Acute coronary syndrome is caused by narrowing of a coronary artery. The coronary arteries become narrowed by a process known as atherosclerosis, which is also called hardening of the arteries. Narrowed coronary arteries may not supply enough oxygen to meet the demands of the heart muscle. Symptoms of acute coronary syndrome occur during activities that increase the activity of the heart.

The process of atherosclerosis includes:

• The inner wall of the artery becomes damaged by:
• Changes in blood flow
• Infection
• Smoking
• Diabetes
• High blood pressure
• As the wall or the artery attempts to repair itself, cholesterol builds up on the inside surface of the artery, forming a plaque.
• Plaques narrow the inside of the arteries, which reduces blood flow. This can lead to blood clot formation inside the vessel.

Examples:

• Atherosclerosis
• Blood clot formation within a vessel