Angioplasty is the technique of mechanically widening a narrowed or obstructed blood vessel; typically as a result of atherosclerosis. Tightly folded balloons are passed into the narrowed locations and then inflated to a fixed size using water pressures some 75 to 500 times normal blood pressure (6 to 20 atmospheres).Angioplasty has come to include all manner of vascular interventions typically performed in a minimally invasive or percutaneous method.