Coronary Artery Disease (CAD) is the most common type of heart disease. It obstructs the blood flow in vessels that supply blood to the heart, caused by the accumulation of plaque on the walls of arteries. Plaque is a yellow substance consisting of fat substances, such as cholesterol, that narrow or block the arteries, leading to reduced blood flow. Although plaque may accumulate in any artery, it typically favors large and medium-sized arteries.