What is coronary artery disease
and what causes it?

About Coronary Artery Disease (CAD)

Coronary artery disease (CAD), also called coronary heart disease (CHD), or simply heart disease, happens when plaque builds up in the arteries, reducing blood flow to the heart.

ventually, this can lead to a heart attack and can cause permanent damage to the heart muscle.

Over time, CAD can weaken the heart muscle, contributing to heart failure and abnormal heart rhythms, called arrhythmias. If the heart cannot pump blood effectively, this will lead to insufficient blood supply to the rest of the body and organs. All these will lead to severe complications.

For both men For both men and women, CAD is the leading cause of death around the world.

Source: WHOAmerican Heart Association,  webMDNIH: National Heart, Lung, and Blood Institute

What causes heart disease?

Coronary artery disease (CAD) is caused by a build-up of plaque in the arteries. Plaque is made up of cholesterol, calcium and other substances. This process is called atherosclerosis of the arteries.

Atherosclerosis will cause narrowing of the coronary arteries, causing the heart to receive less blood and oxygen. Without adequate blood flow from the coronary arteries to the heart, other parts of the body will also be affected.

A narrowed coronary artery may cause chest pain (angina), shortness of breath or other symptoms. A completely blocked artery can result in a heart attack.

What risk factors should people be aware of?

The more risk factors a patient has, the higher the risk of having CAD. Risk factors include:

  • Age (the elderly are at higher risk)
  • Family history of heart disease
  • Smoking
  • High blood pressure
  • Diabetes
  • Being overweight or obese
  • Lack of physical activity
  • Stress
  • Excessive alcohol intake
  • High levels of cholesterol

Source: WebMD, NIH, BHF


Coronary artery disease can lead to:

Chest pain (angina). Due to narrowed arteries, the heart may not receive enough blood when demand is greatest — e.g. during physical activity. This can cause chest pain (angina) or shortness of breath.

Heart failure. If the heart is chronically deprived of oxygen and nutrients, or if the heart muscle is severely damaged  from a heart attack (due to a delay in seeking treatment), the heart becomes too weak to pump enough blood to meet the body’s needs. This condition is known as heart failure.

Heart attack. When the artery is completely blocked by a blood clot due to a ruptured plaque, heart attack will occur. The heart muscle might be damaged if treatment is not received quickly. Hence, the saying, “Time is myocardium.”

Abnormal heart rhythm (arrhythmia). Inadequate blood flow to the heart or damage to heart tissue can interfere with the heart’s electrical impulses, causing abnormal heart rhythms.

Source: Mayo Clinic

Symptoms of CAD

The most common symptom of CAD is angina (chest pain).

  • Chest pain (angina). Angina, which is usually triggered by emotional or physical stress, may be felt as pressure or tightness in the chest. This pain usually occurs on the middle or left side of the chest and usually goes away within minutes after stopping the stressful activity. In some people, especially women, this pain may be fleeting or sharp and felt in the neck, arm or back.
  • Shortness of breath. If the heart can’t pump enough blood to meet the body’s needs, the patient may develop shortness of breath or extreme fatigue with exertion.
  • Heart attack. A completely blocked coronary artery will cause a heart attack. The classic signs and symptoms of a heart attack include crushing pressure in the chest and pain in the patient’s shoulder or arm, sometimes with shortness of breath and sweating.

Women are somewhat more likely to experience less typical signs and symptoms of a heart attack such as neck or jaw pain, than men. Sometimes a heart attack occurs without any apparent signs or symptoms.

Source: Mayo Clinic

Diagnosis of CAD

If a doctor suspects CAD, he or she may refer the patient to a specialist in cardiology.  The doctor will consider the patient’s symptoms, medical history and risk factors before conducting an appropriate test to diagnose the problem.

The most common tests include:

  • Electrocardiogram (ECG)
  • Exercise treadmill test
  • Echocardiography (Echo)
  • Myocardial perfusion scan
  • Electron-Beam Computed Tomography (EBCT)
  • Magnetic Resonance Imaging (MRI)
  • Cardiac Catheterization and Coronary Angiogram

Source: WebMD

Coronary Angiogram

This is a diagnostic invasive procedure, where the right and left side of the coronary arteries will be assessed to check for any narrowing. It can be a single vessel or multiple vessel that has narrowing. The ability of the heart to pump blood will also be assessed. 

Based on the severity of the disease, the anatomy, patient history and other factors, the physician will advise appropriate treatment.

Source: NHS

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Coronary Stent