Coronary artery disease (CAD) is caused by atherosclerosis, when cholesterol enters the walls of the arteries and begins to form a plaque that hardens and narrows the arteries. Plaque is a sticky, fatty, cholesterol-rich substance that becomes embedded in the arterial walls.

Causes of Plaque Buildup

No one knows precisely what causes these deposits to form, but the following factors are thought to be responsible:

  • a high-fat diet
  • physical inactivity
  • smoking
  • genetic inheritance
  • high blood pressure
  • diabetes

Plaque stiffens the arteries and may narrow the space through which blood can flow. Plaque buildup has other ill effects too. It inflames the arterial lining, which in turn leads to microscopic scarring as the artery heals. This scarring thickens the arterial wall, further narrowing the artery and restricting blood flow.

A heart attack happens when a piece of cholesterol plaque ruptures off its base and moves downstream in the blood vessel to cause a blockage that is exacerbated by the development of a clot on the ruptured plaque.