Anyone with symptoms or signs of peripheral artery disease (PAD) should be tested. Some people should be screened for PAD even in the absence of symptoms or signs, such as individuals older than 65 years, or those older than 50 with risk factors like diabetes or smoking.
The diagnosis of PAD begins with a simple examination by your doctor or podiatrist. They will look at the skin on your legs and feet for color changes, ulcers, or wounds that may be slow to heal. They will also feel the temperature of your skin and check the pulses in your legs and feet to evaluate blood flow. Your doctor will also ask you questions about how active you are able to be and if you have any limitations. Your medical record will be reviewed to assess additional risk factors you have for PAD. Blood tests looking for signs of diabetes, kidney disease and high cholesterol may be performed.
If your doctor suspects you have PAD, then they will likely arrange for you to have an Ankle-Brachial Index test (ABI). This is a simple, non-invasive test that can be done in the office to evaluate circulation in the legs. It consists of taking blood pressure in the arms and at the ankles with an ultrasound probe. The exam takes about 10 minutes to perform and you will be asked to rest flat. After the two blood pressure readings, a ratio is then calculated to get the value of your ABI. A normal ABI ranges from 0.96–1.39. An ABI of 0.90 or less is considered indicative of PAD and the lower the number, the more severe the impairment in blood flow. An ABI of greater than 1.3 may represent stiff arteries that may or may not be blocked. Further information is needed to make a determination of PAD in this case.
Special waveforms may also be recorded during the examination that can reflect the quality of blood flow. They are obtained with a Doppler probe, or through a recording that is made when a blood pressure cuff is inflated at a low level in your ankle. Your physician will look at this waveform, your ABI number, and other information to make a determination of PAD. This test is very reliable. If your doctor needs more information, however, they may have you get a similar test which includes blood pressure readings and waveforms from your thigh down to your big toe. You may even be asked to walk on a tread mill while readings are performed before and after exercise.
In some cases, a CT or MRI may be required—usually where the ABI or ultrasound tests have detected an abnormality that requires further clarification for diagnostic purposes, or to guide the best treatment options. Finally, if any of the above non-invasive tests have revealed a significant abnormality, you may undergo an invasive, catheter angiogram which can serve as both a test and a treatment. This procedure involves injecting contrast dye into the affected arteries, and taking X-ray images to see where blockages may be located. If blockages are detected, they may choose to open these arteries up during the procedure by using a device designed to cut, drill or shave through the plaque, or displace it to allow more blood flow to get through. Many of these devices are similar to those used in the heart to open up blockages.