Bypass Surgery is performed to treat severe intermittent blockage of blood flow to the limbs. This maintains tissue viability (critical ischaemia) that is manifested by pain at rest or at tissue loss. Bypass operations are planned using information from clinical assessment, duplex ultrasound and often more detailed images from CT angiograms or MRA. They are most commonly performed from the femoral artery in the groin to a target vessel further downstream to the blockage. Where appropriate, the patient’s own vein is used as the bypass graft; otherwise synthetic plastic grafts are used. Where there are narrowings at several sites in the artery, endovascular techniques using a wire and balloon or stent may be used in combination with the bypass during the operation. The procedure may be performed under general or regional anaesthesia (epidural or spinal block). The artery is exposed through separate incisions several centimeters long above and below the blockage. A further incision may be required if the patients own vein is to be used for the bypass. The bypass graft is joined to the artery at groin level and again to the artery below with very fine permanent stitches. The graft will sometimes lie deep within the leg, and sometimes just beneath the skin. At the end of the operation, the incisions will usually be closed with dissolving stitches which do not need to be removed. Patients will normally stay in hospital 3 to 5 days after a bypass operation. Swelling of the leg is common after bypass and may take several weeks to resolve. More serious complications include blockage of the graft which may require further surgery and wound infections which may necessitate antibiotic treatment.