Femoral artery angioplasty. Coloured angiogram of a balloon catheter and stent (wire mesh tube) in the left femoral artery of a 49-year-old patient. The femur (thigh bone) runs down right. Angioplasty is a surgical procedure used to treat stenosis (narrowing) of arteries, a condition usually caused by atheroma (fatty deposits on the inner walls). A balloon catheter (line running down centre) has guided the stent (shown by black arrows) into place and a region has been inflated to expand the stent. When the catheter is deflated and removed, the stent remains expanded and holds open the artery to ensure normal blood flow.