Assessment of Peripheral Arterial Disease
Patients with suspected PAD will undergo a number of investigations.
In the first instance the examining doctor will take a full medical history.
He or she will then conduct a physical examination including recording blood pressure in both arms, listening to both sides of the neck with a stethoscope to detect carotid artery disease, feeling the tummy to detect abdominal aortic aneurysm, and feeling for pulses in both legs including in the groins (femoral pulse), behind the knees (popliteal pulse), behind the ankles (posterior tibial pulse) and the tops of the feet (dorsalis pedis pulse).
|Blood pressure will be recorded in the feet using a tool called a
hand held doppler.
Blood pressure in the feet should be the same as or very slightly higher than the blood pressure in the arm. By dividing the foot pressure by the arm pressure we calculate a figure called the ankle-brachial pressure index, or ABPI.
|1.2 - 1.0||none||none|
|1.0 - 0.8||mild||probably none|
|0.8 - 0.4||moderate||intermittent claudication (muscle pain when walking)|
|less than 0.4||severe||Pain at rest, especially at night. Danger of ulceration or gangrene|
|Patients may undergo a treadmill walking test to see how far they
Ankle pressures may be recorded again after exercise and the ABPI recalculated. A drop in ABPI after exercise indicates definite peripheral arterial disease.
Blood tests will usually be ordered to check for kidney function, diabetes and cholesterol levels.
The majority of patients with PAD do not suffer any significant deterioration in their symptoms after diagnosis, indeed many find that symptoms improve slightly over the course of several months simply with conservative treatment and best medical therapy. These patients will require no further assessment and can usually adapt their lifestyle to manage their symptoms.
However, a minority of patients, particularly those who continue to smoke, may experience deterioration in their symptoms to the point that they are severely disabled by intermittent claudication, or develop severe limb ischaemia (pain at rest and/or ulcers or gangrene on the feet). In order to relieve these symptoms it is necessary to improve the blood supply to the leg by either angioplasty or bypass surgery, and further assessment is necessary to plan these interventions.
Patients will usually undergo a Duplex ultrasound scan in the first instance, to outline the pattern and extent of their arterial disease. Often a second investigation called an angiogram is also performed. This is an x-ray of the arteries, often using a dye to show up the blockages or narrowings in the arteries in great detail. There are three ways of performing an angiogram:
Each technique has its pros and cons but all give very detailed images of the arteries enabling intervention to be planned very accurately.