Coronary Artery Disease (CAD) is the most common form of heart disease. CAD most often results from a condition known as Arteriosclerosis, which occurs when a waxy substance forms inside arteries that supply blood to the heart. This substance, called plaque, primarily consists of cholesterol, fatty compounds, calcium, and fibrin (a blood–clotting material).

If enough plaque collects in an artery that supplies blood to the heart, the blood flow slows or stops entirely. This resultant lack of oxygen–rich blood increases the risk of heart attack. Sometimes, the narrowed artery is blocked by a blood clot, causing a heart attack. Or, plaque may lead to the formation of blood clots. When plaque bursts or cracks, the body sends cells that aid in blood clotting (called platelets) to close the break. These platelets can form a clot at the site of the break, blocking the artery.

Causes of Coronary Artery Disease
Scientists think the disease begins when the innermost lining of the artery (the endothelium) is damaged. High blood pressure, elevated levels of cholesterol and triglycerides in the blood, and smoking are believed to promote the development of plaque.

Symptoms of Coronary Artery Disease
Arteriosclerosis may be present for years without causing symptoms. This slow, progressive disease process can begin in childhood. In some persons, the condition can cause symptoms by the time they reach their 30s. In others, it does not become apparent until they reach their 50s or 60s. However, as the blockage worsens, the impaired blood supply to the heart may begin to cause Angina Pectoris, a Latin phrase that means, “Strangling in the chest”. Patients often describe angina as a squeezing, suffocating, or burning sensation. The pain usually happens when the heart has an extra demand for blood, especially during exercise or emotional stress.

Angina tends to originate in the center of the chest but may radiate to the arm, neck, or jaw. Some persons experience numbness or loss of sensation in the arms, shoulders, or wrists. An episode usually lasts no more than a few minutes and typically subsides with rest.
For certain patients with coronary heart disease, angina may not be present. Sometimes, the heart’s oxygen deprivation (ischemia) causes no discomfort, in these cases, persons are said to have silent ischemia.