A method of treating blockage or narrowing of a blood vessel, usually a coronary artery, by recanalising it – that is, inserting through a catheter balloon into the constriction to reopen it by flattening the deposits of ATHEROMA which are responsible for the narrowing; the balloon is then deflated and the catheter withdrawn. This procedure, conducted under local anaesthetic and taking about 30 minutes, is properly referred to as percutaneous transluminal coronary angioplasty (PTCA). In most cases, the balloon is surrounded by a metallic mesh, a STENT which is left in place to keep the vessel from reconstricting. When a stent is used the procedure is termed percutaneous coronary angioplasty (PCA).