Percutaneous coronary intervention, also known as coronary angioplasty, opens narrowed coronary arteries. A catheter inserted in an artery in the groin or arm is threaded to the affected artery. A second catheter is then inserted inside the first one. When the catheter reaches the narrowed area, a balloon on its tip is inflated to reopen the artery. While the catheters are in the artery, a stent may be placed to prevent re-narrowing after an artery is widened.