Coronary Artery Disease 101: Causes, Symptoms, Treatment & Prevention

What is Coronary Artery Disease? Learn about the causes and symptoms of coronary heart disease and ways to treat and prevent it.

by Elaine Francis, R.N.

What Is Coronary Artery Disease?

Our heart is a muscle, and like all muscles, it needs to have a healthy supply of blood. Coronary arteries are the blood vessels that transport blood, oxygen and nutrients to our heart.

How does our heart receive its own supply of blood?

When the heart beats, oxygenated blood is pushed through our aorta, the big vessel that all blood has to go through from the heart to the rest of the body. The first small vessel that branches off the aorta goes to our coronary arteries to supply the heart muscle with oxygen and nutrients and keep it pumping. There are three main coronary arteries, and each of these branches off into smaller and smaller vessels to supply necessary oxygen and nutrients to every part of the heart muscle.

Coronary artery disease (CAD) occurs when our coronary arteries – the major blood vessels that supply blood to our heart – is damaged or diseased. Some of the other names commonly used to refer to CAD include:

  • Coronary heart disease: a disease of the coronaries (i.e. the vessels feeding the heart muscle)
  • Ischaemic heart disease: a heart disease caused by reduced blood flow to the heart muscle. 
  • Atherosclerosis: a condition characterised by narrowed, hardened arteries, and fatty plaques, which are deposits of cholesterol and other substances inside the vessels creating extra narrow areas. 

Ischaemic heart disease accounts for almost 20% of all deaths in Singapore and is becoming increasingly common.

In coronary artery disease, there are narrowings or blockages within those blood vessels. This means that the blood supply, and therefore the essential supply of oxygen and nutrients, is reduced or cut off to the part of the heart muscle that’s connected to the diseased artery. 

Every part of the coronary circulation can be affected, but there will typically be some narrowed areas that are worse than others. The severity of the reduction of blood flow and the area of the heart affected can make a big difference to the management and outcome of coronary heart disease. 

Atherosclerosis can slowly reach a point where it causes restricted blood flow, or it can worsen and cause acute problems very quickly. If we have a fatty build up in the vessel, the surface of this build-up can be quite unstable, and may suddenly rupture or shear off. Our bodies’ natural response to a rupture of tissue in the vessels is to start a clotting process, which creates a thrombus or clot in this already narrow area of the blood vessel. This can lead to a complete blockage of the vessel and severely limit blood supply to the heart.

Reduced blood supply causes damage to the muscle of the heart, and we call that ischaemia. Completely restricted blood supply effectively causes areas of dead tissue, and we call that infarction.

What Causes Coronary Heart Disease?

Some people are more likely to develop coronary heart disease than others, and we have a good understanding of many of the causes and risk factors for heart disease. Some of these risk factors are things that we can change, while some are not. We call them modifiable and non-modifiable risk factors respectively.

Non-modifiable Risk Factors

  • Age: As we age, our risk of coronary artery disease goes up. We are also more likely to have other, related or unrelated health conditions as we get older.
  • Gender: Men are more at risk of coronary artery disease than women, for a combination of reasons, some genetic, some environmental.
  • Family History: We are more likely to develop heart disease if we have a close relative who has or had the disease. The risk is even higher if our family member developed coronary artery disease at a young age.

Modifiable Risk Factors

  • Smoking
  • High alcohol intake
  • Obesity: Obesity is often associated with an unhealthy diet, lack of exercise, and high cholesterol. Even without those factors, however, being overweight puts you at a higher risk of heart disease, among other conditions.
  • A sedentary lifestyle
  • High blood pressure 
  • High cholesterol
  • Diabetes

Coronary Heart Disease Symptoms

The fatty lining and plaques in the blood vessels build up slowly at first, so a person may have had coronary artery disease for years before any symptoms even appear.

Once a person starts experiencing symptoms, we may begin discussing acute coronary syndrome (ACS). ACS describes the spectrum of conditions that a person with coronary artery disease may experience. The symptoms of every type of ACS are similar, and includes:

  • Shortness of breath
  • Sudden fatigue
  • Chest pain, pressure or tightness
  • Pain in the left arm or jaw

Some of the conditions under ACS include:

  • Stable angina: Individuals with stable angina tend to experience the symptoms of ACS upon exertion. When we exercise, our bodies need more oxygen to be pumped to the muscles, so our heart works harder and faster. If a narrowed vessel means that part of the heart muscle doesn’t get enough oxygen to meet this increased demand, we get chest pain. If this pain subsides when we rest, we call it stable angina.
  • Unstable angina: Individuals with unstable angina may experience the symptoms upon exertion or at rest. These symptoms may come and go without any obvious cause and are harder to manage. Unstable angina requires urgent medical attention.
  • Myocardial Infarction (MI): Also known as a heart attack, MIs are further subcategorised into NSTEMI or STEMI, which describe how severe the heart attack is based on the tests they do in a hospital. An MI is a medical emergency.

Different people feel heart pain in different ways, with particular differences between men’s and women’s experiences. We shouldn’t rely solely on symptoms to make a diagnosis so it’s always important to get chest pain checked out by a medical professional who can do a range of tests.

Diagnosing Coronary Heart Disease

If you go to a hospital or consult a medical professional with symptoms like chest pain or shortness of breath, the first line of action will be to rule out or confirm a heart attack. They may also look out for other conditions which may cause chest pain, such as lung problems or other heart conditions.

The tests carried out on people with symptoms of coronary heart disease or ACS include:

Blood Tests

If you’ve had some sudden chest pain or related symptoms, your doctor will have a blood test done. Routine bloods may include tests for kidney and liver function, anaemia and infection markers. More specific tests for heart disease are a Troponin test – this is a blood test for a chemical that the heart releases when it is damaged. This test will be repeated a few hours after the first one – it is the difference between the two numbers which tells the doctor whether this is an acute or ongoing event. If a heart disease is suspected, tests for cholesterol may be done at this point.

Electrocardiogram (ECG)

An electrocardiogram (ECG) is a test where wires are attached to your chest with stickers, measuring the electrical activity of your heart with each heartbeat and drawing a graph which indicates if there are any areas of the heart which are damaged, where they are, how bad the damage is, and whether it is evolving. The doctors and nurses may take an ECG when you have pain and another when you don’t, because if there are different readings with or without pain, that can be significant.

Heart Monitoring

People with areas of damage or ischaemia in the heart muscle are more likely to have problems with heart rhythm, especially in the first few hours and days after an acute event like a heart attack. If you are hospitalised, you may have to stay attached to a heart monitor which shows an ongoing reading of your heart rhythm.


Sometimes referred to as ‘echo’ or ‘trans-thoracic echo (TTE)’, this is an ultrasound scan where jelly is put on your chest and a wand is moved over it to show the practitioner an ultrasound picture of the structure and function of the heart. There is also a trans-oesophageal echo (TOE) which shows a similar picture of the heart using a small tube passed into the throat.

Other types of tests include different medical imaging techniques such as CT or MRI scans which can tell us more about the function and structure of the heart and the narrowings in the blood vessels. There are also stress tests to show how the heart functions when it is made to work harder.

Coronary Artery Disease Treatment

Medications for Heart Disease

There are several types of medication offered to people with coronary artery disease. Medication for cholesterol such as statins are regularly recommended to prevent serious problems for high-risk people, even if blood tests show acceptable levels of cholesterol. Blood thinners such as low doses of aspirin are routinely given to maintain good blood flow through narrowed areas of the coronary arteries.


If you experience symptoms of angina (or chest pain), you may be given a type of fast-acting nitrate medication in the form of a spray or a tablet that dissolves in the mouth under the tongue or next to the gum. These are drugs that widen the blood vessels, meaning that blood flow improves through areas of narrowed vessels, relieving heart pain. These can be used as and when required, though if you find that you’re using them frequently, it’s important to see a doctor to consider longer-acting anti-anginal medications or other treatment.

Coronary Angiogram or Angioplasty

A coronary angiogram is both a diagnostic test and a treatment intervention for coronary artery disease. It involves having a small tube passed through an incision made either at the wrist or the groin, which is guided up through blood vessels into the circulation of the heart. A dye is injected into these blood vessels, which shows us where the narrowed areas are on an x-ray. The same tube has a tiny balloon at the end which can be positioned in the narrow areas to compress any fatty deposits, improving blood flow. A stent – a small tube of metal mesh – can be left in place. This mesh beds into the vessel to keep narrow areas open. This test can sometimes indicate slightly narrowed areas which may need further treatment at a later date.

Coronary Artery Bypass Grafts

If there are areas of the coronary arteries which are totally blocked or cannot be opened sufficiently with simpler interventions, bypass surgery may be needed. In this type of heart surgery, a vein is taken from the leg and grafted on to the coronary circulation to take blood past the blocked area. This is open heart surgery and isn’t suitable for everyone, but can be a life-saving treatment.

Lifestyle Changes

Improving your diet, exercising more and tackling any of your modifiable risk factors for disease are important ways to improve your coronary artery disease and reduce the need for more or repeated invasive treatment. You may be offered an education and exercise programme to help you get healthier.

Coronary Heart Disease Prevention

Being aware of your risk factors for coronary artery disease is the first step; reducing your modifiable risk factors is the single best thing you can do to reduce your risk of serious or worsening coronary artery disease:

Stop Smoking

Quitting smoking not only reduces your risk of coronary artery disease but other deadly health problems as well. Attempting to stop smoking can be hard, but help is always available, and it is one of the best things you can do for your and your family’s health.

Limit Your Alcohol Intake

Staying within the recommended guidelines for alcohol intake can reduce your risk of coronary artery disease and other diseases.

Eat Healthily

Improving your diet can vastly reduce your risk of coronary artery disease. It’s never too late to start. Add more fruit, vegetables and lean proteins into your diet and choose healthier fats for better health, cholesterol, and waistline today.


Leading a sedentary lifestyle – one where you sit a lot – is one of the biggest risk factors for coronary artery disease. Fitting a little – or a lot – more exercise into your day can make a lot of difference.

Attend Regular Health Checks

A healthcare professional can help you to assess your risk and take positive steps to change. Attending medical checkup also means you can have bloods taken regularly to assess your cholesterol and test for your risk of diabetes, as well as other serious conditions. If you find it troublesome or hard to make time to visit a clinic for health screenings, you’ll be happy to know that health screening can be conducted in the comfort of your home too.

It’s not always easy to make these changes in your lifestyle, but it can significantly reduce your risk of heart vessel disease and other life-threatening illnesses, giving you a longer, healthier life. A little effort goes a long way. 

If you’re concerned about your risk of coronary artery disease, consult a doctor for more personalised advice. If you’re having chest pains, seek urgent medical attention.

If you need support caring for a loved one with coronary artery disease, we can help.

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  4. Lockyer, L. (2005). Women’s interpretation of their coronary heart disease symptoms. European journal of cardiovascular nursing: journal of the Working Group on Cardiovascular Nursing of the European Society of Cardiology, 4(1), 29.
  5. World Health Organization. (2020). Hearts: technical package for cardiovascular disease management in primary health care.
  6. Goh, L. G., Chua, T., Kang, V., Kwong, K. H., Lim, W. Y., Low, L. P., … & Tan, C. L. B. (2011). Ministry of health clinical practice guidelines: screening of cardiovascular disease and risk factors. Singapore medical journal, 52(3), 220-227.
About the Writer
Elaine Francis, R.N.
Elaine Francis is a registered nurse with 17 years’ experience in healthcare. She turned to writing to follow her passion for realistic medical communication. She loves translating medical jargon into accessible language for the people who need to understand it most. When she’s not writing or working on a busy cardiology unit, she spends her time telling her children to hurry up.
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