I. Introduction
Coronary artery disease (CAD) also known as ischemic heart disease (IHD) is the most common type of heart disease. It is the leading cause of death in the developed countries in both men and women [1]. CAD happens when the arteries that supply blood to a heart muscle become hardened and narrowed. As a result, the heart muscle cannot get the blood or oxygen it needs and this can lead to a chest pain (angina pectoris) or a heart attack.