Angioplasty is a technique which involves stretching an artery to open up narrowed segments to improve the flow of blood through it. This procedure should only be embarked upon after careful patient assessment, as complications and failure may lead to further surgical procedures and possibly the loss of a limb. The procedure itself is very much simpler than a major surgical intervention and eminently suitable for use in elderly patients who would not have been considered for surgical treatment. It is often combined with arteriography and, in many units, patients are prepared to undergo angioplasty at the same time as undergoing the initial arteriography. When a patient has a narrowing of an artery or a very short occlusion of the artery it should be possible, initially, to pass a guide wire and, secondly, a catheter through this segment (see Figure 6.1). Having confirmed that the catheter is still within the lumen of the artery, the catheter can be replaced by a special catheter with a balloon on the end of it. The catheter is introduced such that the balloon extends from the top of the narrowing to the bottom of the narrowing. Once the balloon is in the correct position, it is inflated with saline for a period of one minute (see Figure 6.3). The balloon is then released, before being re-inflated two or three times. The effect of inflating the balloon in a narrowed segment is to compress the obstructing material back into the arterial wall. At the end of the procedure, a further injection of dye is given, to check that the lumen of the artery is now patent (open).