The correct answer to this question is the reduction of blood vessels. Also known as CAD or coronary heart disease, coronoary artery disease is the narrowing of the coronary arteries--these are the blood vessels that supply oxygen and blood to the heart.
When blood vessels that carry blood to your heart harden, with fatty deposits known as plaque buildup. As plaque continues to build, it begins to blocks blood flow to your heart. If pieces of plaque fall off, it can cause platelets to cluster in the area in attempt to repair the blood vessel. This clump of platelets can block the artery, and eventually leading to a heart attack.