Cardiovascular disease has long been the leading cause of death in developed countries and it is rapidly becoming the number one killer in developing countries. Sudden heart attacks remain the primary cause of death in the United States: over 1.4 million attacks are suffered every year, more than half of which prove fatal. Interventional Cardiology is aimed to alleviate symptoms of cardiac pains and poor coronary circulation, and reduce the risk of death and nonfatal myocardial infarction. Our understanding of the coronary circulation has improved several folds due to the introduction of advance technologies. Yet, the microcirculatory flow needs future investigation.