There are 3 main blood vessels of the heart: the right coronary artery, the left circumflex artery, and the left anterior descending artery. There are several branches as well. During a typical cardiac catheterization, all of these vessels are examined by injecting dye into them and watching if the dye becomes narrow in places or is slow to flow. If there are no narrow areas seen, and no areas of slow flow, then the catheterization is considered clean and no stents will be deployed. In general, a clean cardiac catheterization indicates that coronary artery disease (in other words: atherosclerosis of the coronary arteries) is not the cause of chest pain.

A cardiologist can answer if there may be other cardiac causes for somebody's symptoms after a catheterization.