This study will enroll people with coronary artery disease who are undergoing angioplasty. At a baseline study visit, participants will first undergo an angiography procedure, in which x-ray pictures will be taken of the heart blood vessels. Participants will then be randomly assigned to undergo either the IVUS procedure followed by the OFDI procedure or vice versa. Repeat angiographies will occur after each imaging procedure. Next, participants will undergo angioplasty and a stent will be placed at the area of the blood vessel that is narrowed or blocked to keep the blood vessel open. Finally, participants will undergo repeat IVUS and OFDI procedures. For some participants, the study physician may perform the IVUS and OFDI procedures only after the angioplasty. Every six months and for a period of two years, participants will complete questionnaires about medication history and heart problems that may have occurred since the baseline visit.Blood collection will occur if this is done during office visit.