Coronary angioplasty (or PCI) means those ways of opening up narrowings in coronary arteries using fine tubes called catheters introduced usually from the leg.
Under local anaesthesia, a tube (guiding catheter) is passed from the groin to the coronary artery. Your interventional cardiologist uses the Xray screen to track the path of the catheter.
Through the guiding catheter, a wire about the thickness of a hair is passed across the narrowing.
A balloon is placed across the narrowing of the artery and is inflated while being viewed by X-ray-TV. This can effectively widen the artery.
In selected cases, new balloon catheters are available which can also shave and remove the diseased portion of the artery. This is called atherectomy.
Your interventional cardiologist may use a stent (a fine mesh stainless steel tube which comes squashed down on a balloon).
This stent is directed across the narrowing of the artery by the guidewire. The balloon is inflated to expand the stent and artery. The stent is pushed into the artery wall holding the artery open.
The balloon is deflated and removed, leaving the expanded stent in place. Once expanded the stent cannot move.
These stents are coated with a drug that is released slowly to substantially reduce the chance of re-narrowing of the artery and the need for a repeat procedure.