What is Peripheral Arterial Disease (PAD)?
PAD describes narrowing or blockage of the major arteries supplying the legs resulting in a reduced blood supply which causes symptoms such as intermittent claudication (pain on walking relieved by rest). Poor circulation in the legs is a common problem present in over 8% of patients over 70 years of age. It can be found in younger people particularly in smokers and diabetic patients. There are some individuals who have circulation problems in the leg and no obvious risk factors. These individuals probably have a genetic predisposition.
Why does PAD develop?
The narrowing of the arteries is caused by “atheroma”. Atheroma is a fatty material (plaques) that develops within the lining of artery walls. All people will develop small amounts of atheroma in their arteries during their lifetime but patients with certain risk factors form extensive plaques more quickly. As increasing amounts of atheroma is laid down it causes the artery wall to bulge inwards thereby limiting the amount of blood that can flow down the artery. In time the artery can even become blocked by atheroma. It is common for patients to have more than one narrowing or blockage within the same artery.
The same process occurs in all arteries but results in different problems depending on what the artery supplies:
Arteries to the Legs may → PAD.
Arteries to the Heart may → angina and heart attacks.
Arteries to the Brain may → strokes and mini–strokes.
What Risk Factors increase formation of Atheroma?
Diagnosis requires a consultation with a consultant vascular surgeon who will manage the following:
Lifestyle risk factors that can be prevented or changed:
Lack of physical activity (a sedentary lifestyle).
An unhealthy diet.
Treatable or partly treatable risk factors:
High blood pressure (hypertension).
High levels of cholesterol in the blood.
High levels of triglyceride (fat) in the blood.
Kidney diseases causing reduced kidney function.
Fixed risk factors – ones that you cannot alter:
A strong family history
An early menopause in women
Age. The older you become, the more likely you are to develop atheroma
Why does PAD result in aching legs?
Muscles require oxygen from the blood to function. The amount of oxygen required is increased when the muscles work such as when walking. If the blood supply to a leg is reduced because of PAD then the muscle becomes starved of oxygen resulting in pain. When a patient rests the oxygen demand by the muscle is reduced and despite the narrowing enough blood can be supplied to meet this requirement so pain gradually decreases.
The greater the narrowing of the artery the less blood that reaches the muscles and the shorter the distance a patient is able to walk (known as “claudication distance”) before developing pain. Over many months or years patients often notice that their claudication distance has reduced and this represents continuing thickening of the atheroma with subsequent reduction in blood flow.
“Rest Pain” occurs when not enough blood reaches the muscles even at rest. This is significant and indicates that the tissues are threatened. Urgent treatment is required to prevent subsequent amputation.
How is PAD diagnosed?
At your initial clinic visit, a thorough history of your symptoms will be obtained. Your consultant will ask questions about the duration of your symptoms, their severity and how much they limit your activities. Risk factors will be identified such as smoking, diabetes, high blood pressure and high cholesterol. You will be asked specific questions to look for arterial narrowing in other parts of the body.
Your consultant will then examine your abdomen and legs. This will include a full assessment of your leg pulses from the groin to the foot manually and with a hand held Doppler machine (a type of ultrasound). Once that is completed, a blood pressure cuff will be placed around each leg in turn and inflated whilst listening to your pulse with the Doppler machine. This will give a further reading that can be used to help quantify the extent of PAD in each leg.
If your symptoms warrant further evaluation, an “arterial duplex” scan will be arranged. This is a more accurate ultrasound investigation than the hand held Doppler machine. It is non–invasive and gives detailed information about the extent and location of where the narrowing or blockage in your leg is situated. It also helps determine what treatment if required will be most suitable for you to have.
In some cases your consultant may also organise specialised CT scans (using x–rays) or MRI tests. This will also help plan your treatment.
Once peripheral arterial disease has been diagnosed, your consultant will discuss treatment options with you. There are 3 main forms of treatment that are offered:
Medical (tablet) therapy and lifestyle changes.
Angioplasty and Stenting.
Medical Therapy & Lifestyle changes
What is it?
Medical therapy is the use of tablets to limit progression of your symptoms and reduce the risk of suffering a heart attack or stroke. If you are not already on them, your consultant may recommend starting the following tablets which should be taken for life:
Clopidogrel (75mg taken once a day) – clopidogrel also reduces the stickiness of platelets. It does not cause irritation of the stomach like aspirin and is used for patients who may have had previous ulcers or reflux disease.
Lifestyle changes are important measures that you can do that have significant beneficial effects on PAD. They include:
Stop Smoking – stopping smoking is the single most effective treatment for PAD. It increases walking distance by two or threefold in over 8 out of 10 people and greatly reduces your risk of having a heart attack or stroke.
Exercise regularly – regular exercise encourages smaller arteries in the legs to enlarge and improve the blood supply known as “collateral circulation”. Walking on a daily basis is the best exercise if you have PAD. Walk until the pain develops, then rest for a few minutes. Carry on walking when the pain has eased. Keep this up for at least 30 minutes each day and preferably for an hour a day. The pain is not damaging to the muscles. Research has shown that if you stop smoking and exercise regularly, then symptoms of PAD are unlikely to become worse, and they often improve. Your risk of developing heart disease or a stroke will also be reduced.
Lose weight – this will reduce the formation of atheroma and the workload on the heart and muscles. It also reduces the risk of becoming diabetic later in life.
Maintain Good Diabetic Control – whether your diabetes is diet or medication controlled, keeping your sugars within reasonable limits is important. It will slow progression of atheroma and greatly reduce your risk of a heart attack or stroke.
When is medical therapy and lifestyle advice recommended?
These measures are recommended for ALL patients with proven peripheral arterial disease. Studies show that once started on medical treatment and given lifestyle advice, symptoms over 6 years:
Improve in 50%.
Remain the same in 30%.
Get worse in 20%.
Medical therapy and lifestyle advice is considered the only treatment necessary for most patients who can walk further than 100 yards before developing pain. Once started on these treatments most patients will be reviewed every 4 – 6 months to assess how their symptoms have changed. Patients who cannot walk further than 100 yards or who have rest pain will be given medical therapy but also be considered for angioplasty, stenting or bypass operations.
Angioplasty and Stenting
What is it?
“Angioplasty” and “Stenting” are procedures performed by a radiologist that treat narrowing or blockages of the artery. Both use the same method to gain access to the relevant artery but “angioplasty” uses a balloon to stretch the artery and “stenting” leaves a metal tube scaffold in the artery to hold it open. Either way the narrowing is reduced so more blood can reach the leg thereby improving symptoms.
These procedures generally require an overnight stay. It does not need a general anaesthetic and can take anything from 30 to 90 minutes to complete depending on the difficulty of the case. It is important that you can lie flat for the duration of the treatment.
Before your Procedure
Your consultant will organise a blood test for you in the weeks before your treatment. This will look at a number of important areas including how well your kidneys are working. Badly diseased kidneys may not tolerate the x–ray dye used in the procedure and this is a reason for not doing this treatment in certain cases.
If you are a diabetic on Metformin tablets, you should not take this on the day of the procedure and for 48 hours after the procedure.
If you are in warfarin or other similar anticoagulation medicines, you may be asked to stop taking them a 2 or 3 days before the procedure.
Your surgeon or radiologist will visit you before the procedure and ask you to sign a consent form once he has explained the treatment to you.
You will be admitted to the ward the day before or the morning of your surgery. If you are having sedation you should not eat for 6 hours prior to treatment. However, you may drink “clear fluids” like water up to 2 hours before. If only local anaesthetic is used, you can eat and drink normally right up until you are taken to the radiology treatment rooms.
How is angioplasty & or Stenting Performed?
Once you arrive in the x–ray treatment room you will be asked to lie down. Your groin will be exposed and cleaned. Local anaesthetic is then injected with a small needle to numb the area. Once everyone is ready and the skin is frozen, a tube is inserted into the artery in the groin. This is the only uncomfortable part of the procedure. Occasionally it may not be possible to use the groin artery in which case an artery in the elbow is used in the same manner.
This tube known as a “catheter” allows x–ray dye called “contrast” to be administered into the artery. A series of x–rays are then taken to confirm the position and extent of the arterial narrowings/blockages. The contrast will give you a warm feeling each time it is given and may make you feel the need to pass water. This is entirely normal.
A fine guide wire is placed down the groin/elbow catheter into the artery and x–rays are used to guide its passage along the artery and through the narrowing or blockage. A small tube with a balloon on the end is then fed over the guide wire until the balloon is either side of the narrowing. Once in place it is inflated to stretch the artery open. If successful the balloon is deflated and the tube removed. Further x–rays are taken to ensure the artery remains open.
The angioplasty may need to be repeated. If it does not improve the blood flow to the legs, then in certain circumstances a metal tube scaffold (a “stent”) can be placed in the artery at the narrow area using a similar technique. When the stent is in place it cannot be removed and will become covered by the lining of the artery in time.
At the end of the procedure the catheter is removed from the groin or elbow. A doctor or nurse will then press over the site for 10 minutes or until the artery has stopped bleeding. In some cases the radiologist places a special “plug” over the hole in the artery at the end of the procedure to prevent further bleeding. In either case a dressing will be placed over the puncture wound.
After the Procedure
Once the bleeding has stopped you will be asked to lie flat in bed for an hour and then allowed to sit up. You will then be observed closely for the following 6 hours but given something to eat and drink.
When you get home, you should check your wound regularly. You may have some bruising, but if swelling develops, or the area becomes hard to the touch or painful you should contact your doctor. If your wound starts to bleed, you should press firmly on it and contact the hospital immediately.
You can shower 24 hours after treatment but should avoid baths for the first 3 days.
You should drink plenty of water for 2 days after the procedure to flush the contrast dye out of your kidneys.
You shouldn't lift anything heavy or drive for the first week after your angioplasty.
Most patients can return to work after a week.
You will be advised to take aspirin (75mg once a day) and clopidogrel (75mg once a day) tablets after the procedure. These medications thin the blood and help prevent any clots forming which can quickly block an artery or stent. The duration these should be taken for can be discussed with your consultant.
Your consultant will organise a follow–up appointment with you after 3 weeks to discuss your treatment and assess your recovery.
Success rates with Angioplasty and Stenting
Angioplasty and stenting is successful in 90 – 95% of patients. 20% of patients will experience recurrent symptoms in the coming years but can have repeated treatment. In the small percentage it does not work for a surgical bypass operation can be offered as an alternative.
Risks of Angioplasty and Stenting
There are potential complications associated with every procedure. The overall risk of the procedure is extremely low. Potential risks can be divided into the following categories:
The puncture site:
Some bruising is common after an artery puncture.
Very rarely significant bleeding from the artery or blockage of the artery can occur which may require a small operation. The risk of requiring an operation is less than 1%.
Related to the contrast:
Some patients experience an allergic reaction to the X–ray contrast. In most cases this is minor but very rarely (1 in 3000) a reaction may be severe and require urgent treatment with medicines.
The x–ray contrast can, in some patients, affect the kidney function. If you are likely to be at risk of this, special precautions will be taken to reduce the chances of this problem occurring. If you are a diabetic on Metformin tablets, you should not take this on the day of the procedure and for 48 hours after the procedure.
Related to the treatment:
Vessel blockage can occur after angioplasty of a narrowed artery. It can sometimes be treated with a stent.
Vessel rupture following angioplasty occurs infrequently. This can sometimes be treated in the x–ray department by putting a stent with a covering around it (stent–graft) into the artery to seal the tear. If this is not possible, an urgent operation may be required to repair the artery.
Small fragments from the lining of the artery can occasionally break off and lodge in an artery below the angioplasty site (distal embolisation). This may also require an operation to 'fish out' the fragment if it is causing a problem with the blood flow. The overall risk of requiring an operation is low (1 – 2%).
If the artery in the elbow is used, the tube will pass one or more of the arteries supplying the brain. There is a very small risk that a blood clot could form and cause a stroke (1 – 2%).
What is it?
The type of bypass operation performed depends on where the blockage is, but all have the same basic principles. A substitute tube, usually your own vein or a plastic tube, is used to bypass a blockage of the artery. The substitute tube is connected to healthy artery above and below the blockage so that increased amounts of blood reach the previously starved tissues. These operations tend to be performed on patients who have severe PAD with rest pain and tissue loss or in patients with arterial narrowings that cannot be treated with angioplasty &or stenting.
These operations are performed under general anaesthetic and require you to come to hospital the day before your operation and stay for up to a week after it.
Before the Operation
Before your operation you must try to stop smoking as there is good evidence that the risk of bypass failure is higher in smokers. You should also try to see your GP to help control your other medical problems such as high blood pressure and diabetes as well as possible before any operation.
Before bypass surgery, all patients require a number of tests. These are of two types:
Tests to assess your general fitness and suitability for bypass surgery. These will happen a number of weeks before the operation:
ECG – a tracing of the heart rhythm
Tests involved in the diagnosis of PAD e.g arterial duplex, CT, MRI scan etc
Ultrasound of the leg vein that may be used as part of the operation. The course of the vein will be marked on your leg with an indelible pen.
You will be admitted to the ward the day before your surgery. As you will have a general anaesthetic, you should not eat for 6 hours prior to treatment. However, you may drink “clear fluids” like water up to 2 hours before.
Your surgeon will visit you before the operation and ask you to sign a consent form once he has explained the procedure to you.
Your anaesthetist may suggest a tube be placed into your back called an “epidural”. This will allow you to have excellent pain relief after the operation. The tube is inserted in the anaesthetic room just before the operation. Once you are asleep a tube will also be placed into your bladder. This allows us to monitor how much urine you are producing which is a marker of how well your kidneys are working.
How is Bypass Surgery performed?
The specific type of bypass operation will depend on which artery is narrowed or blocked. All bypass operations have features that are similar no matter which operation is performed.
The description below describes a “femoropopliteal bypass” which is one of the most common bypass operations performed to help with blockages of the artery in the thigh.
Once you are asleep, a vertical cut is made in the groin to expose the artery above the blockage. A second cut is made below the blockage usually just above or below the knee. The tube used to perform the bypass will normally be the principle skin vein of the leg known as the “long saphenous vein”. It runs from the inside of the ankle up to the inside of the thigh. Helpfully the vein lies in the line of the cuts (incisions) used to expose the artery. Sometimes the vein can be removed with the addition of one extra small incision about 5cm long at mid thigh level. On occasion, the two main incisions are joined to make one long one. If the long saphenous vein is not available another vein on the outside of the lower leg called the “short saphenous vein” can be used instead. The ultrasound scan of the veins before the operation will determine which, if any are available to use. If no veins can be harvested, then a plastic tube can be used instead.
Whichever bypass tube is used, one end is joined to the artery in the groin and the other connected to the artery around the knee. The connections will be tested during the operation to make sure it is working and your foot examined to ensure it is well perfused with blood.
The wounds will be closed with dissolving stitches or metal clips (which should be removed 10 days after the operation) and a dressing will be applied to cover the wound. You may be able to feel a strong pulse under the wound, this is normal. You will wake up in the recovery area of theatres, where the nursing staff will keep a close eye on you and the leg that has been operated on. They will regularly examine your wounds and feet to ensure the bypass continues to work.
After the Operation
After your operation you will be given fluids by a drip in one of your veins until you are well enough to sit up and take fluids and food by mouth.
The nurses and doctors will try and keep you free of pain by giving pain killers by injection, via the epidural tube in your back, or by a machine that you are able to control yourself by pressing a button.
You will be given an injection of heparin under the skin to reduce the risk of clotting in your veins (DVT or deep vein thrombosis).
Within a day or two, the drip, epidural and bladder catheter will be removed.
You will become gradually more mobile until you are fit enough to go home.
The physiotherapists may visit you after your operation. They will help you with your breathing to prevent you developing a chest infection and with your mobilisation to get you walking again.
You may be given aspirin (or in some cases warfarin) to reduce the risk of your bypass blocking. This will usually be continued indefinitely.
We will arrange for your GP’s practice or district nurse to remove your stitches (if necessary) or metal skin clips 7 – 10 days after your operation. They will also check your wound and should continue to change dressings until the wound is healing nicely.
You may feel tired for some weeks after the operation but this should gradually improve as time goes by.
Regular exercise such as a short walk combined with rest is recommended for the first few weeks following surgery followed by a gradual return to your normal activity.
You will be safe to drive when you are able to perform an emergency stop. This will normally be 2 – 4 weeks after surgery.
Once your wound is dry you can shower or have a bath as normal.
You should be able to return to work within 6 –12 weeks of surgery.
Your consultant will organise a follow–up appointment with you after 3 weeks to discuss your treatment and assess your recovery.
Success rates with Bypass Surgery
Success rates of bypass surgery to treat PAD depend on the location and severity of your disease and the type of replacement tube (vein or plastic) used to create the bypass graft. Surgery to treat artery disease in the lower abdomen or upper legs has 5 – year success rates of 80 – 90%, compared with 50 – 70% for blockages lower in the legs. The bypass graft is more likely to become re–blocked if doctors used an artificial plastic graft instead of vein taken from elsewhere in your body.
Risks of Bypass Surgery
Surgery is a proven treatment option for peripheral artery disease, however there are risks associated with the procedure that you should be aware of.
Bypass blockage: The main complication of the operation is blood clotting within the bypass causing it to block. If this occurs it iusually necessary to perform another operation to clear the bypass. This occurs in about 10% of patients in the six weeks after surgery.
Limb loss: Very occasionally when the bypass blocks, and the circulation cannot be restored, the circulation to the foot is so badly affected that amputation is required.
Major Complications: As with any major operation there is a small risk of you having a medical complication such as a heart attack, stroke, kidney failure, or chest problems. Each of these is rare, but small numbers of patients have fatal complications after their operation. For most patients this risk is about 5%. You will be monitored closely after the operation for any of these and appropriate treatment started promptly.
Leg swelling: It is normal for this to happen after this operation. The swelling usually lasts for about 2 – 3 months but normally resolves completely. It may occasionally persist indefinitely. You should keep your leg elevated on a stool when you are sitting for the first few months after surgery to minimise swelling. You must avoid tight bandages or stockings on the leg as this might compress the bypass graft and cause it to block.
Wound infection: Wounds sometimes become infected particularly those in the groin. This may need treatment with antibiotics.
Graft infection: Very rarely (about 1 in 500), the artificial graft may become infected. This is a serious complication, and usually treatment involves removal of the graft.
Skin sensation: You may have patches of numbness around the wound or lower down the leg. This is very common and can be permanent bsut usually gets better within a few months.
Chest infections: These can occur following this type of surgery, particularly in smokers, and may require treatment with antibiotics and physiotherapy.
Blood clots in the legs (DVT) and lungs (PE): After any large operation there is a risk of DVT or PE. You will be given injections under the skin to reduce the risk, but this cannot be completely negated.
Fluid leak from wound: Occasionally the wound may leak fluid. This may be clear but is usually blood stained. It normally settles in time, and does not usually indicate a problem with the bypass itself.
Bowel problems: Occasionally the bowel is slow to start working again after the operation. During this time (usually 3 – 5 days) you may feel nauseous or even vomit. Fluids will be provided in a drip until your bowels get back to normal and no other treatment is required.