to benefit from bypass surgery.
In an alternative approach to relieving an occlusion of an artery, drugs are administered to cause the vessels to dilate. Not all patients can use such drugs, however, and the results are generally only temporary, as the occluding process can continue, eventually blocking even the dilated vessel.
In still other approaches, generally termed percutaneous translumenal angioplasty, an instrument for dilating the occluded artery is introduced, generally by means of a catheter, through an opening in the skin and through an opening in the wall of a large artery such as the brachial artery or the femoral artery, and passed within the arterial lumens to the site of the occlusion. In balloon angioplasty, for example, a fine guide wire is first passed to the site ofthe occlusion through the lumens of major arteries, observed by radiography as it progresses; then a catheter having a balloon near its tip is passed over the wire to the site, also within the arterial lumens; and finally the balloon is inflated at the site of the occlusion to stretch the walls of the artery and open the lumen. The results of balloon angioplasty can also be temporary, as the occluding process in 30-40% of patients can continue at the site until the vessel is again blocked. Moreover, the procedure carries risks of perforation or acute occlusion of the arteries by the instrument, and the flow of blood through the vessel being treated is interrupted for a time during the procedure. Only selected patients can benefit from balloon