Coronary artery disease (CAD) is the most common type of heart disease. It occurs when the arteries that supply blood to the heart muscle (the coronary arteries) become hardened and narrowed. The arteries harden and narrow due to buildup of a material called plaque on their inner walls. The buildup of plaque is known as atherosclerosis. As the plaque increases in sized, the insides of the coronary arteries get narrower and less blood can flow through them.
Eventually, blood flow to the heart muscle is reduced, and, because blood carries much-needed oxygen, the heart muscle is not able to receive the amount of oxygen it needs. Reduced or cut-off blood flow and oxygen supply to the heart muscle can result in angina, heart attack, heart failure, arrhythmia, and vascular heart disease.