In some patients, during coronary angiography, and alter sound of the arteries that supply blood to the heart muscle is performed.  This study shows:

• The severity of the narrowed coronary arteries which may not be apparent in the angiogram

• The composition of the atherosclerotic blockage

• The need for further intervention, such as deployment of a coronary stent. And in this case, intravascular ultrasound helps to determine the diameter and length of the stent as well

Hemodynamics refers to the physiologic significance of the narrowing in the coronary arteries as the blood flows across the blockage is measured with a pressure device.  This helps the cardiologist to determine the best further treatment for a particular patient.