol levels. For example, you may need statin drugs to control or lower cholesterol.

Your doctor may discuss starting treatment if you are at high risk for developing heart disease or having a stroke.

Your doctor may also prescribe other medications to:

  • Lower your chances of having a heart attack or sudden cardiac death
  • Lower your blood pressure.
  • Prevent blood clots, which can lead to heart attack or stroke.
  • Prevent or delay the need for stents or percutaneous coronary intervention (PCI) or surgical procedure, such as coronary artery bypass grafting (CABG).
  • Reduce the workload of your heart and relieve symptoms of coronary heart disease.

Take all medicines regularly as prescribed by your doctor. Do not change or skip your dose unless your doctor tells you to. You still have to maintain a heart-healthy lifestyle — even if you are still taking meds to treat your coronary artery disease.

Medical and Surgical Procedures

You may need either surgical or non-surgical procedures to treat coronary artery disease. Both PCI and CABG are used to treat blocked coronary arteries. Consult with your doctor to discuss the right treatment for you.

Percutaneous Coronary Intervention

Percutaneous coronary intervention or commonly known as angioplasty – is a non-surgical procedure that opens blocked or narrowed coronary arteries. A thin, flexible tube with a balloon or other device at the end is threaded through a blood vessel into a narrowed or blocked coronary artery. Once in the targeted place, the balloon is inflated to press plaque against the artery wall. This restores blood flow through the arteries.

During the procedure, your doctor may place a small mesh tube called a stent in your artery. Stents help prevent blockages in the arteries in the months or years after the angioplasty.

Coronary Artery Bypass Grafting

CABG is a type of surgery in which an artery or vein from another part of ​​your body is used to bypass around the narrowed coronary arteries. This bypass surgery increases blood flow to your heart, relieves chest pain, and possibly prevents a heart attack.

Cardiac Rehabilitation

Your doctor may prescribe cardiac rehabilitation (rehab) for angina or after CABG, angioplasty, or heart attack. Nearly everyone who has coronary heart disease can benefit from cardiac rehabilitation. Cardiac rehabilitation is a medically supervised program that can help improve the health and well-being of people who have heart problems.

The cardiac rehabilitation team includes doctors, nurses, sports specialists, physical and occupational therapists, dietitians or nutritionists, and psychologists or other mental health professionals

Rehab has two parts:

  • Education, counseling and training. This section of rehabilitation helps you understand the condition of your heart and find ways to reduce your risk for future heart problems. The rehab team will help you learn how to deal with stress to adjust to your new lifestyle and how to deal with your fears about the future.
  • Sports training. This section helps you learn how to exercise safely, strengthen your muscles and increase your stamina. Your training plan will be based on your personal abilities, needs and interests.

Treatment for Patients Diagnosed with Coronary Artery Disease

Coronary artery disease (CAD) can cause serious complications. However, if you follow your doctor’s advice and adopt healthy lifestyle habits, you can prevent or reduce the risk of:

  • Having sudden cardiac death
  • Having a heart attack and damaging your heart muscle
  • Damaging your heart due to reduced oxygen supply
  • Experiencing arrhythmias (irregular heartbeats)

Continuous Care

Lifestyle changes and medications can help control CAD. Lifestyle changes include following a healthy diet, being physically active, maintaining an ideal weight, quitting smoking, and managing stress.

Work with your doctor to control your blood pressure and manage your blood cholesterol and blood sugar levels. A blood test called a lipoprotein panel will measure your cholesterol and triglyceride levels. Also, a fasting blood glucose test will check your blood sugar levels and show if you are at risk for or have diabetes.

These tests show if your risk factors are under control, or if your doctor needs to adjust your treatment for better results.

Talk with your doctor about how often you should schedule visits to the doctor’s office or get blood tests. Between visits, call your doctor if you experience new symptoms or if your symptoms get worse.

Warning Signs for Heart Attack 

CAD increases your risk of having a heart attack. Learn the signs and symptoms of a heart attack if you experience any of these:

  • Chest pain or discomfort. This involves pressure, squeezing, abdominal pain, or pain in the center or left of the chest that can be mild or strong. This pain or discomfort often lasts more than a few minutes or comes and go
  • Upper body discomfort in one or both arms, back, neck, jaw, or upper abdomen.
  • Shortness of breath — which may occur with or before chest discomfort.
  • Nausea (feeling nauseous), vomiting, dizziness, fainting, or cold sweats.

Symptoms may also include sleep problems, tiredness, and lack of energy. The symptoms of angina can be similar to heart attack. Angina pain usually lasts only a few minutes and disappears with rest.

Chest pain that does not go away or changes from its usual pattern (for example, occurs more frequently or when you are resting) may be a sign of a heart attack. If you are not sure if your chest pain is angina or a heart attack, call the hospital.

Let the people you see daily know that you are at risk for a heart attack. They can seek emergency care for you if you suddenly pass out, collapse, or have other severe symptoms.

Emotional Issues and Support

Living with a CAD condition may cause you to live in fear, anxiety, depression, and stress. You may be worried about your heart condition or lifestyle changes that you need to implement in your life. 

Share your feelings with your healthcare provider. Talking to a professional counselor may also help. If you are very depressed, your doctor may recommend medications or other treatments that can improve your quality of life. Participating in a support group with fellow patients can help you adjust to CAD. You can see how other people who have had the same symptoms cope with it. Ask your doctor about local support groups or check with your local health centre. 

Support from family and friends can also help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.

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