Southern Sydney Angiography has performed some 5,000 angioplasties on leg arteries in the past 10 years. This makes our unit one of the most experienced and leading centres in Australia for these techniques. We are able to offer a complete range of interventions for leg arteries including tran-luminal angioplasty, sub-intimal angioplasty, stent insertion, suction embolectomy, arterial thrombolysis and suction thrombectomy. We are one of few sites in Australia to offer all of these procedures and most of them are performed as day-only procedures.
Atherosclerosis is one of the commonest disease processes in the body and remains the commonest single cause of death in the community. It refers to the deposition of cholesterol and other lipids in the walls of arteries. This can affect the coronary arteries, the brain arteries and very commonly the leg arteries. Narrowing of the leg arteries can cause claudication, leg ulcers and in severe situations rest pain.
Claudication is pain in the legs or buttocks caused by walking. It is due to narrowing of the leg arteries. When the patient is at rest the narrowed arteries can supply sufficient blood to the legs but with walking the muscles need more blood supply and begin to ache. When the patient has a rest the pain will disappear and then return with further exercise. Most sufferers can tell you how far they can walk on the flat before the pain stops them. The distance going up hills will be much shorter.
Ulcers in the legs are areas of skin loss which fail to heal. When an ulcer fails to heal it is important to examine the arterial blood supply. If the arteries supplying the ulcerated region are narrowed then the ulcer may not heal. Just as wilting plants need water, ulcers need the oxygen and glucose supplied by arterial blood in order to heal.
Gangrene can occur in the toes from lack of blood supply in the leg arteries. Small patches of one or more toes will turn black and are usually associated with pain. This is caused by narrowing of the leg arteries. It is important to correct this narrowing to allow the toe to heal. An amputation of the toe may be needed but the toe wound will not heal without adequate blood supply.
Angioplasty of the leg arteries utilises a tubular shaped balloon to stretch up the narrowed part of the leg arteries. The patient is given some light sedation and then some local anaesthetic is injected into the top of the thigh. A tube called an arterial sheath is then passed into the leg artery. This tube is usually 2 to 3 mm in diameter. A thin wire can then be passed down the artery using x-ray guidance. The equipment providing this x-ray guidance is called a fluoroscope. It allows images of the inside of the body to be seen in real time on a TV screen. It also allows for the injection of liquid contrast (x-ray dye) into the artery which is called an angiogram. This gives the radiologist a very clear image of the shape of the narrowed arteries. A wire can then be directed down the artery across the narrowed segment. A tube with a deflated balloon is then passed over the wire into the narrowed region. The balloon specifications are matched exactly to the artery. A common balloon for thigh arteries would be 6mm in diameter and 4 cm in length. The balloons come in a whole range of shapes and sizes. The balloon is inflated for 3 minutes and then deflated and removed. Contrast is then injected and a “check” angiogram obtained. If the appearance of the arteries is good then no stent is required. However if the artery is still narrowed, then a metal stent is inserted over the wire and into the artery.
Stents for leg arteries are mostly constructed of nitinol. This is an alloy of nickel and tin. This alloy has unique characteristics which are favourable to leg arteries. The stents are “self-expanding” – that is they exert their own outward push as they try to expand. As they continue to expand this enlarges the narrow segment of the artery. These stents are also flexible which is a requirement for leg artery stents. The leg arteries are very mobile. When you walk, the arteries stretch, contract, twist, and bend. It is better if the stent can move with the artery and each year we have better stents available for this purpose.
At the completion of the procedure the puncture in the artery at the top of the thigh needs to be closed. This is normally achieved by compression of the puncture for 15 minutes followed by 4 hours bed rest. There are arterial closure devices available such as angioseal, perclose and starclose. These can be used to avoid the need for pressing on the artery and to reduce the rest time afterward to 2 hours. In either case the patient can be discharged home on the same day.
There are risks associated with any invasive procedure such as an angioplasty. In expert hands and with excellent imaging then the risks become small. If the operator is less well trained or experienced or if the imaging equipment are out-dated then the risks increase.
Links
http://www.sirweb.org/patients/angioplasty-stent
http://www.cirse.org/index.php?pid=93