Investigations and Prognosis
If you have atheroma in your leg arteries which is affecting your walking there are several steps and investigations involved in determining what is the best treatment for you.
Your vascular surgeon will find out more how you are affected by this process. It is useful to be ready to describe how far you can walk, at normal speed on the flat, what are the symptoms that make you stop walking and how long is it once you stop before you are able to walk again. Your surgeons will also be interested in whether you have any other symptoms which might suggest you have atheroma in other arterial systems – e.g. angina from coronary heart disease. Please ensure you know what regular medications you are on.
Examining you and in particular feeling what pulses are still present can help us locate at what levels in the leg arteries there are blockages.
Ankle brachial index: normally because of gravity the blood pressure at the level of your ankles is a little greater than that in the arm where blood pressure is normally taken. Using a small hand held ultrasound machine (hand held pencil doppler we are able to measure the blood pressure at the ankle and compare it with the arm (brachial) blood pressure this ratio gives us the ankle brachial index (ABI) gives an overall measure of the impairment in blood supply to the foot.
Particularly when there are narrowing rather than occlusions in the bigger arteries the ABI can still be normal at rest so you are asked to walk for a time on a treadmill and we measure your exercise ABI to try and uncover this impediment to blood supply.
Duplex Ultrasound
Ultrasound can be used to directly look at the pelvic and leg arteries to see if there is atheroma within them. A more sophisticated form of ultrasound called colour Doppler and spectral analysis (duplex) can also be used to localize more accurately not only where the atheroma is but also whether the atheroma is having a significant effect on blood flow.
This procedure is painless and safe as no radiation is involved (ultrasound uses sound waves)
At this point there is often enough information available for your vascular surgeon to recommend that you have a catheter angiogram with a view to using wires and balloons and stents with the guidance of x-rays to open up the narrowing or occlusion in your arteries.
If actual surgery is going to be required then more imaging of the arteries will be required. This is so the surgeon has a complete roadmap (angiogram) of your arteries and so knows the full extent of atheroma can plan the surgery with confidence. There are two ways of getting this angiogram.
Computed Tomograph (CTA)
CT scanner now are helical scanners and following injection of dye into a vein can quickly take lots of pictures of the dye flowing through your leg arteries which can be processed in the form of an angiogram.
The dye can occasionally cause damage to the kidneys (usually only in people who already have some impairment of kidney function) and occasionally patients can have an allergic reaction to the day.
Magnetic Resonance Angiography (MRA)
The MRI scanner is also able to produce angiograms. The contrast agent used can also have an effect on kidneys and so this will be discussed with you beforehand. One of the advantages of MRI is that there is no ionizing radiation used which makes it even safer then CT scan. If you have certain implants such as a pacemaker or suffer from claustrophobia will not be able to have an MRI.
Catheter angiography as already mentioned this form of intervention can not only provide us with an angiogram. I.e. diagnostic information but can also sometimes allow for a ballooning or stenting of an artery which means it can also be therapeutic. These interventions fall into the broad category of Endovascular Intervention.