Angioplasty and Vascular Stenting
What is an angioplasty?
An angioplasty is a way of relieving a blockage in an artery without having an operation.
What medical conditions does angioplasty treat?
Angioplasty may be used in either arteries or veins. Angioplasty is suitable for either narrowings of the blood vessel or actual blockages of the blood vessel.
The procedure takes about 1½ hours. A radiology doctor will explain the angioplasty procedure to you and ask you to sign a consent form to confirm that you understand the procedure and agree to go ahead with it. Please do not hesitate to ask any questions that you may have.
First of all you will be given a local anaesthetic into the top of the groin to numb it. Then a small tube (catheter) will be inserted into the blood vessel. A small wire called a guide wire will be passed into the artery. After this, a balloon catheter will be passed over the wire into the narrow or blocked artery. When it reaches the narrowed area or blockage, the balloon will be inflated at the site of the problem to widen the artery. It may be necessary to inflate the balloon more than once. When the treatment is completed, the catheter will be removed and the doctor or nurse will apply pressure on the skin entry site to prevent bleeding.
The aim of the procedure is to improve the caliber of the vessel to increase the blood flow through the vessel to the limb beyond the previous narrowing or blockage.
This is generally a safe procedure but there is some risk associated with any procedure. For an angioplasty, the risks include:
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Sometimes for technical reasons it is not possible to stretch the artery and very occasionally the procedure can make matters worse. In the event of this occurring, an operation may be required.
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Bleeding or bruising may occur around the area where the catheter was inserted into the skin.
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Very rarely, a blood clot may block the blood supply to the leg or a weakness can occur in the artery wall. In many cases, this problem can often be treated by the radiology doctor at the same time as the angioplasty. Occasionally, you may need to have an operation.
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In very rare cases, you may show a reaction to the x-ray dye (contrast). If this occurs it will usually happen while you are in the radiology department but it may be delayed until you have left the radiology department or even after you have left hospital. You may develop a rash or experience breathing or circulatory problems. I must emphasise that this is very rare and the treatment in most cases consists of tablet medication.
How should I prepare for angioplasty?
You will usually be admitted the day before the procedure; if you are on medication to thin the blood, e.g. Warfarin, you will need to discuss this with the doctor arranging your admission to hospital as this is usually stopped a couple of days before the angioplasty. Once admitted, you may be started on injections to thin the blood as an alternative to medication whilst you are in hospital.
If you are a diabetic taking insulin or tablets, you will be given your normal dose on the morning of the procedure and you will be given an early breakfast at around 6.00am but do not eat or drink anything after this time. Your blood glucose will be monitored regularly whilst you are fasting.
You can continue to take any regular medications before and after the angioplasty procedure. You will be given a gown to wear to the x-ray department and you are advised to empty your bladder before leaving the ward.
What does the material for angioplasty look like?
The balloon catheter consists of a very thin long tube with a hole through the middle to pass a guide wire. At the end of the tube is a short balloon between 2 cm & 4cm long in most cases. When the tube is passed into the vessel, the balloon is collapsed around the outside of the catheter. The balloon can be inflated and deflated by injecting x-ray dye into an opening at the other end of the catheter.
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Figure 1 |
Figure 2 |
The balloon dilatation of a constricted vessel
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| Figure 3 | Figure 4 | Figure 5 | Figure 6 |
Figure 3: Stenosis of the right pelvic artery before treatment. Due a constriction in the right groin artery, treatment is carried out from the left side (cross-over-method)
Figure 4 and 5: A balloon catheder is introduced through the groin artery and the stenosis is dilated
Figure 6: After treatment the artery’s diameter is back to normal
If the constriction cannot be extended sufficiently by means of a balloon dilatation, a stent can be placed into the vessel, which usually leads to a more permanent result. A stent is a biocompatible metal mash tube, which is placed in the blood vessel to support its walls from the inside. This way a constricted blood vessel can be dilated and kept open. Prior to deployment the stent is collapsed into a small diameter. Once it has been placed in the stenosis, it is released and self-expands. Within several weeks the stent then grows into the vessel walls it rests against.
Stent implants, first developed in the 1980s, were originally only used as an additional treatment for PTA. In most cases a balloon dilatation is still the first treatment step. Nevertheless in some cases implanting a stent is commendable without trying balloon dilatation first. This is called direct stent implantation.
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Figure 7: A balloon expanded stent
a: The collapsed stent is fixed to a balloon catheter
b: By inflating the balloon, the stent is expanded to its maximum diameter
c: After the stent has been implanted, the balloon catheter is withdrawn
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| Figure 8 | Figure 9 | Figure 10 | ||||
Figure 8 - 10: Stent implantation into the right pelvic artery under x-ray imaging
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| Figure 11 | Figure 12 |
Figure 11: Before the interventional radiological procedure: severe calcific stenosis of the left pelvic artery
Figure 12: Since the constriction could not be extended sufficiently by means of a balloon dilatation, a stent was implanted, leading to a complete opening of the artery.
After stent implantation the treated vessel can re-occlude (re-stenosis) due to uncontrollable cell proliferation in the vessel wall. New treatments, such as balloon- cryotherapy, try to counteract this development. During balloon cryotherapy a balloon is expanded with liquid nitrogen, cooling the occluded vessel walls to a temperature of about -10° Celsius for 20 seconds and killing those cells in the vessel walls that tend to proliferate and create re-stenoses. To the patient this procedure usually feels like a common balloon dilatation; the cold temperature being practically imperceptible.
You may experience mild discomfort when the radiology doctor places local anaesthetic into the skin in the groin. This should wear off after a minute or two. When the doctor passes the tube into your artery, you should not feel discomfort if adequate local anaesthetic has been injected into the skin. You may feel mild pressure or discomfort when the balloon is inflated in the vessel. This is due to stretching of the vessel with the balloon.
You must lie flat for a period of time after the treatment. This varies from hospital to hospital although is usually in the order of 4-8 hours. There will be some bruising around the catheter puncture site and you may feel a little sore as the anaesthetic wears off. Do ask the nurse for some pain killing tablets for this if it occurs. In many cases, you will be asked to stay in hospital over night so that nurses can monitor the site where the catheter was inserted. The doctor will probably discuss the results of the treatment with you before you go home. A letter will be sent to your General Practitioner explaining the details of the treatment. In many cases, you will be prescribed aspirin medication in an attempt to prevent the problem occurring again.
If you are a smoker, it is very important that you stop smoking. Smoking causes the arteries to become narrowed which prevents normal blood flow to the heart and limbs. Smoking can also cause the blood to clot more rapidly.
The single most important thing you can do is to stop smoking. Smoking just one or two cigarettes a day is harmful.
You should reduce cholesterol and saturated fats in your diet. If you are overweight, you should make efforts to reduce your weight as this can help reduce your risk of having further problems with furring up of the arteries.
You should increase exercise as far as you comfortably can after angioplasty. If you are unable to undertake strenuous exercise, you should at least take daily walks gradually increasing the walking distance.
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| Figure 13 | Figure 14 |
A patients femoral artery in the leg before and after angioplasty. The image on the left shows a severely narrowed femoral artery. After angioplasty, the caliber of the artery is very much improved.
Partly taken from www.sirweb.org
edited by R. Morgan,
May 2005