PCI (percutaneous coronary intervention) includes angioplasty (stretching arteries open with balloons) and stenting (fitting wire meshes to hold arteries open). Procedures are usually undertaken via the radial artery (wrist). Occasionally a larger access site is used from the femoral artery (groin). Stents are made from metal alloys such as cobalt-chromium and have a drug-eluting coating to reduce the likelihood of re-narrowing. Imaging of the coronary arteries is undertaken using contrast dye injected into the arteries (coronary angiography). Imaging before and after stent deployment identifies how well the stent is expanded holding the artery open.