Complex Coronary Angioplasty is indicated for patients who have undergone coronary artery bypass surgery. Angioplasty is a medical procedure used to dilate the narrowed arteries supplying blood to the heart. This is accomplished by inflating a small balloon inside the artery to dilate the vessels and increase the blood flow to the heart. The arteries that carry blood from the heart to different parts of the body are blocked by fatty substances called plaque that restrict blood flow to the heart. During angioplasty, the stents are placed in the coronary artery to widen the passage of the blood vessels and improve the blood supply to the heart.