Coronary artery disease describes a condition where the coronary arteries that supply the heart with oxygen and nutrients become hardened and narrowed. This is caused by the build up of fatty deposits called plaques within the endothelial lining of the arteries.
The formation of a plaque in the artery is called atherosclerosis and the plaque is called an atheroma. Eventually, the plaque can harden the artery wall causing it to narrow, reducing the blood flow and supply of oxygen and nutrients to the heart. The plaque may also rupture, in which case a blood clot may form on its surface and almost completely prevent blood from passing through the artery. Eventually, a ruptured plaque also hardens and reduces the diameter of the artery.
These hardened and narrow arteries may lead to symptoms such as angina, a pain in the chest which may be brought about by physical activity, emotional upset or even just eating a meal. As the plaques continue to grow in size and the blood vessels narrow, the risk of obstructed blood flow and a heart attack or myocardial infarction increases. Atherosclerosis also affects other blood vessels and the risk of stroke and kidney damage is increased due to the presence of plaques in the brain and kidneys.
Patients with coronary artery disease may have one or more plaques in their coronary arteries and unless the blockages are severe, there may be no symptoms. As the blockages increase in size, however, angina may develop. In cases of suspected heart disease, a coronary angiogram may be performed to assess the state of the coronary arteries. For this test, a special dye is injected into the blood vessels and images of the heart are obtained that show how blocked the arteries are.
Typical characteristics of patients who are at high risk of coronary artery disease include:
- Men older than 40 years
- Postmenopausal women
- Younger people who already have other risk factors such as diabetes, high blood pressure or previous history of a heart attack
- Presence of chest pain (angina) that spreads to the left arm, neck, back, throat or jaw
- Electrocardiogram showing ST segment depression
- Symptoms ease when nitrates are taken
Reviewed by Sally Robertson, BSc